Question about capacity needs and battery type

Titan_Bow

Member
I'm looking to do a very simple setup of a 100W panel, charge controller, battery and inverter on my M101a2 trailer. I really do not want to spend a ton of money on this. The use is mainly for family camping and winter hunting trips. I dont have a fridge or any other appliance that requires a lot of power. Realistically, I want to have lights, be able to recharge and run laptops, cell phones, GPS.
I was looking on Amazon and saw a 30ah LiFePo4 battery for 165 dollars. Amazon - 30ah Lithium Battery I like the idea of the lightweight and potential portability of this battery. Do you think this would be enough capacity for my needs? The other thought I had, was in an emergency, I would like to jump start my truck battery if needed. Should I just go the route of a deep cycle marine battery or some other "traditional" battery? Or, could something like this 30ah Lithium battery fit the bill?
 

DaveInDenver

Expedition Leader
Work backwards. First define what you need it to do.

You mention lights and charging devices. Make a list of what you mean by that, check their labels to see their consumption. It'll be some combination of volts, current (amps), watts or maybe amp-hours. Next to their power consumption write down how long in hours you expect each to run off the battery.

Once you have a list of device consumption then you can size the battery to support that and next the charging system required.
 

plh

Explorer
Are you sure you need an inverter? And for jump starting, buy a dedicated jump pack.
 

burleyman

Member
What everyone else said about trying to determine loads. After all the math, usage will let you know the truth.

I bought that Eco Worthy battery in September on a lark for a first foray into lithium, to take some load off of a four year old 100ah AGM. I continuously monitor charge and occasionally, discharge current.

With my vehicle's charging system averaging about 14.4VDC at the battery, the BMS limits the charging amps to 30 amps. It shuts off input amps when charged and output at about 10v. Using a fixed load, it seems to provide rated capacity.

Amps drop to single digits at nearly full charge in about an hour, remain at single digits for up to an hour before becoming zero. I don't know what that says about BMS operation. Any ideas or advice? When the amps drop, I generally disconnect from charging. Anderson plugs allow use as a portable to power a 12v fridge.

The BMS limits output, so no good as a jump starter. It would only power a small inverter, probably less 250 watts with no other loads. I've not tested that.
 
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