You are welcome Jim.
There is a lot of good information about batteries on this website, from basic to advanced.
Since batteries are among the most expensive and most delicate components in an off-grid system, it is worth studying them a little bit - especially if you are going to be using expensive batteries and you want them to last a long time.
Thanks for another great link Kyle. It looks like I’ll be able to read about batteries till my batteries are dead.
I worked on some large exide chargers and batteries for electric trolleys.
These were just flooded cell BTW.
The chargers were three stage and could pump out 300 amps in stage one.
All of it was automatic ( in that it had a 3 stage regulator ) and it would float the batteries between shifts or swap out.
Each trolley had a removable pack of cells that weighed about 4 ton ( maybe it was two for the smaller units ).
This was all stuff from the 60s and 70s. and the Nicads from the 90s
Worked perfectly fine as long as the charge rates were set and the chargers adjusted for the battery packs.
Where things went wrong it was because the motor crews would not charge correctly, batteries were not watered and in the case of the nicad pack they did not get the equalization charge ( and would catch fire ).
How to care for batteries has been known for a long time.
Nice video.
This truck had two stacks of SAFT NiCad batteries ( wet cells that had to be watered, and 1.2 volt per cell )
Replacement value at the time of this video was about $100,000 per truck so we instructed to care for them like our lives depended on it.
Some background:
It used a ABB DC motor drive to supply I think 250DC to the bank.
The on board computer would monitor how many amps were going out and base the charge rate on that kwh value and the voltage.
Once connected to the overhead line the main power would come on charge the batteries, but the batteries were always being taxed and charged at the same time.
You can hear the hydraulic pump cycle on and off drawing mower power than the charger could supply.
You can also hear the sounds of the blowers on a second truck no in the video ( also the whine of the main DC drive as the second unit is doing a brake test.
Heat is a real killer of batteries.
Self heating under high load and high charge rates is often over looked until bad things happen.
Those batteries are under the cab of that truck with a greasy oily piece of plywood on top ( the wood was a dumb idea later replaced wit fiberglass one too many fires later ).
A battery fire is like being is a phone booth with a road flare burning.
Oh Ya…
At lunch time the truck drivers would park the trucks and let them “idle” on the ramps to cool and charge.
Alternatively they could be charged by a cable from a 600 volt source and cool.
if you did not let them cool they would overheat and force a shut down of the truck.
Without forced air cooling you could wait a very long time for convection to cool them off.