Custom Dual Battery Build

[350vudu]

the AAL setup used the 18AH dakota cells, while dakatoa doesn’t make those, they state their 20AH as being in the same size and form factor, meaning you could use their setup and have 80AH. i’m curious if you used the dv8 trunk replacement if that would allow for larger cells

This is not true. Dakota Lithium misspoke or is lying. I ordered the 18AH and got two 18AH and two 20AH. They are not the same size. I held them side by side. The 20AH is slightly larger. Just enough to make 4 of them not fit in that cargo space. It’s fine if you only want to fit 3 or less. I returned the 20AH and sourced the 18AH from eBay sellers.

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[cr117]

https://4xspower.com/products/rsv-s5
That would probably be better but still a little too big and not good bang for your buck. I'm probably going to get one of these https://glowevoltage.com/shop/batteries/glowe-voltage-series-3/ somewhere in the back but it's a little too big for the storage compartment.

Im still confused what the use case is for these high amperage batteries. The Ah are so low, it doesn’t make any sense for powering something like lights or a fridge.

 

[cr117]

It's more for big car audio systems. I wouldn't be playing loud without the engine running.

Ah, that makes much more sense.

 

[roboticsrob]

I think those prismatic cells are the right direction for a project like this. That cell you showed is used in a lot of DIY battery systems you can find tutorials on how to put together online. Stick with LiPo for its safety benefits and get a good battery manager in there with temperature sensing. DC-DC charger run off the vehicle with an optional solar input and you're good to go.

I'd skip an inverter. Its not worth the space, for me at least, as there's so few things I've ever desired to run off of AC power while camping, even less so now that just about all laptops can be charged over USB-C PD. I think I've used the AC outlets on my Jackery once in a few years, and that was in my tent anyway not in the vehicle.

I think the real tricky parts for any of these dual battery systems installed in the rear of a vehicle are the temperature, particularly in the Bronco since it's such a small volume there under the floor, and integrating your ports and charge points cleanly. Curious to hear your ideas on where you plan to add ports back there.

 

[cr117]

I think those prismatic cells are the right direction for a project like this. That cell you showed is used in a lot of DIY battery systems you can find tutorials on how to put together online. Stick with LiPo for its safety benefits and get a good battery manager in there with temperature sensing. DC-DC charger run off the vehicle with an optional solar input and you're good to go.

I'd skip an inverter. Its not worth the space, for me at least, as there's so few things I've ever desired to run off of AC power while camping, even less so now that just about all laptops can be charged over USB-C PD. I think I've used the AC outlets on my Jackery once in a few years, and that was in my tent anyway not in the vehicle.

I think the real tricky parts for any of these dual battery systems installed in the rear of a vehicle are the temperature, particularly in the Bronco since it's such a small volume there under the floor, and integrating your ports and charge points cleanly. Curious to hear your ideas on where you plan to add ports back there.

I'm thinking my charger(s) will be mounted somewhere on the driver's side in the gap between the rear roll bar and the window, behind my molle panel. I want to integrate a board in there somehow to screw in a couple of charging devices (DCDC/AC/solar) and then have all the ports accessible right there, up and out of the way. I agree with the inverter sentiment, can probably get by without needing one these days. I do have a 300W inverter I can plug in on the off chance I do need something to charge via AC.

 

[Chrome_Pony]

Small PC fan or two should keep temps reasonable in there without impacting capacity too much if you were really worried about it.

Interested to see where this goes for modularity. For instance, if you had a tailgate sub, you could use the factory sub box for even more capacity.

 

[AXMRDR]

Also worth clarifying that LiFePO4 is a different chemistry than straight Lithium ion batteries and are much more safe.

Lithium titanate batteries are even more safe the LiFPO4 and the Lithium titanate life cycle is 4 times as many cycles. Pay me now, pay me later sorta thing.

Life is choices and everyone has to make their own. Having options is a good thing.

 

[cr117]

Lithium titanate batteries are even more safe the LiFPO4 and the Lithium titanate life cycle is 4 times as many cycles. Pay me now, pay me later sorta thing.

Life is choices and everyone has to make their own. Having options is a good thing.

Correct, LTO is safer and can go through more charge cycles than LFP, hence the higher price tag. I was just pointing out that LFP is still far safer than standard lithium ion batteries.

The problem with LTO is they’re not ideal for standard 12V electrical equipment (lights, fridge, device chargers, etc.) because their discharge voltage range is really wide and more linear, making it more difficult to hit that voltage sweet spot most devices need to run. They seem like they’d be great for starter batteries or when high amperage is needed, but not for sustained lower output.

 

[CalvinT]

I've read that LTO batteries have a higher self discharge rate and lower energy density than LiFPO4. I think arguments can be made for AGM, LiFPO4 or LTO. It just depends on the application. Heck, there could be situations where an Edison cell, Ni-FE, would be best. It's a 125 year old technology.

https://www.nutsvolts.com/magazine/article/february2012_Noon

 

[Tye]

where did this project end up landing?

 

[cr117]

where did this project end up landing?

Had another kid, project got put on the deep back burner.

 

[cr117]

F- it, bringing this project back from the dead. Found a good price on cells and a BMS, totaling just $184. Can’t pass up the opportunity for a 104Ah battery for that price. Finished with my trailer’s lithium upgrade so it’s time for something new.

 

[AXMRDR]

Had another kid, project got put on the deep back burner.

Congratulations on the new baby.

 

[cr117]

Cells have arrived! On to top balancing them…

 

[j_marinelli]

Cells have arrived! On to top balancing them…

Can't wait to see what you do!

Any chance you could share the link to those batteries so I could see the specs? I'm starting to kick the idea around for making up a power bank of sorts for my fridge so I don't need to lug around the Bluetti all the time.

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