Looked inside this poorly constructed contraption meant to jump start a car, contains 20 AA cells branded 'Viatek' 'Only for use on jump start, other use is prohibited' of unknown chemistry. What do you know about ?
Output connector yields 30V, the plug contains a MC34063 IC in some configuration -probably for recharging the cells-

 

That won't start a car. It might put enough charge into a flat battery to enable starting but even that seems doubtful.
Read here (including reviews): https://www.amazon.co.uk/Viatek-MJ01-Mighty-Jump/dp/B004DE2ME6

 

I was initially skeptical but reading from the link ..

• Takes only 10 minutes to charge a car battery enough to start the engine

Confusing listing Quote "Batteries included NO ....Batteries required NO "
In 10 mins Any sort of AA batteries , if you have 20 , should be able to put enough energy in to start a car ..
Just one review .."This gadget has only one goal in life: to save yours. Mighty saved mine, so I also bought a mighty for my sis.
When you need your car, this tool will get you started without even getting your hands dirty. Would recommend it to everyone with a car..." sounds ridiculously over the top , probably bought and reviewed by the seller to get sales moving

 

Probably written by the "Inventors" mother to try and get him out of her basement.

 

If those are either lithium batteries or some flavor of lead-acid batteries, then possibly possible. BUT I would regard that the ad and description are fabrications and that the product will not perform as claimed. The sad fact is that some advertising is just lies.

 

I am a bit surprised at Amazon. They show only 1 overly exuberant 5-star review and yet there are numerous 1-star scathing reviews that are apparently not counted. A sucker is born every day and a fool and his money are soon parted.

 

They do make a lithium version for $40 https://www.amazon.com/Portable-Bat...1+Mighty+Jump&qid=1560643574&s=gateway&sr=8-3

 

Let’s do a calculation instead of just proclaiming that it cannot work.

Assume the AAs can deliver 1A for 10 minutes which is pretty coservative for 30 AAs at 15V. The capacity of an AA alkaline cell is abou 3 AH, so that is about 1/6 of an AH, or 1/18th of their capacity.

The total energy released is 1x 30 x 1.5 or 45 WH. At 12V that is 3.75 AH or 13,500 Amp seconds. Now, assuming 100A to start the car, you will get that fot 135 seconds.

Way more than adequate to start the car.

Bob

 

Cells are not lithium; they are twenty 1.5V AA.
My curiosity is their chemistry, they appear to be rechargeable, labeled 'Only for use on jump start applications, other use is prohibited'

 

Cells are not lithium; they are twenty 1.5V AA.
My curiosity is their chemistry, they appear to be rechargeable, labeled 'Only for use on jump start applications, other use is prohibited'

I would bet they are NiM or NiMH , often made in AA size because they have approaching the right voltage , 1.55 volts fully charged , 1.25 volts when 50% .. outdated battery technology , but companies still have the machinery to churn them out , so they are going cheap ... they could definitely do the job.
10 pairs in series would give the perfect voltage required 15.5V falling to 12.5V when half empty ... could deliver a few Amps .

 

falling to 12.5V when half empty ... could deliver a few Amps

Into a cigarette lighter/auxiliary power socket with who knows what gauge wire.... I smell trouble...

 

Into a cigarette lighter/auxiliary power socket with who knows what gauge wire.... I smell trouble...

That socket will be fused. Providing it doesn't blow the fuse (5A or 10A?) then all will be well.

 

Another way to look at it is total energy.

Let’s say it takes 10 seconds of cranking to start the car. This is very conservative for modern cars which start in more like 2 seconds or less.

So, 12V 100A for 10 seconds is

12,000 Joules.

The energy in 30 AA rechargeable NiMH cells, which are typically 2 Ah is

30 x 1.2 x 2 x 60x 60 = 259,200 Joules. Theoretically enough start a car about 20 times.

There are many inefficiencies here that would reduce the energy available, including that the capacity I used applies only when extracted over something like 20 hours, but there is no doubt that it could start the car once.

Bob

 

Look at the size of the cable and the connector on this battery pack.
This is not going to jump start a car with a dead battery.

The intent of this product is to top up a weak battery in 10 minutes, just enough to give the car battery enough joules for it to start the car.

 

I figure it this way. I measured the peak starter motor current on my 6.0 Liter GMC truck with the gasoline engine. Starting current came in at 200 to 250 Amps on a warm oil day. No clue what some of the diesel engine versions would draw especially considering the current draw of the glow plugs. That's a V8 engine with about a 9:1 or 10:1 compression ratio. Again a warm engine on a warm day with warm oil in the crankcase.

Obviously a smaller 4 cylinder gasoline engine with a lower compression ratio would draw less starter current. I would guess even within gasoline powered engines there can be a wide spread of starter current required. I would rule out any diesel engines for this advertised gizmo unless it is very small in warm weather.

Ron

 

OK, so the device can reasonably be expected to put enough charge into a car battery for a bit of cranking for a number of seconds. That might work in some instances, but probably not in the situations where a car battery that is a couple years old is just starting to fail, or it might just work a couple of times.. The last time I needed a jump start was when the dome light had been on for two weeks and the battery was WAY LOW. And the last two jump starts that I gave others was because their engines were not starting quickly and so the battery ran down. So while this device may work a couple times in certain situations I would not spend the money on it. A decent, but not heavy-duty, set of cables to recharge a battery in perhaps 10 minutes is not that expensive. A Heavy Duty set that will deliver cranking power immediately from an external battery is more expensive and more than most folks need.
I try to carry an extra set of the cheapo ones that will work so that I can give them to somebody who will need them again the very next time.

 

^^ of course ... it's just another piece of junk to clutter up your car ... Are people really going to keep this in their glove box? and keep a check that the cells in it are charged up , just in case of a flat battery ???

Flat batteries don't come out of the blue , you can tell when the ability to turn over the engine is failing , it will deteriorate over many weeks before terminal .

 

Flat batteries don't come out of the blue , you can tell when the ability to turn over the engine is failing , it will deteriorate over many weeks before terminal .

Years ago I would agree, A failing battery gave plenty of signs it was dying. Today, not so much. Car or Truck ran just fine on Monday and on Tuesday wouldn't start,

Ron

Edited to fix spelling.

 

Years ago I would agree, A failing gattery gave plenty of signs it was dying. Today, not so much. Car or Truck ran just fine on Monday and on Tuesday wouldn't start,

Ron

INDEED! Especially when the car normally starts almost instantly, even a rapid drop off in cranking speed is hard to spot if it only cranks for 3 seconds. AND then, there are those instances where the car was parked after a long slow trip with the headlights on and the heater on max and no chance to recharge after arriving.