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Old 11-17-2009, 03:03 PM   #1
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Default venom lipo saddle packs

Hi all,

New to this forum have been into R/C for quite a few years, garage holds a Savage ssx with heaps of hop ups/HPI Wheely King converted into a Crawler,& lastly a Losi 1/10 Comp Crawler.

In the Losi i have a set of 4200mah 7.4v lipo batts.My Question is-
These two batts are wired in "series" which means double the volts and the mah stays the same.(presently charging the combind pacs to 7.4v). Can i wire it so they are "parallel" which means double the mah and the volts stay the same. ? Are these batts 7.4v each or are they 3.7v each ? (they have 7.4v on each batt).
I have specs & pics below

Specifications:
ROAR Approved
Battery Type: Lithium Polymer (LiPO)
Configuration: 2s2p
Weight: 9.17 oz.
Dimensions: 23 x 46.2 x 69mm
Charge Rate: 3C (12.6A)
Continuous Discharge: 30C (126A)
Min Discharge Volts Per Pack: 6V
Max Burst Rate: 60C (252A)
Max Volts Per Cell: 4.2V
Max Volts Per Pack: 8.4V
Watt Hours: 31.08

Could someone please help me ?

Thanks
Scott
Attached Thumbnails
venom lipo saddle packs-ven-15083-actual.jpg  

Last edited by beno3; 11-17-2009 at 08:00 PM.
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Old 11-17-2009, 10:13 PM   #2
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Looks like they are labeled as 7.4V because they are meant to be wired in series. So each separate pack there is actually 3.7V. If you wire them parallel you should have a 3.7V 8400mah total.
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Old 11-17-2009, 10:27 PM   #3
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Hey thanks burnineyes......
The lableing is deceiving , i'll have to keep them in series to run the motor at 7.4volts.

Thanks heaps man


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Old 11-18-2009, 05:24 AM   #4
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There are 4 lipo cells involved in a saddle pack. Each side of the pac has two cells wired in series for 7.4v nominal. The individual side is good for 2100mah at 7.4v. Then these two sides are wired in parallel to yield the final mah.
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Old 11-18-2009, 04:21 PM   #5
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Thanks duster360,

As in the pic in my first post,why are the cables made up for "series"?
I was told by the hobby shop that each pac was only "one cell" not two cell.
Please correct me if i'm wrong.
Also i discharged/charged both batts last night...as per "new batt breakin" & the mah only came up to 2000mah for both @ 8.4v batts in series. Is this right ?


Cheers
Scott
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Old 11-18-2009, 04:46 PM   #6
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It sure looked like the two are wired in series, this would lead me to believe they are 3.7V each. I thought each pack had 2 cells in parallel. I do not own any so Duster may know better than I do.
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Old 11-18-2009, 05:40 PM   #7
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I've only owned on set of these an it was a while ago. I pulled them apart when I had probs and found there were 4 cells , 2 on each side. As lipo tech has gotten better, they may have changed, it may now only be two cells - if the wiring is series, its only two cells and they would be 3.7v one each side with 4200mah. It would take about 10sec with a DVM to know for sure. You should have a decent DVM being in this hobby, mine was about $5 and its plenty accurate enough for what you need.

Then the config you listed as 2S2P is also wrong - that config has a total of 4 cells. This would just be 2S1P - two cells wired in series, none in parallel. Sorry if I caused any confusion, but seeing the 2S2P, I knew this was 4 cells based in that, which its not, its 2S1P which is 2 cells.

The max voltage of a lipo cell and what a lipo charger should charge to is 4.2v/cell, so theres nothing wrong with the 8.4v.

About charging - lipos leave factory with a partial charge, so its not unusual for a new one to charge to less than rated capacity. You discharged first however and only taking 2000mah after discharge is not real encouraging. Venom does not have teh greatest rep when it comes to batts in general - seems their stuff takes too long to get in customers hands and this makes it almost a recovery operating in dealing with their batts. I won't buy NiMh from them for this reason. Lets hope your saddles show some quick improvement, you should get a noticeable jump in capacity next time. If you don't start seing that, I'd be talking to your lhs.
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Old 11-18-2009, 06:22 PM   #8
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Thanks again Duster & Burnineyes...your reply has been greatly appreciated

Cheers
Scott
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