DeWalt 1400 jump starter

[Dave Fritz]

My jump starter won't charge. It stays at 12.1 or half charge no matter how long I plug it in. Battery shot?

Truth be told - I haven't touched it for over a year. My bad I know.

[Bill Howatt]

Unfortunately, it seems that the batteries are a common source of this type of problem and don't have a real long lifetime.

Is it possible to see what voltage is applied to the battery terminals when it is plugged in? It should be a volt or so higher I would think to charge it - your car's alternator will put out roughly 14V when charging.
This isn't a real definitive test because the battery could be keeping the charging output low, that's the wonders of batteries, they are not really just a dumb fixed power source, their characteristics can vary a lot depending on obscure things like chemistry and internal conditions.

[Tom M King]

Put it somewhere that the batteries can warm up good all the way through, and try charging it again. You may get a few more uses out of it like that.

[Bruce Wrenn]

Having just replaced the batteries in two different jump boxes, I can tell you that unused batteries have a shorter life span. I order Mighty Max batteries from Amazon. Due to amp size, one battery was right at $50 and other $40. But for that I got a basically new jump box. FYI, one battery lasted about five years. The other I can't say as I rescued it at dumpsters. Brought it home, popped tops and added distilled water. Worked for several years, so I definitely got my money (none) out of it.

[Lee DeRaud]

I'm a bit puzzled by this thread, given that even the local AAA trucks switched over to lithium-ion-based jump starters several years ago.
Mine get checked once a year, whether they need it or not...the older one (6 years?) only loses ~4-5% of its charge over that interval.

[Keith Outten]

I have a Dewalt battery jump-starter and I have to unplug it from AC to see if the battery is charged.

[Dave Fritz]

Thanks for the information. I'm encouraged to learn I can rebuild it. Keith, I'll try unplugging it and and see if it's taken a charge. I use it mostly to start a wood splitter and put air in the tires of small trailers etc. Obviously it doesn't get much use. I've had knee replacements so haven't been in the shop for some time and it slipped away on me.

[Jim Becker]

Dave, if it doesn't work out, there are many choices available for small jump pack batteries. I keep a NOCO in my vehicle under the driver's seat for that purpose.

[Michael Schuch]

If you purchase a new jump starter buy one made with LiFePO4 batteries instead of LiIon batteries. LiFePO4 batteries last much longer, recharge many more times than LiIon batteries.

[Bruce Wrenn]

I'm a bit puzzled by this thread, given that even the local AAA trucks switched over to lithium-ion-based jump starters several years ago.
Mine get checked once a year, whether they need it or not...the older one (6 years?) only loses ~4-5% of its charge over that interval.Do the LI ones include work lights, air compressor, USB ports,or power outlets? My Sears one does.

[Lee DeRaud]

Do the LI ones include work lights, air compressor, USB ports,or power outlets? My Sears one does.
Light and USB, yes. I use the little drill-shaped Ryobi compressors for tires and such. One of those and an LI jumper take up less space in the trunk than anything I've seen using lead-acid batteries.

If I'm actually working on a car, I use real tools. The stuff in the trunk is strictly for on-the-road emergencies.

[Derek Kessler]

It's definitely common for jumpstarter batteries to lose charge if left unused for a long time. I just replaced the internal batteries on mine.

[Jerome Stanek]

Thanks for the information. I'm encouraged to learn I can rebuild it. Keith, I'll try unplugging it and and see if it's taken a charge. I use it mostly to start a wood splitter and put air in the tires of small trailers etc. Obviously it doesn't get much use. I've had knee replacements so haven't been in the shop for some time and it slipped away on me.

I don't think one og those will start wood splitter or air up a tire

[Jim Becker]

It's definitely common for jumpstarter batteries to lose charge if left unused for a long time. I just replaced the internal batteries on mine.
I set a reminder in my Google Calendar to top off every three months. It's definitely a "sight unseen" issue and yes, like most batteries, they will lose a little charge as time passes.

[Michael Schuch]

It's definitely common for jumpstarter batteries to lose charge if left unused for a long time. I just replaced the internal batteries on mine.

LiFePO4 batteries have a lower self discharge rate than Lithium Ion batteries... about 1 - 3% a month. This with the much longer battery life (Thousands of charge cycles instead of hundreds for Lithium Ion batteries) makes them much better for jump starters.

https://blog.ecoflow.com/us/lifepo4-vs-lithium-ion-batteries/

[Dave Fritz]

The reason I have this style of charger is I use it on my wood splitter mostly. The starter has no switch so when I attach the jump starter and turn it on, the starter engages and starts the wood splitter. Most other jump starters have to recognize a draw to release the charge. The don't have an on/off switch that controls the charge.