my 5s a123 pack shot?
 

i went to the track today and drove my xt8 with no problems and when the battery dumped (dumped instantly) i just drove it up to me and unplugged it.

i get home right now to charge it and it reads 14.8V and it sais output voltage too low so i cant charge it..... i have it set to charge at 8 amps and im using the 1210i to charge it.

anyone know anything i can do?

when i start to charge it it will only charge at about .45 amps then it dies in a couple minutes reading the low output voltage.

thanks!

Check the battery tabs and all connections.

well if the connection was bad it wouldnt make any type of connection at all right?

just an idea - try setting it as a 4s pack to get some volts in it and then swap to 5s...

Just put it in NiMh mode at a couple amps and let it put a couple hundred mAh into the battery. Then it should be good for regular A123 mode.

How well do the A123 cells cope with over discharge? I'm wondering as I am going to have some spare cells and I was thinking about sticking 4 in a stock brushed stampede with no cutoff.

well i ran it down to 0% and all i had to do was put it to nimh mode and its back in its normal goodole charging mode now

metalman thanks alot!

i charged it at 14cells for about 3 minutes and the volts shot right up!

its good to go now

The hyperion chargers treat it like a lipo, It will only trickle charge if voltage is to low. Either repeat several times until you hit minimum voltage then it will kick into full charge rate to use another method to get it some amps.

1) if you have 2 packs parallel them for a few minutes. Pack 1 will xfer e to Pack 2
2) do like above post say and use NMHI. BUT WATCH IT. if you forget and walk away it will kill pack. Just put like 500 MAH into it then go back to standard charge


OH and your pack is just fine... it does not hurt these things to heavy discharge them :)

PS you would be served well to config your a123 packs into groups of 3 cells.
Then you can Zip charge them. I do that most of the time and if I get LV from hyperion on the occasion that I am using it... I just zip charge for 1 min and then Hyperion works fine.

i feel like the zipcharging method would be hard on your batteries.

or no?

ima pm you and learn more about it.

Over on RC groups there is a guy trying to kill his A123 packs. He is charging at 20-30 amps. No problems yet. He is at around 300 cycles now and says the packs at not showing any age.

I personally set my up to charge at around 10-15 amps. No need to charge faster then I will be using them. Since I run 5s, That means I could average 30 AMPS and it would time out perfectly. However I have 3 sets.. and Never run out of charged cells :) I have seen no issues at all and there is a ton of data by everyday flier that say these cells are just not going to fail no matter what you put them through.

Highflier

It

i thought you said it has to be done in 3s sets or w/e?

sorry typo..... I meant to say 6s.
E-maxx 9xl, BK warrior, 6s1p A123

Zip charging 15' 18 guage wire


Highflier

Not to sound like a dumb ass, but what is zip charging? Any specific equipment needed? I am guessing that it is a123 only.

lmao!:lol::lol::lol::lol:



idk why but i laughed so hard at that


anyways.

heres a link

http://www.rcgroups.com/forums/showthread.php?t=747911

Do not zip charge lipo!!!!!!

http://www.rcgroups.com/forums/showthread.php?t=747911

The motherload of info on zip charging is in above thread.

Super short summary.

By using a length of wire and specific gauge, one can reduce current flow. thus
15' of 18 gauge speaker wire to connect a deep cycle battery to a 3s A123 pack.
charge will be about 15 amps to start and fade down to 2 amps. ( Most of the time around 10 amps)

when votage at pack reaches north of 11.5 your done!!!

Cost to make, is a couple of bucks.
Ability to charge a E-maxx pack in 10 min. PRICELE$$ :)

Highflier
PS as you read above threadlink you will find others use shorter wire and charge faster... as fast as 30 amps. who on this thread can charge packs that fast....
Yea I am sure I will get flamed by somebody who does LOL

I guess me sounding like a dumb ass goes without saying...

Thanks for the link, BTW.

lol more like ive never seen you say anything where you didnt know what you were talking about

did tha make sencE?

I usually try to answer my own questions, but sometimes it is easier to ask! I do tend to investigate things myself before relying on others to inform me.

I'm zip-charging a pack of the new smaller A123 cells (black and decker VPX... 1100mah) but I have not had a chance to monitor the current yet. It's not for R/C... it's for a cordless light I use for work. I charge it while driving straight off a lighter socket.

It's a 4s pack... so the vehicle's @14-14.5 volt system is perfect. That's a common voltage with the alternator running. The only bad part is that if my 123 pack is fully charged, and I leave it plugged in with the engine off... it's probably discharging back into the car battery. So I only plug it when while driving.

I'll bet you only get about 80% charge on that VPX pack. But that does not matter as long as you don't run out of juice on the job, Ever consider a 3s pack and a DB terminator. Might be a better solution.

Highfier

Maybe true. Are you on rcgroups btw?

Well...it may not get a 100% charge, but 3.6v x 4= 14.4 and my vehicle system runs at 14.5-14.7 so I think it's getting a pretty good charge. Some vehicles (alternators) may run a little lower voltage though. Even going by 3.7v/cell it's getting pretty close.

Anyway... the idea for this application is to keep it charged all the time... and charge quickly and easily. So far it's been pretty cool.

If your cig lighter circuit turns off when you shut the car off, then it won't back feed into your car battery. However, even if this was true, that pack could still be powering your radio and other accessories. :smile:

while driving is smart.

so hold on.

if i get a cig lighter converter (converts it to a normal ac outlet) and plug in a outlet thingy then clip off the ends and solder deans to them i can charge the pack through that?

do you guys get what im sayin?

YES Highflier is an account on RCgroups and it is ME :)

There are some reports of people using PC power supplies to charge a 3s A123 pack.

I get what your saying about the adapter for cig lighter, But I'll bet they put out 12 volt not the 14.4 an alternator is doing. Thus you are back to a 3 cell pack.

There is one downside to all of this stuff and that is remember to disconnect the pack when it is charged, ( we are slightly over charging them and they seem to handle that just OK, But I don't think you want to hold it at that voltage for hours) that is where the handy little circuit called DB terminator comes in. It is a automated cutoff when the pack reaches full charge.


The whol trick to this thing is trying to find a voltage supply that is greater then 3.7 per cell and less then 4.2 per cell. So a cleaver guy can play with a PC Supply and do lots of cool things.

PC supply ex. thought
-5 Volt and +12 Volt = 17 volts... Hmm that is 4.2X volts to a 4 cell pack.
or
+5 and +12 = 7 volts..... 3.5 volts for a 2 cell pack.... that would get you a 95% charge :)


I am not responsible for any results just throwing some thoughts out there...... Proceed with data in this post at your own risk. I have used only 3s and deep cycles batter so far.

After I get my DB terminator working I may expand my tests!

Highflier

ok so most of this makes sence.

what can i get to watch the volts and mah while it is charging?

the wattsup thing?

I have used 2 solutions.

1) Astro watt meter. It nice since it shows Amps volts and MAH charged into pack.

2) I made this.. (see link) Cost me under $10.00. By watching volts you know when it is charged. It's a dedicated system for me... I use the Astro for a second system when I want to charge 2 at a time.

http://www.rcgroups.com/forums/attac...mentid=1544395

Thats a $2.99 voltmeter from harbour frieght, wired in paralel near the deans plug.
Thats important as you want voltage near A123 not 15' up towards the Deepcycle.

Total cost was about $7.00 It gets me a charge in about 15 min. Chop 5' off the wire and it would probably be 10 min charge.

Highflier

Yes
 

It will work just fine. make sure you get source -> dest proper. byt default it may be reversed as they are usually setup for discharge from a flight pack not charge into a flight pack. Astro works both directions. My feigo only works 1 direction.

Highflier