Solar array with two different batteries

DIY
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Hi Everyone, apologies if this exact scenario has been covered on this forum before. I have an old wooden sailboat that I am converting to use solar/electric for propulsion (a Torqeedo Cruise 6 pod drive with a 48V battery). I also have a Renogy system with a LiFePo4 battery for house loads and two portable 100W panels. Detailed specs below.

I’m trying to figure out the best way to wire up the panels and charge controllers. In a perfect world, I could leave the system untouched and have necessary solar energy go to the battery that needs it most, keeping everything topped off. Obviously the Torqeedo battery is more important.

I’d also like the ability to manually override and force the panels to charge one battery over another if necessary, using a simple switch. Wiring the two solar panels in parallel might slightly exceed the maximum 9A short circuit current for the Torqeedo solar charger. I’m checking with Torqeedo on whether that would be a problem, and if so, I’d probably have to wire in series.

I’m also considering having two completely separate systems, each with their own panel, but of course they would charge much more slowly. Perhaps Victron makes some sort of BMS that can detect charge information for each battery and direct the solar panel output appropriately.

Any advice/insight would be much appreciated!

Solar Panel Output (each)

Max Power at STC: 100W

Short Circuit Current: 5.26A

Optimum Operating Current: 4.96A

Open Circuit Voltage: 23.40V

Optimum Operating Voltage: 20.16V

Efficiency: >23.5%

In parallel: 12v, 10.52A, 200W

In series: 24v, 5.26A, 200W

House Battery

Voltage 12V

Capacity 100Ah

Max charge current 100A

Voltage 12V (Range 10V-14.8V)

5000 cycles 80%DOD, 80%EOL

House Solar Charger

12V/24V/36V/48V auto recognition

Charge current 60A

Load current 20A

Max PV Input voltage 140VDC

Self Consumption .7W-1.2W

Torqeedo Solar Charger

Max module rate current (Imp): 8A

Max module short circuit current (Isc): 9A

Minimum voltage: 12V

Max nominal voltage @ STC (Vmp): 40.8V

Max module open-circuit voltage (Voc): 48V

Max power: 325 Wp

Torqeedo Battery

Capacity 5275 Wh
Nominal voltage 44.4 V
Final discharging voltage 36.0 V
Maximum discharge rate 200 A
Maximum discharge rate at nominal voltage 8,800 W
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Hello Jamie,

Im am the electrician for the boat Auguste 1927.
The Torqeedo Motor Cruise 6.0 FP TorqLink is installed, and we have 2 Torqeedo 48-5000 Batteries on Board.
And a second system, to be defined with 24? 48V?, but not from Torqueedo..

All the gear is going to be Vectron.

We just have to do the last little steps before going back in the water:
(… The complete electricity- wiring … :wink:

In the moment I am really concerned about the possibilities to connect the solarpanels in a useful way to the 48-5000 Batteries.

It seems, that the original torqeedo solar charger is not compatible with Augustes panels..

Maybe you might work with the information,
that the torqueedo 48-5000 seems to be the

SAMSUNG SDI 120AH 12S, used in the BMWi3.

I think it is No way to connect the Torqlink BMS in a usefull way to a Victron BMS system.
(Blue and orange are different colors ;-))

So U are not alone,
I am also searchig for the easy “perfect world, to have necessary solar energy go to the battery that needs it most”

I am going to post more about the topic in the next weeks…

Good luck
& at least a hand’s breath of water under the keel…

Arno

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Unless I’m missing something here, your options are pretty limited

With the 2 solar panel array you have, it cannot produce the voltage required to directly charge the 48v propulsion battery. You are limited to having the solar charging the 12v house batteries, and using a dc-dc charger to charge the propulsion battery. This doesn’t leave a lot of options as far as flexibility but you will still be able to choose whether or not to send power to the propulsion and also be able to “steal” that power from the house batteries for the propulsion if desired

Adding another panel, or new panels of higher voltage of course would open up more options and allow direct charging of the propulsion batteries. This would be the ideal scenario in my mind, solar charges the propulsion and a dc-dc charger to charge house batteries

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