# question

## Using 150/35 solar controllers in 3.6kw installation

I am working out my first pv installation. I have purchased two smartsolar 150/35 controllers. I have also purchased eight 450W panels that have an Imp of just under 11 amps each. I am planning on connecting both controllers and all the panels to a large 12v 700ah lead acid battery.

Question:

- the four panels will have a combined max power of 44amps. will this cause a problem for the charge controller?

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I suggest you use the MPPT calculator and study the spec sheets.

1800W theoretical at 12V is way beyond 35A.

Panels can only be connected to one mppt, not shared, in case you were thinking of that.

I would toss the 12V battery and rather aim for 48V, at least then you could get 1680W off an MPPT.

Save your cash and rethink your idea, it isn’t a good plan right now.

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So if i configure the set up with four x 12v batteries = 48v, can i connect both charge controllers to the same battery bank?

if thats okay, then can i link 4 panels in parallel to each controller to provide 40 volts max @ 1800w. is that too much for the controller?

1 comment

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Correct. You’d use either smart networking or a Cerbo, to coordinate charging between both.

48V would work much better.

Remember, each mppt needs battery voltage +6V to start producing power.

So putting them in parallel is an issue. You’d want to at least do 2s2p. You wouldn’t be able to do 4s unless you used a 250V charger.

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@nickdb i have also been thinking about an other type of configuration. There are very few articles online but i think it is called 'direct solar' - no batteries, no inverter.... and only works when the sun shines!

The aim of this installation is to provide a 12v dc power supply using dc-dc converters like this one - https://www.meanwell-web.com/en-gb/dc-dc-enclosed-converter-input-19-72vdc-output-sd--1000l--12

The panels would be connected in parallel to give 3600w at 40v input and 12v output.

Do you have any experience of configuring like this?

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