Low cost DIY Lithium camper batteries.

[rruff]

I am thinking of diving into the LiFePo deep end, with the above batteries.... unless there is less expensive option available?

Those are listed as EV cells and cost $0.312/Wh.
These are only $0.125/Wh and would be easier to deal with:https://www.alibaba.com/product-detail/-2000-Cycle-Life-Lithium-Battery_60858707229.html?spm=a2700.7724857.normalList.121.5fc45e9fcebNbO

 

[Vic Harder]

Wow, thanks!

 

[buckland]

ruff,,, are those comparable to soldiering 30 cells (parallel) in a pack? If so one would connected four (in series) to have a 13.8 V 100 Amp Battery?

 

[rruff]

ruff,,, are those comparable to soldiering 30 cells (parallel) in a pack? If so one would connected four (in series) to have a 13.8 V 100 Amp Battery?

They are listed as 100Ah capacity and 3.2V, so 4 in series would give you 12.8V and 100Ah.

I know nothing about them other than what is listed. No idea if they will perform to spec. Or what they charge for shipping, although shipping from China tends to be pretty reasonable.

 

[cwdtmmrs]

It looks like you could put together a 200 AH battery that would measure about 13"x10"x6.5".

 

[cwdtmmrs]

I am corresponding with battery manufacturer now. The 100AH batteries are sold out. They do have 90AH battiers available. I have attached the spec sheet. Price per piece is $40USD and Door to door shiping to SoCal is $168USD. For a 180AH (8pcs) delivered would be a total of $468USD or $2.71/AH.

 

[rruff]

Great, let us know how it comes out.

 

[cwdtmmrs]

I will if I decide to go that route. I don't have or intend on adding solar. I only have alternator charging.

 

[rruff]

Solar is easy these days. You could get a folding panel that doesn't take up much space. They are handy too because you can park in the shade and set them out in the sun.

 

[cwdtmmrs]

Solar is easy these days. You could get a folding panel that doesn't take up much space. They are handy too because you can park in the shade and set them out in the sun.

I know, but it just one more thing to deal with. I haven't needed solar in 11 years and don't plan on adding it now.

 

[Stokeme]

Two cents ... “if” you are pre-wired for solar, a great way to stay topped off when not driving around for a couple days, is a portable Flex soft cased panel, w/handle 5lbs, ~ 1/4 thick when folded. You will need to add a better solar controller to this setup, than what is provided with the panel. It is crap. A good stand alone controller mounted in Camper, or a decent in-line type from the panel, if this is all you will use. Pretty bulkless. Straight forward splicing required. No roof mounting needed. Directed at the sun this gives my roof panel setup a good W boost. One year usage, so far so good. I do have a good Victron controller.

 

[rruff]

Thanks for your feedback on those panels. They have a 200W model for $240 also. I was think of wiring it 24v (better for long extensions) and using MPPT.

Also, I just ran across this site: https://batteryblocs.com/batteryblocs/

It might be of interest to someone using individual cells. I think it will work on the ones mentioned in the OP.

Edit: Doh! No they won't fit. Our cells are 32mmx70mm.

 

[buckland]

That would have saved me a number of hours soldiering all those cells together!

 

[Vic Harder]

I am corresponding with battery manufacturer now. The 100AH batteries are sold out. They do have 90AH battiers available. I have attached the spec sheet. Price per piece is $40USD and Door to door shiping to SoCal is $168USD. For a 180AH (8pcs) delivered would be a total of $468USD or $2.71/AH

CWD... did you end up getting these? I am getting closer to buying batteries for the next build, and seriously looking at LiFePo. I need about 300AH because the wife wants an Induction Cooktop (1800W = 144A draw on high!)

I spotted these guys on Alibaba, https://www.greensunpv.com/lifepo4-battery-12v-24v-48v-lithium-iron-battery_p62.html
and frankly, I find shopping there rather intimidating.

Any leads anyone has on DIY or pre-built would be most welcome!

 

[ckent323]

Vic,

As I recall Alley Kat had an induction cooktop in his camper at one time. You may want to contact him for his experience as I think he has removed it now but I cannot recall why.


Regards,

Craig

 

[Vic Harder]

I still get about 4-8A of charging out of my alternator, even at 13.5V, so I wouldn't totally write off alternator charging. It is way less current than you could get out of the alternator, but is about the same as winter time solar charging.

Another inexpensive option I think I mentioned earlier would be to add a DC-DC converter and wire the output to the input of solar charge controller (assuming an MPPT charge controller). Something like this would get you at least 20A of alternator charging if your MPPT is rated for it:
https://www.amazon.com/uxcell-Converter-Regulator-Transformer-Waterproof/dp/B01LWXI4IE/ref=sr_1_7?ie=UTF8&qid=1512316135&sr=8-7&keywords=30a+dc+to+dc+boost+converter

With 2 blocking diodes (one on the DC-DC converter and one on the feed from your solar panel) you wouldn't even need a switch or anything - it would just work whenever the alternator is running.

rando, can you add a bit of info to this idea? I get that the blocking diodes prevent pushing voltage back into the PV array. What I don't get is how the two "inputs" 1) PV and 2) alternator output converted to 24V by that Uxcell --- are connected.

Would you put them in parallel? If so, how would the Victron MPPT (100/50 model) react as it tries to manipulate the input load/current to optimize the output of the PV array, which is now in parallel with an entirely different kind of output device?

Not to mention my confusion about the spec's on that Uxcel... last I checked 30A at 24V = 720W, not the 360 that Uxcell device is listed as being.

I've also tried to find out what I can realistically expect my alternator to put out. As we've noted before, it is kinda "spicy". I believe I have a 145A alternator, and have seen it dump 80A into my AGM batteries, but only for a short time. LiFePo batteries could suck in more, and for longer. That Uxcel would limit the current... so something like 30A (if it is a 360W device). Would that be a level the alternator can sustain for a full day of driving (plus all the other stuff that it has to keep running as well)?

 

[cwdtmmrs]

CWD... did you end up getting these? I am getting closer to buying batteries for the next build, and seriously looking at LiFePo. I need about 300AH because the wife wants an Induction Cooktop (1800W = 144A draw on high!)

I spotted these guys on Alibaba, https://www.greensunpv.com/lifepo4-battery-12v-24v-48v-lithium-iron-battery_p62.html
and frankly, I find shopping there rather intimidating.

Any leads anyone has on DIY or pre-built would be most welcome!

Vic, I did not. I set up an account with Alibaba a few years ago, but have never purchased anything from them, but I have purchased quite a few items from Aliexpress and they are essentially the same company. Alibaba is more business/wholesale and Aliexpress is retail/individual. I would buy from either without worries. Sometimes I get delivery faster from China than from across the USA

You know....it's not just the 1800W Cooktop. Then you need a bigger fridge to carry the extra food and ingredients that needed for the Cooktop. And the food processor to prepare the ingredients, pluss the vacuum sealer for the leftovers from said Cooktop. The waffle maker, don't forget the waffle maker! I'm thinking 500Ah!

 

[buckland]

Hello again rando !

I am at it again after a long winter hiatus. I had to read and reread the thread and I printed out all the photos so I could repeatedly look at them in the workshop. If you have the time and are willing I am, I think, nearing the end. I will attach photos where you can see I nearly copied your set up. I finally completed the soldering of all the cells into packs of 30. Then set up as you did, putting them into series at a junction box. I put jumpers as you did and have the individual four packs shrink wrapped. I am a bit worried that a solder may pop in time. I am not sure how I would know if that happened? These cells had over wintered in my barn workshop which is not heated. I tested with my Fluke meter and each pack was 3.2/ 3.2/ 3.3/ 3.3 Volts. After I then put these four into series I tested and it was 13.22 Volts.

Here is where I stopped. I reread what you sent me and as time has gone by since I need to ask a few questions as I’d hate to screw up at this point. You can see I have 2 battery management balancing gizmos. I am not sure if I need them both and certainly don’t mind using both as I have then.

One of these is on the top (the one with the screen to see the voltage and adjust) and the other beneath next to the circuit terminal. Here is where I need real concrete guidance in steps

At the terminal….

As I have the (2) battery balancers, with the clips with five wires, I’ll ask:
about the orange one which is next to the terminal
2) about the one like yours on top …. where those five wire wires are attached (to the terminal as well… same colors connected as the first balancer?)


3) I think I understand from your previous description but I definitely need to be told twice (sorry). Am I correct the two holes (-B and -C/-P) are for the Main Plus and Minus battery terminals ?

4) Do I then solder the 5 thin colored wires from both balancers to the terminal block?

Included in photos is the new replacement controller (I will have 260 Watts solar) and the current battery box which will hold the new lithium batter and controller

 

[buckland]

I thought I’d also ask if it is possible to put this battery pack on a charger/tender. Attached is the 4 amp tender which states on the box in the top corner that it is good for LiFePo4 12 volt.
I still have yet to attach the battery management monitor. Does this need to be done first?

 

[rruff]

You don't need a tender for LiFePo4, and I wouldn't charge it without monitoring the voltage.