Totally off topic: Anyone interested in a group purchase of LifePo4 cells?

PrivatePilot

PrivatePilot

Ironus Butticus
Staff member
Site Supporter
Forum Sponsor
I'm looking to build a mega Lithium Iron Phosphate battery bank for our camper. I want to eliminate the need for running our generator for overnights while boondocking while still being able to run our little 2200BTU air conditioner overnight for sleeping, charge my laptop, run the electric stove, etc.

I've hunted down some good prices on cells from a very reputable dealer, and ordered a BMS today from one of the manufacturers (JK) on AliExpress.
The cells look like they'll be around $600-$800 from the source I'm looking at for high 280ahx4s.

I may opt for 200ah cells to save a few bucks if something good comes along price wise. 200ah will do what I want, but 280ah is just that little bit better for not a lot less price.

They also have more traditional sizes - a 100ah pack (with a full 100ah ussable, unlike lead acid where only ~50ah is actually usable) could be built for around $400.
Anyone interested, respond here.

My goal is to save some coin on shipping - the more batteries ordered together the better the shipping deal will end up being.
 
I was contemplating building a powerbank for home to load shift to cheaper rates. Being remotely code compliant (and therefore having valid home insurance) smoked that idea. They only accept packaged systems that have been tested and certified to comply with standards. You can't even assemble rated components anymore. Booo.

Good luck with your project, keep us updated on the progress.
 
I’d be interested in your final bar tab when it’s all in. The tech is making leaps and bounds in progress but it’s not cheap ( if done correctly) . Looking forward to hearing all your specs into the system .


Sent from my iPhone using GTAMotorcycle.com
 
The pre packed systems like the Bluetti and such are certainly nifty, but the capacity for the dollar vs what you can build yourself is way low.

That bluetti mode for example, comes out to about 166ah after the conversion, and they want $1800 on sale.

I’m currently spec’ihg ~300ah cells at $110USD each plus shipping on a slow boat (about 2 months) from China. Need 4 to make a 12v pack, so expecting around $600USD ($810CAD). And this is from a very reputable seller, new grade A cells.

Bought a JK 200A 4/6/8 cell BMS yesterday (full Bluetooth programable mode with extreme data feeds, active balancing, high and low temp cutoffs etc etc) from another very reputable seller on AliExpress for $130 with free shipping.

So in the end I’ll have a ~300ah system for around $950 compared to more that double that for half the amp hours.

DIY still makes a lot of sense.

As for code, being in the camper there’s no issues with insurance. On that topic, people who are sensitive to this issue are reportedly just putting their battery banks in an outbuilding….so in the incredibly rare chance that it goes up (LifePo4 is very stable, we’re not talking lithium polymer here) it’s really less of an issue…a shed melts down, no biggie.
 
If I could figure out how to post pictures without resizing them all first I could send you some pics of the battery/BMS I did for my e-bike. I still have a couple of used 72V20AH packs if you are interested. They are still at roughly 80% capacity of their original. There are a couple videos on you tube of guys from Ontario breaking them down to 12V60AH.
 
Thx, but I’m looking at at least 200ah minimum for what I’m looking to do. Not needing to run the generator (or not being able to on some situations) for overnight AC when camping off grid is the ultimate goal. With our super tiny spot AC in the camper I can get around 8-10 hours out of 200ah, which is enough for a night sleep. An extra 100ah is just a bonus for not much more money really in the end.
 
woot said:
If I could figure out how to post pictures without resizing them all first I could send you some pics of the battery/BMS I did for my e-bike. I still have a couple of used 72V20AH packs if you are interested. They are still at roughly 80% capacity of their original. There are a couple videos on you tube of guys from Ontario breaking them down to 12V60AH.
Click to expand...
Use imgbb (or similar) to upload pics and then post link here. Gtam limits picture sizes to save on bandwidth and storage.
 
We ran AC in a small space for about 2hrs to take the sticky out of the air , then could get through the night . Two people in small space make a lot of humidity that adds to ambient air but we got through the nights . The small induction stove ate power pretty quick . The fridge freezer could run 2 days without top up from the alternator. In the last version we put a 250amp alternator on the engine and eliminated the gen set , saves about 300lbs for us .
Make sure you have an extinguisher that will put out a lithium battery fire , I’ve only seen tbe videos but holy crap.
The video of the one burning through the floor of the AirJapan plane was about unsettling.


Sent from my iPhone using GTAMotorcycle.com
 
I think you still need the inverter part of it. How is recharging to be done? If AC you need the transformer and rectifier bit. If DC from an arbitrary input voltage (solar) then you need the DC to DC converter bit. Yes DIY you can pay less for the hardware and pick only the bits you need, but the integration sounds messy.

AFAICT the packaged units are also coming from China. Any idea of the UL or CSA status of those?
 
crankcall said:
Make sure you have an extinguisher that will put out a lithium battery fire , I’ve only seen tbe videos but holy crap.
Click to expand...


Lithium oxide batteries are infinitely more stable vs the lipoly batteries that are the subject of most lithium battery fires.

The *can* catch fire if they are severely punctured while fully charged (not an issue at all if they are installed properly, and not an issue at all in my scenario) or if they are *severely* overheated while charging, something a quality BMS will not allow anyways as it’ll shut down the charge. In short, they’re drastically safer. The only reason they’re not in broader use is that they are almost instantly ruined if you try to charge them when they’re below 0c, but again, quality BMS systems prevent that as well.
 
Brian P said:
How is recharging to be done? If AC you need the transformer and rectifier bit. If DC from an arbitrary input voltage (solar) then you need the DC to DC converter bit. Yes DIY you can pay less for the hardware and pick only the bits you need, but the integration sounds messy.
Click to expand...

I have the inverter already, have had it since our 5th wheel 10 years back, 2000w pure sine TrippLite.

Charging is via an existing 50a charger I already own with a AGM setting which reaches sufficient voltage for a full charge on Lifepo4.

The BMS thoroughly manages *everything* between the batteries and the inverter & charger including output amps, charge rates, temp monitoring, individual cell monitoring, balancing, etc. This is where a *quality* BMS becomes essential kit, and I didn’t spare any expense on the one I bought .

There is no direct connection between the batteries and the draw output or charge input - *everything* in and out goes through the BMS.
 
Last edited:
GreyGhost said:
Use imgbb (or similar) to upload pics and then post link here. Gtam limits picture sizes to save on bandwidth and storage.
Click to expand...
The IT cops at my work won't let my on file sharing sites.
 
PrivatePilot said:
Thx, but I’m looking at at least 200ah minimum for what I’m looking to do. Not needing to run the generator (or not being able to on some situations) for overnight AC when camping off grid is the ultimate goal. With our super tiny spot AC in the camper I can get around 8-10 hours out of 200ah, which is enough for a night sleep. An extra 100ah is just a bonus for not much more money really in the end.
Click to expand...
Check in with Langilles in Port Perry. Mine was originally a 16 packs of 36Vx20AH for $400 (Sorry for quoting my voltage wrong earlier. Forgot I have 2p2s) that came off of a hybrid bus. It was over a year ago but they had lots of other used hybrid bus/car batteries.

I put 4 in my bike, sold the 10 worst as they had already been marked with remaining capacity for roughly $100ea and still have 2 of the better ones left.
 
1669816928849.png

Just flashed across FB. 3.6kwh for $4000.

As per above post I’m building around 3kw for around $1K or under. Again, DIY vs prefab pays. 😉
 
IMG_5744small.jpg
 
Interested to see how this goes I need to do something in our camper as well. Good thing is we have a 12 volt air conditioner unit on the roof I just have to get better batteries Right now it has 200 amp hours of AGM. I have been thinking about adding 300 amp hours of lithium and a 50 amp DC/DC charger and calling it good.

Sent from the future
 
woot said:
Check in with Langilles in Port Perry. Mine was originally a 16 packs of 36Vx20AH for $400 (Sorry for quoting my voltage wrong earlier. Forgot I have 2p2s) that came off of a hybrid bus. It was over a year ago but they had lots of other used hybrid bus/car batteries.
Click to expand...

Thx, maybe I’ll give them a call out of curiosity.

Once you get into higher voltages however then the applications start to vary. For them to be useful in an RV capacity like I’m aiming for them you need to get an inverter that can do higher input voltages. And then a charger than can output those higher voltages (at not insignificant amps) to charge it. Basically you’re into an all in one inverter/charger setup which start well north of $1000 at that point, so the economics stop making sense for a mobile install where 12v is the end desire. It also eliminates the ability to charge from the tow vehicle while underway unless you get into messy step-up transformers which add complexity and cost.


For fixed solar storage installs however the ex-EV higher voltage cells are a hidden goldmine.
Forum Sponsor
 
You must log in or register to reply here.
Back
Top Bottom