Battery Selection

[DanNJanice]

Both.

Here is the link to the 12V to 36V 5A 180W Step Up Booster Power Module, as the Starlink needs more than just 12v from RV battery.

You'll also need this power cord socket, to plug the Startlink mini cable into, which you wire off the booster linked above.

Perfect, thanks Jim

 

[Creek Jenkins]

My Victron shunt showed up, but my batteries won’t be here till next week. I’ve got to weasel the shunt wire thru the wall so I can install the shunt display over the control panel. My lead acid batteries are pretty dead, but I have both solar and main power switches off. It seems a solar panels are still powering the energy display, though I guess that doesn’t hurt anything.
When hooking the batteries up to the shunt, do I need to worry about the length of the cables from each battery being equal?

 

[Oregon_Camper]

When hooking the batteries up to the shunt, do I need to worry about the length of the cables from each battery being equal?

If you have >3 batteries, then the have the same cable length. Coming off NEG terminal to shunt can be different length that cable between batteries.

 

[Creek Jenkins]

I’m getting ready to install my batteries when they arrive next week.
2 x 230 aH, should I use 2-0 battery cable on the positive side?
I don’t have a giant crimper so I usually solder the cable ends on.
Jim I watched your video on your conversion to 3 batteries but I’m not clear on how you held your batteries down. I can’t find a battery box to fit the odd size but not sure I really need one. I’m going to remove the “dropped” battery box in my Paradigm and put a wood floor in so I can use blocks to brace fore and aft, maybe just put a bungee over the top?
The Victron shunt connects to both batteries so that seems straight forward.
I will have read through my battery specs as I am not sure if the BMS includes a max current draw shutoff. If not I should probably install a fuse.

 

[Oregon_Camper]

2 x 230 aH, should I use 2-0 battery cable on the positive side?

Jim I watched your video on your conversion to 3 batteries but I’m not clear on how you held your batteries down. I can’t find a battery box to fit the odd size but not sure I really need one. I’m going to remove the “dropped” battery box in my Paradigm and put a wood floor in so I can use blocks to brace fore and aft, maybe just put a bungee over the top?

You stated you have no inverter, so the largest DC draw you will see is slideouts and leveling...which will be under 50 amps. So 2AWG will be plenty. You could even get away with 6AWG if you wanted. Now...if you have ANY plans of adding an inverter down the road, bite the bullet now and use 4/0 cables now.

For batteries...the video was my prior RV and I did not strap them down. Just had a rubber mat under them and then forced them tight with the framing. On my current Alliance RV, I have them straped down with 2 lashing straps (like this). The kind you pull to tighten, not the lever kind with metal handle. I still think the rubber door mat is a great idea...just grab a cheap door mat at Lowes and cut to size.

 

[Creek Jenkins]

I’ve got the batteries more or less installed, pulled them out this morning after individually charging them, now they are connected together for 24 hours per manufacturer instructions before using. Some things I found after pulling the “drop down” OEM battery box - the floor of the battery compartment is not flat as there was some weld slag caught between the main frame and the metal floor so instead of cleaning it out they just welded the floor over it. I’m sealing it up with silicone. I put down a sheet of thin galvanized sheet steel and then a 5/8” plywood floor. Batteries are sitting on the foam they came packed in. The partition at the rear of the compartment was only held with two screws as they mounted it right on top of the two ground cables. Not a good look Alliance.

 

[Creek Jenkins]

I stuck with the 2-0 wire on positive side and #2 on the negative as that is what I have on hand. Leads to the camper look like #2 or #4.
I am now working on installing the Victron shunt thingy I would like to have the display inside near the main control cabinet but I am struggling on how to get the wire up there. I’m not as flexible as I used to be.
Cheers
Creek

 

[Creek Jenkins]

I had to take a break and go hunting for a couple days. Batteries are fully charged, wired and strapped down. Shunt is installed but display not mounted. I checked the small “vampire” loads before turning anything on, they are at 8 watts or 0.6 amps. Running fridge now to test draw but our ambients are in low 50s now so load pretty low.
Cheers
Creek

 

[DanNJanice]

I had to take a break and go hunting for a couple days. Batteries are fully charged, wired and strapped down. Shunt is installed but display not mounted. I checked the small “vampire” loads before turning anything on, they are at 8 watts or 0.6 amps. Running fridge now to test draw but our ambients are in low 50s now so load pretty low.
Cheers
Creek

The 0.6 amps is what I see on my 32RLS when everything if off. It was about the same on my Jayco.

 

[Creek Jenkins]

After installing the batteries and the shunt I decided to run a little test. Fridge was on, thermostat set at 58 degrees. Unplugged shore power at 6:30 pm, about a 38 F ambient. 12 hours later it was 26 F and it had used 71 aH of power for fridge and furnace. Even though thermostat was set at 58, two room thermometers showed 53F, we have found this thermostat is pretty consistently 5F off.
Battery temperature was 37 and 39F respectively as one battery did not discharge at all and the other was at 66%.
This gives me an idea of how long we can run on the batteries.
I know the batteries don’t usually discharge together, but I was surprised that by the evening (24 hours) one battery was down to 36% and the other was still at 100%. I thought they would switch discharge back and forth.
Cheers
Creek

 

[Oregon_Camper]

I know the batteries don’t usually discharge together, but I was surprised that by the evening (24 hours) one battery was down to 36% and the other was still at 100%. I thought they would switch discharge back and forth.

Batteries should 100% discharge together (at same rate), not independent of each other. Wondering if the BMS in the batteries are not working correctly? Feels like the battery at 100% is somehow turned off..?? Do you have a way to access the BMS via BT/app?