DC DC charger with solar input. Victron

**Gengis** · 2021/01/21, 11:51 AM

Hi All

I want to go Lithium on my second battery and hence the need for a DC DC charger. I was thinking of the Victron 12-30 and I already have a Victron 75-15 solar regulator. Could I use these two in combination without stuffing it up or having the one fool the other with respect to reference voltages for float/absorbtion ext.

Happy to discuss this one openly, please advise.

G

**the_terrible_triplett** · 2021/01/21, 12:10 PM

Originally Posted by Gengis

Hi All

I want to go Lithium on my second battery and hence the need for a DC DC charger. I was thinking of the Victron 12-30 and I already have a Victron 75-15 solar regulator. Could I use these two in combination without stuffing it up or having the one fool the other with respect to reference voltages for float/absorbtion ext.

Happy to discuss this one openly, please advise.

G

I presume if both are connected to the same battery bank, that both will have identical settings ito Bulk/Absorb and Float?
If so, then there will be no "argument". :-)

The MPPT only works when there are panels connected, right?
The Victron 12-30 I presume only works when the vehicle is running?

**DCTheron** · 2021/01/21, 12:11 PM

My below discussion wrt Victron may be of value to you. I now run a 200AH LiFePo4 battery, the 30A Orion-Tr Smart and 75/15 MPPT same time, no issues so far. I do run the BMV-712 as well to have real-time status of what's happening. This was money very well spent.

https://www.4x4community.co.za/forum...t-setup-change

**Gengis** · 2021/01/21, 12:42 PM

Originally Posted by the_terrible_triplett

I presume if both are connected to the same battery bank, that both will have identical settings ito Bulk/Absorb and Float?
If so, then there will be no "argument". :-)

The MPPT only works when there are panels connected, right?
The Victron 12-30 I presume only works when the vehicle is running?

Yes, but this happens at the same time quite often. Still, as you, and the next post mentioned, should not be a problem.

G

**bigboy529** · 2021/01/22, 09:08 AM

This won't be a problem, just be sure to set both the Orion smart and MPPT to lithium mode and also the correct bulk and float voltages for your specific battery.

**ekkekan** · 2021/01/22, 10:34 AM

Just a stupid question. Is there a need to charge say 30A from a DC-DC charger to still add the 75/15 from PV as well? I would have thought 30A is enough to replace the power used during the night from the batteries.

**cainslie** · 2021/01/22, 11:12 AM

Originally Posted by ekkekan

Just a stupid question. Is there a need to charge say 30A from a DC-DC charger to still add the 75/15 from PV as well? I would have thought 30A is enough to replace the power used during the night from the batteries.

Yeah, no need for the PV at all, except when you don't start your car for 3 days.

**ekkekan** · 2021/01/22, 11:11 PM

Originally Posted by cainslie

Yeah, no need for the PV at all, except when you don't start your car for 3 days.

OK. I thought in that case the 75/15 should charge enough. Not driving for 3 days I take it the 2 chargers will still not be used at the same time.

**Gengis** · 2021/01/23, 07:35 PM

Oh, they will work together on occasion, my panels are permanently on the roof when traveling off road, but thats also why the 75 15 is more than enough.
The 75 15 keeps my whole show on the road while camping ( 110ah system with 50l fridge, night lights and lots of camera battery charging via an inverter. 2 x 120 panels in series. ) It's just 2 of us and luckily i don't need to drip feed on beer. i figure a 80 or 100 ah Lithium would be the dogs bollocks.
And then I went and read a thread about building your own battery. HOO boy why do they do this to us.
G

G