Advance on Charge controller

[Andy79]

Hi Guys, New to solar and looking to setup a 400w panel 47v 10A to charge 2 x 12v 44ah lithium batteries. I was thinking about using a 20a PWM charger and connect the batteries in series to charge @ 24v. I know MPPT chargers are recommended but im on a budget.

Is there any difference in the charge time if batteries are in series charging at v24 10A vs parallel charging @ 12v 10A?

What charger would be recommended and battery connection series or parallel?

Just needed to charge a few Laptops and mobiles during the day.

 

[rmaddy]

If your two 12V 44Ah batteries are in series then you have a 24V 44Ah battery bank. Charging a 44Ah battery bank at 10A will take up to 4.4 hours to recharge (from 0% to 100%).

If your two 12V 44Ah batteries are in parallel then you have a 12V 88Ah battery bank. Charging an 88Ah battery bank at 10A will take up to 8.8 hours to recharge (from 0% to 100%).

I don't think the 400W panel is a good choice with a PWM SCC. The voltage difference means there will be a lot of lost potential. If you put your batteries in parallel for a 12V setup then you should buy so called "12V panels". If you put your batteries in series for a 24V setup then you should buy so called "24V" panels. Such panels will be lower wattage but they will have a voltage better suited to using a PWM controller. The 400W panel will work but you won't get anywhere near 400W out of it with a PWM controller.

If you want to keep things simple and cheaper, go with a 12V setup by putting your batteries in parallel. Then you can charge your laptop and mobile directly from 12V.