JR wrote: ↑November 27, 2017, 1:01 pm
I have Kolsat AGM 200ah and they seem much more stable than the flooded Volta 160 I had before. Kolsat were 11.300B.
I could not find the spec on these Kolsat so I used a Victron spec for AGM
https://www.victronenergy.com/upload/do ... ies-EN.pdf
Kolsat AGM 200ah vs Volta 150ah
-------------------------------------------------
THB/Ah ---------------------------> 56.5 vs 40 +40%
Cycle lifetime at 50% DOD--> 600? vs 2000 -70%
Expected Lifetime THB/KWh-> 3.9 vs 9.7 +248%
If Kolsat and the Victron have similar specs than the Kolsat would cost
248% over the expected lifetime of the battery.
Of course AGM has other advantages, mostly applicable to marine usage,
not residential solar homes.
If you are going to consume power at a fast rate (versus the 20hr rate typically
given) then AGM will perform better due to lower internal resistance. This also
reduces the power lost to keep the batteries at float charge. Really should
put those factors into the calculation above.
Also at 80% DOD the difference goes down to +225% but it could be more
as you might be able to reduce the total number of batteries required since
you can actually use more of the batteries you have. Still I think we are
talking at least a 100% higher lifetime cost.
Perhaps the expected cycles are a lot more on these Kolsat batts?
Do you have the spec?
A good write-up on battery types...
http://www.vonwentzel.net/Battery/01.Type/index.html
Another thing is that AGM can get fried pretty easily if your charger has some fault... whereas flooded would be less susceptible.