Hello to all.

Ineed a little help understanding these Li-Po batteries. I thought I understood but now I either do understand and there's something wrong or I really don't get it.

I have 2 5S 25C 5000mAh Hyperion packs hardwired in series to make a 10S. I've been charging the batteries at between 4-6 Amps and it takes about 45-50 minutes to replinish 3000 mAh. The IR on each cell has been at 1-1.2 every single charge for the past 24 charges (That's also how many flights are on these packs). Tonight, I changed the settings on my charger to charge at 10A. Charge time dropped to 37 minutes and it averaged charging at 6.5A. It put back 2827mAh but the IR is now listed at 1.9-2.1 between the 10 cells.

So here's what I"m not sure of. I understand that the higher the "C" the less the IR will be. I also understand that you don't really want to see above 3(ish) for our packs. Did I get a higher IR because I charged the packs faster? If yes, does it stand to reason that the faster you try to stuff back in the mAh, the more resistance you will get? If no, is there the potential for something being wrong with my packs since I went from 1.0-1.2 to 1.9-2.1 in the span of 1 charge?

Thanks y'all,
Scott

I'm no expert by any means, but just by observation, the IR numbers on any particular pack can change from day to day,in the sort of regions you are describing, using the same charging regime(in my case 10s 5000mAH at 1C).
Again in my experience , the variable seems to be the ambient temperature during the charge-the warmer it is, the lower the IR numbers will be.

Scott, I have no experience with Hyperion but do have the impression that if you charge at higher C-rates IR seems to go up a bit. Since your actual values are still very low I would not care about it.

Also, I have found that many variables are in play (temperature, when do you measure (before flight, after flight, before charge, after charge, after storage...). I think the only thing good to do is measure regularely so you start to see patterns and then based on that have the conclusion something might be amiss.

Volkert

Thanks guys.  I flew my Pass-Port four flights today with temps in the mid 90's.  I charged the battery from my truck as normal and the IR was down as usual (1.1-1.3)  It appears ambient temperature does have an effect but also my truck can only deliver 12.2V to the charger.  The Power Supply at the house can deliver more so the charger does deliver more to the battery at the house AND the temps are around 75F inside.  All this is very interesting. 

....the learning curve continues

Hi Scott

you shouldn't charge your packs from you truck. Your truck battery probably isn't a true marine deep cycle battery. Starter batteries aren't designed to be discharged in this way. You'll wipe it out in pretty short order. Buy a real marine deep cycle battery or a generator to use as a power source.

I don't think you need to worry much about the IR unless the values start to consistently climb and reach near 10. That's about the point that they start to really nose dive.

Thank you sir.  I'm going to buy a generator soon.  You're correct that it isn't a Deep Cycle battery and I am starting the truck after every other charge.  I will do as you suggest however right away.  Thanks for responding and good to know about the I.R. number of 10.  That's wayyy different than I was told before.  I like your number much more gooder