OzVMX Forum
Clubroom => Tech Talk => Topic started by: CBR1000 on February 09, 2010, 10:14:41 pm
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Hi guys hoping somone can help got a 12 volt system in my st90 and im getting 14 volts
out of regulator is this to high and likly to burn out the battery
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st90 what beast my first bike was a minitrail with st90 grafted in was a great bike now it is molten metal didnt like the bushfires.
But are you sure your multimeter is correct? :)
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12V systems typically charge between 13.2 and 14.4V (give or take - everyone seems to have their own opinion of what's ideal) - the lower the voltage, the longer the battery lasts but the longer it takes to charge.
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yeah try 2 multi s nealy lost it in fires too
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I was a bit upset it was my first bike dad bought it from a servo and we done it up put the st90 in it and sprayed it red I wish it didnt burn but I grabbed the gt80 last time I was there and brang the pe400 aswell but forgot to grab the st and a mx80 oh well.
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Yes 14 volts is OK, the battery can at least take 14.7 volts and theres even some sytems that cut off at 15.5 volts eg the TS100/125 ERZ. 14 volts AC wont blow globes either. An old skool trick is to use custome made 14 volt AC regulators for night racing as it makes the globes burn whiter.
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As others have said, 14VDC is ok.
A lead acid cell (your battery is made up of 6 cells) has a theoritical voltage of 2.2VDC, this gives a theoretic open circuit voltage of 13.2VDC for a "12 volt" battery. The voltage you see at the terminals of a fully charged battery in good condition will always be between 12 and 13VDC, once you connect a load (lights etc) the voltage will drop down to the notional 12VDC. To charge a battery, you have to overcome the batteries own output voltage, i.e. if your battery is a bit flat and has an output of 11.8VDC then you will to have a charging voltage higer than 11.8VDC, as the battery voltage increases as it charges, you require more voltage to continue the charging process, i.e. 14VDC + to get the battery up to its 13.2VDC.
All lead acid batteries will handle more than their rated voltage other wise you couldn't charge them. The real killer of lead acid batteries is the charging current that they are allowed to draw. The rule of thumbs is that a battery should be charged with a current of 10% of its rated current, i.e. a 10Ah battery should be charged at 1 amp. Like all things electrical, excessive current results in unwanted heat, and it is this heat that "boils" the battery dry. If you are having trouble with your battery getting excessivly hot ( it will get warm, but not that hot that you can't touch it), the easy solution is to turn on your head light. This will apply load to the electrical system and reduce the amount of current that the battery can draw from the charging system.
CJ