Repairing a Battery Jump-Starter

[peterh]

A few years ago I bought a Black & Decker "jump start" battery, one of those portable batteries that you plug into a small included wall charger and has built-in jumper-cables so you can jump-start a car with a dead battery.





They also work as a short-term way to keep the lights on if your trailer battery goes dead. Problem is, like all batteries the battery inside the jumper can go dead, too, and it doesn't help that they use really cheap batteries when they make them.

So mine went dead. During my LED demonstration at the Oregon Gathering my jumper battery couldn't even run my sample display for an hour. It should have kept going for four hours. So I am left with the choice of spending $55+tax for a new jumper battery with the same cheap battery inside, or disassembling the unit and replacing the battery inside with a better one. What do you think I did?

This is what the charger's innards look like with the old battery, and a reference picture of how the battery wiring works. (I love digital cameras: Instant documentation so I can keep which wire goes where straight!)





I bought a replacement AGM battery from a local store called Batteries Plus for $36+tax. It wasn't an exact replacement; I had to drill holes in the new battery's leads so they would allow me to bolt the cables to them. (Actually I drilled and tapped threads into the leads, but used the original nuts that were used with the old battery.) Here's the new battery installed before I closed the case up.





It works just fine, and saved me $25.

[Ed Harris]

Peter
If you can find an alarm system supplier these batteries can be purchased for a huge discount.
I buy them for both alarm and emergency power uses and for Ham radio too.

To give you an idea I pay under $15.00 for that 12ah model.

Ed

[peterh]

Peter
If you can find an alarm system supplier these batteries can be purchased for a huge discount.
I buy them for both alarm and emergency power uses and for Ham radio too.

To give you an idea I pay under $15.00 for that 12ah model.

Ed

Ahh. Now you tell me!

[Morgan]

Peter
If you can find an alarm system supplier these batteries can be purchased for a huge discount.
I buy them for both alarm and emergency power uses and for Ham radio too.

To give you an idea I pay under $15.00 for that 12ah model.

Ed

Ed,

Can you post the name of your supplier and maybe a link?

[Ed Harris]

Ed,

Can you post the name of your supplier and maybe a link?

www.adilink.com

They are the largest distributor of low voltage in the U.S.

Most bigger towns have either an ADI Branch location or another Alarm Supplier.

The batteries are just small SLA (sealed lead acid) Batteries and are marked up a lot at retail.

Ed

[Morgan]

www.adilink.com

They are the largest distributor of low voltage in the U.S.

Most bigger towns have either an ADI Branch location or another Alarm Supplier.

The batteries are just small SLA (sealed lead acid) Batteries and are marked up a lot at retail.

Ed

Ah! That explains the price difference; you bought an SLA and Peter bought an AGM.

[Ed Harris]

Ah! That explains the price difference; you bought an SLA and Peter bought an AGM.

I am almost certain that if you looked at Peters battery that it is an SLA too.

I dont think they make an AGM in these smaller sizes under about 50ah.

The SLA are still spill and leakproof and have a high density construction for the size.

[Morgan]

I am almost certain that if you looked at Peters battery that it is an SLA too.

I dont think they make an AGM in these smaller sizes under about 50ah.

The SLA are still spill and leakproof and have a high density construction for the size.

Have a look here, Ed.

AGM Batteries.

[peterh]

The battery that came with the jump starter was a sealed lead-acid battery, but the replacement I bought is an AGM cell.

Moving up to an AGM cell was one of the three reasons I wanted to replace the battery instead of replacing it with a new store-bought unit. AGM batteries not only last twice as long, they hold their charge longer and recover better from being fuly discharged. All major wins . . . so by using an AGM replacement battery instead of a standard sealed lead-acid unit, I didn't just be make my jump-starter "as good as new." I'd made it better. Much better.

(The other two reasons to replace the battery instead of the whole unit were to save money and do the reduce/reuse/recycle thing.)

[Dan Meyer]

What is the amp-hour capacity of the new battery?

-- Dan Meyer

[peterh]

What is the amp-hour capacity of the new battery?

-- Dan Meyer

Same as the battery it replaced: 9 AH.