How to know when parallel batteries are fully charged using Charge Controller

[TheRealRoland]

Hey,

I'm using a Victron 100|50 charge controller to charge my parallel-ed 100Ah batteries.

Reading the manual about to what levels to charge for bulk, absorption and float, would i keep those numbers when charging both batteries in parallel?

Also, if the charge controller doesn't 'reach' those levels, is that because the solar panels i currently use do not put out enough power to get to that voltage?

Thanks,

Roland

[jkwilson]

Voltages are the same as a single battery when charging parallel batteries. It will take more power to reach the voltage levels, so current needed for the same charge rate will double.

One small point that comes into play with simple chargers is determining charge state based on current draw. It’s common to say a battery is charged when draw hits 1A, but with parallel batteries you can end up charging them pretty hard to get there because you are actually charging until each battery hits 0.5A. You can use more water in that case.

[TheRealRoland]

Yeah, in this case the 4x25W panels would generate about 45W at peak; so i'm sure the charging of these batteries will go faster and further/deeper when i install the other panels.

Thanks!

[TheRealRoland]

NICE - installed the 2x100w (in series) and the 4x25w (parallel), then used a combiner cord to connect those to the main wires going to the charge controller. Wow. Finally, even with a weak sun, and some shade here and there, the batteries looked to be charged fully. I have 2 more 100w panels waiting to go up to the trailer, i guess i'm ready to start thinking about installing an inverter to use all that energy :-)

And yes, that was just it- needed wore wattage, so the controller could properly push the batteries beyond just bulk charging.

[Brother_Bluto]

If you don't have a shunt in your system... highly recommend a Victron shunt to monitor your batteries and power draw/charge. I put in the Victron SmartShunt which is strictly bluetooth via the Victron app. The BMV-712 has a readout you can mount as well as bluetooth.