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Solar (again) with ACR

Posted: Sun Nov 04, 2018 8:57 am
by Starscream
After a long and instructive conversation with this forum last year, I finally placed my order today for two 50W solar panels, an MPPT charger with battery monitor display, an automatic charging relay, and a bunch of wires and fuses.

I am in the process of re-making my bimini top after ripping it this past summer. Bought a bunch of zippers and snaps and material from SailRite and we'll see what happens. I'm going to semi-permanently mount the solar panels into the bimini top, and run the wires down the side and into the boat through the steering cable entry.

I think I have most of the job worked out after reading all the responses to my Adding Solar post several months ago.

I'm going to go with all 10gauge wiring, panels wired in series, Solar MPPT charger wired to the house battery, motor wired to the starter battery, with the ACR between the two to make sure that both batteries get charged with either the motor running or the solar collecting.

I made a little wiring sketch, with the red being what (I think) I have now, and the blue being the new installation. I would very much appreciate comments if anyone can spare the time to have a look.

I also have two specific questions about the ACR: is it worth trying to wire up the Start Isolation Wire to the throttle quadrant, or is that feature a luxury I can do without? Secondly, why do I feel that the ACR on/off switch (for long term storage) is odd in the negative wire? Any concerns there?


And one final question about the ACR in combination with a dual-bank charger: does it make more sense to disconnect one of the batteries from the dual-bank charger and let the ACR do its job with only one battery on the charger? I'm just not sure what the ACR does when there are two charging sources, especially intelligent sources like the dual-bank charger that are optimizing the charge process individually for each battery type and condition. (These are Optima AGM batteries).

Re: Solar (again) with ACR

Posted: Tue Nov 06, 2018 7:25 am
by Highlander
Very interesting I'll have to follow up on this when I get back from Scotland :) on wed.
If we have another mild winter this will become my next winter project
J 8)

Re: Solar (again) with ACR

Posted: Tue Nov 06, 2018 10:07 am
by Spector
I have a combiner (acr) and have hooked up only one side of the dual charger. The combiner kicks in as expected. I haven't tried to hook up both sides of charger. I worry that it would create a short thru the combiner but that's just a guess. Next set up will be to connect batteries in parallel as one bank and eliminate combiner. I carry a NOCO genius boost in case it is drawn down too far. Looking closely at the Firefly batteries but $$$$

Re: Solar (again) with ACR

Posted: Tue Nov 06, 2018 7:03 pm
by Sumner
Spector wrote:....Next set up will be to connect batteries in parallel as one bank and eliminate combiner. I carry a NOCO genius boost in case it is drawn down too far.

If one uses the ACR I'd run all the charging sources to one battery and let the ACR take care of the other. That seems to be the preferred method.

On the Endeavour, where we have a start battery and four 6 volt batteries I use the ignition cut-out feature (Start Isolation Wire), since the starter draws a lot of amps, more than what I'd want going through the ACR.....

Image ... age-5.html

.... If you use adequate size wiring and the outboard doesn't draw that much you are probably fine without the cut-out. I can connect the engine starter to the house bank if needed with a main 1-2-Both-Off switch. The engine alternator, solar and 110 charger all go to the house bank and the ACR keeps the start battery up. Has all worked fine so far.


1300 miles to the Bahamas and back -- 2015

The MacGregor 26-S

The Endeavour 37

Trips to Utah, Wyoming, Idaho, Canada, Florida

Mac-Venture Links

Re: Solar (again) with ACR

Posted: Thu Nov 08, 2018 10:17 pm
by Starscream
I received the solar shipment from Amazon. I added a 6A Minnkota single-battery digital charger to replace the heavy dual bank 10A MK precision charger that I bought a few years ago. I think I'll hook the charger to the opposite battery as the solar, just to minimize connections per terminal.

I sewed a square of Velcro loop onto the repaired Bimini top, and used stick-on Velcro hoop around the perimeter of the panel underside. I will probably add little loops of webbing sewn onto the Bimini as anchors for the panel's corner grommets. now I have to do the other one. I also took the opportunity to reinforce a few of the stitches on the Bimini and fix the rip that I stupidly caused on the last trip.

The solar panels are remarkably light. I'm having second thoughts about the series wiring. I'll have to try it both ways, I think.

Re: Solar (again) with ACR

Posted: Mon Dec 10, 2018 4:45 pm
by Starscream
I finished the repairs to to bimini top (I lost my balance putting up the flags and ripped it where the backstay passes through...the patch is sort-of visible in the photo) and the mounting of the solar panels. I'm getting relatively good with the sewing machine after a ton of frustration. The sewing machine is a small "industrial", meaning Costco, Singer that punches through several layers of Sunbrella and edging without any real problems. It's a bit small in terms of what you can stuff in past the needle between the needle and the machine base, but nothing's impossible. The main problem was the thread wouldn't stay tight on the bobbin, solved by using this stuff: ... 16455.html

and winding it real tight. I put stick-on velcro on the underside of the solar panels, and sewed the mating velcro to the bimini. I also added a few tie-down loops sewn into the bimini so that I can really tie the panels in place securely. Going to run the wiring underneath the panels, down the side or maybe down the backstay, and into the boat through the throttle-cable well. I bought MC4 Y-connectors so that I can do parallel or series, depending on how much shading the boom, backstay, and flag will cause.


Went with these panels: ... UTF8&psc=1

and this controller with the battery monitor: ... UTF8&psc=1
and the temperature sensor, not because I need it but because it was $14 and what the heck when you're spending half a boat-buck or so.

Got the Blue Seas ACR relay too. Too darn cold out to do any wiring until April.

While I was at it, I re-sewed all the zippers, borders and edging, for good measure. Kinda fun, once you get going.

Re: Solar (again) with ACR

Posted: Tue Mar 26, 2019 7:45 am
by Starscream
The time is coming close, when I am actually going to have to go out and DO all this wiring. I updated my wiring diagram on onedrive, which changed the photos on my original post from my hand sketch to the CAD file.


The pink fuses will have to be added: all other fusing is inside the components - motor, charger, solar panels. Looking at the drawing, it does look like I have a few wires between the batteries and the components which are unprotected. The whole CAD drawing is color-coded, but the screenshot doesn't show that very well.

The ACR will require two 90 Amp fuses, which I didn't think about until just now when I added them to the wiring diagram. My Etec90 has an alternator output of something like 80amps, although I think the real amps going to the batteries can't surpass 25A ("81 Amps Total/25 Net Dedicated" whatever that means.) Going back through previous responses, I think I can see a set of fuses in Sumner's photos of his ACR, so I'll go back through his website for details. Speaking of Sumner, haven't heard from him in a while...?

I'm thinking about using two of these: ... ay&sr=8-12. I would totally appreciate any feedback or comments on the revised wiring diagram!