Miniature Jump Starter

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Mike69cuda

Mopar Moron
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Saw this Jump start battery pack at Lowe’s. Box said it would jump start a 6 cylinder car. Laughed to myself, but bought it anyway it since it was on the clearance rack for $20 (was $100).

It is about the size of a cell phone, only thicker. I had my LS1 Trans am in storage over the winter, battery was completely dead. I hooked this thing up and it started right up. I was amazed. Turn the car off when I got home and it wouldn’t start again. Hooked it up again & it did it again. It only lost 1 out of 5 dots on the charge indicator. Never would have believed it if I hadn’t done it myself.

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I always wondered if those things actually worked?? It could probably charge 1000 cell phones!!
 
I bought one from Harbor freight. It works great. I have jumped my Sport Fury, and today I jumped the mower twice. Not as small as the OP's
 
I've been eyeballing those. Up here best price is around $60-80. So wanna not buy junk. Got specs on the craftsman?
Saw this Jump start battery pack at Lowe’s. Box said it would jump start a 6 cylinder car. Laughed to myself, but bought it anyway it since it was on the clearance rack for $20 (was $100).

It is about the size of a cell phone, only thicker. I had my LS1 Trans am in storage over the winter, battery was completely dead. I hooked this thing up and it started right up. I was amazed. Turn the car off when I got home and it wouldn’t start again. Hooked it up again & it did it again. It only lost 1 out of 5 dots on the charge indicator. Never would have believed it if I hadn’t done it myself.

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I have bought the harbor freight and other brands of the jump start boxes with the sealed lead acid batteries and they only last 2-3 years. Interesting to see how long this one lasts.
 
I have one of the smaller NOCO Jump starters. Its "only" rated at 500 amps. Seeing it in action I would say its delivering every bit of that.

From a convenience perspective its nice to have something that is small enough to store in the car.
 
I'm not any kind of electrical wizard but I'm guessing there must be some kind of a capacitor in there that holds a charge that's enough to turn over a battery that's got a little juice in it still. We need our electrical gurus chime in and explain this phnomena. Lol
 
I'm not any kind of electrical wizard but I'm guessing there must be some kind of a capacitor in there that holds a charge that's enough to turn over a battery that's got a little juice in it still. We need our electrical gurus chime in and explain this phnomena. Lol

Nope. It is a lithium battery. The technology keeps advancing. They have very high energy density.
 
I think the key to how "well" these work is that they have some level of smarts inside of them.

Most of the ones I have seen take a bit of warm up time before they are ready to actually jump the car. My guess is that the box is getting some baseline for the battery charge. As soon as it sees the voltage tank (when to go to turn the engine over) they deliver their "jump". The spike they provide has been compared to the discharge of energy observed when you short a out a battery.
 
I think the key to how "well" these work is that they have some level of smarts inside of them.

Most of the ones I have seen take a bit of warm up time before they are ready to actually jump the car. My guess is that the box is getting some baseline for the battery charge. As soon as it sees the voltage tank (when to go to turn the engine over) they deliver their "jump". The spike they provide has been compared to the discharge of energy observed when you short a out a battery.

They do have battery management electronics in most today, but that isn’t what makes them work. It is all battery chemistry & design. They have to have a very low equivalent series resistance so that they can deliver a large amount of current.

The one I have says it is rated for 26 watt hours. That would be about 93KW seconds (26x 3600). A watt second is a joule of energy. So my battery pack has 93KJ of energy.

300 amps at 12 volts to start a car is about 3.6 KWatt (12 x300). Let’s say you crank your car for 5 seconds. 3.6 KW x 5 seconds is 18 KJ.

So my battery pack has 93 KJ of energy and it takes 18 KJ to start my car. This means I might be able to start my car about 4 times at 5 seconds a try.

This is an over simplification, but gives you a good idea of how it works.

On a safety note, high voltage electrical energy levels above 50 joules are considered lethal. Things start getting kinetic at about 100 joules. Not quite the same here, but you get the idea. If not handled properly, it is a potential bomb.
 
I bought one of these, very overkill for my dart.

https://www.amazon.com/dp/B016UG6PWE/?tag=fabo03-20

It works flawlessly. I went oversized so I would not be taxing it.

It only takes about 40 amps or so to turn over an engine and it only needs to provide that for a few seconds.

As stated earlier LI batteries can pack slot of energy in a small space. And they can discharge a lot of that energy in a short amount of time.

The biggest issue with them is internal drain, of left on the shelf long enough that will have no charge and may not be able to be recharged.

The noco unit asks to be charged every 3 to 6 months.

My daughter is at scho in SD. over Christmas break (5 weeks) her taurus sat outdoors.

When she got back the battery was dead. She hooked up the novo unit I bought her and the car started right up. She took the noco off and then proceded to drive away she turned the headlights on and the car died.

Jumped it again and ran it at off idle for 30 minutes before she could drive with the lights on. It took a week of 30 to 40 minute drives to get it to start on its own. Best money I ever spent on her.
 
$20 is a great price. I paid ~$60 on sale at Harbor Freight a few years ago. They do work if the engine isn't too cold or cranks too long. Definitely not the power of the lead-acid battery, but better than nothing. One oversight is that most turn off the "crank" mode after about 1 min, which confuses many people and also makes it hard to use as a general 12 VDC source to test things. Another problem is their capacity decays over time. I recall something like 50% left after 3 years or so. But, large jump-packs with lead-acid batteries aren't known for lasting much longer either, indeed I have had a lot of car batteries fail within 3 years lately, and a few from Autozone within just a few months, though the prices continue to rise.
 
the power tour facebook page has people bringing their 18v drill batteries to jump start their cars..

i have this one and it spins the darts 360 over like nothing.. https://www.amazon.com/gp/product/B07QDXL1PW/?tag=fabo03-20


just picked this one up because it was on sale. curious to see how it works... looks nice, great case and all.. https://www.amazon.com/dp/B085HCWD8T/?tag=fabo03-20

The drill battery comment got me thinking. My Ryobi has a 4 amp hour 18 volt battery. 4 amps x 18 volts is 72 Watt hours. 72 x 3600 (# of seconds in a hour) is 259K joules (watt-seconds). That is about 2.5 times more energy than my jump starter.

If you made an adapter to connect some big wires with clips to your drill battery, you might have a jump starter for about free. That is if it can put out enough current fast enough. From the Power Tour comment, sounds like it is possible.

I am going to have to try this....l
 
The drill battery comment got me thinking. My Ryobi has a 4 amp hour 18 volt battery. 4 amps x 18 volts is 72 Watt hours. 72 x 3600 (# of seconds in a hour) is 259K joules (watt-seconds). That is about 2.5 times more energy than my jump starter.

If you made an adapter to connect some big wires with clips to your drill battery, you might have a jump starter for about free. That is if it can put out enough current fast enough. From the Power Tour comment, sounds like it is possible.

I am going to have to try this....l


It sounded like quite a few people were doing it. Let us know how you make out.
 
I thought about this some more, maybe not the best idea to hook up 18 volts to a modern car with all the electronics, maybe doesn’t matter as much on an old car.
 
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