Battery
Posted: 26 Jul 2006, 10:02
First, find out why Battery went flat. Did you leave lights on, or something. If you have a short somewhere you could damage other Battery
Firstly it depends on what type the "other battery" is.
If it is a proper lesiure battery NO you mustn't use it to jump start anything, it will seriously damage it.
If it is a normal car battery, then yes this is fine.
BUT - bear in mind that flattening any normal car battery, by any cause, does it a load of harm and can virtually ruin it overnight.
You need to find out why the main battery went flas ASAP.
Checking the alternator is dead easy if you have one of those little digital "multimeters" ( usually yellow these days ) with a voltage scale on it.
A good gharged battery should read about 12.5 Volts without the engine running. Then start the engine and take a battery voltage reading at a fast tickover, if it is between 13.5 to 14.2 then your alternator is working and the battery is likely to be faulty ( or summat is draining it overnight when it shouldn't be )
A faulty alternator can flatten a battery, and it can be an intermittent thing, some days doing it and some not - explantaion on request !! - if you need help with that aspect, post back.
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