Simple two battery solar set-up?

[TopHat]

Hi,
Im trying to get my head around a simple two battery solar set-up that im looking to install.
Have removed the inboard(gone to outboard, without charging circuit), have a 40W & a 10W panel making 50W coming into a "Duo" solar pwm charger, that keeps the batteries separated.
The plan is to keep the two batteries completely separated from each other, as they are of different, age, type (one is AGM the other maintenance free lead acid), size (80 & 100 ah) & quality. So I thought I could have one switch panel per battery, say having:

Battery 1:
Autopilot
Fixed VHF
Sounder
Spare
& 12vdc accessory plug & USB plug charger

Battery 2:
Cabin lights
Stereo
Compass light
Nav lights
& 12vdc accessory plug & USB plug charger

One problem I can see if the autopilot runs down battery 1, then that & the other equipment on that panel/battery will be out of order, I think im missing something....??? or some way of easily having the equipment source power from the other battery if one of the batteries dies.
I cant think of anything, bearing in mind my KISS approach I am trying to maintain.
Thanks for any suggestions

[motion30]

not much battery capacity and not much solar production. May be okay if your usage is very Lite

[TopHat]

Hi m30,
yes usage is very lite, coastal cruising in a pocket cruiser, all LED lights, use the tillerpilot as a back-up to my arm(I like to hand steer). I have found 50w (40w on an atom solar tracker bracket) more than adequate for my current requirements, Am re-doing the electrics...cant get my head around setting it up properly, cheers

[motion30]

I think just a simple battery switch will fix your problem. Simple
Perhaps a small honda gen set and a battery charger for those times where it is cloudy for several days. That will always get you out of trouble

[newhaul]

The best idea I can come up with is to use one on all and use the second as a backup. Which battery is which? One gives you an available of 50 ah and the other gives you 40 ah. BTW I personally have never seen actual deep cycle batterys with that low of an ah rating.

[maxingout]

I would just put a simple battery switch to separate them, and then with a flick of the switch both batteries would be on line. I do the same thing with all my Land Rover trucks when doing expeditionary travel.

[TopHat]

Thank You all.
Yes a simple ON/OFF on a positive between both switch panels, sounds like it will work.
Keep it in the OFF position, when using batteries separately.
If one battery dies, I can isolate it that battery to OFF (with its own ON/OFF) then turn ON the "connecting" ON/OFF to operate all equipment from the remaining battery.
I was over complicating it in my mind.
cheers

[smac999]

I don't think you want 2 different panels going into the same controller... nobody has mentioned that.

I would run both batteries into a 1,2,all switch and run everything off the same battery, treat one as a back up. there are solar controlers that will charge 2 batteries and keep them separate. that would be your best bet.

other option is an acr but I doubt an acr will help you as I don't your panels will never get the voltage high enough while using the boat.

[newhaul]

Originally Posted by smac999

I don't think you want 2 different panels going into the same controller... nobody has mentioned that.
.

Actually that is incorrect you can run as many panels of the same volt type 12 volt panels 24 volt panels etc.).
As long as you don't try to put in more amperage or voltage the controller is designed for.

[Sarge17]

Tophat, I have two deep cycle batteries of different ages and capacities. I have them hooked in parallel when the battery switch is on both or A&B. The boat is sitting right now with the switch on both and the self controlled solar panel connected. I always make sure the cells are healthy and topped up with distilled water and I've never had a problem. I think when you use unlike batteries in a series configuration is when you have problems. Sarge

[Drift Woods]

Originally Posted by smac999

I don't think you want 2 different panels going into the same controller... nobody has mentioned that.

I would run both batteries into a 1,2,all switch and run everything off the same battery, treat one as a back up. there are solar controlers that will charge 2 batteries and keep them separate. that would be your best bet.

other option is an acr but I doubt an acr will help you as I don't your panels will never get the voltage high enough while using the boat.

Smac999 is correct, the 1 2 all switch works great. A few months ago I installed my solar to my number 1 house bank. By 1 or 2 pm my SOC is at 100 percent and I simply turn my battery switch to all and it will charge battery 2 thru the switch.

Sent from my SAMSUNG-SM-G890A using Cruisers Sailing Forum mobile app

[barnakiel]

I think your question is very interesting.

My intuition would be to charge both at the dock then use exclusively bat "A" until 'empty' at which point switching all to "B" and running it down until empty.

This is how I would wire and operate the solar panels:

- while I am on bat A all solar charge is on A too, unless there is excess,
- when I switch to B, I leave solar on A until it is nearly full,
- when I switch back to A, I leave solar on A, unless there is excess.

One ends up with B empty, unless there is a lot of sun or a days' break in sailing.

Plenty depends on how many days your trips can last.

b.