Portable Jump Starter

[sea2summit]

The problem with these smart chargers is, they need to sense volts to provide volts. So if the battery is super dead, the boost pack won't sense enough volts to provide any boost.

That is their only downfall. I get it's for liability issues and they don't want to be sued for putting volts to a battery that will explode. But they should be upfront about this one downfall.

I keep a few dumb chargers at the ranch just to jump super dead batteries, like those left in equipment that only gets started once a year.

So those boost packs might still be good. It was a super dead battery that was the problem.

I’m sure that’s true of some but I don’t think they all sense at the battery. They sense demand, probably the resistance across the poles.

 

[Snobdds]

In project farm testing, he hooked them up to vehicle cables to jump start with the battery out. How did that work?

The boost pack is the battery at that point and is it's not sensing any dead or shorted cells.

Put a dead battery in there and it won't work.

 

[Snobdds]

I’m sure that’s true of some but I don’t think they all sense at the battery. They sense demand, probably the resistance across the poles.

It a safety feature to not put power to a shorted out cell, causing that acid to blow.

 

[ArlyA]

So if your battery failed out in the field, you could disconnect the + cable on it, connect your power pack and get home?

 

[LittleBill21]

Most have an override, my taklife one does, and so does my nocco charger, both will fire up with no battery or low battery present, my taklife also provide a 12v cigarette lighter for my air compressor to blow up air mattress, etc, i love it have it 5 years 0 issues

 

[Snobdds]

So if your battery failed out in the field, you could disconnect the + cable on it, connect your power pack and get home?

It will be able to start the engine since the boost pack is sensing it's own power. But you should not leave it in place of the battery. You just have to hope the ECU dosen't run off of battery power instead of alternator power.

 

[2manyrocks]

The Mahindra 3525 I used to own had a warning label not to run it without a battery connected to the alternator circuit. I was never sure why they had that particular warning, but it makes me wonder what would go wrong if you tried to disconnect a totally dead battery and then run a tractor or UTV off a portable jump starter? Mine is charged by a USB charger like you charge a phone with. I'd think something bad would happen to the jump starter if it were charged by alternator power, and I'm guessing something bad could also happen to an alternator that didn't have a battery that could handle its output power?

 

[not2old]

It was probably my 1967 Volvo with an alternator that had a warning not to disconnect the battery while the motor was running as it would fry either the alternator or the regulator. I've made it a practice not to do that to any vehicle just in case.

 

[sea2summit]

The boost pack is the battery at that point and is it's not sensing any dead or shorted cells.

Put a dead battery in there and it won't work.

Mine works fine with no battery at all.

 

[deserteagle71]

The boost pack is the battery at that point and is it's not sensing any dead or shorted cells.

Put a dead battery in there and it won't work.

Went through this a few days ago with my Microstart XP-10 I referenced in my post ^. Tried to start my truck and it was totally dead. Hooked the Microstart to the leads connected to the battery, touched the "jumpstart" button and the truck fired right up.

Then I had to go buy a new battery...the 7-1/2 year old one in the truck would not take a charge at all.