How do you choose LIPO number of cells.

[griff7373]

I understand what MAH means, my question is as I am looking at LIPOs preferably 2S I see a various amount of number of cells what does that mean.

I am looking for my Axial EXO and don't want to buy the wrong batteries.

 

[Greywolf74]

the more cells the more voltage. the more voltage the faster the motor will spin. You have to look at see what the maximum amount of cells or voltage your ESC and motor can handle in order to know which lipos are compatible. The EXO is designed to run on 2S or 2 cell lipos. IDK if it can handle a 3S but even if it can it was really meant to be run on 2. For example I know that the Traxxas Ruslter VXL can technically handle 3S according to the specs but its mostly designed for 2S operation. Running on 3S usually results in tearing stuff up....It is however fast as crap and can sometimes be worth the extra wear and tear, but that a decision that only you can make

 

[griff7373]

Thanks I understood the 2S or 3S issue, my concern was I was seeing 2S with 20 to 60 C which I understand has something to do with the discharge rate. I talked to a few other people and the tech support at Castle Creations and finally understand it now. Man I miss the days of the simple NICD and NIMH.

Here is what I got from Castle a few minutes ago.

The term 2s stands for a 2 cell LiPo. We recommend no more than a 2s LiPo with a minimum of 5000mAh or higher and a minimum 30c continuous discharge rate or higher.

I ended going with these based upon feedback from one of our sister sites:

http://www.ebay.com/itm/261814831109?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT

 

[Greywolf74]

Venom makes decent lipos. I generally only buy 40C or higher lipos. 30C you can get away with in some kits but I prefer to just get 40C+ so that no matter what I use them in they'll be fine. The higher the C rating the better although some companies I think have bogus C ratings...like maxamps for example.

5000mAh is a pretty basic pack size. I generally buy them arount the 5000mAh size. The bigger the better but if you get much bigger than 5000mAh you have to start looking at the height of the pack. For example a 10,000mAh pack is gonna be about twice as thick as a 5000mAh lipo and most kits would have an issue fitting that in the battery tray.

In the future Id recommend you check into SMC lipos. There at least as good (IMO theyre better) than Venom and generally a tad cheaper.

 

[griff7373]

Thank you I will check into the SMC ones when these go bad.

 

[ninnon]

Thank you I will check into the SMC ones when these go bad.

You need to buy balance chargers with lipos to, so that each of the Cells is charged evenly...

 

[griff7373]

You need to buy balance chargers with lipos to, so that each of the Cells is charged evenly...

great thank you my charger comes with the balance board, the only thing needed now is the storage/charge bag for the LIPOS

 

[ninnon]

great thank you my charger comes with the balance board, the only thing needed now is the storage/charge bag for the LIPOS

Yes, they're also very important- if these things do go puff, some of those gases and liquids aren't exactly the nicest of things...

 

[flm_savage]

There is also another spec that most people don't pay attention to which will tell you how many cells make up the lipo. For example a 2S lipo could be 2 or 4 individual cells. It all depends on how they are wired internally. This is where your 2S1P and 2S2P come from

 

[griff7373]

So I am finally going to have some free time over the next few days and am wanting to charge these LIPOs I bought they are the ones listed above. The are 50C my question is what charge rate can I use I believe 5 amps is the max can I go lower to charge them a little slower just to be on the safe side.

 

[flm_savage]

Those lipos have a 1C charge rate so 5A is max. Lower is fine but I would recommend 5A. If you go too low and your charger has a time limit, it may not fully charge. (Because it will time out)

 

[griff7373]

Those lipos have a 1C charge rate so 5A is max. Lower is fine but I would recommend 5A. If you go too low and your charger has a time limit, it may not fully charge. (Because it will time out)

Excellent thank you, still cautious with LIPOs.

 

[Greywolf74]

5A on a 5000mAh Lipo is completely normal and safe. Its your typical 1C charge which is standard for all LiPos. You shouldnt have any problem charging them at that. Just make sure you storage charge them if your not going to use them for a week or more.

 

[griff7373]

Ok thanks so basically always charge them when I am done with them.

 

[griff7373]

finally charging them how long should it take at the 5 amps

 

[griff7373]

took about 1.5 for the first one second one still charging

 

[flm_savage]

My 2S 5000's take a little over an hour to charge if i take them down to 3.2V per cell

 

[SchrodeMode]

Ok thanks so basically always charge them when I am done with them.

Not fully if they'll sit for a while. You don't want them to sit fully charged/discharged for any extended time, if your charger has a "Storage" mode, I'd use that.

 

[griff7373]

I don't believe it does, I guess I can just run them down some when I am going to put them away

 

[SMaxxin]

What charger do you have?

If your charger actually doesn't have a storage charge your going to want to store them at 3.8v per cell or 7.6v for a 2s pack.