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Help!!! Charging 2 7.2V 6C Batts Simultaneously!!

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Help!!! Charging 2 7.2V 6C Batts Simultaneously!!

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Old 04-26-2008 | 12:13 AM
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Default Help!!! Charging 2 7.2V 6C Batts Simultaneously!!

Hello guys! Just wanna ask if it's possible to simultaneously(both at the same time) charge 2pcs. 7.2V 6C Nimh Stick packs with Triton Jr.(which I just ordered) using a series connection like the one posted below. I really need a way to charge 2 7.2V 6C stick pack since emaxx uses two 7.2V batteries. Buying 2 charger is not an option at the moment.

Also, According to the specs sheet. The Triton Jr can charge 1-14cells Nicd/Nimh upto 5000mah so theoretically I guess it could charge two 7.2v 6C Nimh stick packs at the same time provided you use a series connectors to charge the batteries. I'm not sure if my theory is correct so pls. let me know if I'm wrong.

Charger I want to use.

http://www3.towerhobbies.com/cgi-bin...&I=LXMAH9&P=ML

Similar Connector I want to make but I'll be using traxxas connectors instead of deans shown on pic. I'll also be putting banana plugs on the end instead of another connector. So two male traxxas connectors and banana plugs on the ends.(Ignore the cable with white connectors)


http://cgi.ebay.com/iMax-B6-Serial-C...ayphotohosting

These are the Batteries I'm gonna use on the Triton Jr.
http://www3.towerhobbies.com/cgi-bin...?&I=LXTAT8&P=7
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Old 04-27-2008 | 12:58 PM
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Seems like you are on the right track. Just be sure to keep the batteries matched in charge level, capacity, age/condition and such as best you can.
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Old 04-27-2008 | 02:05 PM
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I think it's better to just charge them separately because it's not going to be easy to always get them to the same state of charge/discharge and if they aren't close in charge you run the risk of overcharging one pack. I guess you could discharge them separately and end the discharge at a specific voltage but if you're going to discharge them separately it's probably just as easy to do the same for charging.
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Old 04-27-2008 | 02:23 PM
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One suggestion, while charging keep be aware of the pack temps. If one pack is heating up more/quicker than the other, this would indicate a mismatch.

Certainly as cell counts go up there is more possibility of problems, 6 cells will help but not eliminate that, not until you go to single cells. But you are already discharging together, so no way to completely avoid this issue. Which suggests another bit of advice: Don't run the vehicle all the way down, stop as soon as you detect loss of power. Other wise weaker cells might get reversed.
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Old 04-28-2008 | 04:34 PM
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Thanks guys for the Infos!!!

Anyone here knows how to disassemble a male traxxas connector w/o damaging it? I cut the male connectors on my EVX2 and want to use it in my soon to arrive Novak HV.
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Old 04-29-2008 | 05:36 AM
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charge in parralell at twice the amps. parralell will mean the two packs are automatically matched (the full one will charge the flat one if there is any mismatch).
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Old 05-06-2008 | 08:01 AM
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I would also charge in parallel because they would self balance.
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Old 05-06-2008 | 06:08 PM
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No!!! It won't work!!!

If you hook up the packs in series the charger will see one 12 cell pack, or 14.4 volts. In order to push the current the charger would have to put out more than 17 volts. That charger would burn out.

If you hook up the packs in parallel it would take twice as long as it would to charge one pack, and one pack would overcharge before the charger would see the peak.

Charge one pack at a time. It will cost you much less in the long run.
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Old 05-06-2008 | 06:17 PM
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Okay, I read the spes on the charger and apparently it can charge up to 14 cell packs, but it doesn't say at what current. I'm gonna guess low (like less than 5 amps). So you're charging the packs in series is sound, but I still wouldn't do it. Think about it, charging 12 cells at the same time, and I'll bet they're not matched packs. At least one cell will go into overcharge and potentially ruin one or both packs.

The only people who should experiment are those who can afford to blow stuff up!
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