Yes, it is possible to add two 12V chargers to your 24V battery system by wiring them in series. Since your battery bank operates at 24V, two 12V chargers can work together to charge the system. Here’s how you can integrate them:
Understanding Series Charging for a 24V System:
Your battery bank is a 24V system (likely two 12V batteries in series or equivalent series combinations). To add two 12V chargers, you will need to connect them in series so that each charger charges one-half of the battery bank.
Wiring the 12V Chargers in Series:
First Charger:
Connect the negative terminal of the first 12V charger to the main negative point of your battery bank on the charge side of the shunt or battery negative bus).
Connect the positive terminal of the first 12V charger to the midpoint of your 24V battery bank (this is where the two 12V batteries are connected in series).
Second Charger:
Connect the negative terminal of the second 12V charger to the same midpoint (where the first charger’s positive is connected).
Connect the positive terminal of the second 12V charger to the main positive terminal of the battery bank.
This setup ensures that each charger is responsible for charging one 12V half of the system, and together, they function as a 24V charging system.
Fuse the Connections: Ensure that you fuse both chargers appropriately on the positive side for safety. The fuse rating should match the charger’s maximum current rating (e.g., for a 25A charger, use a fuse rated slightly higher than 25A).
Charge Profile Configuration:
Ensure that both 12V chargers are set to the same charge profile, especially if you are using lithium batteries. They need to be synchronized in terms of voltage cut-offs and charge parameters to avoid imbalances between the two halves of the battery bank.
Monitoring: You may want to monitor the system’s midpoint voltage to ensure that both halves of the battery bank are being charged evenly. If your system uses Victron monitoring (like a BMV or Color Control GX), you can set up midpoint monitoring to detect any imbalance between the two 12V chargers.
Power Source: Your 27 kVA Cummins Onan genset will provide more than enough power to handle the additional load from these two 12V chargers, along with your existing MultiPlus units.
It may also be feasible to install another Multiplus. Also you will only get 25A of charge at 24V, not 50 amps and the shunt will measure 25A going into the battery.
Hi Andrew. I’d probably just add in another Multiplus, even standalone.
But you need to take a closer look at the model numbers you’ve quoted. A real 24/5000 should do 120A each (and maybe they’re set up wrong}. A 24/3000 is usually rated 70A.
You did not confuse me the only 24V 25A charger is the Victron Phoenix Smart Charger and 2 of those cost more than another multi I assumed you would be buying 12V chargers. If you have 2x 25A chargers then you can add them if you have a shunt just put the negative on the charge side.