Need Advice: Charging 12V Batteries with 24V Solar Panels

[lyrawinslow]

Hey everyone, I need some advice. I recently set up a small solar system at home. My panels are 24V, but my battery bank is 12V. At first, I thought I could just connect them directly, but I realized that might damage my batteries or waste a lot of energy.

So I bought a DC-to-DC MPPT charge controller from ( https://offgridstores.com/) to handle the voltage difference and make sure my batteries charge efficiently. I’m new to this, though, and I want to make sure I’m using it the right way.

Has anyone dealt with a setup like this? Any tips or things I should watch out for to keep the batteries safe and get the most out of my panels?

 

[cavemanrich]

I have solutions on using 24 volt power to charge 2,,, 12 volt batteries in series connection. But I'm not familiar with solar, and Solar controls.
Let me tag @jthornton . Lets see what his view/ideas may be.


WISHING YOU BEST,,,,,,,,,,,,,,,,,,and

 

[jthornton]

I have solutions on using 24 volt power to charge 2,,, 12 volt batteries in series connection. But I'm not familiar with solar, and Solar controls.
Let me tag @jthornton . Lets see what his view/ideas may be.


WISHING YOU BEST,,,,,,,,,,,,,,,,,,and

I live deep in the woods we have to pipe in sunlight so solar is no go for me.

I agree with @cavemanrich to use a 24v charger on 12v batteries you need to connect the charger in series to the two batteries. For example + from the charger to + on battery 1, - on battery 1 to + on battery 2 and - on battery 2 to charger -.

When I charge my generator I disconnect one 12v battery while charging each one with 12 maintainer.

JT

 

[Smokerbill]

The charge controller you bought converts solar panel outputs of the solar panels to voltage ranges that are designed to charge 12 volt batteries of various types. The manual for your controller tells you all you need to know.

https://cdn.shopify.com/s/files/1/0058/2769/0553/files/RS-MPPT50DC_Manual_250218.pdf?v=1743565936

 

[lyrawinslow]

I live deep in the woods we have to pipe in sunlight so solar is no go for me.

I agree with @cavemanrich to use a 24v charger on 12v batteries you need to connect the charger in series to the two batteries. For example + from the charger to + on battery 1, - on battery 1 to + on battery 2 and - on battery 2 to charger -.

When I charge my generator I disconnect one 12v battery while charging each one with 12 maintainer.

JT

Really thank you for explaining this so clearly. I really appreciate it because your words are exactly right.

 

[Theurbanhomestead]

I have built a bunch of small scale solar systems for around my house so if you have questions I can try and help but here are some basic things about solar.

Most solar cells are actually a higher voltage than what the batteries are. This is why you need a solar controller to charge the batteries. You can also use a voltage regulator to control voltage but that will not keep your battery from draining or overcharging so a controller is usually the better choice.

Keep in mind you will need to set the controller to the battery type you have. Usually there are presets for that in the manual. Otherwise you need to manually set the charge/discharge voltage which varies depending on your battery type (LiFePO4, lead acid, Li-ion, ect).

Also keep in mind that temperature matters. Most batteries should not be charged under 0C (32F) unless you have a BMS on the battery that says you can do that.

 

[jthornton]

Also keep in mind that temperature matters. Most batteries should not be charged under 0C (32F) unless you have a BMS on the battery that says you can do that.

For those that don't know what a BMS is it's a Battery Management System.

JT

 

[Taranakian]

Half of my solar panels are 30V, and they're connected to my 12V batteries.

Not only is it ideal to have a voltage difference, it's necessary, else there's no way for the energy to flow. Also, generally the higher the voltage rating the earlier in the day/the less direct sunlight is required to reach enough of a voltage difference to start charging your batteries.