Dayton,
The 4 digit value on all batteries is the miliamp x hours the battery is capable of delivering. I understand this to be a combination of time vs power output. There are two things that everyone wants, long runtimes and high speeds. So the bigger the number the better for either, but typically the more of one the less of the other. Correct?
Yes, in order to achieve longer run times (without using a smaller prop) we need more mAh. However, more mAh does not mean higher speeds. The reason, for instance, IB4200s are faster than say DTX3800s is probably due to the IBs being better all around cells, with lower internal impedance and construction. Usually, the higher the mAh, the more internal "resistance" you will have. The trick that OC found out was with the use of IB4200s, (having just the right amount of weight, punch, and least internal resistance). I'm sure there are other cells out there with similar mAh rating, but with lower internal impedance, but we don't want to spend bookoo $.

The way I understand it is that the best packs have the lowest resistance (meaning good quality cells (still trying to understand what that is) and they are tied together in a way to lower discharge resistance) IE good, thick wires, deans connectors, and bars replacing wire where possible. Yes, you got it. Also answered above too. The best cells will be balanced, basically meaning they all put out the same within the same time frame. The voltages b/w cells will be within say .03v of each other. Where as unbalanced cells might be w/in .07 of each other.

I've read a great deal about battery care where I think the whole idea is to get all the cells even and to their max potential.
As we've found found out from others, matched race packs are the best, however, they lose their balanced voltage b.w cells after about 10 or so cycles. Better off buying unmatched cells because we balance "form" them when we get them to begin with. We use the "C/10" charge for this and every month to "re-balance" them. Simply put, if you have 3800mAh packs, form charge them when you get them at .38A a couple times before you run them in the boat. Also do this about every 4 weeks.


Also I see refrences to "getting them up to operating temp by topping them off. I assume this makes sure they are maxed out and also warm (does temperature speed the chemical reaction?)
Grim led us onto this one. Top off the packs before racing by bringing the cells up to 120F, then run them as soon as possible. I think this agitates the chemical process, but it also will lower the overall operating temp of the cells while in use. When I run my CF48 and X645 prop, the batts are very close to a safe theshold of 145F. After using Grim's recommendation, the packs are about 5deg cooler.
There is also about a 2-3mph gain on the water. It is very noticable when you compare performance of packs prepped this way against ones that were charged the day before or even a few hours before racing. NiMh packs lose their stored charge fairly quick.
Repeak (more than once if necessary) them on race day to 120F using no more than about 2A and you will have better performance. The reason I say 2A (1A will be better, just takes longer.......I like 2A) is if you go higher, the more unecessary heat is produced in the packs and less mAh. I don't run my packs more than once on a race day, so I don't use the higher charges. And I'm not saying fast charging is bad, but when using higher charge rates, you try and cram more mAh in the packs at a faster pace. This means more heat and less mAh.