posted this in electrical, but I'll cross post it here too-
Well, the dual battery and fuse block install is done.
I have been wanting to do something about my battery for a while. My 8 year old NAPA battery was getting a bit long in the tooth and I wanted to replace it with something a bit better. I was eyeing up the dimensions of a Odyssey PC2150 and PC1500 to see if I could shoe horn 1 or 2 in my engine bay. The one spot I could get a second Group 34 battery would be near the PS Reservoir/ABS Module. That spot has been earmarked for an air compressor so that was out of play. I wanted to keep the cable runs short and while looking at other setups on the interwebs, I came across a few people who were running dual Odyssey PC1200's. A bit more research and I was sold.
While a smaller battery physically, the PC1200 is certainly no slouch. With 540CCA and 1200 Pulse Hot Cranking Amps (5-seconds) starting would not be a concern. After I got the batterys I actually took the old one out of the truck, hooked it up, let a new uncharged (arrived at 12.5V) PC1200 sit overnight outside in -40C for 12 hours. I wanted to see if one could do the job and the next morning sure enough no problems. I was sold. If I needed it, I could have 1080CCA and 2400PCHA running them in parallel. With 42Ah nomial capacity and 78 reserve capacity minutes it would certainly run any fridge I'd need overnight and then some before getting re-charged. Also, a svelt 38.2 lbs, I was gonna be at just shy of 80lbs for both, the same weight as a PC2150.
Shameless plug, but thank you Enersys for sending me the two batteries.
When it came to controllers/relays/solenoids, I there are ALOT of options. I have been a huge fan of Blue Sea Systems for years and they make some solid 12VDC kit. While a bit on the $$ side, you get what you pay for. I went with the Blue Sea 7622, a 500 Amp magnetic latching (bi-stable) relay which can automatically combines batteries during charging and isolates batteries needed. It draws very low votage, less than 40mA when off and can be configured in a few different isolation modes. The 7622 came with the rocker switch, a nice Contura V, and has the yellow latch on top of the unit itself incase you have any issues with the remote and need to force combine them.
To hold the batteries, I whipped up a bracket out of some 2" 1/8 thick angle iron. Two square nuts and a 7in 3/8x16 bolt work together for the tie down. The top is a piece of 16GA 3/4 square tied together with a chunk of 1/8 flat bar. The ML-ACR is attached via a 16GA bracket, drilled the tapped for some M5 Hex Bolts.
Once I got it in the truck and test fit, I welded it to the stock sheet metal and gave it a coat of paint.
With the bracket out of the way, I could start working on the wiring. I was going to do the "Big 3" upgrade using 2GA wire. However, after looking at where the - Battery to Chassis/Engine ground was, and not wanting to re-run that cable, I stuck with the OEM stuff which looks dead in between 2GA and 4GA. Automotive jacketing is deceiving. Either way, even with my upgraded alternator @ 130AMPs, still in the specs and ratings for that cable. Also, since I got left post positive batteries, the OEM fusebox, alternator and ground cables all reached where I needed them to go. So that was selling point number two.
So, the wiring is pretty straight forward. Blue Sea gives you great wiring diagrams and if you have any questions, you can call their tech support. I wanted to make sure I could run the unit hoirzontally and also wanted to clarify where is best to pick up my grounds, and they were easy to work with and happy to help.
All of the cables on the 7622 are made from 2GA welding cable. They were all crimped and then soldered then wrapped with flex wrap and heat shrinked. Looks good and works great. I actually laughed at the ones I made for the + Battery to ML-ACR terminals because its pretty much the smallest piece of 2GA I've ever seen. I actually had to cut about 1/4 off of each of the copper cable lugs to get it to fit the distance I needed.
I got all the big cables done for the ML-ACR, and man oh man I love me some 3/8 screw top terminals. I just converted my old cables to mil style battery terminals before I did this, but I am in love with screw tops now. To easy.
When I was ready to start running the 2 AMP fused line to the control switch, I realized I needed to get my install done on my fuse panel/breaker, as that's where I wanted to take that from. A few hours later and some CAD (cardboard aided design) a bit of plasma cutting and some bending, some grinder and file work, I had a piece of 16GA formed up and ready to go. Design is nothing crazy, but it does what I needed it to do. Holds the Blue Sea 5025, 100AMP 187 Breaker and my switch for my underhood LED's. Also, on the back, I left space for 3 relays to be bolted onto the back.
Here you can see me using a socket as a spacer to figure out height for mounting. I had my fenders off at this moment, so I drilled the side of the truck and put weld nut son the back side. Beats drilling a hole and using self tapping metal screws. Also, with the lack of space in that area, I had to cover one fuse box. Newer Toyotas seem to have moved to one single big fuse box, instead of 3 separate ones. Either way, I can still get the lid off, check the diagram on the top if I am having any issues and if I had to change out something on the back side, all I'd have to do is pop the - on the 5025, + on the breaker and the two M6 bolts holding it in. I've owned the truck for 4 years and the only fuse I've blown was a towing related fuse. Certainly nothing to worry about to leave me stranded.
Once I got the tray finalized and mounted up, I made the 4GA cables for the fuse block the same was as before. Crimped, soldered, flex wrap and then heat shrunk.
Once the fuse block was installed, and my underhood lights, LED bar and ML-ACR ground was all rounted and out of the way, I could now finish off the in cab wiring for the rocker switch.
and put the switch in, just below the driver steering wheel. Sits by my right knee. I wanted it a bit out of the way since the two red led's are on when the batteries are combined/charging. I was thinking about wiring it up to my dimmer system in the truck, but I just don't have any good visible spots to put switches anymore, and the ones in the center cubby are ear marked for air compressor/locker switches.
So that's pretty much it. Very happy with how it turned out. Went for a quick test drive tonight and everything worked flawlessly.
Some final pictures -
Thanks for reading. Any questions feel free to ask!
