Quote:
Originally Posted by IamIan
That would not be easy.
The second pack could end up being asked for ~1/2 the assist or regen during IMA usage.
A cable for ~50 Amps for each of the 20 subpacks... would have significant design issues.
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The end cables would of course have to be capable of dealing with at least 50A, but I was figuring the balancing cables would see current only from voltage differences from differing responses between the two paired cells to charging and discharging, allowing much thinner gauge cable. 5A capability in theory, 15A in practice to give a good safety margin is what I was thinking.
Quote:
Originally Posted by IamIan
Voltage alone is the most basic / least accurate option when it comes to NiMH SoC determination... it increases the risk of over charging and over discharging.
Remember there is an artificial voltage elevation that happens during charging and a artificial voltage depression that happens during discharging. ...
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The graph you provids showed very clearly that voltage has squat to do with SOC (plus a bunch of zener diodes wouldn't provide temperature/pressure/this/that compensation). Perhaps it's in the overcharge region that internal resistance (or impedance... not sure how that applies to DC other than generator-sourced peaks and valleys not fully smoothened out) starts to climb per some other graphs I've seen.
So timer control with ramped-down current (pref. with battery pack temperature feedback) would be the best mimimum for home charging, with megabuck$ EV chargers perhaps being far better. I was really hoping to find a way to avoid the latter's cost.
Thanks,
Roger
