Re: US L16HCXC 420amp batteries in 24V bank
TexSun, heat kills! You got 8 years from your first bank.... I think that's very good considering the heat down there.
Both your first bank (5 strings) and your second bank (4 strings) are what I call 'Massively Parallel'. When you changed from 5 strings to 4 strings you obviously changed your wiring, but you indicate (in your 2nd post) that you don't understand the wiring diagrams at smartguage.com. Getting the wiring right is critical in any parallel system. Can you submit a schematic or a photo of your wiring to this forum for us to evaluate? Read (or reread): http://www.wind-sun.com/ForumVB/showthread.php?14674
You did not answer BB.'s question about whether you have a battery temperature sensor. At high temperatures the charging voltages must be reduced or you will 'cook' your batteries. That is true even with one string of batteries. And even if you do have temperature compensation it is difficult to get all parallel strings charged properly because if one string is just a bit warmer than the others (inevitable) it will draw more current than the other strings which will make it warmer which will make it draw more current which will make it warmer which will make it draw more current, etc.
The current clamp meter will help you figure out whether you have equal current flowing in each string, whether because of wiring problems, different string temperatures, or battery failure. It is best to take the measurements while bulk charging.
Assuming you get the wiring and temp compensation under control, you might want to think of ways to keep the batteries cooler. I'm in Vermont and don't have to deal with that issue, but there have been several discussions on this forum... I recall reading about swamp coolers, battery sheds in earthen berms, a water cooling system (circulate water underground to cool it and then into the battery box, and then back underground).
Hope this helps, and let us know what you find diagnostically with your clamp ammeter.
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