Are you sure you can combine the rails? Most of the dual 12v supplies I've seen are seperate and go to different sections (like one 12v line for all the drives and the other for the mobo). I paralleled one once and one of the switching transistors got very hot, very fast. I would only do that if the specs say you can, but that's just me.

Sounds like a driver interference issue? Was this an older psu unit?

Actually, lot's of the dual or quad rail psu's are actually one rail, with each 'rail' having it's own current limiting circuit, so for those it would be no problem.

:005: I'm not going to say it...


At this point, I am wishing I had got the 40v/5amp version of my power supply unit (i have 20v/10amp), but not that big a deal as you can still split the pack up...

Just run in series, but charge in parallel. :)

Yeah, you can always do that, it's just nice charging your entire pack in ~30 mins like I am now. :027:

Outstanding, thank you guys once again for the information!! Apologizes for the extended response time, I got sucked out of town to VA on work..., what fun...

You know, I've almost decided to run my packs as 3S2P and just get the bloody A123 Charger for $99.00 so that I can charge them "right"... My only problem with it is that it displays nothing, we just blindly trust it to manage the cells, that kind of drives me nuts. Not to mention I'd have to buy two in order to charge the packs at the same time...

I'm probably going to break down and go with the Xtrema and a good PS. Any thoughts on if a couple of new, redundant, hot swappable Enlight PSs would work, I believe they're 500W PSs if I'm not mistaken. What are you guys doing, just clipping the ends off one of the 12v leads and wiring plugs on, can it be that simple??

Thanks!!

Yes you can go for a charger and PSU unit, or you can go with a good quality programmable power supply like I use, which would take up less space, is VERY flexible, and you can see exactly whats going on.

Here is a pic of mine approaching a complete charge at about ~22 mins, it takes a little over 25 for 100%. As you can notice, watts, volts, amps, CC/CV, completely programmable charging sequences... all the good stuff. YOu get that for a very decent buy at $240, a steal if you ask me.

HERE is pic.

zpb, that's the BK 1696, correct, you may have already told me that?? :-) So no "charger" per say, your charging your packs right from the psu, amazing, I can't believe I've never really thought of it quite like that.., though I was a nitro guy until I found this website. I guess all a charger is really, is a semi-programmable psu, huum, nice idea and very flexible, as you pointed out!

Now I'm in a pickle, $240\250 + ish (for a bit larger unit to charge the 6S), fully programable and can charge just about, if not, anything, or $190 + $psu for the Xtrema setup... How large a psu we talking to charge either 6S1P or 3S2P, if it makes any difference, I haven't built my packs yet. I think I'm actually leaning towards the Xtrema with psu, seems more "boob" proof for me being "new"er to electric.

I've had some older, simple "C" cell and Nimh, Nicd, RCs and have actually converted a couple of nitro "MAXX" trucks an E-Maxx and a few Savages, with my newest being a Revo 3.3, but the ICE and a couple handfuls of 6000mah 7.4v li-pos is about as crazy as I've gotten, lol...

Thanks!!

A programmable supply like ZPB has is certainly a very good way to do it. However, just be aware it will be missing any cell-counting safety features that dedicated chargers have. Don't want to turn you off on it, just something to think about.

BrianG, I actually agree, when I submitted my original comment I hadn't paid attention to the next post about the Xtrema.., that'll teach me to read on before I respond, lol... I was thinking the same thing, I've been in RC for years, but all simple packs and simple chargers, for the most part, the Xtrema with psu sounds like a solid, about same cost, solution :027: I'm going to see what I can scare up on best prices and may ask my LHS what they can do, any suggestions on psu to run it??

Thanks!!

Oh, I actually have a 12v, 9A MPI power supply for my ICE, any good?

The Xtrema has a 180w limit. So, taking into account charger efficiency of about 75%, that is 240w. At 12v, that is 20A. Of course, if you aren't using the charger to it's max rating, it won't need that.

That 12v, 9A supply can put out 108w. Figuring charger efficiency, that supply can be used with a charger that will draw 81w. So:
At 3s, that is 6.43A max charge rate
At 4s, that is 4.82A max charge rate
At 5s, that is 3.86A max charge rate

This calculator can help pick a suitable supply. It really depends on what voltage and current you will be charging at and what the power limit for that specific charger.

Correct, it's the 1696 version, it's a solid 200watts 24/7 power rating. You can also control it from your PC through serial connection, quite neat, you can see all real time parameters graph and everything.

You can only charge up to 5s A123 on it, so any higher you have to get the 40v/5A version, there is also a 60v/3A as well, not that it matters.

Like BrianG said, there is no cell count obviously; but if you just have the right voltage set, it's not going to get 'confused' and pick the wrong voltage/cell count... whatever you want basically.

OK, another crazy question, I've read that good quality pc power supplies can be used? I have two, very good quality, brand new Enlight Pro Spec dual, 350 Watt power supplies, they are in a single power chassis and both connect to a large positive and negative copper power rails. Easy enough to use, just plug them into the wall, and I don't care how I have to modify it there collecting dust now, so if I can use them??

Thanks!

To power the Xtrema of course, not direct charge :005:

There will be a green wire in the main ATX mobo power connector (20+ pins), all you have to do it make an on/off switch in between that and ground, which is the case of the PSU unit, or you can just direct connect it and use the rear switch to turn on, but the first option is recommended, IMO.

Then if you want more voltage, SOME psu's have calibrating pot's on them, so they can be adjusted to put out higher voltage than 12 volts.

Quite simple really. :)