Greyhawk 12 Volt System Upgrade

[Kave&Lucky]

After some issues with our current battery situation, We decided to upgrade our system. Below are pictures of the pre-build upgrade. I will post pictures throughout the build for anyone interested in following the process. Before I go any further I want to give a big SHOUT OUT to my man RoyBraddy, JOF member, who has been invaluable to me as we planned this build.

For reference, we had 2 Interstate Batteries, SRM-29 wired in series that went bad. After talking with RoyBraddy, I realized one of my problems was ALL cables were not the same length which was a major contributor to our problem. So we are replacing all cables from the batteries to a marine battery switch. Also, I wanted to add an on board battery charger as a means of maintaining the batteries in an optimum state during storage. As a matter of safety we will add a circuit breaker in the power line from the battery switch to the coach. We are replacing the interstate batteries with 2 Trojan T-1275 12 volt batteries.

Again, I will post pictures of the build throughout the process. I plan to begin the build this Friday. Here's what we have so far excluding pictures of the 4-gauge battery cables.

 

[reitrof]

Don't you mean in parallel? Or are the batteries 6V that went bad? Also curious about the wires not being the same length? Which wires specifically are you referring ?

Interested in your ongoing install.

 

[Kave&Lucky]

Don't you mean in parallel? Or are the batteries 6V that went bad? Also curious about the wires not being the same length? Which wires specifically are you referring ?

Interested in your ongoing install.

Hey Bruce, t's not what I say it what I meant (At least that's what I hear at home occasionally). Yes, it was 2 -12 volt batteries hooked up in parallel. Also, in the previous setup the positive & ground cables to the 2 batteries were not equal lengths resulting in an uneven drain on the batteries causing premature failure.

 

[Mustang65]

Also curious about the wires not being the same length? Which wires specifically are you referring ?

Interested in your ongoing install.

The length of the cables connected to the batteries positive terminal to the load termination and the negative terminal to the frame ground connector should be as close in length as possible (internal wire resistance). In the RV industry this is a little difficult, but the cables from the battery to the 120 volt inverter should be as close in length as possible, as you will be pumping anywhere from 10 to 100 amps over those cables.

This is really critical in a regular home SOLAR installation, where you may have 10 or 20 batteries in your battery banks, there ALL the cable lengths are critical.

I always recommend that the cables that connect the 2 batteries together should be one size larger than the load cables.

Nice setup!!!

Don

 

[Kave&Lucky]

PLANS? WHAT PLANS! at our house one has to be flexible! As I geared up to get the Cave Away (our greyhawk) out of storage to begin the battery and control board mod, I receive a phone call from my oldest son. Our granddaughter has a fever! Pa's gotta keep her for the day. What great snuggle time we had! So when her mother picks her up after work I'm EXHASTED! So no work on the greyhawk mod.

Saturday we get the coach out of storage and get the control panel and batteries installed, which took longer than expected. Man these batteries are heavy! Below are a couple of pictures. The Trojan T-1275 was a little taller than the standard battery so I had to trim a little area of the door flange for the post to clear the compartment door seal (1st picture). This control board is mounted using (4) 1/4" self drilling screws inside the access panel behind the left rear tires (2nd picture). I've still got to install the circuit breaker on this panel then I'll be ready to hookup the battery cables.

I stopped working on the build Saturday afternoon as it was time for our standing neighborhood "KOLD BEERZ bull session". There's always next week!!

 

[Kave&Lucky]

Well It is Finished finally! Below are pictures of the completed mod. We're pleased with how it turned out. We connected each Trojan T-1275 to the Blue Sea battery switch using 10 ft. 4 gauge battery cables and 4 ft. 4 gauge. ground cables. We grounded each battery to the frame using self drilling screws and the star washers for extra bite. We installed a 1 ft. 4 gauge from the battery switch to the circuit breaker and an 8 ft. 4 gauge cable from the circuit breaker to a Blue Sea Buss Bar where we made the final leg connection to the original connections.

One mod I was not expecting was the T-1275 was larger than the oem battery and therefore the latch would not catch in the keeper hole on the battery box. so I purchased a piece of flat bar and secured it in front of the latch using self drilling screws. (pic below)

Upon completing installation, I turned on a couple lights and used my meter to check the battery drain. Using bat 1 & 2 my readings were 2.3 amps (bat 1)& 2.5 amps (bat 2). Running the batteries individually the readings were 5.6 amps (bat 1) & 5.8 (bat 2). (pics below) Not sure but but I think the .2 amps difference between the batteries is acceptable, do any of you expert think differently? I then used some cable ties to tidy up the install.

Finally, I plan to incorporate LED bulbs over the course of the next few months. Thanks for looking!

 

[carlb]

So one battery in the stock spot and the other one mounted to the frame?

 

[Kave&Lucky]

Yes sir that's correct. The second battery is located just behind the rear spring hanger on the drivers side.

 

[carlb]

Part number and source on the battery bracket? Been looking to expand the system myself as well and the battery box was the more vexing element to source.

 

[Kave&Lucky]

Part number and source on the battery bracket?

Sorry but I designed it and had it fabricated locally. Then I mounted it to the frame. I'll be glad to take some pics and send the demensions of the homemade bracket if you want.

 

[carlb]

Yes please!

 

[Kave&Lucky]

CarlB, sorry it took so long to respond. I was out of town last week at meeting.

I bought this battery tray on ebay.

Boat Battery Tray with Hold Down Strap for Standard 29 and 31 Series Batteries. The tray dimensions are (Overall inside dimensions) 13" L x 7-1/8" W x 1" H

The bracket I had made measures 14” x 9” x 12”. We used angle iron for the tray support & uprights and a piece of flat bar for bracket strength.

I drilled (4) 5/16 inch holes in the frame and bolted the bracket to the frame using lock nuts on the bolts.

I’ve attached some pictures that should help. If you need additional assistance feel free to pm me. Good Luck!

PS: Don't laugh at my drawing please!!!!