R31 - length of solar wire run?

[Gin]

Hi All. I’m hoping to upgrade the solar on my 2019 R31 soon. I know I need to make sure that the amperage does not exceed the rating for the 10 gauge factory wire that is already in place (since I do not want to try to run a new wire). To calculate that requires knowing how long the run is from the controller to the panel. The wiring is mostly in the innards of the hull walls and behind the cockpit ceiling panels.

Does anyone know the approximate length of that wire run? If the factory ran the wire as part of a wiring harness, it might be something other than a reasonably direct route and significantly longer than might meet the eye’s guesstimate.

Gini

 

[Submariner]

Upgrade the panel to a 24 volt panel and upgrade to an MPPT solar controller (charge controller).
The higher voltage will reduce the amps.

I have 400 watts of solar (2x 200 watt panels, hooked up in series). This is basically a 400 watt panel at 48 volts.

At peak wattage (400 watts), I'll see 63 volts at 6.5amps from the solar panel to the controller.
From the controller to the house bank I'll see 13.4 volts at 29.4 amps.

I have 10awg wire from the solar panel to the solar controller (factory installed). 7 amps is well within the limits of 10awg.

I did upgrade the wire from the MPPT solar controller to the house battery from 10awg to 6awg and upgraded the fuse to 40 amp.

Victron MPPT Solar Controller at 400 watts (max/peak)
https://www.letsgochannelsurfing.com/solar-power?pgid=kxcvhybj-c81c6041-518b-4612-89ff-45e95f26efc5

 

[Gin]

Good advice, Martin, and basically the direction I’m headed. I watched your solar video some time back. (Thanks for all the highly educational videos you post!). I already have the Victron 100/30 to install, and now am working through panel options, which include a couple that would be higher voltage/lower amps. I realize that approach permits going with what might otherwise be undersized wiring, and with that approach I should be more than safe with the current wiring. It bugs me, though, not to have a better idea about how long the run is — 10 ft? 20ft? More? It makes such a difference. On the chance that someone on the forum or from the factory has that info, I thought it was worth asking.

Oh, and thanks for the reminder about how you upsized the wiring from the controller to the house battery. I had forgotten about that and it’s worth doing!

Gini

 

[Submariner]

Good advice, Martin, and basically the direction I’m headed. I watched your solar video some time back. (Thanks for all the highly educational videos you post!). I already have the Victron 100/30 to install, and now am working through panel options, which include a couple that would be higher voltage/lower amps. I realize that approach permits going with what might otherwise be undersized wiring, and with that approach I should be more than safe with the current wiring. It bugs me, though, not to have a better idea about how long the run is — 10 ft? 20ft? More? It makes such a difference. On the chance that someone on the forum or from the factory has that info, I thought it was worth asking.

Oh, and thanks for the reminder about how you upsized the wiring from the controller to the house battery. I had forgotten about that and it’s worth doing!

Gini

Thanks!! I'm glad you found our videos useful. I know how the cable for the solar is ran on an RT27-OB. I'd guess it to be about 25 ft round trip. I use the 3% voltage drop in my calculations since it's battery charging.

Another good tip... and this is specific to Victron... If you're running a Victron BMV712 Battery monitor, you can pair it wirelessly with the MPPT 100/30 so the two units can talk to each other. That'll give you voltage compensation from solar to your house battery.

As an alternative, you could install a Victron Battery Sense (about $30) on your house bank. It'll then pair with the MPPT controller and provide voltage and temp compensation for solar battery charging.

 

[Gin]

I added the Balmar SG200 a few years ago. I really like the unit, and the one thing it has that the Victron doesn’t is the ability to monitor voltage on 2 auxiliary banks (I.e., both engine and thruster banks) in addition to provide all the detailed data on the house bank. The Victron would let me monitor only one auxiliary bank, and requires a second monitor to add more banks. Still, it might be tempting to swap the Balmar out for the Victron at some point because of how well all the Victron components talk to each other and the app. I am adding the battery sense for now.

Gini