Reversed Battery Polarity - Dual Battery Tray Caution

EDIT: Off-Grid Engineering makes great products and are not at fault! I was able to fix the issue with some new fuses and lengthening factory wiring. The intent of this post was to seek TW help about a reversed polarity issue with blown fuses. Everyone's configuration and battery choices are different.

In preparation for a camper, I decided to do a little spring cleaning, then got to installing this brand new "Off-Grid Engineering" side-by-side bracket for the dual battery set up.

The product itself was well machined, but for $200 it could have also had the edges taken down a bit. I had a file handy so no big deal. After all, I already had remorse to make this work (because who spends $200 when you already have a dual battery set up installed).

before:


I was after more space, as with this Off-Grid Engineering bracket, it would put the Blue Sea ACR switch off the factory fuse box (which i can't get into), and make more room for a soon to be installed solar controller. I already had a fuse panel taking up all the other room, so it was this or move the house battery to the other side of the truck. Plus, the new bracket was shiny, and we all love shiny things on our trucks.

Begin take down. Remove two 50lb batterys, some elbow grease, a few holes in the truck, and bam... time to put the batteries back in. Looking at the new bracket, theres no way the battery terminals can face each other without shorting against the bracket. SO i went online and double checked my work, because the instructions had no diagram of the battery installed... just one picture of the tray put in. Sure enough, the pic (below) showed terminals facing out.



So i threw batteries in, connected the pos, then neg, and BOOOM. It arched, horn honked, and i swear i heard the alternator spin backwards. F#*K

Yep. I had done it. The infamous reversed polarity and there I was cursing this bracket. The factory positive cable got plugged in wrong because i had flip flopped the battery, needless to say it was only long enough to reach the negative terminal. SURELY, there should have been some warning or mention that with this bracket, you'd have to re-do, and lengthen the factory wiring to reach the now distant positive terminal.



After scouring the site in panic, I come to realize there is a note about needing to lengthen the factory wiring on the page where it sells this bracket with the complete wiring set up. It needs to say this in the instructions that come with the product, or on the page I purchased it from.

I went from 0-110. Now I'm in shit creek, heart racing. Hoping no damage was done I removed, and REINSTALLED the old set up. As expected, the car didn't start, or even turn over...

I yelled f bombs uncontrollably for about 10 minutes. I got on the phone with a friend and was told to check the fuses. Sure enough, the 140 AMP looked cooked. So I cleaned up my mess (now dark), and went inside to peep TW.

I found that this can be real bad news if it didn't end with the fuses. Alternator, computer, more fuses etc. So I looked up the part number for the 140 amp fuse and am having it delivered tomorrow to begin trouble shooting. I get to find out how pleasant it will be to get this 140 Amp fuse replaced... as I hear its nearly impossible to remove.

I'm going to gather my emotions, and hope I find a solve before towing it to the stealership.

ANY advice from those that have dealt with this is welcomed.

 

I'm sorry this happened to you. However, OGE isn't at fault here for not having enough warning. That negative sign at the battery terminal and the red terminal boot cover on the battery cable are plenty of warnings before hooking them together. You just rushed it with the installation.

 

I’m sorry to hear this happened, the 140 amp fuse protects against over current and shorts. I’m not exactly sure on reversed polarity, but you’ll find out with after replacing the fuse.

I’m not a fan of dual batteries, just biggger batteries and external portable generators. This is my homemade wooden bracket.

 

Im aware of the mistake I made. However, any customer of this product that is more successful than I, and does not connect the battery reversed... is going to find themselves no way to get to the store without uninstalling. Hence Caution in the title.

site:
“No trips to the hardware store necessary”

 

Looks like this guy made a similar mistake. Appears it was just a few blown fuses that needed replacing.

https://www.tacomaworld.com/threads/blown-fuse-wont-start-need-help.467809/

And step 6 of this thread shows how to properly remove that plastic piece to access the bolts that hold the fuses in.

https://www.tacomaworld.com/threads...-box-battery-wire-replacement-upgrade.420450/

 

that second link is gold. thank you!

 

Not a problem man. I can understand the stress you're going through! Just take a deep breath and everything will be alright. Hit it with a fresh mind in the morning.

 

says the guy "EatSleepTacos" love it.

yeah i keep finding thread after thread of people spending 2 hours ripping apart that fuse box. stealership has charged one guy up to $400 to install. Amazon should have it here tomorrow for under $20. here's to hoping the fuse did its job, and all i have to do is DRIVE to west marine for more cables...

 

Yeah reading through other threads that what I was finding too. What a few people did was just use a box cutter to gain access to those bolts, so keep that in mind as an option.

Here's another trick I found from a YouTube video on the subject. The video itself kinda sucks though.

"For those of you fighting the tabs, the little tab goes inward. Once you push the tab inward, use a toothpick or other small thing to keep the tab disengaged. Once you have all four tabs disengaged, then use a flathead screwdriver from both narrow sides to pry upwards. However, don't pry outwards, twist the screwdriver so it grips the side and then lift straight up. It doesn't take much effort."


https://www.youtube.com/watch?v=LO9UgFbt1tY

 

Definitely helps. That fuse box is nothing short of a Rubiks cube

 

From the off-grid image, isn't the trucks's positive connected to the upper right battery terminal close to the febder? Which should have enough length to reach? Yours was connected to the upper left which is negative and the bottom left (positive) seems way tos far for the harness.

Edit just checked under my hood.. no the factory harness cannot go anywhere far

 

The other problem with the side by side tray is it puts batteries uncomfortably close to the oil filler neck, and there is a good possibility it will break the neck if you go offroading.

Speaking from experience.

 

Hopefully it is only fuses blown.

Me neighbor installed a car battery backwards and blew every fuse in the car, but luckily that was it. Then proceeded to complain about the cost of fuses...

 

the hype is real. this is a bit of a pain, but this is the link you need: https://www.tacomaworld.com/threads...-box-battery-wire-replacement-upgrade.420450/

also, you’re gonna need 6 very thin flat heads. or in my case, my late grandpa’s filing kit.

those fuse box tabs are relentless. all in all, after checking all fuses in the cab and in the engine bay, that 140amp and 2 10amp fuses are blown.

waiting on Amazon, then it’s on to seeing the results.

 

Congrats on getting them out!

 

It also puts a lot of weight in one spot.

 

Yall are putting two batteries on your fender?? I feel sorry for the inner fender metal !

 

Truck started. EatSleepTacos you are the man.

While i was in there, i ran some larger and longer gauge wire from the fuse box to the positive terminal, so NOW it can reach and I can use this new bracket.



So out came the old tray (above), and in went the new (below).



Now that the truck runs, I can do a lap to West Marine to make and tidy up the cables... and of course zip tie till I’m satisfied.

I’m gonna give the Off-Grid guys a ring on monday just to make sure they update their site so another bone head like me doesn’t go down the same route. Now I have room for the solar controller, and i can access my fuse box (which I know backwards and forwards now thanks to the help on TW).

100lbs is a lot for one side of the engine bay. For those looking into a dual battery setup, make sure you spend the extra to mount the house battery on the passenger side. When I installled my setup years ago, I was not aware of that option. Fortunately I’ll still use that space for a dual air compressor.

drinks beer

 

Hell yeah man!!! I’m so happy for you.

 

it’s the fuse box cable to the positive terminal that needs to be lengthened. to do this, you have to remove the fuse box! in short, there are easier (and better) way to do a dual battery setup. the only other reason you’d have to do this is for a bigger alternator I imagine.