DIY LiFePO4 battery system for Camper Conversion

[G8trwood]

Thanks! I laughed out loud when that read that because its true. I have a soft spot for boxes on wheels.

and I almost said a mog and a bread van, just didn’t want to be harsh..... lol

 

[Tiktaalik]

and I almost said a mog and a bread van, just didn’t want to be harsh..... lol

I won't be offended! That's pretty much what they are.

 

[Johnson]

@Positronium

Newbie question: So if I assemble eight of the 100Ah 3.2v Cells from Overkill Solar what will be the total output capacity?

8 cells in series would give you a 24V 100AH battery (2.4kWh)

 

[carl2591]

that thing looks like a bad ass milk truck.. 4x4 at that,, dang.. be sure to check out mobile-solarpower.com to get ideas. That were Will does reviews and gives a lot of help on system set up, components and such.

Hi Everyone!

I just joined the forum and I am relatively new to solar so I thought I’d jump into the deep end right away and build a DIY LiFePO4 System for the Camper Conversion of a Mercedes 814DA that I purchased recently.

Just to give a bit of reference, the van is the older, big brother of the sprinter van with a GVWR of 16,500 lbs and the electrical system in the van itself is 24v.

I’d love to get everyone’s feedback of my thoughts so far so that, hopefully you can steer me in the right direction.

I am considering 8-12 200Ah cells that I would assemble, balance and configure into my own DIY power bank.. Judging from Will’s LiFePO4 DIY video, 8 cells seems to be the max before you have to start configuring things a bit differently. If I decide on 10 cells, would you then arrange the system in two sets of 5 that then join together at some point? What would be the best way to configure a 10 cell LiFePO4 power bank?

There will be 1-2 fans and an AC installed on the roof but the roof is pretty big so there should still be room for 1000 - 1200w worth of solar, roughly guessing.

I definitely want the ability to also power the LiFePO4 power bank with the vehicles 24v alternator. If that means replacing the stock alternator with a marine alternator I’m ok with that or if there is room I would install a second marine alternator that is dedicated to the power bank.

The vans electrical system will remain 24v so I thought that for simplicity’s sake to also have the solar system be 24v with a step down to 12v for certain accessories like phone chargers.

Any tips, advice or thoughts on where I am headed so far? Any recommendations for how to configure this system, what 200Ah cells to get, etc?

Thanks!

 

[Tiktaalik]

that thing looks like a bad ass milk truck.. 4x4 at that,, dang.. be sure to check out mobile-solarpower.com to get ideas. That were Will does reviews and gives a lot of help on system set up, components and such.

For sure! I bought and read his book and am reviewing his site and this forum to learn as much as I can.

 

[Terrapin]

WOW

 

[Terrapin]

No problem! Indeed they are. There's only 3-4 of these in the US right now. I'm not too worried about adding/replacing the alternator. That part I'm more familiar with.

What an awesome beast of a rig...

 

[Tiktaalik]

I love that rig!!!

Thanks! It's shipping out from Europe later this month. Mine's the tan one. The white one is a photo from Mercedes. Perhaps I should create thread on this forum so you can follow long on our solar panel system design and installation of this rather unique vehicle.

 

[Tiktaalik]

What an awesome beast of a rig...

You can check out more on Instagram: @Tiktaalik

 

[GSXR1000]

@Positronium

Newbie question:

So if I assemble eight of the 100Ah 3.2v Cells from Overkill Solar what will be the total output capacity?

Is the math as simple as 800Ah total?

so.... 3.3V @ 800AH - 2600wh
13.2@ 200AH - 2600wh
26.4v@100AH - 2600wh

 

[Tiktaalik]

so.... 3.3V @ 800AH - 2600wh
13.2@ 200AH - 2600wh
26.4v@100AH - 2600wh

So if assemble two of these 100Ah 26.4v systems that would provide 5.2kWh then?

 

[GSXR1000]

So if assemble two of these 100Ah 26.4v systems that would provide 5.2kWh then?

you need to be more exact.. if 16 cells 100ah then yes

 

[GSXR1000]

this is my 7.3KW battery.. I did 12 volt.. but a 8s BMS and move some bus bars you have 24v at 280ah 7.3w

Thread 'Just ordered Lifepo4 prismatic cell 3.2V 280Ah lithium lifepo4' https://diysolarforum.com/threads/j...smatic-cell-3-2v-280ah-lithium-lifepo4.14955/

 

[Ampster]

What would be the best way to configure a 10 cell LiFePO4 power bank?

As others have said, if you want the system to remain at 24 volts, I would configure them as eight cells in series and keep two as spares. Ten cells would be a system with a nominal voltage of 32 volts which would be much harder to find components for, if not impossible.

 

[Tiktaalik]

I could use everyone’s input on my latest solar installation plan.

I plan to build two Lithium solar systems. A larger 24v system using 8 x 272Ah cells that will go in my camper van conversion and a smaller 12v 4 x 272Ah system that will go in my current vehicle.

The van hasn’t arrived so I can’t estimate exactly how much room we have for solar panels on the roof but it’s a big van at 20.5k’ long by 7’ wide so I’m guessing 900w - 1200w would be possible (24v). The second vehicle is smaller and I’m guessing 700w is possible (12v).

With these Amp hours and watts as guideline for these two systems (12v and 24v) what do you recommend in terms of other components? How many Amps should the MPPT be for each of these systems? What gauge wiring should I be using for each of these systems? What size fuses and inverters should I go with? Anything else I need to consider?

Thank you almighty hive mind!