Dual Battery Install-Way Verbose

[Cruiserdrew]

There is more than one way to skin a cat, so I thought I would post up my recent dual battery install using the Hellroaring Isolater/Combiner system. I am not an electrical genius and this system is a bit more plug and play than RavenTai's recent excellent write-up. You do have to fabricate your heavy guage wires and need way more cable ends than Hellroaring supplies with the kit. Since the Hellroaring BIC(battery isolater/combiner) operates on a slightly different design philosophy than the Slee circuit design, I'll go into that first, then the install, and then some pictures.

It all started with a call to CDan. I was buying FJ40 parts and happened to ask if he had a 91-92 battery tray. Yep-instock with all the J hooks, bolts and the works-SOLD. With that on the way, I called Slee, got the washer relocation kit sent out and started investigating the options. I like clean installs and having to find and put together solenoids, switches, shotgun shells, circuit boards and the like was not going to get me up and running before the Norcal Wagons Death Valley trip next week. I wish I had Raven's talent for this stuff, but no. My friend Derek Lee (dclee) had installed the Hellroaring BIC on his 80, and I had seen him run his main battery all the way down by running his fridge in Rubicon Springs. To start, he flipped a switch in the cab and we were ready to go. Nice!

So I called Hellroaring and they had made their BIC even better, with the ability to flow even greater amounts of current without heating up, So I ordered the high end model in their line the 95300B. With this system they reccomend you run all your loads off the main battery, since 99% of the time that is sufficient anyway. Then if you do happen to drain it, you ALWAYS have a fully charged battery ready to go. If you ran your fridge off your back up battery, you could be in the position of draining both batteries and having no start options. You can also combine both batteries fully charged to boost winter starter performance, or for winching. THis produces some real advantages when winching since you get less voltage drop and about 3X the performance of a single battery. All of the isolator/combiner functions are controlled from a switch in the cab. The only down side to this, is that your main battery now has to be deep cycle capable, so I also had to buy a huge Optima Marine Dual purpose-Group31. It barely fits in the tray, but has over 1000 CCA for starting and can deep cycle without damage. For those of you concerned about voltage drop-Hellroaring addressed this electronically and both batteries charge at the same full voltage when the truck is running. They state the voltage drop in the unit is less than the voltage drop of the wire from the main battery-less than .001 volt.

So the first step is to move the washer bottle with the excellent Slee kit, and mount the new battery tray-CDan even sent the appropriate OEM bolts that mount the tray to the body-a nice touch. The first real decision is where to mount the BIC. It is about the size of a deck of cards and needs to be protected from shorts. They reccomend vertical mounting to decrease the risk of accidental shorts to ground. That made sense, and I mounted mine on the back of the new battery box in the space between the box and the aircleaner. That is a perfect and well protected space with short wire runs, but you could mount to the firewall as well. I wanted to keep the wire runs as short as possible and the #2 battery has about 1 foot of 4 guage wire to the BIC.

Then from the BIC to the main battery it took about 5 feet of 2 guage cable. For the cables I used Marine spec wire from West Marine. It's expensive but each strand of the copper is tinned and their cable ends are nice tinned brass, so corrosion is not likely. The Marine heat shrink is really excellent, but pricy. I ran the 2 guage wire from the BIC, between the fender and the new battery box, then behind the overflow bottle and into the factory wire race just in front of the radiator. To get there, I had to dissassemble everything in front of the radiator and that took more time than anything else. The 2 guage wire then connects to the main battery-the BIC uses this connection for it's voltage signal and to pass the big currents associated with back up starting or winching. All the wires were sheethed in flexible conduit and tied down to prevent chafing.

To ground the new systen, I used an idea I got here. There is a 10mm threaded boss at the base of the right side of the engine block. The threads are 10 x 1.25mm and I cleaned up the threads and the boss and bolted in my #2 battery ground wire. I fused the ground side of the #2 battery and that protects all of the #2 batterys wiring in the event of a short. There are reasons not to fuse the ground of your main battery, but for a backup it works great.

The next step was the controller. I mounted the switch to the center console tucked out of the way under the dash. The wires pass under and through the dash, then through the firewall grommet on the right side. This makes for short wire runs to the BIC. Everything again got sheethed in conduit and tied down with wire ties to prevent chafing.

You will also notice in the pictures that I converted to all military spec terminals. This makes the job of bolting the big cables together much easier though you do have to modify your fusible links-the wire connectors have a 5/16 hole but the military terminals have a 3/8 bolt-so you have to carefully drill out the center of the connectors. Be careful doing this as I destroyed one set of fusable links. I had a couple of spares (reccomended, only $12 or so) so no big deal.

The Pics are the BIC mounted in place, the remote controller, and the new battery tray with the cabling in place. I will post a few more pics in another post.

edit-I forgot to thank my friends Alvaro Rodriguez and Derek Lee with helping me with the install and especially fishing the controller wires from the cab to the BIC.

[Cruiserdrew]

A few more pictures of the new main battery, and hopefully my auxilliary fuse panel that runs the power to my accessories. There is also a pic of the fused ground for the #2 battery.

[RavenTai]

"There is more than one way to skin a cat"


Definitely,

Good write up, and the install looks good.
Glad to hear a group 31 will fit, I did not think they would. That makes the optima's much more attractive as the group 31 optima’s are head and shoulders above the other optima’s in terms of available power.

Fusing the negative side is unusual, should work the same and protect the larger wires.

A lot of people like the Hellroaring BIC, this will be helpful.


One favor please, I don’t know how the Hellroaring BIC works; they do not give enough info on their site for me to figure it out. Could you hook a volt meter to both + posts with the engine running and report voltage difference in all its modes?

[cruiserdan]

I REALLY like the pick-tag on that new tray......

[yomama]

Those Blue top Optima's are nice. I had one in the truck same as Drew here, but kept getting this power drain (posted sometime back) my boy had flipped my high/low beam Hella switch and that left my relay on 24/7, also had my CB booster running. By the time I realized what it was, it had already drained the optima dead, I was about to leave out of town, so I threw the trickle 2 amp charger on it. It over charged my second battery (non deep cell as Drew has setup) and when I returned I could smell sulfer in the garage. I figured and have read else where that by using a regular battery and a deep cell is what caused it. So I went to replace my normal battery I had as backup, problem was that big ole optima would not fit in my (where spare tire used to be) battery box. So I ended up buying two new red top's. I'll save that big blue for the boat.

Yomama

[Cruiserdrew]

Yomamma-I reused my starting battery as you noticed but in the #2 position. It's only 2 years old and it seemed a shame to toss it. Plus, this spur of the minute mod ended up being fairly expensive, I'll wait to spend that $150 on a new Optima. For the #2 battery I am planning on using the Optima blue top dual purpose that Costco sells. I have one in my 40 that works great to run the fridge and I've always been able to restart. My 80 sits for long periods without driving, so we'll see if the batteries will self discharge. I doubt it, but if they do, then that's my reason to get the new Optima for the #2 position.

Raven-Will do on the testing, but likely not untill next weekend. The most difficult part of the Grp 31 battery is making the metal retainer fit-it does, but then only one bolt can fit on the end of the J hook. I've been looking around for one inch longer J hooks, but I'll wait to find some stainless ones like the guy at www.stainlesstrays.com sells.

[LabRat11]

Originally Posted by Cruiserdrew

It all started with a call to CDan. .

Man - how many saga's begin that way.

Great write-up!

[bkgiii]

Good stuff...making my Hellroaring installation a little easier. Couple of questions Drew (and anyone else who wan't to chime in):

* rating of ground-side fuseable link, and mfg/part#?
* Any concerns about the #6 jumper (i.e, any need to go to larger?)
* See any reason I couldn't replace the remote module switch with a modified rear heater switch?

[Cruiserdrew]

Originally Posted by bkgiii

Good stuff...making my Hellroaring installation a little easier. Couple of questions Drew (and anyone else who wan't to chime in):

* rating of ground-side fuseable link, and mfg/part#?
* Any concerns about the #6 jumper (i.e, any need to go to larger?)
* See any reason I couldn't replace the remote module switch with a modified rear heater switch?

1-Bussman 200 amp, bought from Hellroaring, but West Marine sells an equivalent.

2-I don't know but Hellroaring is very detailed about this thing and I assume have worked all of this out. You could go with 2 #4 wires to individual poles of the BIC, but I just went with Hellroarings reccomendation.

3-No, it should work, but you loose the led. It is very useful to show when the batteries are charging and when the BIC is on and off, It has other diagnostic modes as well, if it flashes, it means something else. Mine stays on when running (normal) and off when the motor is off indicating isolation of the batteries. In automatic mode (usual) the unit turns on at 13.4 volts to send alternator charge to both batteries. If your alternator is crapping out and can't make 13.4, the unit will not come on and trigger the led-that's your sign to check the charging system.

One thing I didn't mention is the level of info you get if you call Hellroaring and talk to Mike. He stayed on the phone patiently answering questions for 20 minutes. You can tell he is really into the electronics of the BIC unit and makes great reccomendations. I got the idea, he may have been the one to design the BIC.

[Girlslovedirt]

If you have your main battery thats dead and you hit the switch for your back up does it isolate your back up battery from your main ?

[Rich]

Drew, thanks for the pics.

To what ever degree it matters, Optima is rather specific to not parallel their batteries with anything other than an identical model of the same age.

[Big_Moose]

Andy,

Good looking install / nice job!

Can't wait to check it out in DV next week!

Joe

[dclee]

Originally Posted by Girlslovedirt

If you have your main battery thats dead and you hit the switch for your back up does it isolate your back up battery from your main ?

If you're asking if it prevents in-rush, yes. No problems. Trust me, it'll start right up. What Andy forgot was, not only was I running my fridge chock full of goodies for two days in the Springs without starting the engine once, but I also spent quite a bit of time using my 55W camp light to help Andy see what he was doing as he prepared some truly insane peach cobbler in his Dutch oven! The morning we got ready to head up Cadillac, just flipped the switch and she fired right up!

The one advantage of the Hellroaring switch (or similar from Radio Shack) is that it is locked in position. You have to purposely pull up on the switch to release the locking collar before you can change positions. Prevents accidental changes that could lead to dead batteries.

[dclee]

Originally Posted by Rich

Drew, thanks for the pics.

To what ever degree it matters, Optima is rather specific to not parallel their batteries with anything other than an identical model of the same age.

That's if you're using a traditional solenoid or diode-type system. The beauty of the Hellroaring unit is that the two batteries never "see" each other during normal modes of operation (e.g. charging).

[Rich]

Derek, what do you mean that they never "see" each other?

As far as I can tell from Hellroaring's documentation, with the install pictured here, any time the backup battery is being charged it is paralleled with the primary battery. Any time the backup battery is being used to supply power it is also paralleled with the primary battery. If I understand Hellroaring's docs the only time the batteries are not paralleled is when the engine is off and the control switch is not set to combine.

I would guess that whatever concerns Optima has about paralleling dissimilar batteries would apply to this design also.

[Cruiserdrew]

I'll drag this back to the top with a field report. I used the system on a 4 day trail run to Death Valley with the Norcal Wagons. I ran the fridge full time, it was hot 80-90 degrees. Everything worked perfectly, although I never had to dip into the backup battery. My truck sat for a week without running after the trip, then fired right up, so the main optima does not seem to discharge into the backup, even though it's a different battery type.

I'm very happy with this mod. THe Hellroaring unit installs easily and works as advertised. My install must be ok as we pounded down miles of washboard road in the Saline Valley and nothing shook loose.

For Raven-My voltmeter is not digital. I'll borrow one from a friend once he gets back from Columbia and get those promised voltage readings.

[dejablu311]

sorry to drag up an old thread.

Will a 31 group battery fit in the spare 91-92 tray or would i have to go with something smaller?

Also, with the hellroaring unit, since the winch would only used in short spurts and both batteries are charged when the vehicle is running, would it be okay to hook the winch up to the spare battery?

[dfmorse]

Here's a pic of my HellRoaring unit in my dual batt set up:

http://homepage.mac.com/dfmorse/BattProj2/page13.html

...

[nakman]

two quickies: first is a big thanks to Cruiserdrew, I've successfully replicated his dual battery setup, and it's working great. Like you said, one of the more enjoyable mods.

Second is an endorsement of some quality service by Mike at Hellroaring. He totally knows what he's doing, and doesn't mind answering the same dumb question again and again. I ended up frying my unit: didn't have a 2nd battery yet, so I popped the battery from my camper in the 2nd, tray, just to make sure it's all working, etc.. can't tell you how many dumb stories begin with "Well I didn't have the right ____, so I just used this ____ I had sitting around instead."

Anyway, in the pic you can see the 2nd battery installed, also the Hellroaring unit mounted inside the fender, and the ground fuse mounted to the engine side of the battery tray. But pay special note to the location of the terminals.. up front there they get real close to the hood. Turns out if that positive terminal touches the hood, lots of white smoke starts pouring out of the engine compartment. A hole gets welded into the bottom of the hood, and a guy on the trail in a Rubicon ends of giving you a battery cable that helps lower the connection point. So my endorsement is, I completely FUBARed my Hellroaring unit, and Mike gave me a swinging deal on a replacement, in exchange for my "core charge."

Just got the new one this week, and all hooked up today. good to be back!

[Rich]

Everytime I see pics of battery installs without terminal covers I cringe. I cover the negative post in addition to the positive post in order to minimize the possibilty of crowbaring the terminals together with a mishandled tool.

For what its worth, there is more clearance between the bottom of the battery box and the hood towards the center of the engine compartment. Given this, consideration should be given to locating the passenger side battery positive post towards the center and away from the fender.

[YngTLCOwner]

What battary did you end up using Tim?

[Cruiserdrew]

Nakman-glad it worked out! Could you detail what exactly fried your Hellroaring unit with the camper battery? Any 12 volt battery should have worked. I'm about to buy another for my FJ60 as I have liked the one in the 80 so much.

For everyone else, after 6 months of intermittant use, the Hellroaring unit is great. It works as advertized with no "issues".

[Rich]

I'd expect that shorting out the aux battery resulted in more current passing through the combiner than it could handle. Overload, overheat, burned out.

[desertdude]

...and to ad - those terminals on the HR unit are quite close - special attention is needed to keep those from touching.

[firetruck41]

Definitely turn that battery around, so the terminals are farther from the hood and better protected. I wish I had a dual bat set up :^(

[Beowulf]

[HiJack-on]
Nakman,
There are a couple other non-stock items in your engine bay. What's that do-hickey between the air filter canister and the washer bottle? And what's that between the air filter canister and the engine?
[HiJack-off]

-B-

[desertdude]

can I guess? a light and an engine manifold meal cooker