The other day I was having some real range issues. I got to work with ever so slightly less than I would normally see, but going home my range was falling WAY more rapidly than it should have. When I eventually got home (I had to take it easy the last 10 miles), I unplugged the Gidometer and plugged my ELM in instead, only to see that the voltage range between the lowest and highest cell was a whopping 68mV! It is HIGHLY unusual for my pack to be over 20mV, and it's generally between 15mV and 17mV. So pretty obvious why I ran low on charge much earlier than I would have expected.
But the question is...how can I mitigate this in the future?
Well, clearly it would help if I was using the ELM all the time, instead of the Gidometer. If I'd seen my pack was either out of balance already before leaving home, or noticed that it was edging towards becoming unbalanced at the mid-point, I might have been able to do something about it. But I do have my issues with the Android device - the first of which is I find it difficult to read the screen while wearing polarized glasses. Perhaps an OBDII splitter might be the answer to that (if there is such a thing?), so I can keep both devices going at once.
But the bigger question is...what exactly can I do if I found my pack appeared to be badly out of balance? Would any charging event attempt to re-balance it, assuming the BMS sees the imbalance (and hopefully it would!)? Would it need to be a charging event from a relatively low SOC? Would I have to just tough it out until the next time the BMS decides a rebalance is needed or could I force the BMS to rebalance?
Edit: Oh, one nugget I can give you is that my pack "seems" to be more out of balance on Mondays, especially after it's sat at a relatively low SOC all weekend because I haven't needed to use it.
2011 Blue Ocean SL with 84,000 miles
2015 pack on 12/30/15
Bosch AGM 12v
Ecopia 422+ tires
L1 EVSE upgrade
Superbright LED lighting
2013 sun visors
GT-R map lamp lenses
Altima illuminated door switches