Adding a second battery to my coachbuilt motorhome

[BarryBeard]

I have solar and it produces more than enough power to keep my single battery charged. When its night and I have heavy usage (such as watching tv) the battery drains.

I'd like to add a second battery but the existing plastic compartment doesn't have space. If I cut away the internal housing, do I need to build a new housing around it? (Its positioned under the bench seats) Is there a danger of noxious gases?

If I do need to build a housing, would it need to be plastic or would I be able to use plywood? (Danger of fire?)

 

[trevskoda]

You could do a f glass box or buy a marine plastic box with a lid, make sure you are using sealed lead acid batts, you should have a drop out hole under the tray if open vented, my ex liberty bus had its battery in the passengers footwell with no dropout hole and it was open vent to boot, very dangerous from a bus converter, remember to join the bats like this if possable.

 

[Nabsim]

I have solar and it produces more than enough power to keep my single battery charged. When its night and I have heavy usage (such as watching tv) the battery drains.

I'd like to add a second battery but the existing plastic compartment doesn't have space. If I cut away the internal housing, do I need to build a new housing around it? (Its positioned under the bench seats) Is there a danger of noxious gases?

If I do need to build a housing, would it need to be plastic or would I be able to use plywood? (Danger of fire?)

Have you checked if you can fit any under the passenger seat? I know in my Sprinter based moho its just an empty space

 

[alcam]

I have solar and it produces more than enough power to keep my single battery charged. When its night and I have heavy usage (such as watching tv) the battery drains.

I'd like to add a second battery but the existing plastic compartment doesn't have space. If I cut away the internal housing, do I need to build a new housing around it? (Its positioned under the bench seats) Is there a danger of noxious gases?

If I do need to build a housing, would it need to be plastic or would I be able to use plywood? (Danger of fire?)

Curious about size of single battery [Ah] ?
At present I have 2x70Ah , 3 years old and think they're starting to lose power .
Heaviest use , like yourself , is TV
Due to charging unit limitations [Sargent EC176] I can't bump up the power . Supposed to be no more than 120Ah . Though present set up has worked ok for 3 years .
Actually thinking of putting in a single battery [125Ah] rather than change charging unit

 

[trevskoda]

I have 2 90ah batts and would like more, maybe next time it will be 2 125 ah lead carbon units.

 

[mistericeman]

I fitted 2 extra 100ah AGMs under the dinette seat and another under the floor in the original spot...
Cabling was a pfaff BUT doable after drilling a couple of extra holes...
Charged by a 400w Bifacial panel on the roof and managed by a ring rscdc30 combined solar/B2B regulator...
And Victron smart shunt monitoring.

 

[Nabsim]

Curious about size of single battery [Ah] ?
At present I have 2x70Ah , 3 years old and think they're starting to lose power .
Heaviest use , like yourself , is TV
Due to charging unit limitations [Sargent EC176] I can't bump up the power . Supposed to be no more than 120Ah . Though present set up has worked ok for 3 years .
Actually thinking of putting in a single battery [125Ah] rather than change charging unit

You can put as much solar on as you want, you simply run the panels to a new controller then direct to the battery bank. Its exactly what anyone with older EBL units have to do, not just Sargent

 

[SquirrellCook]

I have 2 90ah batts and would like more, maybe next time it will be 2 125 ah lead carbon units.

Forget the lead carbon, I just love the way lithium suck the energy out of the solar panels. Or at least it looks that way. Make the most out of the sun shining.

 

[wildebus]

Sargent have a recommended maximum battery size for a given unit. I have not see a specific reason for it and I am guessing it might be that the bigger the battery bank, the greater the chance of running the charger at its full capacity for longer and they don't seem to like running at full pelt for extended periods.
There is no reason to change out the whole sargent unit if you want a bigger battery bank as it is pretty simple to fit a bigger - and better - charger.

There is no doubt charging Lithium is more efficient than Lead, but there is still the elephant in the room of the greater upfront cost of a Lithium Battery and the associated bits and pieces that may need to be added to a Lithium install.