alternator/battery problems
Discussion
hi all ,more problems
when i have heater,lights,radio,heated rearwindow on my indcators will only work when the engine is reved to about 2000 rpm
i have put a meter on the battery with engine running and nothing turned on it reads 13.99 volts turn every thing on and it drops to 12.45 volts is this right or is it time to spend more money if so on new alternator or battery.
thanks david
when i have heater,lights,radio,heated rearwindow on my indcators will only work when the engine is reved to about 2000 rpm
i have put a meter on the battery with engine running and nothing turned on it reads 13.99 volts turn every thing on and it drops to 12.45 volts is this right or is it time to spend more money if so on new alternator or battery.
thanks david
Are you running higher powered bulbs in the headlights? Do you have spotlights on as well?
You need to do a power consumption check. Add all the wattages together, divide by 12 and that gives you the amperage taken from the alternator. Don't forget to add in all the rear light bulbs, side-light bulbs, instrument panel lights, fuel pump(s), wipers, radio, etc.
When I added together all the electrical services on my rally car, I got a nominal wattage of over 500, and that was without the heated front screen. So the alternator needed at least 43 amps just to 'break-even'. If the battery was at low-charge' to begin with it never really re-charged at all, and a few engine starts soon depleted the remaining charge. so I fitted a 65 amp alternator and there have been no more problems. Below about 2000 rpm it doesn't charge at maximum either.
With the battery fully charged, even with everything on, the indicators should still work OK, maybe a little slower though, as they take very little extra current, 20 watts, I believe.
Check the battery capacity. One thing often forgaooten is that if a battery is only half charged, to fully charge it can take at least half-an-hour of normal daytime driving with no electrical units switched on (say a 50 AH battery and a 50 amp alternator).
You need to do a power consumption check. Add all the wattages together, divide by 12 and that gives you the amperage taken from the alternator. Don't forget to add in all the rear light bulbs, side-light bulbs, instrument panel lights, fuel pump(s), wipers, radio, etc.
When I added together all the electrical services on my rally car, I got a nominal wattage of over 500, and that was without the heated front screen. So the alternator needed at least 43 amps just to 'break-even'. If the battery was at low-charge' to begin with it never really re-charged at all, and a few engine starts soon depleted the remaining charge. so I fitted a 65 amp alternator and there have been no more problems. Below about 2000 rpm it doesn't charge at maximum either.
With the battery fully charged, even with everything on, the indicators should still work OK, maybe a little slower though, as they take very little extra current, 20 watts, I believe.
Check the battery capacity. One thing often forgaooten is that if a battery is only half charged, to fully charge it can take at least half-an-hour of normal daytime driving with no electrical units switched on (say a 50 AH battery and a 50 amp alternator).
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