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diy solar

2x 410W Panels and existing 8x 12V Bosch Batteries

solarRH_Duis

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Sep 8, 2022
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Hi, I have a quick question about converting from trickle mains charging to solar.
I have two 410W, 24V Monocrystalline panels that I bought cheap. Existing setup is 8x 12V Bosch car batteries (about 4kWh) that charge with a hidden fast charge trickle charger. Please can you tell me what the cheapest suitable inverter is to do the job.
Thanks :)
 
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Pretty sure that you’re gonna need to provide a bit more info. Is this a 12 or 24 volt system? By “inverter” do you mean charge controller or a legitimate inverter? Btw, what’s a “hidden fast trickle charger”?
 
Hi, I have a quick question about converting from trickle mains charging to solar.
I have two 410W, 24V Monocrystalline panels that I bought cheap. Existing setup is 8x 12V Bosch car batteries (about 4kWh) that charge with a hidden fast charge trickle charger. Please can you tell me what the cheapest suitable inverter is to do the job.
Thanks :)
You don't wnat an inverter for that (inverters take DC and produce AC). What you want is an MPPT that is sized appropriately for you rpanels. given 820w at 24v, something like the SmartSolar MPPT 150/45 would be a good fit.
 
False economy with the cheap mindset and car batteries. I'm assuming used / trashed too yes?

The only way for this to be minimally practical, even with brand new car batteries, is to pull no more than 10% capacity per charge cycle since vehicular starting batteries are purposely designed to draw no more than about 10%C worst case each start. And that's assuming you reach a full charge each and every time. You might be able to nurse 3-4 years with only a 10% C discharge.

That's a heck of a lot of "dead lead" to be piling up - and if replaced, typically ends up costing more than twice than doing it right the first time.

Before going any further, have you charged each on up *individually* with an ac-powered charger to attempt to bring them into the same state of charge?

Just trying to save you money.
 
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