Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.
Do you have a temp sensor on the batteries? If so does it get submerged?
I am available for custom hardware/firmware development
IMO, the optimal design is a large chiller and a large water tank such that all the water cooling can be done when you have excess power and there is no charge effect on the batteries. Waterwheel's numbers indicate that there would be some benefit to more water.
Dave Angelini said:
Too bad you can't cool the electronics also with some evap cooling. Too humid for that....Still a good project!
The engineering formula is 2x increase in life for every 10C/18F reduction in temperature (or 1/2 the life for every 10C increase).Note that if your batteries are only "hot" for 12 hours per day for 3 months of summer--That means instead of aging at a rate of 1.5 months during elevated temperature, they are aging 3 months (or 3 months of summer is 1.5 normal + 3 elevated temp aging = 4.5 months of "aging" at 10C increase in temperature for 1/2 day) over those 3 months of summer or ~13.5 months aging in 12 months of year.If I got the math right (no guarantees).-Bill
IMO, for LA batteries, the battery manufacturer chooses the Reference Temperature -- often it is 77F, sometimes 80F.
It is the Reference Temperature that is used for Capacity data, etc.
Many battery manufacturers do seem to use the "for every 10 degree C increase in battery temperature, above reference temperature, battery life halved", and the converse.
Had not seen the Sandia 8 C increase, battery life is halved.
It has seemed that the 10C number was based on chemical activity, in general.
FWIW, IMO, Vic
Might be something to consider though probably not. Costco sells 20 pounds of ice for $2 - in Colorado.
$2 for 20 lbs is (as far as I know) for "water ice".... Not "dry ice". -Bill