12V battery wiring

[Bobbie54]

I found this diagram for how two 12V batteries should be wired in parallel and in series.

The other pics show how mine were wired. The wire going over the top (trailer) edge of the first goes to the trailer wiring. The extra attached to the red is the solar charger hookup (which I didn't find when I needed it!) the wires to the 2nd battery run in the covered lines to the 2nd battery directly from the first. So the first battery is wired to the trailer system and the second is just wired to the first.

It may not matter since I intend to put just one battery in place of the two, but curious about this wiring scheme.

[padlin]

Well, it's in parallel but a goofy way of doing it. I'd move either the + or the - that goes to the converter and ground to the other battery as shown in your first image, right side example.

At the very least I'd repair or replace all the rusted components and move one of the house connections.

[Bobbie54]

I'm going to have only one battery and will put new connectors on.

[Bobbie54]

So next question- I've read I should charge the battery after installing- that's fine as I'll hook up to house power for the next few days getting ready for Maryhill. Then discharge it about (varying percents suggested) and repeat cycle a few times. Correct/Not? How far to let it go down.

[padlin]

I would charge it to 100% then just use it, trying to go no more then 50%.

[Ron in BC]

From my point of view that was a poor way of wiring two batteries. A simple battery switch would isolate each of them allowing for the redundancy of a second battery fully charged and ready to go. They can still be used at the same time for extra amps.

If one of you old batteries is still in fair or better condition I'd keep it as a spare isolated with a battery switch. There's a lot to be said for redundancy in systems.

Ron

[Bobbie54]

Both are six years old and dead. I'm going to replace one and if I decide that isn't sufficient will do as you suggest later. I like the switch idea.

[Patandlinda]

Originally Posted by Ron in BC

From my point of view that was a poor way of wiring two batteries. A simple battery switch would isolate each of them allowing for the redundancy of a second battery fully charged and ready to go. They can still be used at the same time for extra amps.

If one of you old batteries is still in fair or better condition I'd keep it as a spare isolated with a battery switch. There's a lot to be said for redundancy in systems.

Ron

Ron would like to change out the switch . Any suggestions ? We have the dual battery installation. Pat

[Bobbie54]

Originally Posted by padlin

I would charge it to 100% then just use it, trying to go no more then 50%.

I rarely run on battery alone but I can let it run for awhile at home and make sure all is okay.

[Ron in BC]

Originally Posted by Patandlinda

Ron would like to change out the switch . Any suggestions ? We have the dual battery installation. Pat

I didn't know that you also had a dual 12V set-up. I've seen battery disconnect switches sold at non-marine type stores but I tend to stick with marine ones. West Marine has a large selection. Almost anyone of them would do and one with an alternator field disconnect isn't required.

My trailer one is a Blue Sea m series. I like having it recessed, not surface mounted as the wires are behind and not visible.

Ron

[Bobbie54]

Originally Posted by padlin

At the very least I'd repair or replace all the rusted components and move one of the house connections.

Which leads to I hope the final question- the wires were attached to O connectors and the screw posts with wingnuts. Is there any advantage of connecting via that vs. the non-screw posts (the big ones that you clamp an adapter to, such as used in car batteries?)

[padlin]

For the relatively small load from out RV's I would think the screw down connectors are fine, if kept in good condition. But that's just a guess.

[Bobbie54]

Considering that they were not in good condition and were still working- I suspect you are right! Duh, should have thought of that myself. Well, when I get things hooked back up I'll have had a small education in batteries, something I haven't learned on cars since they've always been replaced by someone else and almost always been sealed.

[Patandlinda]

Originally Posted by Ron in BC

I didn't know that you also had a dual 12V set-up. I've seen battery disconnect switches sold at non-marine type stores but I tend to stick with marine ones. West Marine has a large selection. Almost anyone of them would do and one with an alternator field disconnect isn't required.

My trailer one is a Blue Sea m series. I like having it recessed, not surface mounted as the wires are behind and not visible.

Ron

Thanks Ron . Like Blue Sea those are my switches on my solar . Another mod coming . Pat

[Brian B-P]

Originally Posted by Bobbie54

Which leads to I hope the final question- the wires were attached to O connectors and the screw posts with wingnuts. Is there any advantage of connecting via that vs. the non-screw posts (the big ones that you clamp an adapter to, such as used in car batteries?)

The "O connectors" are ring terminals. Threaded posts (normally with wing nuts) and ring terminals are normal for this purpose, are easy to remove and easy to keep tight, and are suitable for the current involved (even with a large inverter, which you apparently don't have). The tapered posts used for automotive starting batteries are used because of the much higher current involved, but mostly because they are cheap and traditional. I would certainly not use the tapered automotive posts when the threaded posts are available.

[Bobbie54]

Thanks, Brian.

[Brian B-P]

Originally Posted by Patandlinda

We have the dual battery installation.

Pat, you have dual 12-volt batteries (which must be in parallel)? I assumed that you had dual 6-volt (which must be in series; the available option from Escape). If dual 12-volt (Ron's setup), did you set that up yourself? I don't think it has ever been an Escape option.

[Patandlinda]

Originally Posted by Brian B-P

Pat, you have dual 12-volt batteries (which must be in parallel)? I assumed that you had dual 6-volt (which must be in series; the available option from Escape). If dual 12-volt (Ron's setup), did you set that up yourself? I don't think it has ever been an Escape option.

Brian we have dual 6 volt Interstate batteries wired in series from Escape . I was just thinking to move the on and off switch and get the Marine one . I remember lots broke the switch handle and it is too far under the dinette for our liking . I made Myron's cover to protect it but hate getting down on the floor to switch on and off . That is my reasoning anyway ? Pat

[Brian B-P]

Originally Posted by Patandlinda

Brian we have dual 6 volt Interstate batteries wired in series from Escape . I was just thinking to move the on and off switch and get the Marine one .

Ah, so just wanting plain on-off switch comparable in construction to Ron's, but not a selector switch.

The on-off variant of Ron's Blue Seas m-Series looks like a good switch, but isn't normally recessed. Ron's is rear panel mounted, so the knob protrudes but is still unlikely to be accidentally switched (or even broken) like the stock toggle switch. This style of switch could be mounted in a recessed box, if you can find or make a suitable box.

[Patandlinda]

Originally Posted by Brian B-P

Ah, so just wanting plain on-off switch comparable in construction to Ron's, but not a selector switch.

The on-off variant of Ron's Blue Seas m-Series looks like a good switch, but isn't normally recessed. Ron's is rear panel mounted, so the knob protrudes but is still unlikely to be accidentally switched (or even broken) like the stock toggle switch. This style of switch could be mounted in a recessed box, if you can find or make a suitable box.

That will work Brian , Thankyou ! I bookmarked it to easily find it . Looking at the specs it looks to handle a lot more power ? Need to see it in person and then decide on maybe a little case for it . Pat