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diy solar

Maximum electrical/fire safety in an offroad-use vehicle

Yurtle

New Member
Joined
Dec 27, 2023
Messages
25
Location
Bailey, CO
greetings all... I know there are thousands of posts on here regarding electrical system safety,
but I'd like to get a thread started about a system I'm building with particular focus on how to maximize safety in this particular situation.

I have a 4x4 E-250 and regularly drive very rough and washboard roads, so the point being to devise an electrical system capable of withstanding very high vibration and relatively violent levels of movement, as compared to a stationary system (where even just small movement caused by much more subtle things like cell swelling, shelving deflection, and heat cycling, etc can have us shaking hands with danger).

The basic concepts I'm currently brainstorming:

1. physical stability: every component needs to be locked down/fastened very securely to a stable mounting point. To reduce vibration of electrical components I'm planning to use sorbothane pads between each item and whatever it ends up mounted to

2. isolation: I (probably stupidly) bought some super cheap LiFePO4 batteries. I'm going to suppose these are likely the highest (fire) risk elements of the system. My plan, which I'll detail more fully as the build progresses, is to install them within a stainless box vented to the exterior of the van. I have a bunch of leftover high temp insulation from building a propane forge that I'll likely use as well (and/or maybe some sort of "fire-blanket"), and I plan to install at least one or more automatic fire suppression devices. The hope here obviously is to attempt to protect flammable materials for as long as possible from the heat and flame generated if the batteries were to blow. I wouldn't expect 100% containment in the event of a catastrophic failure, but at worst these precautions should at least buy time.

3. cable routing and protection - there are lots of sharp metal edges in a vehicle

4. overkill over-current protection - I'm still doing A LOT of reading and research here. I'm very familiar with residential a/c systems, but all the different types and applications of DC Ignition protected fuses/OCP are a bit confusing so far

anyway, more to come, and thank you all in advance for your participation
 
Threadlocker on all bolts. Its incredible how effective this stuff is on my SxSs and motorcycles.
 
The main concern is cell stability, if the individual cells shift you will stress the buss bar connections and the cell terminals. Loose connections, heat/fire.

If it was me I would make sure the batteries you use secure the cells well, if not I wouldn’t use them, not worth burning your truck up. See if there are any tear down videos.

I put mine together using diagonal custom buss bars and mounted on vibration dampers, this is in an off road work truck that sees rough gravel logging roads and off grid projects.

IMG_8937.jpegIMG_8872.jpegIMG_8935.jpegIMG_9093.jpeg
 
Oh and I wouldn’t use anything but DLO cable in a vehicle application especially if running along the frame rails under the vehicle.

DLO
 
Oh and I wouldn’t use anything but DLO cable in a vehicle application especially if running along the frame rails under the vehicle.

DLO
good stuff, thanks.
yeah, will have exterior cables for compressor and winch. otherwise most major wiring should be pretty much inside the van.
will likely use various combinations of conduit/loom/grommets etc



The main concern is cell stability, if the individual cells shift you will stress the buss bar connections and the cell terminals. Loose connections, heat/fire.

If it was me I would make sure the batteries you use secure the cells well, if not I wouldn’t use them, not worth burning your truck up. See if there are any tear down videos.

I put mine together using diagonal custom buss bars and mounted on vibration dampers, this is in an off road work truck that sees rough gravel logging roads and off grid projects.

View attachment 281498View attachment 281499View attachment 281500View attachment 281501

yeah, internal cell damage is my concern as well. I was thinking of building my own batteries but for the short term going with the couple cheap 12v200Ah.
Already searched for reviews/ tear down, couldn't find any...

So you're suggesting I cut open the battery case to assess internal construction and reinforce if necessary?

What size cells did you use for yours?
I've read that smaller cells (<200Ah) tend to be less vulnerable to internal damage in a rough environment. Makes sense, I guess... but quality of manufacture/materials must be a factor as well, which isn't always easy to assess.
 
on mounting fasteners for sure.
on electrical lugs maybe not so safe... need to be careful to not reduce conductance
The lugs are rated at the surface area and not the actual bolt/threads. I'd rather have a tight lug 95% conductive than a loose bolt melting. I'm assuming all commercial batteries use threadlocker or something similar
 
My prior toy hauler camper made it down some roads it shouldn't been on. Very rough BLM and Forest Service roads. My DIY batteries and Victron components did just fine. I had a calendar item that prompted me each year to check all the fasteners. The bolts holding down my cell busbars had no lock washer or thread locker and these were the fasteners that needed retightening the least. I was surprised.

In a high vibration environment solid crimps (without solder!) are critical as is strain relief on every cable.
 

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