What to do with Sunsaver Duo PWM Controller?

[RWHenhouse]

I recently installed a Victron 150/45 SmartSolar and BMV-712 on our 2022 RT31CB. Also upgraded the wiring from controller to the house batteries to 6 gauge, in preparation for a 410 watt solar panel which has not yet been picked up or installed.

I'm not sure what to do with the factory Sunsaver Duo PWM controller. I've left it as is for now minus the the solar panel input, which is now hooked up to the new Victron controller. I'm wondering:

1. Will the existing PWM controller serve to charge the house bank from the engine while under way?
2. If not, do I need to do something so that the alternator charges the house bank or will the ACR handle that?
3. What does it hurt just to leave it as is, without the solar input? The remote monitor is still functional, no use removing it and leaving a hole.

I recall Martin (Channel Surfing) mentioning in one of his videos that it would act as a DC-DC charger but I am unable to find it.

Thanks for any wisdom!

Rory

 

[watson1987]

The Victron output could be up to 45amps - although highly unlikely with a 410W panel. However, the input on the Sunsaver Duo is only rated for 25amps

I would remove it, it provides no purpose, and the Victron won't work properly because it won't be able to detect the voltage of the bank in order to provide the correct charge profile (bulk/absorption/float)

The ACRs will handle sharing the charge with either solar or alternator input with the standard configuration. The two battery output of the Sunsaver doesn't really make sense, because once charging voltage is supplied, the ACRs will open up to equalize the house/engine bank anyways. Just connect the Victron to the house bank.

In terms of replacing the remote monitor, I have a post here about what I did

https://www.tugnuts.com/threads/bezel-for-victron-mppt-control-display-replacing-rm-1.23196/#post-148717

 

[RWHenhouse]

The Victron output could be up to 45amps - although highly unlikely with a 410W panel. However, the input on the Sunsaver Duo is only rated for 25amps

I would remove it, it provides no purpose, and the Victron won't work properly because it won't be able to detect the voltage of the bank in order to provide the correct charge profile (bulk/absorption/float)

The ACRs will handle sharing the charge with either solar or alternator input with the standard configuration. The two battery output of the Sunsaver doesn't really make sense, because once charging voltage is supplied, the ACRs will open up to equalize the house/engine bank anyways. Just connect the Victron to the house bank.

In terms of replacing the remote monitor, I have a post here about what I did

https://www.tugnuts.com/threads/bezel-for-victron-mppt-control-display-replacing-rm-1.23196/#post-148717

Yes, I can't imagine the Sunsaver ever seeing 45amps. The output from the Victron goes to the main bank (via new 6 gauge wiring with a 40 amp circuit breaker), so the Victron would have to be cranking out 40 amps and the main bank absorbing none of it for all of the current to be exposed to the Sunsaver via the factory 10 gauge wiring. Plus, there's a fuse that should protect it between the main bank and the Sunsaver. I guess my Q is - does the Sunsaver allow current to flow from one battery bank to the other even when there is no current supplied by the solar panel?

I wish I would have saw your post detailing the cover plate earlier. Sadly, I've already cut a 2 1/8" hole immediately below the Sunsaver remote display and installed the Victron battery monitor remote display...

Thanks,

Rory

 

[watson1987]

Does the Sunsaver allow current to flow from one battery bank to the other even when there is no current supplied by the solar panel?

No, I don't believe it would. That would defeat the purpose of having 2 bank outputs even more than having the 2 banks connected with ACR externally.

 

[RWHenhouse]

Makes sense. So what I've got is a back-up voltage monitor on the house and engine battery. I have attached a Victron SmartSense to the house bank and networked it to the Victron controller so that's where it should be getting it's voltage and temp data from.

 

[Submariner]

I recently installed a Victron 150/45 SmartSolar and BMV-712 on our 2022 RT31CB. Also upgraded the wiring from controller to the house batteries to 6 gauge, in preparation for a 410 watt solar panel which has not yet been picked up or installed.

I'm not sure what to do with the factory Sunsaver Duo PWM controller. I've left it as is for now minus the the solar panel input, which is now hooked up to the new Victron controller. I'm wondering:

1. Will the existing PWM controller serve to charge the house bank from the engine while under way?
2. If not, do I need to do something so that the alternator charges the house bank or will the ACR handle that?
3. What does it hurt just to leave it as is, without the solar input? The remote monitor is still functional, no use removing it and leaving a hole.

I recall Martin (Channel Surfing) mentioning in one of his videos that it would act as a DC-DC charger but I am unable to find it.

Thanks for any wisdom!

Rory

Personally, I'd just toss the PWM Sunsaver Duo controller and would remove the gauge in the cave.
Every solar upgrade I've done (on my own boat, and on other boats), I replace the PWM with a Victron MPPT controller and toss the PWM controller.

On a NW edition boat, when the sun is shining bright and you're at anchor, especially with a 400 watt panel, your ACR's will close allowing solar to charge all 3 battery banks. However, it's not really necessary. On an LE edition with LFP there isn't an ACR. I do not get solar charging of my engine or thruster battery. A factory LE with LFP using a Kisae DMT1250 also does not get solar charging of the engine and thruster batteries. It's a nice to have, but not a requirement in my opinion.

The newer boats which come with a 20 amp MPPT solar charger (Epever) do get some engine and mostly house charging from solar. The Epever MPPT controller has outputs for engine and house battery banks. Very few MPPT controllers that I've seen have more than a single output (to the house battery).

When I redesigned Channel Surfing's electrical and converted to LFP, I was fine with solar not charging engine or house banks.

To leave the PWM controller installed without any solar input is another set of wires that are energized, with inline fuses, that is performing no function on the boat. I'd classify that as a fire-hazard and is why I would remove it from service. It's also a device that would cause confusion to anyone trying to troubleshoot an electrical problem on your boat.

Here's what I do when I do solar upgrades on boats:
I pull the fuse from the PWM solar controller to the engine battery.
I pull the fuse from the PWM solar controller to the house battery.
I label the wires to SOLAR-PANEL, SOLAR-ENGINE and SOLAR-HOUSE. (2 wires each).
I connect the SOLAR-PANEL and SOLAR-HOUSE wires to the Victron MPPT solar controller.
I add a label to the SOLAR-ENGINE wires labeled NIS. I also crimp a 10awg butt connector so as to not have a 'loose wire' floating around.
I install the fuse back into the MPPT to SOLAR-HOUSE cable.
I never install the fuse for the SOLAR-ENGINE inline fuse holder, and add a label to the cable NIS.

NIS = Not In Service.
That'll help the next person out who's troubleshooting and leaves the unused wires not energized.

The PWM Sunsaver Duo is not a DC to DC charger.

 

[RWHenhouse]

Thanks for the insight Martin. I'm gonna need a cover plate!

 

[Submariner]

Makes sense. So what I've got is a back-up voltage monitor on the house and engine battery. I have attached a Victron SmartSense to the house bank and networked it to the Victron controller so that's where it should be getting it's voltage and temp data from.

Just as an FYI... a Victron BMV712 battery monitor (and the smart shunt from Victron) can pair via bluetooth with a Victron MPPT SmartSolar controller to transfer voltage and current and temp.