Lithium jump starters

I didn't look, but try including search terms such as "schematic" and "tear down".

--sp

You're right. Amazingly little information available. Not even the usual reference circuits. Try: "Lithium Ion jump start schematic" "Li Ion jump start schematic" I would not search for text, but rather for schematics. Like these: The tbm=search string tells Google to do an image search. The rest is just like a word search, but for images. Well, no schematics, but I did find a little detail:

You should also try searching for patents. Looks like quite a few patents found. Note that some are for Lithium Ion batteries used in vehicles, not in the jump start product.

My guess(tm) is that the PCB is some kind of charge controller and battery protector circuit, also known as a BMS (battery management system). It would not do to have voltage spikes from the engine starter perforating the seperator inside the LiIon cells. Since the nominal voltage of the LiIon battery is 11.5v, while the car battery is about 13.6v, diode isolation is needed to prevent the car battery and alternator from attempting to charge the LiIon battery. The PCB might also be parts of a balance charger arrangement to equalize the charge going to each cell of the LiIon battery. Looks like a 5V regulator for USB charging is also thrown in. If there's a controller chip on the PCB, get the number and Google for it to determine how it works.

A good start would be to stop using google as they have sold out to marketers and sales douchebags to put their hits first.

Alternative search engines are available and are likely to give you better hits. Duck duck go.com and yahoo.com are a couple of examples. Art

Having been bitten by chinese specsmanship in regard to lithium batteries before, I would be very wary of any specs on this type of consumer device.

Li batteries are really good, and making your own jump starter is actually pretty easy. Just pick batteries of a brand and quality you trust.

Personally I would use LiFePO4 battery chemistry rather than Li-Ion. Its not as good in power density, but its a lot safer. The one thing you dont want in an emergency start situation is a bigger emergency.

"lithium jump starters for dumbasses"

Exactly the crap I was trying to avoid,that question gets the same commercial crap I was getting with my initial questions not the technical info I was looking for. Your post was a bit dumbass,not helpful in the slightest, Thanks.

And thank you for living up to my expectations. Although originally intende d as a joke, that search term turns up information on its first page from w hich you can discover not only all the technical characteristics of the cur rent practice but the entire history of the technical development of this p roduct category.

Seeing that you are being so helpful could you please point to the site you are referring to on the first page that illustrates your point?

Did not think so.

I used

It does seem pretty amazing, a lithium battery that weighs only a pound (while the cables and clamps are more than a pound), and yet it can provide

Some lithium cells are rated up to 100C, so these are probably 4 A-h cells. For 12 volts that would be 48 W-h, so maybe they are 200C rated. You can get such cells and battery packs from HobbyKing:

That is for 5 A-h 4S pack (14.8V) with 65C continuous current rating (325A) and burst rating of 130C (650A) for list price of $82. You can probably design the circuitry to provide the safety features, and you can put the jump starter in a steel enclosure or one of the Lipo-Safe battery bags that are rated for fire protection.

Paul

Just got a bee in my bonnet and took my $50.00 dangerous,good luck with it, as others have said,lithium jump starter and disconnected the battery on my 3 litre V6 and connected the jump starter, it started immediately(with no car battery connected), hardly got warm,still has all charge lights alight

Yep, adding "teardown" to a search gives you all sorts of neat videos and links

Michael