Planning to build a lithium portable power station

Zimm

New Member
Joined
Apr 7, 2022
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3
I'm interested in building my own Lithium battery power station. I spent a morning reading blogs that I'm realizing are geared more towards amazon clicks than getting any specifics. So I came here hoping for some real knowledge.

What I want to do is build a better jackery/goal zero box with a replaceable battery and more customization.

Goal: To have a box that can: Serve as power back up in my home during a power outage to keep the internet on and my fridge running. Go camping and supply power to all the electronics. Ride in my Jeep as power my ARB 12v fridge instead of sucking down the main battery, yet recharge while driving.

Features: Inverter (2000w?). DC charging to charge up while driving in my Jeep. AC charging for charging at home. Solar controller for add on ability later for using a solar panel. Some kind of fancy display because I'm geeky like that and want a good battery monitor. AC plugs, USB/USB-C ports, 12VDC outlet, the typical stuff. Plan to stuff it into some kind of pelican type case. Battery- LiFePO4 100ah?

Does anyone have a write up or place to start looking or more info and recommendations for specific components?
 

joanna_lannie

Maybe sleepwalking now
Joined
Sep 14, 2021
Messages
190
From what you're thinking, it seems like what you need is a DIY LiFePO4 battery pack. First of all, you must confirm the LiFePO4 battery capacity, because if it is too small, you will not be able to use it, and too much will cause waste. It should be noted that if you plan to use it for a long time, it is best to choose a battery with 20% more capacity than you expect (since the recommended depth of discharge for LiFePO4 batteries is 80%). In addition, when DIY batteries, you need to buy some batteries with a good brand reputation, otherwise you will regret the battery quality for a long time. Some OTS batteries are also great options if you don't need to DIY. Also, I'm curious, are you going to be constantly switching the battery between jeep and camping and UPS?
 

chrisski

Solar Boondocker
Joined
Aug 14, 2020
Messages
3,398
Here is my build. I used 50 amp Anderson plugs for a removable battery. There’s a parts list with links.


This is not back up for your house, but is the other things you asked for.

For your house you need a power audit of what you expect to run at a bare minimum. This 300 watt inverter wont run a propane blower motor to keep your pipes from freezing but will feed a family of 4 with meals cooked from a crock pot.
 

Zimm

New Member
Joined
Apr 7, 2022
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3
So doing some load calculations:

Home backup loads: DC powered
Internet modem: 2 amps @ 12v. = 24 watts
Internet router 1.1 amp @ 14v = 15 watts

AC:
Kitchen Fridge: 6 amps @ 115v= 700 watts = 67 amps from battery (85% loss inverter)
Charging brick - 2 amps @ 115v = 230 watts = 22.5 amps from battery (from inverter)

So the fridge really depends on how much it runs. If it was constantly, that 100 amp/hr battery will be done in about 90 minutes.

As for use in the Jeep- the ARB fridge pulls 7 amps @ 12v = 84 watts while running. Assuming a 50% duty cycle and 80 amp/hr useable from battery, that's 22 hours. So at least a day which is fine, I'm usually traveling each day. Or that's where a solar panel comes in to augment.
 

chrisski

Solar Boondocker
Joined
Aug 14, 2020
Messages
3,398
Best thing I found to calculate AC loads is use a kilawatt meter at the hottest time of year.

Also, may seem a 1000 watt inverter will need to be several times the size for start up wattage. There is no hard and fast rule about whether you need a 2000 or 3000 watt or bigger inverter, seems you need to search real hard to find someone who uses that inverter, or buy and hope for the best.
 
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