solar panel controller wiring issue

[John Barnet]

Has anyone got this arrangement and using solar panels.

Two domestics batteries controlled by a three position tumble switch. The switch options are to run the domestic load off of battery one or two or both.

In essence the two batteries are working either independently or when the switch is selected to both - in parallel.

I have a duel solar controller. To enable me to charge both batteries independently which is fine when the domestics are isolated ( the three way switch selected as off). And of course if one battery is selected for the domestic load.

However, when the tumble switch is turned to both, the two batteries are then effectively switched into parallel, that is my two independents are now one battery bank.

Will this cause me problems with the controller, as I assume the two outputs will be effectively linked through the switching when both batteries are in play.

thanks

[Paul C]

What solar controller do you have?

[Paul C]

http://www.canalworld.net/forums/index.php?showtopic=57538&hl=

[WotEver]

What solar controller do you have?

 

That was going to be my first question.

 

If the instructions don't say if the dual outputs can be linked, then I guess it would be a question for the supplier.

 

Tony

[bottle]

My first question is.

 

Why have you got your two domestic batteries wired in this way?

 

or

 

Do you have one start battery and one domestic battery.

[DHutch]

http://www.canalworld.net/forums/index.php?showtopic=57538&hl=

Duplicated topics merged.

[WotEver]

My first question is.

 

Why have you got your two domestic batteries wired in this way?

 

or

 

Do you have one start battery and one domestic battery.

I assumed he meant the latter. However, you know the meaning of "assume"...

 

Tony

[smileypete]

Will this cause me problems with the controller, as I assume the two outputs will be effectively linked through the switching when both batteries are in play.

thanks

Should be fine, though it'd help to know what controller it is, is it one of these?:

 

http://www.mpptsolarcontrollers.com/epipdb-com-10a-20a-dual-battery-ep-solar-charge-controller

 

cheers, Pete.

~smpt~

[John Barnet]

My first question is.

 

Why have you got your two domestic batteries wired in this way?

 

or

 

Do you have one start battery and one domestic battery.

hello all been away sorry for the delay in picking up your threads

yes smiley pete it is one of them (20A)

http://www.mpptsolar...arge-controller

 

 

wotever -the batteries are wired this way because i have a low rev engine, it is a common wiring on old traditional boats.

and yes i have a separate starter.

[Paul C]

The simple answer is "no".

 

However, the way you've split the 2x domestic batteries into 2 banks is inefficient - it would be better if they were simply joined up, and did everything (charging and discharging) together. The 2nd output on the solar controller could be used for the starter battery.

[bottle]

Well, wotever is not the way to go, see Paul C post above (#10)

 

Without going into detail two batteries wired as a bank is more efficient and less stressful on the batteries and it should enable them to have a longer life.

[John Barnet]

yes maybe i will have to parallel them up, I'm a bit reluctant as the boat has run for 25 years on this arrangement, the current batteries are six years old and still holding a full charge.

I suspected the diodes within the unit would restrict any back feed damage to the controller when the "both" switch were engaged but not too sure ( it works fine with my onboard Sterling charging system when i run it off the generator or occasionally plug in to England). likewise with the alternater from the engine, which also has an in line controller - seems to work ok

Problem with solar panels is they are constant, I would hate to come home to find a melted box and an engine room full of smoke!

thanks for all your input.

 

like your view thouhg smiley pete - your link is the very item.

[smileypete]

hello all been away sorry for the delay in picking up your threads

yes smiley pete it is one of them (20A)

http://www.mpptsolar...arge-controller

 

Looks good, should be fine. For some reassurance you could check the voltage on each batt with a multimeter, at times they should be different showing the controller is charging them independently.

 

BTW the connections from the controller to each batt should have a fuse in the positive at the batt end, value depends on cable size from controller to batt but a 20A fuse should protect 4mm² csa (cross section area) cable OK.

 

The controller also has a charge priority setting to split the charge when both batts need charging, maybe check it out in the manual and try it on 50%:

 

http://www.epsolarpv.com/en/uploads/news/201209/1348708145533798.pdf

 

As for using the batts separately, why give just the OP a break If the OP is happy switching between each batt and it's working fine then all power to them Probably the batts are getting plenty of charge anyway from the solar anyway, and not being run down too much at all.

 

Can't be any worse than the people with waaaay oversized solar setups or huuuge batt banks or massively complicated and expensive electrical setups. Sounds like the OP is happily boating with something a lot more modest which is good to hear . About all I'd recommend is to maybe get a cheap <£10 panel voltmeter (and small fuse to protect it) to get an idea of how the domestic batts are doing.

 

cheers, Pete.

~smpt~

Edited June 18, 2013 by smileypete

[John Barnet]

Thanks for constructive comments smiley pete