Lithium batteries and new solar charger
I am replacing my 4 6V batteries I think 2 lithium, have never been impressed by the 30A PWM charger for my 600W solar, probably my fault for using 8 avg wire on a 9m run. Thinking if I get a Victron ...
Forum Discussion
BFL13 wrote:
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Voltage drop matters greatly with MPPT though. You benefit from the 24v needing thinner wire than 12v, but adding panels will increase the amps and it could be a wash so you could need fatter wire anyway.
Two LFPs will have fewer usable AH than four 6s, but with the solar you will only notice when there is an overcast for a couple of days so you need your battery bank as a "reserve" until the sun comes back out. It "depends" whether your two LFPs will be enough reserve, but it also "depends" whether the four 6s would be enough, so there is no way to be sure. You have to figure the odds on that. Obviously the odds are better in CA than in WA, eg.
1. With MPPT, you manage losses due to Voltage drop by increasing the solar output voltage by wiring panels in series. This is no 'big deal'. Even if you keep all the panels in parallel, the MPPT can outproduce PWM. In contrast, PWM cannot outproduce MPPT.
2. I have purchased 4 x 280Ah, 3.2V LiFePo cells to create a nominal 12.8V battery. If I were to use 8 cells I could have 2 12V batteries equaling 580Ahs. Wouldn't that be more Ahs that 4 x GC2's at 440Ahs?
HTH;
John
