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BMJR
09-16-2005, 10:01 PM
I'm looking to buy a large packs or packs to use on a larger power system. Total needs to be 7s with enough in parallel to handle 50 amps.
Right now I'm looking at some of the new 16C cells from TP as well as some from Tanic. There are others that I have looked at which are slightly less expensive.
Regardless of the name on the pack, most are sold in series configurations of 2s, 3s, 4s, 6s, 8s, 10s, 12s, but I havent seen any 7s packs listed.
So I would need a 7s pack put together or use a 4s and a 3s pack with a series Y connector.
I'm wondering which would be best.
I've read all about the concerns of charging multiple series cells, yet it's very common it seems. one problem that I can see is supplying the charger with enough current to charge the battery. For example charging a 5000 mah pack at 1C would mean pulling what.. approx.. 12 amps from the power supply or 12v battery.
I have also read of concerns using two packs in series.

What are the pros and cons of each?

JWN
09-16-2005, 11:36 PM
From what I have read here from those that know far more than I, it is best to use multiple packs with Y connectors so that it's much easier to prevent, or correct, cell imbalance while charging. I would also imagine the cost of a charger which could handle 7s, if one exists, to be quite high.

Unbalanced prop
09-17-2005, 01:53 AM
BMJR.......I have never come close to using that size packs, but why not give Bryan a call at Tanic packs and see if he can make something up for you. He has always made any configuration I wanted. The astrflight 109 charger will charge up to 9cells at 8 amps and should handle that size pack easily as long as it is hooked to a good battery or power supply.

Doug

Tweet
09-17-2005, 03:16 AM
The Astro 109 will handle your setup no problem (cost = about $130). As long as you have a good 12VDC power supply or are using a battery you'll be in good shape as well.

Even 2P (4,000 mah) will handle your current draw. If you go 3P (6,000 mah) you should have some buffer, not work the batteries too hard, and have extended flight times.

It is pretty straightforward to wire your own series or parallel harness.

BMJR
09-17-2005, 04:52 AM
Thanks for the info.
I should have mentioned that I already have a couple of 109's as well as a power supply and a couple of 75ah 12v field batteries.
I'm just torn between using a single pack or 2 packs connected in series.

2dogrc
09-17-2005, 05:37 AM
Hey Buddy,
I can special order you 3 or 4 s 4000 mAh Dualsky Xpower packs. They testing is done and they are running the production right now!