MRBF and ClassT together?

[gr8pix]

Hello, confusion again about wiring connecting 2x 24v 200AH batteries in parallel. I recently decided to add another 200AH 24v battery and am confused about the fusing requirements and would be grateful for any suggestions. Originally with one battery I had a 225A class T in between the battery and the Lynx distributor. In parallel, should I be fusing the positive terminals on the batteries and then connecting to a bus bar, and then fusing the bus bar to the Lynx with another higher rated class T? The MRBF would be 225A on each battery and the Class T 400A in between the bus bar and the Lynx? I'll be up-sizing all the 2/0 wire to 4/0 as well.

 

[MisterSandals]

I'll be up-sizing all the 2/0 wire to 4/0 as well.

Why? Have your loads doubled since you added a second battery?

3000W / 20V cutoff / .85 efficiency = 176A

Originally with one battery I had a 225A class T in between the battery and the Lynx distributor.

If it were me, i'd put a 225A class T on each battery as well as a cutoff switch for each and feed that to the Lynx.

 

[gr8pix]

Why? Have your loads doubled since you added a second battery?

3000W / 20V cutoff / .85 efficiency = 176A

If it were me, i'd put a 225A class T on each battery as well as a cutoff switch for each and feed that to the Lynx.

No the loads haven't doubled all still the same, so I'll stick with the 2/0 for the wire.

I can add another Class T 225A and cuttoff switch and attach with one of these rated for 250A to the Lynx

Amazon.com

 

[MisterSandals]

I can add another Class T 225A and cuttoff switch and attach with one of these rated for 250A to the Lynx

I was pondering your BMV wiring. I think the BMV positive sense wire would connect to where the battery positives are joined.

I am second guessing and wondering if you anticipate needing to run with one battery. If not, perhaps connecting the batteries in parallel first might be simpler. Then a single class T and single switch.

 

[gr8pix]

Thank you, that's a good point about the Smartshunt, I don't anticipate having to run with only one battery and from what I've been reading it's pretty much plug and play in connecting in parallel as long as both batteries are installed at 100% charge. As for the Class T sizing should I stick with a 225A in parallel?

 

[gr8pix]

I was pondering your BMV wiring. I think the BMV positive sense wire would connect to where the battery positives are joined.

I am second guessing and wondering if you anticipate needing to run with one battery. If not, perhaps connecting the batteries in parallel first might be simpler. Then a single class T and single switch.

One other thing I forgot to mention is that to two batteries are not going to be side by side, one will be under the steps in my RV and the other will be in adjacent and above it in the interior, the terminals on both will be around 12"-18" apart from the Lynx, se a quick photoshop piece together

 

[MisterSandals]

My gut feel is that with 2 different locations for batteries, i'm back to fusing each, cutoff for each and joining at the Lynx.

 

[gr8pix]

Haha! I was thinking the same thing myself when I look at the photo, the perspective is off so it looks like the distance is greater than it actually is. I'm open to anything that's safe. What about connecting to a busbar with the same length wires? Then to the lynx so the smartshunt can work as intended? I did the measurements from the terminals on the battery under the steps and it's 14" to the bluesea disconnect switch attached to the lynx. I have to contact Redodo to see if the battery can be mounted upside down or else that adds another 8". to both.

 

[MisterSandals]

What about connecting to a busbar with the same length wires?

Or equal length wires to the class T, then everything else is as you have it.
Quite a few ways that will work. I always look for easiest safe way with the parts i have on hand if possible.

 

[gr8pix]

Unfortunately, it's not that easy to get anything in Mexico, but I'm pretty much an hour's drive to San Diego where I have a mailbox and lately I've been frequenting regularly with this project. I'll update you tomorrow & thank you again for your help MisterSandals, you're an amazing dude!

 

[gr8pix]

Or equal length wires to the class T, then everything else is as you have it.
Quite a few ways that will work. I always look for easiest safe way with the parts i have on hand if possible.

When all else fails read the manual that came with the battery ;-) It says to charge both batteries to 100% separately, then bridge the positive & negative terminals and let the batteries sit for 12-24Hrs. to equalize, then wire the plus and minus loads to bus bar's, then Class T, disconnect and shunt. Easy peasy!!! Thanks again on this one MisterSandals

 

[gr8pix]

My gut feel is that with 2 different locations for batteries, i'm back to fusing each, cutoff for each and joining at the Lynx.

How does this look for my fusing? I'm concerned about that trailer wire joining the batteries, and it it even needed as the batteries are connected at the bus bar with equal length wires, also is a fuse needed between the bus bar and the disconnect switch at the Lynx? The other option would be to fuse each positive terminal with a MRBF fuse and stack the trailer wire on it.

 

[gr8pix]

My gut feel is that with 2 different locations for batteries, i'm back to fusing each, cutoff for each and joining at the Lynx.

I decided to not put one battery above and have them both on the same level, the distance from terminals is now only18in apart.