Battery jump start packs ....how is it working..magic?

[Iliade]

I bought one this year because I had left all of my batteries ganged together and on charge while running a few instruments to, hopefully, dispel some moisture inside them. When I went to the boat someone had unplugged the shore lead and all of the batteries were flat...

 

[ghostlymoron]

When I was rescued by a battery pack, the cause of the flatness was a faulty diode splitter. This meant that the batteries were not being charged. Also the charging system hadn't been installed correctly and lost 0.7v anyway. I replaced the diode thing with a VSR and had no further problems. I also later fitted a small solar panel which replenished the house battery while on my swinging mooring.

I've just competed an engine room re-wire on a boat with two 6 litre diesels.

Each engine has it's own battery. Each engine can also be started from the other engines battery, or from the domestic bank.

If by some inconceivable circumstance all three banks were discharged and unable to start the engines the generator will power the battery charger.

Not really much need for a jump pack on a carefully planned installation.

 

[PilotWolf]

I've got one. I paid $30 for on some deal. I used it to start the car for about a week before I replaced the battery. Recently we had a power cut and I used the light on it conservatively and thought I'd run it flat before recharging - it took nearly 2 weeks to run flat using the light!

When I worked for AAA they were the go to tool, rarely did I need to use the tow truck jump leads.

W.