Work truck 12v-560ah no solar.

[S Davis]

Figured I was far enough along to start a build thread, this is going into a 2019 Chevy Silverado with the diesel.

A little back ground, the truck is used for off grid construction projects roads/trails can get bumpy and rough. Also can sit in the ferry line (no idle zones) for hours at a time. System needs to be robust and reliable. This has been a multi year project.

 

[S Davis]

I originally had the idea to build a box for the dc/dc charger, buss bars, inverter and install it in the bed of the truck.

I have a long bed with a 6.5’ cargo body commercial cap installed, this gives me about 1.5’ in front of the cap.

 

[S Davis]

Originally I had four Trojan T-105s in two sets on either side of the inverter box.

 

[S Davis]

I ran 1/0 DLO positive and negative charge lines to the bed from the aux battery for the dc/dc charger and another set of 1/0 DLO run from the bed down underneath and up through the floor under the center console between the front seats.




I added fuses and used this to power a ARB portable compressor fridge and for a 300watt psw inverter to power an electric blanket.

 

[S Davis]

Just a note, if you decide to go through the floor under the center console that is where they hide the airbag module and it’s not good it you happen to accidentally drill through it. Don’t ask.

 

[S Davis]

About this point I found this and other sites about lithium batteries and decided to redo the system with a new lithium bank, I could install them in the cab and not worry about venting.

First order of business was removing the rear seats and building an enclosure for the system to go in.

I used the mounting points for the rear seats and bolted it down.

 

[S Davis]

So the decision was to buy or assemble the lithium batteries, I spent a couple months researching and decided to assemble so I would have a better understanding and could customize the parts list.

After a lot of research I decided to compress my cells as this is being used in an off road mobile application, I didn’t want the cells shifting around causing issues, loose connections, heat, fire.

I purchased 28 LF280N cells from Docan power, and assembled them into 12volt batteries with Daly 250 amp BMS with cells arranged so buss bars run diagonally and made custom buss bars.

.

 

[HarryN]

Looks like a good project.

 

[AnarchyJet]

Never seen the diagonal bus bars before. What is the reason to do that instead of rotating ever other cell 180*.

 

[chrisski]

Do you have an alternate way to charge the batteries? I saw a DC to DC charger.

 

[S Davis]

Never seen the diagonal bus bars before. What is the reason to do that instead of rotating ever other cell 180*.

To lessen stress on the battery terminals from expansion and the other reason is I can compress the cells and parallel top balance without reconfiguring them after for series operation.

 

[S Davis]

Do you have an alternate way to charge the batteries? I saw a DC to DC charger.

Yes, I have a Victron 12/3000-120 Multiplus, but rarely use it for charging. I am charging from the alternator at 50amps and increasing that to 100amps.

 

[S Davis]

So to lessen stress on the batteries I decided to mount them on 1” vibration dampers, I bolted angle to the bottom of the compression plates on the battery and mounted the dampers in the bottom of my battery boxes.

 

[S Davis]

Since this is going in the truck and the batteries needed to stay above freezing and preferably above 50 for capacity, I decided to heat the battery boxes instead of the cells/batteries directly.
I could build two heaters and be able to swap in/out the 5 backup batteries as needed.

I made channels in the boxes and mounted a computer fan up high blowing air across a 25 watt silicone heat element sandwiched between two thin pieces of aluminum. I had this in mind when deciding how to mount the batteries to have air flow all the way around.





I bought four cheap temperature controllers to cycle the heat pads and used a four channel fan controller to turn the fans on and off.



This has worked well down to 7f during the last cold snap we had. The original temperature controllers one by one for un known reasons let out the magic smoke, I found another model and it has been working for a year and a half now.