Don’t hold or lift the battery by the wires.
Oh yeah, seen that one too many times. Probably been guilty of it myself on occasion. The problem I’ve seen in lifting by the wires is it loosens the bolts at the battery connector. This increases the resistance at that joint which reduces the voltage in the rest of the circuit under load. I’ve wanted to add some velcro (soft material) patches to the batteries to allow something like tubular nylon straps and the hook material to be used to help extricate the battery out of the robot. The team tends to make them a tight fit which in turn makes it difficult to extract them out for changing because of friction fit. This is the no. 1 reason I’ve seen students use the wires - to help get the battery out of its holder.
As an aside, I’ve picked up some temperature strips and slapped them on the batteries and motors - I’m wondering what the temperature is like after discharge/charge cycles. I know it takes a while for the temperature to migrate to the case which is why I what to measure it with the liquid chem strip – might be interesting data. I’ve got a couple to give away at the BAE NH Regional (like 5-6). Anyone reading this, track me down in the 1073 pit area and ask for one. They aren’t doing me any good sitting in my coat pocket.
I’m not convinced that high current loads warp the plates, that would require differential heating which I suspect would be difficult to achieve with the lead plates in the AGM technology. Not impossible, but not sure it happens. I did manage to warp plates on a fork lift truck flooded cell battery once - the battery was 3’x3’x4’ and I accidently dropped a screw driver shaft across the terminals. Vaporized the screwdriver and popped all the vent plugs off. Exciting.
The depth of discharge (DoD), that is deep discharges of 75% DoD and how long the battery stays at anything below 75% SoC have a lot more effect on battery life. With high current discharge you can hit 80%-90% DoD in a matter of a few minutes. The life cycle charts for the battery lists the test conditions as using only ~0.2CA (~5A) discharge over 3hr. My random guess is that you’d have to derate the lifetime cycles in the specification chart if you used higher, like 3CA (54A), discharge rates. Setting up and measuring the internal resistance seems like something definitive that could be checked on batteries exhibiting early capacity issues as that is a good indication of how “old” a battery may act.