![]() The powerbank function charges electronic appliances including smart phones and tablets. ![]() The intelligent clamps safely manage power between the jump starter and vehicle, plus the device features reverse polarity, short circuit and anti-spike protection. The safe connect system protects the user, vehicle and jump starter when in use. The compact design fits easily into your glove box, without compromising on power. Also provides power to recharge electronic gadgets. Able to start 12V vehicles up to 6L petrol and 3L diesel engines. ALL the jumps start packs sold have no chance of starting a car directly.A powerful, safe and compact Lithium Cobalt LiCoO 2 jump starter, ideal for small to medium cars and vans. It charged and ran OK after that and I have no idea why it behaved that way. ![]() It only just worked and his leads nearly melted. The AA was called and he had a monster battery and lead set. I've seen it done once when all normal attempts failed. If you have REALLY heavy jump start leads, big solid connecting clips and some luck then you may be able to jump start directly from the remote battery. A starter motor would not even notice that such a battery was there. I have started cars from battery packs joined with twisted connections and thin wire and connected to the battery by 3 feet + of "lamp cord.Įureka! Very satisfying when it works. Note: You will find much discussion on whether jumpstart energy is first saved in the car battery. such supplies probably cost in the $US5-10 range on ebay. If the car battery loads down the supply then the current limit should work. What you need is a power supply with Vin is at least 9V - 13V, Vout is say 13V-14V and current out is limited to say 5A. You could make such but you can but them on ebay for less than you can make them for - or from China for perhaps slightly less again. What is needed is some limit on safe maximum current, and a voltage for charging that is suited to the car battery in any state. The laptop battery would be good for this purpose if properly used. You can still get excessive current the other way. But, as above, maybe not.Īdding a series diode of suitable current rating will protect against charging the laptop battery. In many cases you may be able to 'just connect the batteries " +ve to +ve, -ve to -ve and get an acceptable result. "Vent with flames" / fireball / pyrotechnics may well eventuate. A battery that may not start a car may happily deliver 10 x as much current as the laptop battery can safely handle. Max safe charging voltage for your laptop battery is probably about 8.4A (A = Ah rate). If the laptop battery was rather flat (around 9V) and the car battery had modest life in it (eg starter relay goes click-click-click but starter will not turn, headlights light dimly) then the car-battery voltage may be usefully greater than the laptop-battery voltage and the charging may occur in the opposite direction. This will probably not usually be what happens. The laptop battery open circuit voltage may be lower than the car-battery voltage and no energy transfer may occur. ![]() If the car battery is very high impedance due to eg major internal sulphation the voltage may be around 12V when open circuit. The laptop-battery can be damaged and lose cycle capacity and worst case can "vent with flame" - spectacular high energy melt down. If car battery is very flat its terminal voltage may be low enough that the laptop-battery provides more current than is wise. At 9V if it does actually charge you are in the area where it is doing damage to the battery to use it. Actual cell voltages will be about 4.2V fully charged and 3V dead dead, so the battery = 9V to 12.6V. Even when the car-battery has been run flat by lights left on or whatever, it has the ability to accept energy from the external source and then to return it to the starter motor.Ī 11.1 V LiIon battery probably has 3 cells in series.ġ1.1/3 = 3.7V/cell. The starter motor draws hundreds of amps - probably 100-200 Amps in a very good situation and 400-600-800 Amps in various other cases. What is often not generally appreciated is that energy to turn the starter motor during a jump start does NOT come directly from jump-battery to starter but is first transferred from jump-battery to car-battery and then from car-battery to starter motor. Getting it to do so safely and effectively is "the trick". The laptop battery described could typically provide quite a few jump starts.
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