New LiFe for Old Jump Starter (Spoiler alert: it’s a solar generator now)

[Snubeazy]

Hello and welcome to the forum!


Technically you can get away without the shunt-based capacity monitor but then you'd have no good way of knowing your battery state of charge (SoC). It's almost impossible to just use battery voltage to determine SoC for LFP due to the flat charge/discharge voltage curve. I don't recommend skipping this part of the build.

The RJ12 extension jack and Renogy-BT1 are definitely not necessary. Especially if you have a battery capacity monitor since that will tell you how much power is coming in when you're charging.


I used these busbars so that I only had one connection to each of the battery terminals then everything else connected to the busbars that are positioned above the battery. With the 30Ah Amped Outdoors battery on its side there isn't enough room to connect more than one lug and wire to the battery terminals.


See comments about battery monitor above.

Hopefully this helps. Good luck figuring out the best build/system for you.

Thanks for these links! I'll have to go over the LiFePO4 Cheat Sheet to familiarize myself more with lithium batteries. Back to the drawing board. Thanks again!

 

[Bob142]

Wow, it's been a year since my jump starter overhaul system went into service...

I'm happy to report that it ROCKS! I use it constantly and it has not let me down. I still wouldn't change a thing. On sunny days I've been able to power three laptops for the whole day so my family can be outside anywhere and avoid being tethered to a desk. It just takes three quick solar panel adjustments during the day to track the sun and we never run out of juice.

 

[svetz]

I love mine too, great use for an old dead jump starter. Really surprised we don't see more people converting theirs.

 

[Bob142]

Really surprised we don't see more people converting theirs.

I agree. As much as I love building with milk crates, the form factor of the old jump starters make them really great options for DIY portable power.

 

[45North]

I'm staying at a campground with yurts and guess what runs my lights and usb?
Put it outside in morning and host will charge it.
Think I need one of my own when I get home!

 

[Bob142]

I'm staying at a campground with yurts and guess what runs my lights and usb?
Put it outside in morning and host will charge it.
Think I need one of my own when I get home!

Good to hear from you, 45!

 

[45North]

2 phones drained it.
Musta been an old lead acid.

 

[Bob142]

They must not have followed this thread!
Gotta get the lead out and go LFP. Spread the word.

 

[Bob142]

Hurricane Henri is currently projected to punch Rhode Island in the nose. Time to charge up all my backup units. I've got a nice 110W going into the converted jump starter. It'll be topped off and ready in no time.

 

[Bob142]

First component failure of this build: the little Giandel inverter gave out on me. It encountered an overload event, screamed its head off and never recovered. Not sure if I’ll shop around for a different brand or just replace with the same.

 

[Bob142]

Replaced with the same model. It's back in service.