Solar Panels - Connecting to Batteries - Questions?

G

Gilbertsons

New member
I'm making plans to install a couple of 100W flexible solar panels to my battery system and don't quite know the best way. I have inserted a diagram of my 2 battery system (1 Start, 1 House) with an ACR (Automatic Charging Relay). I guess this a typical set up with a single engine C-Dory like mine.

I understand that I need to connect the solar controller to the battery. I would guess that I would only need to connect only to the Start battery....(If I'm understanding how an ACR works). In my mind that would mean I would leave the battery switch in the "On" position so that the ACR senses the charging voltage coming up on the Start battery and then combines to charge the House battery automatically? I store the boat outside so this would ensure that my batteries are always topped off....(Is that wise?). But I also see that some solar controllers have the ability to connect to two batteries. Wouldn't this be unnecessary if you already have a ACR setup?

Most of the discussion I have found on the forum revolve around mounting the solar arrays, required wattage, interconnecting the panels, etc.

Any comments on how folks best connect to batteries and operate on a similar set up as mine?



2batt_1eng_3.thumb.jpg
 
If you connect the solar controller to the start battery, it will be on the wrong side of the VSR (voltage sensing relay), i.e., if it is on the start battery, the VSR can't redirect the charging current to the house battery. You could connect it to the upstream side of the VSR so it can direct which battery it goes to I suppose, just the way it does with the charge from the alternator, but there is really no point in that. The VSR is going to make sure your start battery is always fully charged. All the load is on the house battery. You only need solar if you have loads that deplete the house battery, usually a fridge or freezer. So by me, you should connect your solar controller to the house battery.
 
I recently set-up a solar panel to keep the start and house battery charged over the winter. I was tired of taking the 2 batteries in and out of the boat for winter storage every October. I use 2 Solar Charge Controllers, one for each battery and one solar panel that is connected to the the 2 controllers.
 
I take it that in both these scenarios if you are hooked up directly to the battery and not through the ACR then the Battery Switch is off and the Solar controller is doing it's magic.

Pat, it makes sense to me that the real need is to charge the house battery. You mention that "The VCR is going to make sure your start battery is always fully charged". Do you mean that the VCR automatically engages (with the Main Battery switch in the "Off" postion) to charge the start battery when the solar panel has filled up the house battery?

I'm definitely showing my lack of experience with marine systems :smileo
 
No, my solar panels only charge my house battery bank. If you want the VSR (not VCR, that would be a video cassette recorder, if you are old enough to remember those!) to control charging of both batteries automatically, then you have to hook the solar controller to the "upstream" side of the VSR, the same terminal to which the positive cable from the engine alternator is connected. Then the juice goes where the VRS sends it, which is first to the start battery, and when the VSR senses that it is fully charged, it automatically switches the charging over to the house batteries. What I meant is that when you run the engine, your start battery is always fully charged first.
 
Thanks Pat,

Now I understand how you are set up on your boat.

Sorry for the slip of VCR, yes I definitely old enough to remember those! Mine is a Blue Sea Systems ACR (Automatic Charging Relay). Your VSR must be the same thing. Or maybe a ACR has a VSR built into it so that it "senses" and then automatically charges............. I thought I got away from all the acronyms when I got out of the telecommunications business! :).

But boating is full of it too!
 
First be sure that your ACR or VSR does not draw current when at rest and hooked up. This can deplete a battery over a period of time.

Pat, some of the ACR are bidirectional--that is if they sense higher voltage on the secondary battery they will combine the two. We don't know which VSR or ACR he has.

I agree with Pat, that you probably want to maintain the house battery. 200 watts is a good amount of power, and in many circumstances enough to run a freezer or refer.

We don't know exactly how your "switch" works, but generally you want the house bank separated from the start bank, thus, you leave the combine switch "off".

With the small trickle charge solar panels, I put one on each of the start and house banks, when leaving the boat for a long period of time without a charger. I am not sure but that it might be possible to overcharge a battery, if you left 200 watts of solar power connected continuously. You would have to have a controller, which was basically a "smart charger", and you might even want a thermal component part of the circuit to protect the battery. For example, you would want the controller to go to a "Float" stage, with very low current and 13.4 volts or less, after the battery is fully charged.
 
Renogy has their 100 bendable solar panels on an eBay Black sale until Monday
http://www.ebay.com/itm/301163158004?_trksid=p2060778.m2763.l2649&ssPageName=STRK:MEBIDX:IT

They are regular priced at $220.00, on sale for $186.99

I have bought two panels to change out the panels on Discovery. My old panels were heavy, glass faced, fragile and only 90W. These are light, bendable and much more efficient. They can be scratched, but not broken and are sealed against salt water.
 
The ACR I have is PN 7610. It came with the Blue Sea Systems Add-a-Battery PN 7650. It appears that from my reading it is "Dual Sensing", I don't know if this is "bi-directional", but I know that it's main functioning is Start Isolation when you are starting your engine and then automatically combining the house battery and start battery when you have charging input from an alternator or charger. Blue Seas Systems does state.... " An ACR will work with all charge sources, including an alternator, AC charger, or solar panel. However, low current charge sources might not produce the voltage rise required to force the ACR to combine. Given this I will connect the solar controller directly to the house battery.

Bob, I suspect you are right about checking for a potential draw on my system. When I had the Dual Circuit Battery Switch in the "Off" position and left the boat set for about a month and even my start battery was dead. I would think that with even "phantom power draw" on the House battery the ACR should have reacted to the drop in voltage in the House battery and isolated the Start battery. I'm wondering now if my system was installed correctly. I did some research and found out that the previous owner had this installed by Felix Marine in Ft. Meyers, FL and I assume it is installed correctly.......maybe I shouldn't assume. I guess I'm going to have to roll up my sleeves on this one even though electrical systems is my least favorite subject in boating.

Thanks Brent for pointing me to the sale on ebay. Renology was the flexible panel I was looking at. It always pay to check several sales channels for a manufacturer. There own website and Amazon have it at $220 while it is discount on eBay.
 
The PN 7610 is bi directional--that is it will sense charging on either battery, and then combine--not just from Start to house, but also from house to Start.

If you had flat batteries in a month, there is something very wrong. Something was not "off". Sensing bilge pumps (which come on for a few seconds every few minutes will do this, as will memories in some stereos etc.

You need to get the digital volt meter out and do some hunting.

If the batteries were drained flat, then they need to be conditioned (pulse charger) or replaced if there is any suspicion of not being up to par.

The PN 7610 will sense 13.0 volts at 2 minute and combine at that lower voltage, so it will work even on a low voltage charger. (13.0 is below most float charger levels of 13.3 volts min. It will totally disconnect at 9.5 volts, so it would not be the cause of the flat battery.
 
When I first had my re-vamped electrical system (which includes a Blue Sea ACR) hooked up, my (very small - since replaced with larger) start battery was drawn way down by "something." That something turned out to be the ACR. I'm not sure how long it took to do this as there was a period of months involved. I contacted Blue Sea just to get their thoughts, and they said that the ACR, if wired "as suggested" will draw a load even when the battery switch is "Off." Their initial suggestion was for me to put a switch in the ground wire of the ACR and then remember to turn that off when leaving the boat. That did not appeal to me -- after all, one reason I had set up this system was to have my "one big On/Off switch" to just shut off the boat when leaving, and not a bunch of little things to remember to also turn off and on.

I mentioned that, and they suggested an alternate way to wire the ACR, which I did. Now it shuts off when I turn off the boat switch so no "secret" draw. What they suggested was the two "big" leads of the ACR be run to the two load sides of the switch (i.e. the side that does not have power when the switch is off).

I don't know if this is what caused your problem, but just relating my experience. I followed Blue Sea's alternate suggestion and it seems to have worked fine over the past year or so.

I'll be hooking up a couple of solar panels over the winter, so I, too, will be thinking about where to "put them" in electrically. I store the boat indoors, so for me their main purpose is to charge the house bank when I'm using the boat - that likely differs for others.

Sunbeam
 
Agreed - I use RC's articles as baseline info for many of my projects. He knows ABYC and follows or exceeds it. I'm actually referring to a couple of his articles right now as I re-do/upgrade some of the electrical system in my RV.

That said, he doesn't show every possible combination or setup - and most of his (and his customers') boats are cruising sailboats - so sometimes you still have to "extrapolate" a bit for our setups.
 
Thanks for the tips on the ACR and results of the the call to Blue Sea....I have more to consider now. Also the link on solar was very informative. It's really great that this forum is so active!
 
Back
Top