Tiny LIPO based car engine starter - too good to be true?

[awemawson]

There has been a discussion on the welding forum regarding a very small 'starter pack' able to start cars with a flat battery.

http://www.mig-welding.co.uk/forum/threads/pocket-jump-start.51707/

 Seems too good to be true, and I'd welcome comments from the members if any have experience of these things.

The actual item in question is on ebay:

http://www.ebay.co.uk/itm/FLOUREON-16800mAh-Car-Jump-Power-Bank-Pack-External-Battery-Charger-for-phone-PC-/151426364134?pt=LH_DefaultDomain_3&hash=item2341b6f2e6

This sounds ideal for cold mornings in the farm yard getting machines moving but being a skeptical sort and not wanting to waste hard earned cash I'm sounding out your opinions 

[lordedmond]

Andrew

You know what they say to good to be true

Those leads look a bit thin to jump a Diesel engine 😱

It's only a 16 ah pack so the engine would have to kick in first turn , it would not support runing the glow plugs first then a crank

Knowing lipo cell I would not want to be near it when you put a near short on it

It would be fine for its first line eg phone ,laptop charger to top up , but with the car bit in green it's seems to me that it's been appended to increase sales

It's my opinion I have not seen the device it may work as advertised so caveat emptor


How's the tup these days still doing his stuff or have you eaten him😳

Stuart

[vtsteam]

Andrew, just gut feeling, I personally wouldn't have one. And I own about 20 Lipos of various sizes for model planes. And often need to jump start cars and tractors in cold winters. But I wouldn't want a lipo based jump starting system even if it was free. That's based on the danger factor. That thing scares me. And I know and handle lipos regularly.

For effectiveness, my guess is:

Lipos normally are classed for output by C factor.

That lipo has a C of 16.8 (16,800 mah capacity).

Max output generally ranges between 20C for cheap cells to about 50C for expensive lipos. So the usable amperage output would be in the range of 20 to 50 times 16.8 A, or 336 A to 840 A.

Above those rates and there is a real risk of overheating, fire or explosion. Lots and lots of R/C modeler's house fires have been caused by lipos a tenth of that size, just by overcharging. At the very least, an overheated (or "puffed) battery must be discarded. And that is serious business since they are hazardous -- you need to be able to discharge a damaged cell safely down to zero. And if successful, you've still lost your investment.

Okay back to usefulness. So Lipos output is very adversely affected by cold temperatures, but say you have a high quality one and it's warm -- you've got say 500 cranking amps for a total of 16.8/500 = .0336 hours or 2 minutes. That's to full allowable discharge. Actually, you won't achieve that much time, realistically at that rate. And better not over-discharge, otr you're asking for a puffed cell (ruined, and yet dangerous)

Will 500 cranking amps get your particular piece of equipment started? If so,  okay, now calculate the wire size to deliver 500 amps. And compare that to the leads and clamps delivered in the kit. If the kit leads are too small, expect reduced starting power and overheated cables.

Anyway, that's a start on a realistic idea -- maybe it would all work out for your usage -- that's the only real determinant.

The other big thing I would worry about is, the charging system for a giant lipo like this is serious business. I'd expect to spend well over $100 for a reasonably safe smart charger for this size rig, and even then I wouldn't charge inside the house, and would have it in a special fireproof charging container that could handle a big lipo fire or explosion. Most lipo fires happen while charging.

Not to be discouraging, or anything........ 

[awemawson]

Steve you are just confirming my own gut reaction - when things seem too good to be true they usually are just that 

However the people saying that it worked for them on the welding forum are not 'placed' by the seller, and have been posting good sensible posts for years to my knowledge so there must be something in it.

But the bottom line is (having read the Wiki on LiPo's) there are many different constructions of the cells, with varying safety records none of which are particularly encouraging.

Physical damage seems to be the cause of many accidents concerning these cells, so what happens when a model plane nose dives to destruction - is it in reality the successor to the magnesium based fire bombs that we had raining down on our cities in the 1940's 

[vtsteam]

....However the people saying that it worked for them on the welding forum are not 'placed' by the seller, and have been posting good sensible posts for years to my knowledge so there must be something in it.

I believe it. It probably does work for a lot of automotive situations -- I haven't read what you have read, but I trust they're the truth. I did see a unit in my local trusted car parts outlet. But again my own gut reaction is, that's not for me.
The problem I see is not performance under the right circumstances, but that they aren't yet common enough for the accident reports to filter in. There are probably millions of R/C planes flying. The proportion of modeler's house fires is small. But sobering when you see pics of what happened. Or can happen.

It's kind of like owning a chainsaw but never having heard of a chainsaw before. If you are a general consumer who doesn't know what a lipo is, and ignores all the fine print warnings (which are on everything now, and so, useless as warnings) then the inevitable is going to happen when the number of owners is high enough.

...But the bottom line is (having read the Wiki on LiPo's) there are many different constructions of the cells, with varying safety records none of which are particularly encouraging.

There are other kinds of safer lithium cells, like LiFe (lithium Iron) which have much better safety records, and are easier to charge, and of course Lithium Ion cells in laptops and cell phones and cameras. But Lithium Polymer cells (Lipos) are the ones with the really high output rates -- and the least tolerance for a lack of knowledge or improper conditions -- the ones I'm used to. And I'm guessing those are in the small booster packs. I f not, then I'd be more comfortable.

Physical damage seems to be the cause of many accidents concerning these cells, so what happens when a model plane nose dives to destruction - is it in reality the successor to the magnesium based fire bombs that we had raining down on our cities in the 1940's 

I've crashed countless times and never punctured a lipo. But I fly small foamies (planes made of styrofoam) so they are quite protected. I can't recall reading about many lipo model plane fires caused by what must be innumerable crashes that the huge numbers of modelers must be producing daily. Maybe one that I can recall. and it only burnt the plane. Usually fires come from shorts, not crashes damaging the lipo.

I do recall a modeler crashing into salt water and seeing a glow in the water as the plane went down!

Most of the model battery fires I've read about happen when charging in a basement or garage. Or for some reason spontaneously when left in a car -- probably heat. Kinda irritating to have your pickup go up in flames from a new store bought  toy model plane sitting on the seat. I actually read about one of those awhile back.

Of course in the old days, we flew 2cycle engines with glow plugs made of balsa and nitrate dope painted paper wings, with a full tank of methanol and castor oil spiked with a bit of nitromethane. Back when modeling was safe......

The popular saying in the boat world is that a cup of gasoline spilled in the bilge has the explosive power of 8 sticks of dynamite (as I remember it -- take that with a grain of salt!) And yet we ride around at 60 mph with a tank of the stuff under us with a bunch of maniacs doing the same thing, so you pays yer money and takes yer choice. 

[Pete W.]

Hi there, Andrew and Steve,

A couple of decades or so ago, I was a member of a development team working on a system, some of whose units would need to be battery powered.  We'd assumed NiCd rechargeables because that was common in the customer's inventory already.

One day we had a visit from a sales rep for a branch of a well-known multinational company - he'd come to try to convert us from NiCd to Lithium (I don't remember which lithium) batteries.  He did a very skilful delivery of his sales pitch and it all sounded quite modern and marvellous.  But then I think there might have been a mention of a visit to his firm's premises for some demonstrations.  At this, his demeanour changed, his face fell and he said that would not be possible - their laboratory had burned down!!

But he made a quick recovery - his face brightened and he said 'Well, I did tell you Lithium's a high energy system'!!!!!!!!!!!!!!!!!!!!!          

[BaronJ]

Just sticking in my 2 penny worth here because I've never had one of those booster packs.

However my theory goes like this, You connect the booster pack across the existing car battery, and the first thing that happens is the fully charged booster pack starts charging the relatively flat car battery and at a fairly high current.  This causes the car battery to charge up.  After a period of time there is now sufficient charge in the car battery plus whatever is left in the booster pack.  This is probably enough to start a car engine.

If you have ever noticed even with a battery so discharged that it can barely turn the engine over, the car can usually be push started.

[dsquire]

Just sticking in my 2 penny worth here because I've never had one of those booster packs.

However my theory goes like this, You connect the booster pack across the existing car battery, and the first thing that happens is the fully charged booster pack starts charging the relatively flat car battery and at a fairly high current.  This causes the car battery to charge up.  After a period of time there is now sufficient charge in the car battery plus whatever is left in the booster pack.  This is probably enough to start a car engine.

If you have ever noticed even with a battery so discharged that it can barely turn the engine over, the car can usually be push started.

This only works for cars and trucks with standard transmisions.   

Cheers

Don

[vtsteam]

Baron, that would be do-able -- maybe it works that way. You'd need a fairly high voltage to push say 80-100 amps into the other battery like a fast charger does. Four lipo cells would produce about 16 volts. I don't know if that is enough to do it. The more cells at 16,800 mah the higher the cost. But maybe it works that way.

You couldn't just clip and go, you'd need to wait a few minutes to get enough charge. Maybe that's how they do it...

[Pete.]

Well I'm one of the responders in the welding forum thread AND I have one of these packs, so let me pass along my experiences.

Firstly, my pack is not Li-po - it's Li-ion. The one discussed is I believe a Li-po, and it's less than half the cost of mine (actually looks to be a Chinese rip-off since it uses a similar case, leads, clips and charging adapters).

I got mine because someone lent me theirs and I was impressed with it. We have a diesel-engined skid-steer loader on site and one day it wouldn't start, a dodgy relay connector was stopping it from injecting diesel so the guys did what comes naturally and cranked it until the battery was flat. The fitter who came the next day carried one of these in his van and at first I scoffed at it but he said 'try it and see' so I clipped it to the starter hit the key straight away and it cranked quite smartly and fired right up.

I realised that this would be a handy thing to own so I got the wife to buy me one for Christmas. Right out of the box with no charging done I used it to charge my phone from half-flat and my tablet from half-flat and the battery indicator was still above half (about 3 hours charging done). I then gave it a full charge.

When I went back to work in the new year I took it because I knew one of the 5-ton diggers had a tired battery and sure enough it was too flat to start. I clipped this onto the battery gave it two heats on the plugs and it too fired right up. No waiting involved.

So what do I think of it? Let's see.

Does it charge stuff like it says it does? Yes, it does do that. I think the figures quoted are 'up to' and definitely best-case but if you're travelling and you need a boost for your phone or to power your laptop for a hour then it'll do that with ease.

Does it crank engines like it says? Yes it does. Both times I have tried it I've hooked it to a flat, but not totally dead battery and both times it bolstered that battery enough for an instant start. The fitted had claimed that he had disconnected the battery from his transit and started it 3 times in a row, though I did notice that the booster wires on his showed signs of having been heated.

Do I believe the performance specs? No, I don't see how you can put 400 amps down those wires, but that doesn't mean it doesn't work as a booster-pack - I've used it and it surely does.

Am I satisfied? Damn right! Would have been even more so if I had known you can get them for less half the cost I paid for mine (though the quality is as yet un-proven) but even at £150 I'm happy with it. I had four tipper lorries booked and a flat 5-ton digger to load them with. It paid for itself on the first working day of this year and with interest.

Would I recommend it to others - yep I would and I have. I think that so long as you understand what it's intended for - boosting a flagging battery on a family runaround, not cold-cranking a Scammell truck - you'll not be disappointed. For me the most endearing feature is the tiny size of it. 6"x3"x1" is tiny for what it can do.

[BillTodd]

perfect reply Pete

there's an old saying:

 experience replaces nothing ,  but nothing replaces experience.

[vtsteam]

I totally respect what Pete says. And have no disagreement with a Li-ion version costing nearly $225 U.S!  I'd be happy to receive a $225 LI-Ion (or LiFe version) for Christmas.

As I said earlier, there is a big difference between Lipo and Li-Ion (and LiFe) in terms of safety (and price).The version I saw locally was I believe $75 and a Lipo, and I also stand by what I said about that. I wouldn't own one if it was free.

The plain fact of the matter is that 99% of consumers don't know the difference between various "Lithium" batteries, and could care less about what the abbreviations mean.

And if they can get one at a third the price, they will consider themselves lucky. Maybe unfortunately.

There are other kinds of safer lithium cells, like LiFe (lithium Iron) which have much better safety records, and are easier to charge, and of course Lithium Ion cells in laptops and cell phones and cameras. But Lithium Polymer cells (Lipos) are the ones with the really high output rates -- and the least tolerance for a lack of knowledge or improper conditions -- the ones I'm used to. And I'm guessing those are in the small booster packs. I f not, then I'd be more comfortable.

[vtsteam]

Here's a list of reported Lipo fires on a forum I participate in:

http://www.rcgroups.com/forums/showpost.php?s=&p=15776103&postcount=4

[awemawson]

  Yikes 

Just a few then 

[lordedmond]

This thread is a very good example of trying to compare different technology's ,it this case lipo and l-ion the later as reviewed by Pete works and is a safer option but to compare it to lipo cell is a dangerouse oversight

One works and is safe but expensive the other may work and carries a danger and is cheap

As I posted caveat emptor

Stuart

[vtsteam]

And Stuart It's also a good example of differentiating between technologies -- those reading this discussion probably now have a better understanding of the subject, and can tell what would best suit their purposes and comfort level. Which is the reason it was raised. The title of this thread was "LiPo" which is why I responded.

I know I do also now have a better understanding of these devices.

[Will_D]

And its not just RC models and LiPos:

http://en.wikipedia.org/wiki/Boeing_787_Dreamliner_battery_problems

and for the model plane airfields that have a scale firestation:

http://www.boeing.com/assets/pdf/commercial/airports/faqs/787batteryprocedures.pdf