Solar Addition on R23

[Cambarner]

Hi All,

I am about to install a solar array to my 2015 R23 (outboard), which did not come with any solar from the factory. My house batteries were old and struggling to hold a charge when we bought the boat two years ago, so last year I replaced them with x2 155Ah Vmax deep cycle batteries (310Ah total) in preparation for adding solar this year. This was a great addition, but we leave the boat on a mooring all summer and the lack of shore power means that we barely are able to use the electronics without worrying about draining the batteries.

My current plan that I have purchased equipment for is to add x1 200w renogy panel on the roof rack, and combo that with a Victron mppt 100/50 charge controller (slightly oversized to allow for more panels in the future) and a Victron BMV-712 smart battery monitor.

My main goals for the system are to be able to leave the fridge and the anchor light 24/7 through the season, and to heat the hot water tank off the inverter occasionally (beginning of an overnight) while also running the engine (200hp w/ 40A alternator).

So my questions are:

- Does anyone out there have real life data on fridge energy usage and maybe water heater / inverter usage?

- I am expecting to get around 800 to 1000 WHs from my 200w panel per day (in Maine in the summer) do you all think this is realistic?

- And lastly, what is the make/model/capacity of the stock inverter that comes (or came) with the R23, or even just the location on the boat so I can find it?

Any other thoughts on the potential set up are much appreciated! Cheers!

 

[glider4]

I’ll take a stab at one of your questions.
From a 200 watt solar system during the summer you should see on average about 50 AmpHrs or 600 WHrs. I know Renology says more and some days you will see more than 600 WHrs with a 200 watt panel but I wouldn’t count on it on a daily basis.
In the past the stock FM supplied solar systems are not state of the art to put it kindly. I would replace a factory provided solar controller (Morningstar) if you had one. The highly recommended favorite would be a Victron Energy MPPT SmartSolar 100/20 Solar Controller ($90) for panels at/under 250 watts or the VE 100/30 Solar Controller ($125) for a panel up to 400 watts. The VE 100/50 ($185) would be overkill unless you are planning on a 400+ watt solar system in my opinion. I have no idea how you would get a panel delivering over 400 watts on the sports rack of an R-23 given the panel size.
I use the phone app with the VE system components. Install a SmartShunt ($115) and you really don’t need the BMV-712 - it’s redundant to the info you get from the SmartShunt and other components I mention.
Also get at least two VE Smart Battery Sense long range ($35 each) for the house and engine battery banks and you will have a complete understanding of your battery bank health & performance at all times.

PS: At 19.2% efficiency, the Renology 200 watt panel is not one of the more efficient panels out there. Better panels are rated in the 21-23% range. My older 335 watt LG panel is rated at 21.1% efficiency.

 

[Cambarner]

So maybe unfortunately, the panel, controller, and monitor have already been purchased. My plan is to eventually add an additional 200w panel, which for some reason I thought would require the 100/50 controller (maybe I miscalculated). My in-laws also use the boat a lot and while they are decently tech savvy, I think it will be very helpful for them to have the physical display that comes with the 712. As for the panel, I've used the renogys before, they've worked well for the price. I'm sure there are better options, but Se la Vie!

As for the smart battery sense long range devices, do these add value beyond what the 712? Maybe some added detail about battery health that I wont get from the 712 monitor?

Thanks for the reply!! Really appreciate the insight.

 

[Cambarner]

I ask about the inverter because I am trying understand why people are so hesitant to run the water heater off the inverter even if they have a battery upgrade?

My understanding is that the water heater draws around 750w (6-7A @ 120, which means ~65-70A pulling from the 12V batteries with the inverter loss baked in). So if I have 310Ah of battery, with 70A going out to the water heater, and ~8A coming in from solar, and ~20A coming from the alternator, that means I'm burning about 42A. So I should have about 1.4 hours of that before my bank hits 80%. Seems safe to me as long as all the wiring can handle the 70+ amp pull, which considering 200A fuse that between the batteries and the inverter, should be a piece of cake.

Thoughts?

 

[watson1987]

I've re-wired my hot water tank to run off a transfer switch with my inverter. One input (primary) is on the shore power side, and the other (backup) is on the inverter side. This configuration allows me to utilize two breakers on my AC panel. I leave the shore power one on all the time and can toggle the inverter side when I'm on the hook for a few days and want to turn it on. The transfer switch keeps it safe if I forget to turn off the inverter side before plugging in the shore power.

I have zero issues running the hot water tank off my inverter, it is a resistive load, and the 750-800W is well under my 3000W inverter. A 400Ah Lithium battery house bank and a 390W solar panel help the situation.

https://www.victronenergy.com/transfer-switches/filax-2

 

[Pandion]

Perhaps my experience with our R27OB will be of some value. I don't know what water heater or inverter you have so it may not be exactly the same. We have an Isotemp 750W water heater and a Kisae 2000W inverter. Charging is via 375W of solar and our F300 which outputs around 50 amps.

Under way with normal systems in operation (two refers, nav, radar, etc.) it takes about 2 hours to fully heat water. The load on the house bank will be around 25 amps. Without the engine contributing, the house load will be around 80-85 amps. Solar can help, but we usually heat water under way in the morning before getting much panel output, not to mention our usual Washington cloud cover.

The issue is the factory-installed automatic charging relay (ACR). After a few minutes of heating water, the large load from the water heater will pull the AGM house battery voltage down to the point the ACR opens, effectively isolating the outboard from helping power the water heater. The ACR remains open for 30 seconds, the house voltage rises, then the ACR closes. In about ten seconds, house voltage drops again, ACR opens, repeat. The ACR will continue this very consistent cycle (as it's designed to do). Our solution was to combine the engine and house battery by using the parallel switch when heating water, basically bypassing the ACR. This can cause other issues, like not being able to start your engine if you forget to switch it back, so if you're going to do this, you should understand the risks. Once the banks are combined, the F300 will continuously deliver around 50 amps.

Which brings up another issue...when pulling that large of a continuous load from the outboard, the voltage will drop to around 12.6 to 13.1 volts. So while we're getting 50 amps from the outboard, the lower voltage reduces the available wattage to get work done.

We've heated water off of our outboard many times but there are some quirks to be aware of when doing it.

 

[Cambarner]

Thank you! That was the info I needed!!

Cheers!

 

[Hamster]

I’d confirm Pandion’s numbers. I just did a test, running for about an hour with Inverter on, water heater on and Parallel switch to combine engine and house. Also, navigation and refer on. I was pulling -25 amps while running around 30 mph with my Yamaha 300HP. After an hour, I did have hot water. Most importantly, I remembered to turn off Parallel switch and my batteries are now getting topped off with solar.

 

[CruisingElvinRay]

2021 R-23

Ran the water heater yesterday at anchor. Was averaging 72A of current on my Victron BMV 712 battery meter. Solar was contributing about 3-4A.


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