Hellroaring Dual Battery Install

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Feb 1, 2007
Bellevue, WA
Finished this up last week. Love the results and have a whole new level of confidence that I won't run out of juice. I don't know if the Hellroaring is for everyone as it's main suggested install is to run EVERYTHING (including winch) off the main. I see where that might not always be a good thing, but for me it works well. The theory is simple - you have 3 settings on the HR BIC (Hellroaring Battery Isolator/Combiner) - all these can be controlled from the switch in the cab!
1) Normal = main battery doing the work (use a deep cycle/starter battery for SURE!!). The BIC will trickle charge the backup so it's always in great shape.
2) Isolated mode = just as it sounds
3) Combined mode = if your main runs low use this for starting, if you're winching this will give you 3x the power, or more, than the longevity of just your main (good if you need to winch without engine running, but if it's a HUGE job stop winching if you hear things dragging a bit, then start the rig to charge for a bit, then resume). So, not perfect but I like it. The Powergate might be better for some people. It's a little more spendy but looks to be a damn nice unit.

  • Hellroaring BIC 95300B with Remote Switch and 150 AMP Buss fuse http://hellroaring.com/4wheel.php
  • 4 new marine grade battery terminals
  • New Optima Blue Top (moved my 3 month old Red Top to the back-up position)
  • Slee Battery Tray
  • LOTS of new 2AWG marine grade cable, HD shrink tube, marine lugs in various sizes - got it all here, great prices at about 1/2 of a local marine store: http://genuinedealz.com/
The work is pretty simple but takes time. I built ALL NEW cables, including for the existing main battery with bomber cables, tinned marine grade lugs and all cables and lugs where soldered together with slugs..... these are KILLER http://shop.genuinedealz.com/Marine%20Electrical%20Supply/Solder%20Pellets%20and%20Flux/. That part took a lot of time but I measured things a lot, was patient and just walked through the instructions carefully step-by-step and didn't run into any problems at all.

I plan to use the extra posts on the Blue Top main for the Warn M12000 install in a few weeks.

Slee Tray install was slick, but had to do one mod.. there is this little silver box thing (I know technical term) that was using a bolt that the Slee Tray is supposed to use. I removed it, then mounted the Slee Tray, then reattached the "thingy" to with that same bolt after bending the attachment arm in the vice - easy.

The custom piece I am most proud of is the remote switch install in the dash. I dismantled the switch box, drilled holes in the face plate that surrounds the remote mirror control and used a dremmel to router out enough space behind the plat to install the swtich, light and wires...I LOVE the results... looks OEM to me - well, maybe a stock 3 position rocker switch would be better but I don't think they have one!! I know the heated seat is a 3 position switch but that was a little mutch to tackle...

STILL TO DO - getting rubber terminal covers this week as well

Here are the pics
Wiring diagram (I didn't go to the starter, just straight to the main pos.)
Close up of the BIC
Backup Battery Top view

ENJOY. :grinpimp:


AA Wiring.JPG
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more pics

Backup Red Top
Engine Bay
Main Battery
Engine Bay.JPG
again with the Pics

Opened up Hellroaring switch
installed into OEM mirror surround
Back together (with Tacoma light switch that will be used for the Hella 4000's)
Opened Switch.JPG
new swtich.JPG
Installed Switch.JPG
Looks Good!

Something to think about.
I'm sure lots have survived without this but.............

The 150 amp fuse on the second battery will limit the current out of that battery. Probably OK for starting with a flat main battery for short duration, it probably won't blow, but for winching you may want to go to a higher fuse.
The fuse is an extra resistance in the circuit, therefore it causes a voltage drop across it and heats up and finally blows. Look at the phyisacal size of the fuse, what is it, about 20 AWG or less, yet you run 2AWG cables?
The fuse also causes a volt drop to the winch when drawing high currents. I would be putting a fuse in line higher than what you want to draw from the battery so you don't run into problems when winching or cranking an engine that has just sucked in some water. If you can't get something bigger then you can parallel a couple up together, not the best way, but it will reduce the resistance in the circuit and give you a bit more leeway when high currents are drawn. CCA (cold cranking amps) availability of the red top is 800 amps, and you may want 200 - 300 amps from this battery when winching with the rest coming from the bluetop if is is not already partially discharged.
Personally I do not put any fuses in high current circuits like winch or start applications. Toyota do not fuse their starter circuits, nor does anyone else AFAIK. A winch is like a starter, it is a high current essential piece of equipment which you can't afford to have fuse in circuit to fail. Yes there is one in the charging circuit and everything else, but it's up to you. If you don't fuse a circuit, you need to install it correctly with no open connections, heavy duty cable and protection so there is no chance of rubbing through and shorting out, because if ther is a short then thousands of amps can flow and start a fire.
My thoughts only
Please seek professional advice before doing any of the above.
interesting note... maybe I'll up it to 300 amp? I am NOT an electical guy, just followed the recommendations of the manufacturer.
Then what's the fusible main link?
The fusible main link is in circuit with the supply to the main fuse/relay/junction box under the bonnet. It is 120 amp. In the 03 model he has, it has fusible links for the Alternator 140 amp, 120 amp x 1 for main fuse box and 3 x 120 amp for the junction/fuse blocks. IT does not have any fuses in the main starter motor circuit.

interesting note... maybe I'll up it to 300 amp? I am NOT an electical guy, just followed the recommendations of the manufacturer.
As I mentioned.....I'm sure lots have survived without this t............., I am sure the manufacturer is correct in putting it in there, he has to protect his butt and this helps. What I mentioned before is only what I do and I would not recommend doing it unless you get professional advice.
Totally forget all I have said, have just read the specs for the 75300 and it is good for 300 amps for 20 seconds or 150 amp continuous so go with the fuses the manufacturer recommends or smoke may end up coming out of it!
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thanks 100, your feedback is good as I'd rather have questions and be safe than just do this without any comments. Do you think I should stick with the 150AMP or go to 175 or 200 or more???
ah, great point Christo, if not I'll just go to the main posts....
thanks 100, your feedback is good as I'd rather have questions and be safe than just do this without any comments. Do you think I should stick with the 150AMP or go to 175 or 200 or more???

Stick with the manufacturer recommendation for the fuse (150 amp you said), I hadn't read the specs when I first commented (oops) and thought the product was rated at a higher current rating.

sleeoffroad said:
Check with Optima, not sure if you can connect a winch to those. I know the side terminals are out, but not sure about those little ones.

I previously contacted Optima about the 5/16" stud rating when I was going to install a blue top, but I went with a yellow top D31 (no extra studs) and I can't find the reply from them, but definitely worth chasing up.

If you intend to do serious winching I would put in a manual combining switch which could be wired to bypass the fuse and also bypass the Hellroaring unit. The ideal switch for this would be a dual circuit Bluesea switch No. 5510e which wil handle 300 amps continuous or 525 amps for 5 minutes. This switch has 2 seperate circuits that switch at the same time, one would be used to bypass the the fuse and one would be to bypass the Hellroaring. I doubt you need this but others may need or want it so I mention it for general info. Please seek professional advice before doing any of the above.
Clean install. Looks good.
I installed the same unit 3 years ago in my 80 series. Despite lots of fridge time, I never had to use it to start my truck.

Last week I was in Death Valley running 2 fridges, one set on freeze to keep ice cream. Only 1 morning I had a no start condition. Flipped the switch, waited a few seconds and it fired right up.

I think the HR is a great little unit and worked exactly as designed with a minimum of fuss.

I fused the negative side of the #2 battery and used a 200 amp fuse. The HR cannot flow much more than that so I would not worry about the voltage drop. If it heats up, you want it to blow. I think your 150 amp is fine. If you talked to Mike and he said 150, that's what I'd stay with.

Nice job on the install.
Glad I checked (and glad SLee TOLD me to check) on the Optima - Blue Tops can NOT handle a winch load on the spare 5/16" terminals.... Talked to them directly just now

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