A123 Hypersonic Charger Balancing/connector
 

I just bought a Dewalt 36 volt pack from a big seller on ebay (2800+ feedback @ 100%). He originally messed up the auction and put 9.99 Buy It Now:eek: + $10 shipping, and I grabbed it quick as lightning, but he caught the mistake, and refunded my money within an hour. I asked him what kind of deal he could give me on it so that I could leave him good feedback, and he said $75 +10 shipping was as low as he could go. I thought that was still a pretty good deal, so I accepted that. I learned just a while ago that he's going shipping it for free:018:. So I get a brand new Dewalt 36 volt battery pack for $75 shipped, so $7.50 per cell, which is pretty good, I think.

Now, I will also be getting an A123 Hypersonic charger for a little less than $100 shipped, and I was wondering what kind of connector I will need to use the balancing thingy in it? I will be making two 3s packs and two 2s packs from the Dewalt. I would really like to be able to go up to radio shack and get a few rather than order it from the net. Is there any way that I could get my own to put on it so I don't have to buy one off the net? It would only need 2 wire slots, right?

Also, if I buy a computer powersupply to run the charger, how many watts will it need to be at least to charge at 10 amps? I can get a good deal on a 350 watt one, if it will work. The charger says, Input Voltage: 10vdc - 15vdc.

Thanx,
Brijar!!!

That's a great deal indeed! ~1/3 the cost of LiPo, very nice.

I just bought two 36v packs as well (~$100 each), I am building a 7s2p pack for my truck to run a Neu 1512/3D (1700kv), it should go pretty good, and stay a lot cooler than my 7XL on 5s2p A123.

Anyways, to get to the point, you need an 'Anderson' balancing connector. I don't know where to get these at the moment though, and I am not sure if there is certain wiring sequence for this plug. I'll see what I can find.

Nevermind, they don't have them anywhere. Try A123 Racing directly; I think they have just the balancing plugs for sale. The down side is that you have to order direct...and it will probably cost you more than it should.

I use a 365 watt PC power supply with my hypersonic charger. I have the Hypersonic charger and 2 NimH chargers in use at the same time and the power supply is not even breaking a sweat. Figure 20 amps max.

Pretty good deal?

That's a great great deal.

Yay, he should ship the batteries out today! Now for the wait:025:.

Ok, that's good to know about the power supply. snellemin, is there any way to put a different balancing connector on your Hypersonic charger? I would think that if it had a small lead to the connector, you could cut it off and replace it. If it was more like the connector on an internet router, then you'd have to get inside to get to the wires.

Does anyone have just a spare male anderson balancing connector lying around? I could pay for shipping if you'd be willing to ship it to me:027: at 64015.

It's just about time to order the charger and power supply. I think I may try and get a 400 watt PS on Ebay, for around $14 or so. Wouldn't want it to have to work hard to power the charger, now would we:007::005:.

Brijar!!!

im in the process of looking around for some more a123s. dont feel like spending 80 bucks for the 3s1p packs that i have...

are there 20 cells per dewalt battery?

also once yuo start to put them together you think you could take some pics for us people who dont know how to do it?!?!?!?:027:

i think it would help everyone out alot (or just me :005: if you showed us how to configure everythign!)

Hey, I sure would take some pictures. There are only 10 cells per Dewalt pack, at 3.6v per cell, they give it the 36v rating.

I will be following this walkthrough on how to disect them, but I will be making two 2s packs and two 3s packs, so I can run a 2s, 3s, 4s, 5s, 6s, 7s, 8s, or 10s configuration, or a 2s2p, 3s2p, or 5s2p configuration. I'm not sure how I'll be assembling them, because I don't know how to solder to aluminum. If that is too hard, I will just configure the packs without soldering, like this:
http://img236.imageshack.us/img236/6...kconfigvg9.png

I'm not sure how the bus bars will hold up, but I think they will be ok. I think for the 2s packs, I'll just bend the batteries over so that they are end-to-end. I'm not sure what I'll do with the 3s packs, as my rusty's chassis can't fit 3 in a row, or 2 side-by-side. I'll think of something:027:.

Brijar!!!

BTW, the pack is somewhere in MD right now :D

I got my two 36v packs in Brijar. I have taken pictures of the process so far, and will post a thread on making a 7s2p pack, single pack.

I already posted that link in another thread, i forget where though. :032: oh well:005:

You can solder to the aluminum cans, it is coated with nickel (or something, not too sure), so it's easily soldered, but not recommended with the A123 (or lithiums for that matter), you should try and make as few solder joints as possible.

cool looks good! i might take apart the packs that i have right now to see how they did it. that will probably be my best bet.

Well, I would really rather solder the cells instead of using the spot welded bus bars that they come stock with. I know almost all battery companies advise against soldering their batteries, but NiMH's solder just fine, if you are quick. I have an 80 watt Weller iron, will that be quick enough to not heat up the A123's too bad, or is there other concerns I should be worried about when soldering?

Thanx,
Brijar!!!

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

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)

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.

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.

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

If you get the FLM Rusty chassis, you can fit 3s flatpack with ease.

Yeah, I thought about an FLM chassis, but I would rather spend the $60 on better electronics. I have yet to get a Mamba 5700, so that's another $180 down the hole, plus the $100 or so for the charger. I'll just do some custom cutting on the chassis to make the packs fit. I'm sure I'll think of some way to do it.

Now that I think about it, I think making the packs SxS would be better to fit in my boat. What I may do to my Rustler is dremel down the little lip by the battery tray so that it is flush with the chassis and I can put the A123's in there SxS.

Brijar!!!

Well, the battery just came in a couple hours ago. I have already dismantled it to just the cells. I measured the whole pack and it read about 32.9v-33v. I left my soldering iron down at the lake with my other tools, so I won't be able to put leads on the packs yet. I have taken a few pictures during the process, so I'll post those later. We'll see how it goes from here. The charger and power supply are next on the list.

Brijar!!!

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

thanks!

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!!!

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+

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!!!

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...

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!!!

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

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!!!

Thanks.
What capacity rating are the Dewalt cells?

Thanks,
Mister_Anderson

A123 cells are 2400mah, unless I am mistaken.

you are.
they are 2300mAh