Here is how I made a robust lightweight portable jump starter for my car. I love the peace of mind having a spare battery to jump start any car in the event of a weak engine battery.
I got a 99usd, 210CCA, lifepo4 battery from Amazon.com that weighs only 2lbs. My actual car battery is 3lbs and uses the same chemistry! These lifepo4 battery are robust, long life and environmentally friendly.
Using this spare battery I went about creating a portable Jump Starter!
Step 1: High Current Connectors.
Using a pair of XT60 connectors, I went about making a means to easily connect and disconnect battery clamps to my nifty lifepo4 battery.
Step 2: Soldering.
Each XT60 is polarized. The flat side is for positive. I used my 100watt soldering iron to bond the heavy Gauge wires to the connectors.
I had a spare battery clamp with built in diodes to have worry free connections if the wrong polarity was made. If you have non diode protected spare clamps, just verify polarity before connecting the a depleted car battery.
Step 3: Connection of the Battery Leads.
Connecting the leads with the supplied bolt and nut was easily. It's important not to over torque the bolts. Each bolt can be tightened with a 10mm spanner or a Phillips head screwdriver.
Step 4: Insulation!
Using liquid tape in generous volumes, I insulated exposed conductors at the XT60s and at the battery terminals.
Step 5: Completion!
Here it is! My new portable Jump Starter! Since this is based on an engine start battery, I expect the lifespan to be long just like the one for my car's engine.
I had a spare pouch which I used to bundle my latest creation into. Looks neat now!
Not bad for 99usd eh.