PrivatePIlot
New Member
- Joined
- Nov 26, 2022
- Messages
- 33
Hey all! I'll try to get what I'm hoping to accomplish across here without writing a novel. But it'll probably be a novel, I'm overly thorough LOL.
I'm looking to build a DIY 200AH Lifepo4 system for our tiny camper. We travel extensively with it and upwards of 90% of our camping and overnights are completely off grid or boondocking - overnighting in non-traditional places while travelling.
Currently, whenever we're without services, we're relying on a 100ah SLA for lighting and light 12v loads, and an inverter generator for nights when we need AC.
I'd like to eliminate the need for the generator for overnight AC as in some campground situations without service - running it all night is simply not an option, so we end up sweating and uncomfortable.
Now, before we go any further, I know some people are already doing mental math on "200ah" and "Air conditioner" LOL. This is a very tiny 2200BTU suitcase style AC. The AC wattage draw @120v is literally 200w +/= 10w or so, measured and verified personally, and by many others - these particular AC's are well known in the tiny-RV crowd for their miserly consumption. So, a 200Ah system with my Tripplite 1500w pure sine inverter, having done the math, is more than enough to run the AC for a solid 8-9 hours sleep with some capacity leftover.
Currently, solar is only a few hundred watts, but for faster recharging, the vehicle we tow with is setup with low gage wiring direct from the trunk mounted battery in the vehicle to the battery on the camper - it can pass around 70-90A continuous and the tow vehicle has no problems supplying this via a DC to DC converter as the tow vehicle is a PHEV, but that's another story. So, long story short, recovering ah's to the battery bank through the day while underway and travelling is not an issue.
So, building the pack.....this is where my head starts spinning.
I am in no rush....hence, I'm looking at sourcing a lot of stuff from Aliexpress as it seems like the options and prices just can't be beat.
So, here goes the questions:
- Cells. It seems like there may be some better deals on 100ah cells so I was thinking of going with a parallel-series setup using 8 cells to achieve 200ah@12v. This may work better due to space limtations where the bank needs to go as well. Or I might go with 4 ~200ah cells instead and keep it simpler. Yet to be decided, and will be based on pricing and availability, and size.
- BMS. I want at least a 150a controller so that I can max out the inverter for other loads if wanted. I'm unclear on the requirements for the BMS however - is one designed for 8s backwards compatible with only 4s, or do I have to buy one that matches my cell count?
- Since I live in a cold climate and do go winter camping, I also need a low temp disconnect. And built in balancing would be preferable - or am I better to go with an separate balancer? And bluetooth. LOL. Is there a reasonably priced "all in one" option like this? Recommendations?
Thanks all.
I'm looking to build a DIY 200AH Lifepo4 system for our tiny camper. We travel extensively with it and upwards of 90% of our camping and overnights are completely off grid or boondocking - overnighting in non-traditional places while travelling.
Currently, whenever we're without services, we're relying on a 100ah SLA for lighting and light 12v loads, and an inverter generator for nights when we need AC.
I'd like to eliminate the need for the generator for overnight AC as in some campground situations without service - running it all night is simply not an option, so we end up sweating and uncomfortable.
Now, before we go any further, I know some people are already doing mental math on "200ah" and "Air conditioner" LOL. This is a very tiny 2200BTU suitcase style AC. The AC wattage draw @120v is literally 200w +/= 10w or so, measured and verified personally, and by many others - these particular AC's are well known in the tiny-RV crowd for their miserly consumption. So, a 200Ah system with my Tripplite 1500w pure sine inverter, having done the math, is more than enough to run the AC for a solid 8-9 hours sleep with some capacity leftover.
Currently, solar is only a few hundred watts, but for faster recharging, the vehicle we tow with is setup with low gage wiring direct from the trunk mounted battery in the vehicle to the battery on the camper - it can pass around 70-90A continuous and the tow vehicle has no problems supplying this via a DC to DC converter as the tow vehicle is a PHEV, but that's another story. So, long story short, recovering ah's to the battery bank through the day while underway and travelling is not an issue.
So, building the pack.....this is where my head starts spinning.
I am in no rush....hence, I'm looking at sourcing a lot of stuff from Aliexpress as it seems like the options and prices just can't be beat.
So, here goes the questions:
- Cells. It seems like there may be some better deals on 100ah cells so I was thinking of going with a parallel-series setup using 8 cells to achieve 200ah@12v. This may work better due to space limtations where the bank needs to go as well. Or I might go with 4 ~200ah cells instead and keep it simpler. Yet to be decided, and will be based on pricing and availability, and size.
- BMS. I want at least a 150a controller so that I can max out the inverter for other loads if wanted. I'm unclear on the requirements for the BMS however - is one designed for 8s backwards compatible with only 4s, or do I have to buy one that matches my cell count?
- Since I live in a cold climate and do go winter camping, I also need a low temp disconnect. And built in balancing would be preferable - or am I better to go with an separate balancer? And bluetooth. LOL. Is there a reasonably priced "all in one" option like this? Recommendations?
Thanks all.
