POLL - IMPORTANT Inspect your battery cables!

[John E Davies]

Note, these pics are from Hull #218 delivered May, 2017. The big cables Oliver installs for the inverter are in fact 4/0 ("four ought") welding cable, with an abrasion resistant rubber coating, for dragging around a shop floor. Unfortunately they are NOT very chafe resistant. They need to be covered in plastic split loom to prevent this, which was due to it lying on top off the steel battery tray in back, when everything is pushed tight into its normal position. This particular damage happened after one camping season, and I subsequently covered the cables. I recently removed the cables entirely to rewire the batteries, and I cut a piece to show exactly what is happening.

 

The insulation in the top pic is worn well over half way through! If the RED one wears completely through and shorts out to the tray, you will have a fire - the tray is steel, and it bolts to the fiberglass floor (which has a heavy aluminum liner inside it) and THAT connects directly to the main aluminum frame by way of its support post. If your cables are not protected, inspect them closely, and repair or replace any that is worn more than this one. If the conductor wires are not cut, you could add a couple of layers of thick self adhesive heat shrink tubing. And cover them completely! There is a big fuse (250 amps in my trailer), but it is "downstream" from this area and it won't blow if there is a problem here inside the box.

FYI these cables also become damaged simply by hanging in the plastic  "pass through" grommets, they are very heavy and they move around when towing, and the grommet compacts and chafes the insulation. The conductor cannot short out there because the surrounding area is fiberglass. NOT so with the main cables and the tray.

John Davies

Spokane WA

 

[NCeagle]

Hull 688, delivered November, 2020 had split plastic loom installed at the factory.  There's also no cable anywhere near the bottom of the battery box or tray - it's all up top - at least on this one which is full with the 2 LifeBlue's.

[Jim_Oker]

It's a bit early in  the  lifespan of my setup to see much  if any wear but thanks for the heads  up to watch for  it.  My setup is the same as NCeagle's. 

BTW, the LifeBlue lithium batteries' data sheet includes the following:

• Short Circuit Protection: 850A for 500µs
• Short Circuit Protection release: 30 Seconds

I do not know enough about the potential risks here to know if this would sufficiently  mitigate against a fire if there  is a short on a cable in the  battery compartment as John describes. From what very little reading I've done suggests, the main goal of this bit of protection seems to be to mitigate against the risk of the battery itself exploding or starting a fire, but would it also be sufficient to prevent a fire if an otherwise unfused cable there in the  compartment s shorts to  the tray?

[John E Davies]

Jim, you can easily add terminal fuse blocks to your positive posts. 

 

John Davies

Spokane WA

Edited March 6, 2021 by John E Davies

[Jim_Oker]

3 minutes ago, John E Davies said:

you can easily add terminal fuse blocks to your positive posts. 

 

Yes, I guess what I'm  wondering is whether the in-battery short circuit protection suffices.  I  imagine there's little to no harm in adding the blocks though (potentially along with cutoff switches for each post to make setting up for longer  storage a tad easier).