Adding a second lithium battery

[alanerickson]

I have a recently built 19' and it came with a single lithium battery and solar panel and the GO Power solar controller. The Go Power controller manual indicated that a second battery can be connected to the controller. If I add a second battery should I add it to the controller, or is adding the second battery in parallel with the first battery sufficient? I assume adding to the controller is preferred, but wanted to double check before going through the extra work that this will require. Thanks.

[Vermilye]

The second battery should be the same capacity & brand as the first, and should be added in parallel.

The "second" battery described in the GoPower controller manual is usually the vehicle battery, and if you plan to use it for the trailer, would only maker sense if you used a switch that allowed you to choose which battery powered the trailer.

[alanerickson]

Got it. Thanks. I was assuming that the controller would balance the power between batteries, but after reading your reply I dug into the manual more and found the single sentence where they talk about the controller charging battery 1 until it's "full" and then switching to battery 2 for charging that battery, which isn't the operation I'm looking for.

[John in Santa Cruz]

2 12V batteries in parallel double the amp*hour capacity.

ideally, wire them like this...



(the lower picture, not the top). this is because even short heavy gauge wires have SOME resistance, by connecting the + to one battery, and the - to the other, then both batteries have the same total wiring resistance and will be better balanced.


OH! when you first parallel a new battery to an existing battery, make sure both batteries are at the same state of charge BEFORE connecting them, otherwise the more charged battery will dump a ton of current into the lesser charged battery as soon as you connect the bridge.

[alanmalk]

Originally Posted by John in Santa Cruz

2 12V batteries in parallel double the amp*hour capacity.

ideally, wire them like this...

OH! when you first parallel a new battery to an existing battery, make sure both batteries are at the same state of charge BEFORE connecting them, otherwise the more charged battery will dump a ton of current into the lesser charged battery as soon as you connect the bridge.

Just wanted to ensure this didn't get overlooked.


Use your multi-meter to verify that both the old and new battery have the same voltage before making the connections.

[alanerickson]

Thanks. I knew about the wiring, but didn't think at all about the charge, so that's a good catch. And in order for my existing cables to reach I'm going to need to have the batteries oriented different from each other, but that's not that big of a deal. Basically your diagram on the bottom but the left battery rotated 90 degrees CW and the right one 90 degrees CCW, and then some jumpers, but everything wired as you've shown.

[John in Santa Cruz]

Originally Posted by alanerickson

Thanks. I knew about the wiring, but didn't think at all about the charge, so that's a good catch. And in order for my existing cables to reach I'm going to need to have the batteries oriented different from each other, but that's not that big of a deal. Basically your diagram on the bottom but the left battery rotated 90 degrees CW and the right one 90 degrees CCW, and then some jumpers, but everything wired as you've shown.

make the bridge wires the same length and gauge, even tho one could be much shorter than the other

[meekhotglass]

Does anyone know which brand lithium battery Escape using?

[alanerickson]

Yep, it's these. At least that's what mine came with a couple of days ago.

https://gpelectric.com/products/100a...solar-battery/

[Vermilye]

I must have missed the news that Dometic bought GoPower. Let's hope the great service provided by GoPower doesn't go the way of most Dometic products...

[rubicon327]

Originally Posted by Vermilye

I must have missed the news that Dometic bought GoPower. Let's hope the great service provided by GoPower doesn't go the way of most Dometic products...

That stinks. I will officially never buy anything from GoPower now.

[Chama]

Sad but true:
https://news.cision.com/dometic-grou...--llc,c3330659

[RangerMan]

Bets? How much longer will ETI last before being 'swallowed' up'?

[Brian B-P]

Originally Posted by RangerMan

Bets? How much longer will ETI last before being 'swallowed' up'?

Not by Dometic, which makes RV components but not RVs.

[John in Santa Cruz]

ETI already got bought, by the same company that acquired Northern Lite (fiberglass slide-in campers).

[rubicon327]

Originally Posted by John in Santa Cruz

ETI already got bought, by the same company that acquired Arctic Fox (fiberglass slide-in campers).

Northern Lite

[John in Santa Cruz]

Originally Posted by rubicon327

Northern Lite

oh, right. i confuse those.

[alanerickson]

https://imgur.com/nHmLSE1

test picture

[alanerickson]

https://i.imgur.com/g1E3eiB.jpg

test jpg

[John in Santa Cruz]

Originally Posted by alanerickson

https://i.imgur.com/g1E3eiB.jpg

test jpg

why are you posting that link in this thread about adding a 2nd lithium ?

you can't use imgur to embed an image here anyways, you need a photo hosting site that allows cross linking, such as smugmug.com