24v/12v charging

DIY
, , ,
1

Hi - I am using a Smartsolar MPPT 100/30 to charge my 24v boat batteries (fed by 2 x 130W panels, soon to be doubled to 4 panels) and was advised by community members to use an Orion 24/12 30 dc-dc charger to charge the boat’s 12v batteries from tge MPPT unit output.

The dc-dc charger puts such a load on the MPPT controller when it switches on (bulk charging) that the input voltage drops significantly resulting in the dc-dc unit shutting down - voltage then recovers and the dc-dc charger cycles on and off ever few seconds, which I assume isn’t ideal for charging.

I have fitted isolator switches between both units and their respective batteries.

All batteries are bog standard lead acid; 3 x 110Ah in oaralkel for the 12V system and 4 x 110Ah in series-parallel for the 24V

Any advice on unit settings or physical configuration would be welcome!

2

The 100/30 MPPT does not have a load output, so i assume you connected the Orion directly to the battery poles of the 24V batteries.

If the voltage drop is too big, then your cable resistance is too big. What cable crosssection did you choose, how long is the input cabling, have you checked for bad connections?

Is it an Orion smart? Can you readout the voltages trough the VictronConnect app? Have you adjusted any settings?