Charge battery with just BMS

[Jordi]

Greeting everyone,

Having a basic question.

Can I charge a 12V 18650 battery pack with a solar panel directly connected to a 12V BMS?

I would like to save the solar charger PWM because I am not expecting to give intensive use to the 20W solar setup.

My main concern is what happens when the batery is full and the sun still there. Any overheating expected?

The solar panel I expect will easily deliver enough voltage over the 14,8V full-charge voltage.

Other suggestions accepted.

Thanks for your input.

 

[time2roll]

The battery will probably have a shorter life. I don't recommend having the BMS to be the primary limit on voltage.

Amazon $12

 

[Ampster]

Can I charge a 12V 18650 battery pack with a solar panel

If the 18650 is NMC chemistry that could be a fiery experiment, like in serious overheating. As mentioned above, with any chemistry it would not be optimal. A charge controller is needed to convert the higher solar panel voltage to a safe voltage for the specific battery.

 

[Jordi]

If the 18650 is NMC chemistry that could be a fiery experiment, like in serious overheating. As mentioned above, with any chemistry it would not be optimal. A charge controller is needed to convert the higher solar panel voltage to a safe voltage for the specific battery.

Thanks for your input. Could I maybe use a DC-DC step-down buck instead? Just to protect the BMS and supply the required 14,8V.

 

[Supervstech]

Thanks for your input. Could I maybe use a DC-DC step-down buck instead? Just to protect the BMS and supply the required 14,8V.

“Could” you? Sure... it would work...
It will not be best... and as said likely will shorten the life of the battery.

 

[Just John]

Thanks for your input. Could I maybe use a DC-DC step-down buck instead? Just to protect the BMS and supply the required 14,8V.

A step down buck converter used to charge a battery from a solar panel is normally called a solar charge controller.

 

[Jordi]

A step down buck converter used to charge a battery from a solar panel is normally called a solar charge controller.

Isn't there any difference? I thought the controller can stop charging and the Step-down buck not. But maybe this has to do with voltages so in reality the working principle is the same.

Thanks all for your replies.

 

[Supervstech]

Isn't there any difference? I thought the controller can stop charging and the Step-down buck not. But maybe this has to do with voltages so in reality the working principle is the same.

Thanks all for your replies.

Correct. The step down will output constant voltage as long as solar is up to the set point voltage.
A charge controller will use profiles and charge the battery properly to a point, then stop, or switch to a lower setting when battery levels peak.

 

[Thorsonic]

I guess the next question is, is there such a thing as a solar charge controller for charging 18650 cells 4P...?

 

[mikefitz]

solar panel I expect will easily deliver enough voltage over the 14,8V full-charge voltage.

Any solar controller that allows user set up of charge voltages or is designed for lithium ion, should be suitable. Since its a low power panel, 20 watts, there are low cost modules available,

Amazon.com : Solar charge module 12v lithium ion

 

[Thorsonic]

Just ordered:

https://www.amazon.com/Lithium-Battery-Charging-Controller-Protection/dp/B082939ZXX?ref_=ast_sto_dp

This with the BMS board & solar panel my 1S4P 18650 pack will be ready!

 

[Thorsonic]

Just ordered: View attachment 175208

https://www.amazon.com/Lithium-Battery-Charging-Controller-Protection/dp/B082939ZXX?ref_=ast_sto_dp

This with the BMS board & solar panel my 1S4P 18650 pack will be ready!

OMG, nobody should buy this item it's main design is to separate you from your money and give you nothing of value in return...

 

[Supervstech]

OMG, nobody should buy this item it's main design is to separate you from your money and give you nothing of value in return...

What does it do/not do?
Total garbage?