Blue Sea Dual Battery Install

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mtkreitz

mtkreitz

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Location
Phoenix, AZ
I bought a Blue Sea add-a-battery kit (P/N 7650) a few weeks ago and figured I would get started on installing it. I searched the forums for install tips with this kit, and didn't find anyone who had installed this exact kit. So I figured I would chronicle it for those who are thinking about it.

Here is what I want to accomplish by installing a dual-battery:

1) When camping, I want my radio, head/dome lights, cigarette lighter, etc... all running from the auxiliary battery (only).
2) When I forget to turn off the dome light at the airport (never happens) I can self-jump from the auxiliary battery.
3) Auxiliary battery should be charged automatically. I do not want to have to flip a switch to make it happen.

That's it! I do not have a fancy winch or refrigerator that I plan to attach to it yet, but perhaps in-time.

I needed a few other things before I got started. CBT supplied me with most of the parts:

1) PS battery box (74403-60100)
2) Battery hooks & nuts (74551-60040/90080-18071)
3) Battery bar (74453-60060)
4) 4-AWG battery cable (RED) Napa (736108) - Battery Switch
5) 4-AWG battery cable (Black) Napa (736102) - Battery Switch
6) 1/0-AWG battery cable (Black) Napa (736150) - SI-ACR
7) 1/0-AWG battery cable (Red) Napa (736121) - SI-ACR
8) Ring Terminals 4-AWG & 1/0-AWG (TBD)
9) Scosche EWFH Single ANL Fuse Holder (4x)
10) Scosche EDB 9.5mm to 6.5mm Quad Distribution Block (1x)
11) Scosche EBT Battery Terminal with ABS Cover (2x) - *Note* - Both terminals have a (Positive +) on them that I do not like. It makes it a little confusing to look at. I looked for a (negative) version but could not find one. I plan to use a Dremel to remove the (positive +) from the negative terminal.

I plan to make a custom windshield washer bottle relocation bracket, which I will add to this thread later. If it works out well, I will post a drawing.

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subscribed = post up your progress MK ~
 
It has been a few weeks since I posted that I was going to attempt this, thankfully it is now (finally) done. I will do my best to recount all the steps.

I also changed some of the parts that I used. If anyone is TRULY interested in duplicating what I have done, let me know and I will post up the length of the individual cables so you will know how much 1/0 battery cable to purchase.

If I had the chance to do things over, I probably would not have added the manual switch. It requires a LOT of labor and 1/0 cable, and is really only useful to completely disable the house load, or to self jump. If you simply keep a set of jumper cables in the truck, you can accomplish a self jump without the cost or complexity.

The first thing I needed to do was install the 2nd battery tray. As I have seen in other threads, it does not fit exactly, and requires some trimming around the radiator shroud. I used a cut-off wheel, but be careful. The plastic material heated up and melted as the wheel cut through it, throwing hot plastic at me.

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I did not need to modify anything other than the one side of the battery box (that faces the radiator shroud). It bolted right in. Since I chose to install the dual battery isolator near the 2nd battery box, it was necessary to remove the air filter canister to gain access. Had I known this at the time, I would have removed the air filter canister as it probably would have made installing the 2nd battery box a little easier.

Next the hard part. Running all that 1/0 battery cable. The thickness of the 1/0 cable makes it very difficult to bend and manage. The first thing I did was make a diagram of what I intended to do, and sent it to Blue Sea for confirmation. They were very responsive and validated my proposed setup. With that confirmation, I began running the wiring.

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The main problem is the volume of the large diameter cabling to run. At $7 per foot, it is also important to find the shortest route. I chose to run the connection between the house battery and the starter battery across the front of the truck. This required removing the core support. Once the core support was removed, I was able to run the cabling, tie it up neatly with wire ties and put it all back together.

The next challenge was getting a new connection to the starter. This was one of the downsides of using the switch. I could have used the old starter cable and created a junction, but I preferred to keep it as clean as possible. There is also not much room to work on the drivers side, so I removed the starter battery box as well. This allowed me to run the connection from the starter battery, the starter and the house loads to the switch under the charcoal canister and ABS system. It wound up being a fairly tidy installation, but I am still wondering if I broke anything (existing) while trying to muscle all that cabling into place.

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Then I installed the charging isolator and ran the cables to the fuse and battery. I wound up not liking the acrylic Scosche fuse holders, so I changed them out with Megafuse holders by Littlefuse Inc. It was necessary to trim off the small mounting posts on the base (and a little around the cable opening) to make room for the 1/0 cable and cable lugs. But in the end, the holder is much tougher and looks better than the Scosche unit. I also went back and added wire loom to all the cabling.

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Thankfully I turned the switch and everything seems to be working as it is supposed to. The batteries stay isolated when the engine is NOT running and all of the house loads draw from the 2nd battery. Once the engine is started, and the battery voltage goes above 12V, the little green light on the isolator comes on, and it begins charging the 2nd battery.

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Nice install Mike! :cool:
 
I asked the same question when I started the project due to the cost of the copper. The answers that I received varied, but most leant toward 1/0. You could probably get away with less, but I wasn't willing to risk it with all the work involved.

Landcruiserphil, what are your thoughts about this?
 
Considering the relatively short lengths involved under the hood, 1/0 is overkill. Especially based on the diagram at the top indicating the links are fused at 100 amps. (I am a fan of "overbuilding/overengineering" too, but if cost is a factor, many might shy away based on thinking they need 1/0).

Here is a helpfull calculator - http://www.bulkwire.com/wireresistance.asp

Even at max rate (100 amps for this example) for a distance of ten feet, it only calls for #6, six feet only calls for #8. Much less expensive and easier to work with. (Personally I would not use anything smaller than #4, but that's me)

We all have a tendancy to use a much larger wire than necessary. This of course depends on what YOUR actual usage and needs will be. I tend to use #2 for a lot of what I do simply because I have a couple spools of it at the house.

If you plan on adding a more substantial load to the system down the road, nothing wong with building it today with that in mind, no need to spend the time and money twice. If your load will be relatively low and you just want the safety and gee whiz factor of dual batt's, save yourself some money.

Hope that helps.
 
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One quick comment; you may want to make sure you have a good solid 1/0 wire from the engine connected to the chassis. Motor mounts make bad conductors, and you don't want to weld gears and bearings with stray current.

As for bendable wire, buy tinned marine grade (lots of strands); more expensive, but super flexible.
 
I installed twin grounds on each battery using #4 cable, directly to new aluminum ground lugs attached to the body in addition to the ones directly attached to the block (2x). We grounded good!
 
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