Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: thedoc on 31/10/2016 14:53:01
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Andy Moore asked the Naked Scientists:
I have seen advertised a pocket sized flat car battery booster (the Thane MINIMAX).Compared to conventional boosters, it does seem to good to be true. It is claimed that it is so efficient due to the Lithium Cobalt battery that it will start up to 8 vehicles on one charge. It comes in a case with accessories, but also shown being carried in a shirt pocket. Is this Lithium Cobalt really that good, would it be safe to carry in your pocket and why would it be only suitable for petrol vehicles?
Andy Moore
What do you think?
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The battery only needs to have enough energy to start the engine, which then runs on the fuel (petrol, diesel etc.). Once the engine is started, it will recharge the onboard battery.
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"Up to 8 petrol vehicles" is the weasel phrase. A warm motorbike is a very different proposition from a cold diesel truck. It seems that the gadget can deliver about 200 coulombs or maybe 1000 at 12V which is good for a pocket sized lithium rechargeable but not exceptional. Whilst a diesel is more likely to start on the first compression, that is only the case if it has been preheated which requires up tp 500 coulombs in cold weather. and the cranking current is always higher fore a diesel. .
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Isn't a small charger only suitable for petrol vehicles, because the fuel in a petrol engine gets ignited by a simple electric spark. Such a spark can be produced by even a small charger.
Whereas, in a diesel engine, the fuel won't ignite, unless it gets heavily physically compressed. And a small charger can't provide enough energy to produce the necessary compression.