A123 Hypersonic Charger Balancing/connector

[suicideneil]

Originally Posted by 71istight

will these cells work with a mamba max esc? tmaxxracer why dont u answer to my pm???????/

Take a chill pill. Any battery will work with any esc, its just a case of matching the voltage & amperage requirements of your set up.

[Finnster]

There are somevery detailed and great threads over @ RCGroups in the batts section. the forum is more for planes, but same things apply. Most there were just using the bussbars. They seem to hold up well enough, but they don't draw the huge currents we do for the most part. There is one bar that is thinner, possibly acting as a fuse. Most leave the bars and sodler some copper wire to assist where needed. I'd post links, but that site is blocked from work :010: Search A123


Also, I thought I had read where someone did some testing, and the V drop w/ buss bars showed nominal decrease vs using batt bars. Ie, it really wasn't worth the trouble (which is quite a bit w/ the A123s)

[zeropointbug]

Yes, I have read that at 35 amp draw, the stock strips loose 1% voltage, so anything higher is going to have exponentially higher losses, naturally.

I have talked to A123 Systems, they sounded quite stern about soldering their cells, they told me cycle life would be significantly decreased. Definition of 'significant', I don't know, but they should still last far longer than lipo.

An 80 watt iron should do the trick. I have a 300 watt iron I use for this kind of stuff. Also, one spot you should beef up is the thinner strip, it is there to act as a fuse for too high of currents.

BTW, from the 'developer kit' I bought last year when A123's were first released, and the cells I got from the two packs, there seems to be quite the quality difference. The older cells I have seemed to have been 'clones', they were like 'pro extreme team matched' so to speak, these new cells from the dewalt packs all vary in voltage when fully charged for some reason.

But I will wait until I get a few runs into them first, in case it's a 'break-in' issue or something.

[t-maxxracer32]

71sight you know im running 6s a123 on my revo lol why did you ask that?

[t-maxxracer32]

what do you use to measure the voltage count? id really like to get me one of those.

thanks!

[brijar]

I just used a volt meter. I got a couple from harbor frieght, which is a very good place to get tools for cheap. I got one of these, only mine is yellow. It has worked very well for a long time. You could also get one with a backlight for easy reading, but it costs a bit more. They are very useful to have around, especially if you do a lot of work with batteries and voltage.

Brijar!!!

[Finnster]

Originally Posted by t-maxxracer32

what do you use to measure the voltage count? id really like to get me one of those.

thanks!

That would be a voltmeter, available at most home supply stores (home depot), Ratshack, hell even pep boys for cheap ones. :027:

I was basically doing the same thing last night. I took my pack apart and prepped the cells. Stupid thing tho is I was easing the cells out of the casing, when all of a sudden it just went and all the cells crashed to the floor looknig a like a string of sausages. Worse yet its there was a little spark. :o One end has a little scorch mark, but for the life of me I can't find what bit it shorted against. My batt luck has been a bit down lately, despite the extra care I've given.

However, its not too bad. So I'll just see. I tested every cell, every one was 3.301V, so I would say currently well balanced. I'm not sure if i will add balance taps. I prolly should/will, but many others have stopped balancing as it seems they tend to self balance.

I made two cuts in the tabs to create a 5S pack and a 2S and 3S. I shooglued them together (like making nimh SxS), and tonite I'll solder a bit hopefully. I'm going to offset the packs to minimize the width. Looks like final width will be just over 50mm, about same width as TrueRc lipos, so should fit in my batt tray w/o mods.

(Poorly) Illustrated:
-ooooo+
.-ooooo +

versus as packaged in 10S
ooooo-
ooooo+

[brijar]

I've done some looking around, but I can't find if anyone has successfully used the Dewalt 36v 1hour charger to charge these batteries. That would save me a lot of money if I could just buy one and do a little bit of rewiring. I wouldn't even need a power supply.

I will have 4 packs that the Hypersonic charger can charge, so it will take me an hour to charge all 4 at 15 minutes each. The Dewalt will charge all 4 packs at once in an hour, but costs a lot less on Ebay. I guess I wouldn't have to do very much rewiring, but just make a harness that plugs into the balancer thingy that I took out of the pack, and then attach the balancer thingy to the charger.
The only thing I don't like about that is that I won't be able to charge just one or two packs at a time. I'll have to have all the packs discharged about the same before I can charge them.
I think I may just stick with the Hypersonic Charger.

Brijar!!!

[BrianG]

If you don't mind sitting around watching the charge, and you have a decent NiMH charger, you could simply charge in constant current mode only. When the pack voltage gets to 3.6v/cell, continually reduce the charge current to maintain that 3.6v/cell voltage - basically simulating the cv stage of the charge...

[brijar]

Well, that's the thing, I went cheap in the beginning, and now it has come back to bite me you-know-where. All I have is a Duratrax Digital Piranha charger and a Dynamite Twin Peak. The digital one is about as close as I get to being able to control the charge. Whenever I charge, I can look at the voltage readout, but it always says like 10+ volts for one of my 7 cell GP3300 packs, so I wouldn't know when to stop the charge. I also notice that that charger pauses every once in a while and drops the charge amps to 0, then goes back to what it was set at.
Thanks for the idea anyway.

Brijar!!!

[Mister_Anderson]

Sorry about stealing the thread but here I go anyway.

So what I'm gathering from this thread is that the hypersonic charger will charge cells of 3.6v not just 3.3v?

It doesn't mind capacity differences?

What rating are the Dewalt pack cells?
What MaH? Discharge C rate?

Thanks.
Mister_Anderson

[brijar]

No, the Hypersonic charger charges 3.3v M1 cells to a full charged state of 3.6v, but they drop back down to 3.3v very quickly and remain there till almost the very end of the charge.

As far as capacity goes, it will charge any capacity until it reaches 3.6 volts per cell, up to 3 cells.

The Dewalt cells are the same ratings as the A123 Racing cells, but they may be lower quality units. Sometimes you may get a bad cell in a Dewalt pack that doesn't hold full charge voltage or capacity.

Brijar!!!

[Mister_Anderson]

Thanks.
What capacity rating are the Dewalt cells?

Thanks,
Mister_Anderson

[suicideneil]

A123 cells are 2400mah, unless I am mistaken.

[wallot]

Originally Posted by suicideneil

A123 cells are 2400mah, unless I am mistaken.

you are.
they are 2300mAh