Conference vmszoo::rc

    
    
    They don't own Kyosho. Tower Hobbies is a division of Great Planes
    Co. and this company is the exclusive distributors of Kyosho stuff 
    for the US.
    
    Their DELTA-PEAK auto charger is very good and foolproof. It has
    all the goodies except an AC input. I'm in the looks for a good
    charger as well and I have considered this model seriously since
    its one of the best around however it lacks two features which I
    need. These are the AC input and discharge capabilities. 
    
    I have scanned different models and the one which comes closest
    is the B&B Juice Machine. It is a good instrument of quality cons-
    truction with discharge, timer, tricke/fast charge, ac/dc inputs
    and ammeter. This model lacks the voltage-peak capability.
    
    I've figured out I might end up designing my own one with all the
    goodies that I want since I can't find it off-the shelf. 
    
    I need ideas on how to implement the delta-peak detecting circuit.
    Is there any chip out there that does this for me or will I have
    to implement it with op-amps?
    
    Ideas are welcome
    
    Orlando Rodriguez.
    
    

    Not to get overly picky but isn't Great Planes a division of Tower
    Hobbies as opposed to vice-versa?

    STEVE MCCLOUD
    
      YES I OWEN A KYOSHO QUICK CHARGER AND HAVE
    HAD NOTHING BUT TROUBLE SOMETIMES IT UNDERCHARGE
    AND SOMETIMES IT WILL OVERCHARGE. I HAVE SENT
    IT IN FOR REPAIR BUT WHEN IT RETURNED I HAD
    THE SAME TROUBLE.IT WAS PURCHSED FROM TOWER
    AND SERVICED BY A TOWER HOBBY BACKED KOYSHO
    SERVICE CENTER.IT NOW SITS ON THE SHELF IN
    MY JUNKROOM.
    
    PS.I COULD HAVE SHUT MY MOUTH
       AND TRYED TO SELL IT HERE
       THIS IS THE REASON YOU SHOULD
       TRUST ME
    
    

    ALSO WHEN I SENT YHE OLD CHARGER BACK
    I PUT VERY SMALL BLACK PERMANENT MARKER
    DOTS ALL OVER INSIDE AND OUT JUST TO SEE
    IF I WOULD GET THE SAME CHARGER BACK
    AND IF I DID WHAT WAS CHANGED WHEN IT
    WAS RETURNED IT WAS A WHOLE NEW CHARGER
    WITH THE SAME PROBLEMS
    
    IF YOU THINK THIS IS OP ERROR PLEASE LET
    ME KNOW
    
    ALSO THIS WAS DONE ON SEVERAL DEFFERENT
    BATTERY PACKS

    			-< Just what you need >-
    
    I have some circuit plans and a PCB mask to build a realy fast Nicad
    charger. When you charge nicads with a sawtooth and monitor the
    decay current it becomes clear when the battery has reached it'e
    peak. Too long and you have refried beans.
    
    This unit detects the change in decay current and switches over
    automatically to a tricle charge thus keeping the battery topped
    up for when you need it.
    
    It charges in about 50 mins what used to take 10 hours.
               
    I am an english man working in Holland, but I,m going home for the
    weekend. I'll dig the guff out from my attic.
    
              _|_
    john   ----�----              
              / \
             �   �
    John   

    
    
    STEVE,
    
    WHICH KYOSHO MODEL WAS YOUR CHARGER???
    

      I presently own the KYOSHO AUTOCHARGER that was first
    mentioned.This item catalogs' presently as item #KYOP1050,
    and sells for $79.95.It is also a co-venture with LAMBDA
    who is a major manufacturer of power supplies and such.
       When purchased this model did not have any "JACKS" to
    monitor voltages with a "DVM" or "DMM". It does now.
       This item performs flawlessly when connected to a 
    Wet-Cell battery,but has problems when  hooked up to
    a D.C. Supply of adequate current/voltage ratings.
       Recharge times are about 25 minutes at the highest
    charge-rates. 
    

      Trying to finish a reply before your system shuts down can
    be frustrating!!
       To update my previous reply,the original autocharger
    as listed in the *Tower* catalog did not have "jacks" for
    the "meter". The current charger as listed in the *Spring*
    sale catalog *does* have the jacks installed. This charger
    is also the venture I spoke of.

	On the recommendation of a friend, I purchased a Tekin charger
	(the "cheap" model, BC 870). The unit has adjustable constant
	current charge rates from 1 - 4.5 amps and uses a pulsed output
	circuit (they imply this is important). The peak detect is based
	on voltage drop, shutting down to trickle automatically. It has
	jacks to monitor voltage or amperage (same jacks with a switch
	to read either, amperage is read on the DC voltage scale of your
	meter, nice touch).

	The unit has no discharge or AC input, which present no problem
	to me. A resistor will discharge and, if necessary, a car battery
	charger (4 amp min) can be use for AC.

	The unit has performed flawlessly in the heat of battle. The unit
	was used almost non-stop for 4 hours yesterday charging 6-cell
	packs. While it was warm to the touch, it never came close to
	overheating. There was never a hint of under charging (which is
	quite evident when your cars are geared to run out of battery at
	the time limit), nor did I melt any of my Sanyos.	

	The charger worked as advertised, I recommend it.

	Tower sells it for $72.25.

	For those into the real hi-tech stuff.....Tekin now has a charger
	(which is based on the unit above) which has an LCD readout of the
	charge flowing into the pack. The meter resets when you start the
	charge cycle and starts counting upward at a rate determined by
	the charge current. When the battery peaks, the meter locks on the
	accumulated charge, giving you an indication of how much power you
	put into the pack. This Coulumb meter sounds like an interesting
	way of getting an indication of the relative goodness of a pack.
	This feature comes, of course, at a price.....$189.99 list.

	
	Chris

I recently purchased a Pro-Tech 707 peak-detecting charger thru Towers.

Summary
=======

It is junk

Details
=======

I had first called tower and asked how many cells it could handle.
They said 4-8.  After I received it the specifications (such as they
were) said 5-8 cells.  They specifically said it could charge 1200 SCR
and SCE packs and 500 mah 8 cell packs (Transmitters).

This device can fast charge to peak two packs at a time and automatically
switch to trickle after that.  It has an amp meter build in and weights
a ton.  Seemed to be of great quality with good connectors.

I had a brand new (never charged) 7 cell 900 mah pack from SR Batteries.

They warned that new batteries should be first trickle charged.

I was too impatient for that and hooked it up to AC and plugged
in my new pack.  I watched the current and measured the voltage with
my external meter.  I got a false trip after a couple of minutes.

The manual (such as it was) warned about fast trips and they can be
caused by bad connections (not the case here) or fluctuating AC voltage.
It appears that they don't regulate the DC so if your furnace kicks on
it trips the charger into trickle mode.  

No you have to wonder - what good is AC peak charging if you push the
button and when you return later you can never tell if it really peaked
or got a false trip and switched to trickle.  Anyway I keep pressing
the charge button and it started charging.  The pack got hot.
Real hot - couldn't hold it long.  Eventually it tripped again (after
about 35 minutes of charging).

I let the pack cool and ran the pack down and let it cool again.
Then I tried again - this time cooler but still took forever and still
got hot.  It starts off at about 4 amps then crops to 3.5 amps in about
30 seconds then drops to 3 amps in about a minutes then eventually drops
to about 1.5 amps and goes 40 minutes. 

I then tried it on DC.  I hooked it to an old Sears Die Hard in my workshop
that I seldom charge.  It got the pack really hot and took about 45 minutes
to trip.  It didn't trip until the peak had decreased by .5 volts.

I asked Dan Miner about this and Dan said he stops after he sees a peak
of .02 volts.  

So I figured maybe my Die Hard is not so good a test.  I hooked it to
my car battery and it worked perfectly.  Pack stayed cool and the
thing tripped after the voltage dropped .02 volts.  So far so good.
Well sort of - it still took 24 minutes to charge the 900 mah pack.

Then I waited a while to let it cool (although it didn't feel hot to the
touch this time) and plugged it in and hit the button again.  Just to
see what it would do with a fully charged pack.  It got hot and kept
charging at approx 1.5 amps for 10 minutes and tripped.  This time it
waited till the voltage had dropped approx .2 volts (not .02).

So I called Tower and told them I had to return it.  I got some
really crabby lady and she told me that I have had it over 10 days
so I could only send it back for repair.  After arguing with her
for some time I finally said that I was sending it back period
and expected a refund.  She kept citing the 10 day limit to me.
At one point she suggested that I send it to them and they would send
it to Pro-Tech and after they repair it and send it to me then I could
return it to Tower because then it would be NEW and UNUSED and I would
have had it less then 10 days.

Well for better or worse I packed it up and mailed it to Tower
and asked to exchange it for the Pro-Tech model 700 (one that has
just current adjust and a timer with a digital amp/voltmeter built in).
I told them it was a gift so that was the reason that it took me over
10 days to return it.

It is the first time Tower has ever given me a hard time about anything
and I have spend thousands there (yes I keep tract).

I liked the idea of peak detection but it would appear that the best charger
should have an optional peak circuit and also an current control and timer.

So for the time being I am without a charger and I have no idea what
Tower is going to do with their mail.

Wish me luck.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

    What a bummer.  I bought one about 3 weeks ago and except for an
    occassional false peak (the fridgerator turning on), the unit funtions
    perfect; although I only use 1200, 1300, and 1700mah 6 or 7 cell
    packs.  I have noticed, however, that each of my packs trips at
    its own specific voltage peak--no surprise there I suppose.  My
    packs never get hot--warm but not hot, but the unit gets VERY hot
    (the manual says something about that).
    
    I thought I might have some problems with the unit when on the
    very first time I used it, the amps (on fast charge) would'nt adjust
    to the book spec.  I later talked to a retailer who said "Oh, Pro
    Tech charges have NEVER charged to book spec...but they're good'uns."
    Anyway, after about 4 packs had gone through fast charge, it started
    functioning to Full Book Spec.  I even had one pack go to 8 amps.
    
    So for me, its been 'so far-so good'.
    
    I hope you have better luck with your replacement unit.
    
    Fred
    

    I have a 702 model and recently also got the 707 (anyone want to buy my
    702? Make an offer...). Anyway, mine too works fine, although I too
    have not seen charge rates as high as the book specs. It does
    occationally false peak early in the charge cycle. It takes about 25
    mins to charge a 7 cell pack. A second peak to make sure completes in
    about 90 secs. Cells get warm, not hot. This is all with AC supply, I
    haven't tried 12V DC input yet.
    
    I originally got it to charge my 10 cell (yup 10) funny car packs. It
    took way too long, so my solution now is to have 5 cell packs that I
    can charge separately and then connect in series. Works real good that
    way. Have you noticed that the red LED chase lights cycle faster as the
    unit reaches the peak? I thought I was seeing things at first... :-)
    
    Jimi.
    
    p.s. for you car folk, you have to see a 10 cell pack running a Trinity
    Top Fuel II motor (11 turn double) to believe it. 65000+ rpm, and the
    current draw is, err umm, ammusing. I'm working on a multi-stage
    slipper clutch to handle it...

    I just got a 706 from Tower (digital version of the 707), and it
    seems to work well.  Tower and everyone else I called have been
    out of stock on this for quite a while, so I think some design changes
    may have been made, or maybe it's just the attractive price/feature
    ratio.  I haven't tested it exhaustively, but I did open it up and
    found the workmanship to be adequate.  The pc board is glass-epoxy
    but it isn't supported well.  Several design changes are evident
    on the board.  My biggest complaint so far is that the DVM appears
    to be connected to the charger side of the limiting resistor during
    trickle charging and not the battery side.  This produces a high
    and not useful voltage reading when the unit switches into trickle.
    I'll see if I can change that.
    
    Tony

    Hobby Lobby doesn't list the Graupner model 3326 in their catalog.
    They do have the model 3330, max. of 24 cells, for $239.
    
    Other high end chargers they carry:
    
    Astro 112, 28 cells, $104.90.
    
    TRC Engineering, 18 cells, $158.
    
    
    I've been using the smaller 10 cell TRC charger for 3 years and find
    it to be excellent. Requires no attention or intervention from
    the user throughout the charge cycle.
    
    Terry

    I want a charger that does everything for the least amount of money.
    The guy at Hobbies Plus was very helpful. He showed me a weird charger
    called a "class I" I think. It had variable current and variable peak
    sensitivity. It holds current to what ever you set it. The problem is
    it only does up to 7 cells and is AC only. The variable peak sensitivy
    is real nice and a must for SCE cells he said. You can also disable the
    "switch-to-trickle" mode so that it does not "flatten" (kill it's
    punch) the pack. Cost ~$150.00 He had 6 on order and 3 were already set
    a side.
    
    He showed me another slick one (sorry I forget the name). But it's very
    small and everything is done through an LCD PAD similar to the
    programable radio interfaces. It has similar problems though, only up to 8
    cells and is DC only. But you can use a 12v power supply which he did.
    Cost over $200.00.
    
    I want more cells (at least 10).
    I want peak (I've blown two packs forgeting to shut mine off).
    I want constant current once it's set.
    I want adjustable current.
    I want adjustable sensitivity but I was told the "class I" was the only
      one that had it. And that box does not meet my needs. Maybe I can add
      it to what ever I buy.
    I want it for under $150.00
    I like AC/DC supply. But with DC you can use a 12v powersupply
      which would stay on the bench.
    
    Turns out there is such a charger. The ASTRO-FLIGHT 110A. I didn't
    realize the current was adjustable because most pictures are out of
    date. The A in 110A stands for adjustable. I just called them and they
    said it will hold the current. It also handles up to 12 cells. It's DC
    only so I will have to have the 12v power supply. The AC/DC model only
    handles up to 7 or 8 cells and does not have adjustable current. I
    think the 110A is good bet and it's only around $90.00.
    
    This is a bit off the subject but this was talked about early in this
    note once before. Okay I'll make it official "Chargers for Poor Man
    F3E's" :-)
    

    re: -1
    
    I own an Astro Flight 110A charger and am very happy with it, my only
    caution is try to gauge what your future electric plans may be.  I now
    own 2 chargers(the 110A and an AC/DC 7-cell Aristocraft) and believe it
    or not may have to buy a 3rd because I plan on projects that will use
    more than 12 cells.  The TRC charger sold by Hobby Lobby for $158 is
    supposed to be a great piece of equipment, it will do up to 18 cells
    and is DC only.  Interestingly enough I had a conversation 2 weeks ago
    with Ed Slegers(electric columnist for RCSD) among other things about
    Astroflight motors.  He claims that the Asto 015 runs very well on 7
    cells and recommends it over the 05 because you gain the flexibilty
    of being able to use 7-10 cells.  Keep us posted on your ASw22 project.
    
                                                  Regards,
    
                                                  Jim

    I'll vote (yet again) for the TRC charger. It's not adjustable, other
    than a high/low switch (on the low setting you can recharge your
    radio flight packs at the field. No more cancelled flight sessions
    because you forgot to charge the night before). The set and forget
    feature is great at the field. Just plug in the discharged pack, go
    fly with a charged pack and when you come back, the pack on charge
    is ready to go. No knobs to tweak or dials to watch, or overcharge to
    worry about.
    On the bench I run mine off a 7 amp power supply. Previously I used
    a 3 amp supply which is marginally sufficient with some packs (7 cell)
    but caused too many premature drop outs, hence the switch to a 7 amp
    supply.
    
    Terry

    I called ASTRO on the 110A and they said it will "HOLD" constant
    current on what you set it to. Is this true?
    
    Regarding the TRC, I figure after 12 cells I would split up my packs
    anyway. And I'm not going to sit in the car and wait for 18 cells to
    charge no matter what the charger anyway. If the TRC had adjustable
    current I might consider it.

>                       <<< Note 89.18 by NICCTR::MILLS >>>
>                   -< TRC = $60 more and no current adjust >-
>
>    I called ASTRO on the 110A and they said it will "HOLD" constant
>    current on what you set it to. Is this true?

Of course it's true - Astro has a good reputation.  I don't have one
but I'd be willing to bet $5.00 they didn't lie about it!
    
>    Regarding the TRC, I figure after 12 cells I would split up my packs
>    anyway. And I'm not going to sit in the car and wait for 18 cells to
>    charge no matter what the charger anyway. If the TRC had adjustable
>    current I might consider it.

Where R U finding these TRCs advertised?

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

    Hobby Lobby, but I bought mine direct from the mfg. in Mich., 3 years
    ago. No savings in price.
    

    
    I know ASTRO-FLIGHT makes good stuff, that's why I'm leaning towards
    it. But AUTO-PEAK, 12 cells, Variable current, and Good name seems to
    good to be true for $90.00. The secratary sceens calls for the
    technical people. I didn't get past her on this one (even though she is
    pretty good). On some of their chargers they advertize "CONSTANT
    CURRENT" quite clearly and on the 110A they don't. For all I know you
    have to have constant current to do the peak detection. I'd like to
    hear from someone that owns one to be sure though.
    

    Is the adjustable current feature very usefull ? When and how you would
    use this feature ?
    
    The Pro-Tect 702 is about $10 less than a Pro-Tect 707. The only
    difference is that the 707 has adjustable current feature where the
    702 lack. Is it worth the $10 difference ?
    
    Ken ( who never played RC car and just bought one for the kid )
    

    It depends on what packs you use. The problem is most chargers with
    fixed currents are fixed for 6-7 cells 1500 mah packs (probably most
    common in RC cars). In planes the cell count and mah vary much more
    widely (600mah to 1700mah) and 5 to 28+ cells. How can you possibly
    charge all those configurations optimally at the same rate. Sometimes
    the fixed rate is too high (damage cells) and sometimes too low (takes
    longer than it should).
    
    One thing you may found and I don't know if it's true or not is. For
    the same charger (ex. 702 vs 707 or 110A and 112) does having the
    varible current cause you to loose the "HOLDING" of a current once set.
    Some of the less expensive fixed rate chargers will hold the fixed
    current. But does having variable current break the "HOLDING" ability
    in this price range. Expensive chargers +$150.00 do both HOLD and have
    variable current. I was told the 707 will not HOLD. So I suspect the
    110A will not HOLD either. The HOLD keeps charge times down and helps
    train your packs. But I'd rather have variable current than fixed if I
    had a choice between the two, because my biggest concern is not to
    damage packs ($$$).

>    it. But AUTO-PEAK, 12 cells, Variable current, and Good name seems to
>    good to be true for $90.00. The secratary sceens calls for the
>    technical people. I didn't get past her on this one (even though she is
>    pretty good). On some of their chargers they advertize "CONSTANT
>    CURRENT" quite clearly and on the 110A they don't. For all I know you
>    have to have constant current to do the peak detection. I'd like to
>    hear from someone that owns one to be sure though.

    I own one.

    It's constant current.

    You need constant current to do peak detection (if the current changes,
    so does the voltage, and you can't detect the peak, which is a voltage
    change of a few millivolts).

    The 110A has adjustable current output.

    It uses a DC-DC converter to get the charge voltage up over the
    available 12V supply.

    If you pay $90, you're getting ripped off.  The 110A is one of the best
    bang-for-the-buck choices you can make.   I recently bought one for me
    and one for my father from Tower, I paid $54 each.


    Randy

    
    Wow $54.00 thats a great price. As usually Hobby Lobby has it's usual
    mark up. I was going to shop around for prices before I ordered. Thanks
    for the tip. It really does seem to good to be true. It will probably
    be back ordered for months knowing my luck.
    

    
    I think you mis-quoted the price. It's on sale for $64.99 normally
    it's $76.95.
    

    RE: last few replies
    
    	As for now, we are using the Sanyo 1500mah 6-cell pack. There is a
    hobbie place in Salem, NH sells the 702 for $49 and 707 for $59. Based
    on the last few replies, I will get the one with adjustable current
    output. Does the 707 really do voltage peak detection ? The salesman
    told me that the 707 doesn't do peak-detection.
    
    Where is Tower ? What is there phone number ? 
    Does the Astro Flight 110A uses AC input ?
    
    

    I don't know that much about the protech series. But Tower lists it as
    a "peak" charger. There is several methods of detecting peak.
    
    1) Drop in voltage (some chargers allow this to be adjusted)
       (for some applications, SCE batteries, can over charge)
    2) Decrease in voltage increase (TRC model) safe for SCE
    3) Battery temp checked. This has slow feedback but is a nice safety
       in addition to the above.
    
    The 110A is DC only one of its few drawbacks.
    The 111 is AC/DC but does not adjust current.
    
    Most chargers use method 1 and I assume 707 does. According to a dealer
    at Hobbies Plus the 707 will not hold current even though it says its
    a peak charger and goes against what someone replied earlier. I think
    it is possible to do peak and have the current fall off. Because on my
    115 (no hold no peak) charger the current can fall off and still have
    the voiltage increase. The resistence of the pack changes during charge
    and is not a fixed resister. Therefore drop in current does not lead to
    drop in voltage.
    
    If this is for a car (6 cell 1500) pack then.
    
    1) If I had the $$$ I'd get Class I (I think that's the name) call
       hobbies plus in Nashua $150.00 This guy really knows cars.
    
    2) If I was tight on money I'd get the 707 (I personally don't like this
       brand) or 112 (I like the name but it has the draw back of no adjust
       current but should not matter if you stay in the 1500 mah range).
    
    Tower is one of the largest R/C mail order companies (Get an RCM
    magazine) Tower assistence 1-800-637-6050
    
    If you buy from a local dealer ask for a demo (or no questions asked
    return policy) too see if it holds current and is what you want.

>                        <<< Note 89.27 by MSEE::CHENG >>>
>
...
>    	As for now, we are using the Sanyo 1500mah 6-cell pack. There is a
>    hobbie place in Salem, NH sells the 702 for $49 and 707 for $59. Based
>    on the last few replies, I will get the one with adjustable current
>    output. Does the 707 really do voltage peak detection ? The salesman
>    told me that the 707 doesn't do peak-detection.
>    
>    Where is Tower ? What is there phone number ? 
>    Does the Astro Flight 110A uses AC input ?

1st let me warn you.  I wouldn't give a dime for a truck load of Pro-Tech
chargers.  I now own the model 700 (AC/DC Digital) and I owned for
a few weeks the model 707 (AC/DC Peak Charger) which I returned.

I have written notes about these chargers in the past (I'll search and attempt
to find them to avoid redundant entries.  

Tower lists the 707 for $59.99 + shipping
                702 for $32.99 + shipping
             my 700 for $64.99 + shipping

These might be great machines on 6 cell packs but on seven cell packs
they are too slow.

Call me at DTN 293-5695 if you want to talk.

Tower's phone number is 800-637-6050 - if nothing else ask for
a copy of tower talk and their big catalogue.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################


    

> <<< Note 89.29 by KAY::FISHER "If better is possible, good is not enough." >>>
>                             -< Pro-tech chargers >-
...
>I have written notes about these chargers in the past (I'll search and attempt
>to find them to avoid redundant entries.  

89.10 fyi

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################


    

From:	IMOKAY::"mantry%[email protected]"  4-FEB-1992 17:04:30.19

  In the Pikes Peak Soaring Societies Jan 92 newsletter there was a 1 
page add from Integrated Circuit Systems that I think all us RC'ers 
would be interested in.  The add reads:

"The product works great, but the battery dies..."

When your product depends on rechargeable batteries, insist on Quick 
Saver controllers
Designed-in IC intelligence for Faster, Safer Recharging, and 
Full-Charge Efficiency, of nickel-cadmium batteries.

Fast.
Complete charge in as little as 20 minutes (vs. all day!)

Safe.
Total battery protection and longer battery life through "intelligent" 
charging technology.

Full-Charge Efficientcy.
Eliminate memory effects for increased productivity of your products.

Now you can design in all the convenience and versatillity of super 
fast, "full-charge" nickel-cadmimum battery recharging without 
worrying about battery damage, thanks to the ICS 1700 "QuickSaver" Rapid 
Charge Controller.
	ICS "QuickSaver" controllers ensure a full-charge every time, 
and can actually enhance the nickel-cadmium battery reliabiltiy and 
prolong battery life.
	That's the kind of convenicence and efficiency that can make 
your product stand out from the rest.
	See for yourself. Call ICS toll-free at 1-800-220-3366 for your 
FREE ICS 1700 "QuickSaver" Sample Kit with all the details on the most 
exciting nickel-cadmium battery rapid charge controllers on the market.

Developing New Standards in Systems Technology.

FREE QUICKSAVER Sample Kit, Call toll-free 1-800-220-3366

Integrated Circuit Systems
2626 Van Buren Avenue
P.O. Box 968
Valley Forge, PA 19482-0968
215-666-1900 FAX 215-666-1099

I called and they said that it does have the capability to do a dischage 
cycle and will go to a maint charge (trickle) when the batteries are 
charged.  He said that they do include a diagram on how to build a 
sample 2 cell 600 mah charger circuit.  I'll have to wait and see what 
the sample kit has.  But I'm very interested if it will do a fast charge 
and/or maintain a trickle charge.

Let me know if anyone else has heard anything on this.

Take care....

Mark Antry
[email protected]

I'm back in here again with more questions...

I'm in the process of building an Astro 25, 16 cell ship using a motor I've owned
for quite some time. I've gone and gotten a reasonable speed controller and now 
it's time to spend some bucks on a charger. What's the story on the Astro 112? 
Is this a good charger for larger numbers of cells? Who's got the most features
and bang for the charging buck? I can live with DC only since I can rig up a
power supply on my bench but I'd like to be able to set it and forget it and 
go fly one set of cells while set 2 is charging. I'd also like to keep the 
price down so I can buy other things this building season 8^)

Price, where to find it, and features to look for are suggestions I'd like to 
hear about.

On the same note... does anyone in the Central Mass area have a charger 
capable of charging 16 cells that I could take a look at and try?

    There's one I can highly recommend. My Graupner Ultra-Duo plusis a
    piece of art. You've seen it before, and when we'll get a chance to
    hangar-fly next week, I'd be happy to show you all details on it. If
    you want to check it out, you may borrow it for a night or three, no
    problem. Technical data:
    
             battery 1:		4-30 cells
    				4 A max (up to 16 cells)
    
    	     battery 2: (RX pack) 4 cells, 330 mA constant
    
    Normally, you just connect the battery. It will automatically start to
    charge with .3A for 15 seconds. After that it will measure the battery
    for voltage and resistance and decide what battery it is. There is a
    memory for all different cells on the market (even the new 1800 mAh SCR
    from Sanyo) and choose the ideal current. It will follow the curve with
    sample-and-hold and reduce the current when approaching peak. It will
    show actual current, voltage and time of charge simultaneously. Once
    the battery is full, it will beep intermittedly (for a minute), write
    'voll' (=full) in the display and display the charged capacity.
    
    You can also specify charging current or (!) discharging current (max.
    1 A) and charge-discharge or discharge-charge cycles.

    It's all �-Processor-controlled. The thing is programmed in C, and 
    software upgrades or possible when new batteries are on the market.
    
    I have to admit, though, that the price suffers a social deficit... But
    as far as I (and several reports I've seen) can tell, it's worth every
    one of the about $270.
    
    Ed (Siegmann), any more comments on your longer experience with the
    Ultra-Duo (last years model)?
    
    Jim, maybe you can take a loan regarding the anticipated Gremlin
    revenue after next months RCM article?
    
    No, Graupner does not pay me to sell these things...
    
    Best regards,
                  Hartmut

Sounds like just the ticket. Yes, I was very impressed with the features. I was
disappointed last night to find that the only choice for more than 12 cells was 
the Astro 112 which seemed pretty feature deficient. If I could borrow it for a 
night or three, I could try out the new speed controller and get everything 
worked out with this setup. I could grab it at the BS session next week and get 
it back to you before the weekend when you might want to get in some flying.

I've killed a flight box battery by overcharging it so I need as intelligent a 
charger as I can afford. I hate to commit so much money to a good charger but 
it's probably cheaper than replacing ruined packs due to not having the features. 
Still hoping for some comments from Jim Blum (Mr F3E lots.of.cells 8^)

    Jim,
    
    if you want, you can pick up the charger tonight or tomorrow. I don't
    think I'll be flying this weekend. And even if I will, I still have my
    7-cell charger. Since I'll be off most all of next week, it would be
    sufficient if you could return it before the weekend after next. If at
    all :-)
    
    Let me know when it suits you.
    
    There is a charger out here with similar features, only in a bigger
    package. I think it was reported on in the August RCM. I'll try to dig
    it out for you. I'm afraid it's not much cheaper, though. Maybe even
    more expensive? I have to look it up.
    
    Saving precious battery packs is a very valid argument, though. The
    reason why I got rid of the do-it-yourself peak detection circuit I
    had. It did work nicely - occasionally...
    
    Best regards,
                  Hartmut

    I think the U.S.A. charger Hartmut is referring to is the one made
    by SR Batteries. Give them a call.  I also think it is in the $300.
    range...  :-(

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Castor Oil!! "    
                      |_____/

    Jim,
    
       I am using the Astro 112 DC/DC charger for charging the 14 1000mah
    Sanyos in my Calibra.  The unit will charge up to 28 cells and *does*
    hold constant current(unlike some of the older model Astro chargers).
    I set the washing machine timer for the 15 min max at 4 amps, then
    use a DVM to peak the pack.  My 14 cell pack peaks out at about 22.5
    volts and takes 20 minutes to achieve this.  I power the charger on my
    bench with a homemade power supply which allows me to trickle charge
    the pack at 100mah(recommended every 10 flights, or so).  I paid $75
    for the charger from Tower Hobbies.  I think it is the only
    commercially available charger that can do 28 cells for this low a
    price.
    
    The High-tech, peak detecting chargers, such as Hartmut's, probably do
    a better job and are certainly more convenient.  Like most electric
    flight equipment, you get what you pay for!   I do feel the Astro 112
    represents an excellent value and will work sufficiently well for the
    "sport flyer".  You must have a DVM to "peak" the pack however.
    
    BTW-what design are you contemplating for the Astro 25, Jim. I have
    always thought the Astro 25 in an UHU fuselage with a nice skinny set
    of wings would be nice!
    
    
                                                               Regards,
    
                                                               Jim
    
                                                              
    

Thanks Dan and Jim. I was out of the office yesterday afternoon but I did 
manage to stop by Hartmut's to pick up his charger after work. What a nice
charger.

Yes, the RCM article was the SR charger which lists for $300. Do any of the 
mail order places carry SR products so I can check and see if they're offering
it at a discounted price? Hartmut's charger is very nice and would fill all
my imaginable needs but I'm concerned about service if something goes wrong.
Is there Graupner service available here in the US?

Re Plane:

Well Jim, keep talking about F3E 8^) I do like performance and could easily get 
hooked once I get started but the initial plane will probably be an old sedate
H-Ray that I have sitting in the shop. Big fuselage and plenty of area and I 
have no current plans to do anything with it. I think the 25 would give 
acceptable performance in it and I did lighten the structure because it was 
originally built for single design racing (10+ years ago 8^) Since I do my own 
core cutting and bagging, something hot will probably come out of my shop this 
winter. I'm open to suggestions but it will most likely be a scratch built 
project since I have all the tools from fiberglassing on up. My second attempt
(depending on the H-Ray experience) will probably be an electric fuselage for
(third place in F3B 8^) Ninja. Since the slope version isn't exciting but the 
wing has good speed retention/characteristics, I think that this would be a 
resonable performer with this engine. Again, these engines are almost 20 year 
old ferrites that have been sitting in my shops and moved from house to house 
since high school. I want to check these out before I make any future purchases
of state of the art engines. Along those lines, the specs on the motor call for 
it turning 9k RPM with a 9-7 prop on 16 cells. They warn about over/under 
propping and heat. I've been using an APC prop with it for my bench tests and 
it seems to be doing ok but I do wonder if there isn't a better prop/cell 
combination (a lots been done in the last 20 years 8^)

Last night I charged the original battery packs with Hartmut's charger. I did 
them as two separate 8 cell packs and they each charged in about 30 minutes to
1400maH as reported by the charger. Over the weekend I hope to configure my
Novak 828 speed controller and run the motor on the bench (I need to clear out 
the sawdust 8^) to get everything set up. The H-Ray should only take an 
afternoon to reconfigure and then I'll have an electric for lunchtime.

So, Jim, is it realistic to put this engine/controller/batteries into a Ninja
fuselage and expect some interesting performance? 8^) What's a reasonable wing 
area to get various levels of performance out of this combination?

    Jim,
    
       The past two years there has been a guy at KRC with an electric
    Ninja.  He was using an Astro 015 with 12 800 Sanyo AR batteries.
    The ship flew very nicely.  Add up the weight of everything and
    calculate the wing loading.  I would not feel  committed to using
    16 cells, you may want to try 14, which would result in lower
    current draw(longer run time), or even 12 cells.  Experiment to
    find the best combination of run time, thrust, and what you can
    jam into the fuselage.  
    
    The Ninja's I have seen do not have tremendous L/D, so it should be
    relatively easy to land.  As Hartmut as well as myself can atest,
    landing a clean, high wingloading airplane can be tricky(read 
    broken fuselages).  I think since you already own the Ninja it
    would be an excellent choice for an electric.  It should be quite
    aerobatic with its SD6060 airfoil.  Let me know if you pursue it,
    I will be anxious to see how it works out.
    
                                                       Regards,
    
                                                       Jim
    

That's all the encouragement I need 8^)

Since I really don't want to have several 6, 7, and 8 cell packs around, how 
do you suggest I figure out the optimum pack configuration?

    Jim,
    
       One of the most important things I have learned from the "experts"
    in electric flight is don't be afraid to make your own battery packs!
    In fact you are going to have make your own packs if you desire to
    fly anything other than a large "boxy" airplane.
    
    I remember how difficult it was to disassemble my first commercially
    made pack!  I use 3/8" copper solder wick(Hobby Lobby) and a 40 watt
    chisel tip soldering iron.  Works great!  You will need to custom
    build "clusters" of cells which fit into the space available in your
    fuselage.  You will get very good at this if you fly electric gliders
    or pylon racers.  The Commercially made packs usually cannot take
    F3E currents(40-60 Amps)- the solder tabs melt!
    
    Start with single cells, and make a pack that will fit your ship.
    
    
                                                     Regards,
    
                                                     Jim

Yes, I'll probably go that route in the long run since I am aware of the cost 
savings (and there aren't a lot of 8 cell packs available in the hobby stores 
I frequent). My first goal is to get something in the air with the components
I already have. If this proof of concept works, I'll need to get more packs so 
I can fly more than one flight at lunchtime. If it doesn't pan out, I've got a
minimum investment to stick back under my shop bench.

Another concern (which will probably make me try things in the near future) is
that being a contractor, my current contract runs out the middle of November.
For the first time in 4+ years I have more options outside DEC than inside. I
may very well lose this wealth of knowledge I have here at my fingertips. The
rapid access to information and interactive forum for questions would/will be 
a great loss.

    Jim,
    
    this is not fair and you know it. The electric notes seem to come to
    life now that you are getting into it, and you threaten to leave! You
    have a responsibility to share your experience with this forum, and I
    expect you to value this file as an asset of a DEC job. I don't care
    how many outside opportunities you have. Pick one of those inside.
    
    I might be forced to recalculate the charger price in case you leave.
    After all, I know there is a lot of money outside of this company.
    
    
    You know, I am....
    
    
    
    
    
    
    
    
    
    
                                                         .....kidding.
    
    Anyway, I'd hate to see you leave. 
    
    Best regards,
                  Hartmut

To quote Monty Python:

I'm not dead yet! I'm feelin' much betta. 8^)

If I have an inside and outside offer, This file has been a DEC plus in the 
past. However, one needs to have the offer to make that choice. This is the 
first time that the choices are more on the outside. I'll keep you posted. 
I've still got 3 weeks (I've changed in the past where I walked out friday 
without a job and still started inside on monday)

I would greatly miss the DEC modelling community if that comes to pass.

I just spent a very enjoyable 20 minute talking with Larry at SR Batteries about
their smart charger featured in the Silent Flight column in the August 1992 
issue.

The charger does everything the Graupner Ultra Duo does with a few exceptions
and there's a Deluxe model coming in a month or two with more features.

It will fast charge at up to 5 amps. Peak detect, temperature detect, and maximum 
time all at once. A temperature probe is included and more are available at $6
each. All the cables detach with panel mounted Sermos connectors so you don't 
have an octopus to carry to/from the car. There are motor connections so you can 
use it as a 250amp ampmeter for selecting props. It will tell you how many cells 
it detects and you can override it for discharged pack (when seeing what's left 
in a pack). The display tells you the charge rate, time of charge, and peak 
voltage reached and you can do the math to get maH (the Ultra Duo displays maH)
There is an ESV built in (not sure if this is regular or deluxe) that allows you 
to select the load and press a button and it displays the voltage and a yes/no 
fly recommendation. The standard is for this and field charging of 4 cell Rx 
packs only but the Deluxe will do 4, 5, and 8 cell packs. The deluxe model will
use the temperature probes in the battery packs to decide if the pack is cool 
enough to charge and wait until the temp drops before starting the charge. The 
Deluxe will have a faceplate strobe that will be visible at some distance (he 
said 1/4mi) and flash when the pack is ready (to supplement the beeper).

The down side is that the Ultra Duo has a dedicated Rx circuit that can be used
at the same time as you're charging the motor packs, the SR doesn't. The Ultra 
will adjust the charge rate depending on the pack resistance, the SR is a 
straight constant current charge rate.

I'm getting literature and price lists in the mail. I'm currently leaning towards
the SR Deluxe.

Prices:

Larry thought that Hobby Lobby was selling the Ultra Duo for $400+
SR is only selling the chargers direct. $300 for the standard and $350 for the 
added features of the Deluxe. The standard can be upgraded to the Deluxe after 
the fact (ROM swap). 

Initial warrenty was 90 days. This has been bumped up to 6 months and they are 
leaning towards 1 year. They don't know what service will be like since no units 
have failed and been returned (they have been out in "Beta" for 9 months)

It was funny because we got talking about what kind of stuff we were flying and 
he mentioned that he was flying a wing and he had been looking at the Gremlin
article in the December 1992 RCM to check out the trim setup. I hope to try an
electric Gremlin at some point.

One more difference on the deluxe model. Both the Ultra Duo and the standard 
model have charging cutoffs if the source drops below 10vdc. The deluxe model 
allows you to set this cutoff to 10, 11, or 12vdc so you can start your car 
to recharge/go home.

    One point of caution regarding the Ultra Duo plus - and possibly other
    computer chargers:
    
    Mine was damaged when I first tried to use it back here. It started off
    okay (self check etc.) and checked the beattery with 300 mA, but as
    soon as it wanted to go to higher currents, the real current was 0.0 A
    and it shut off soon.
    
    At first I was afraid I had fried it when I tried to run it on a power
    supply.
    
    Anyway, I had to send it in and received it back from Graupner this
    week. A Schottky diode was gone, indicating a short between the car
    body and the charging jacks. I don't for the life of me have an idea
    where that could have happened (manual suggests to put the charger on
    the ground, some distance away from the car to avoid this, the leads
    are long enough).
    
    It was an expensive lesson to learn (no warranty for that kind of
    failure, material cost DM 5.70, labor DM 55, and with taxes, S&H etc.
    DM 83 ($ 50 +). I'll take very good care from now on.
    
    They said this is a weak point of all computer chargers, so be careful!
    
    Best regards,
                  Hartmut
    
    P.S.: Jim, yes, I agree, it is a good idea to make sure there is
    service around...

Very sorry to hear that the charger had problems. I appreciate the caution 
about using them. I still hope to check out the SR Smart Charger at the 
WRAMS show but I'm still considering the less automatic options.

I still have an Astro 25 sitting on my bench looking for something to go 
in. The WRAMS show might lead me to something to build also.

    Re; -1
    
    Jim,
    
       Larry Sribnick showed and explained his Smartcharger at KRC
    this year.  It appears to be a nice but expensive(about $300)
    unit.  From what I heard, it does it all.  Everything from cycling
    to peak charging, and local(USA) service is available.
    
    The stumbling block of course is the $300.  The pivotal point is
    how seriously involved with electrics you intend to get.  I am
    an electric only flyer and by trying to "save money" have ended
    up with the following 3 chargers:
    
    1) Cheap 7 cell AC/DC charger $60
    2) Astro 110 Peak detector $80 (12 cell max)
    3) Astro 112 DC/DC charger $75 (28 cell max)
     
    I have spent $215 and do not have a charger that has the performance
    of the SR, Graupner, etc.  even though I have spent over 2/3 the cost
    of these units.  I should have purchased a quality computer charger
    last year instead of the two Astro units.  Hindsight is always 20/20.
    
    
                                                         Regards,
    
                                                         Jim