is there any truth in line i am being fed by my dealer that the battery does not re-charge unless the vehicle is at cruising speed ie town driving is no good!!!
- posted
19 years ago
battery problem on forester
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- posted
19 years ago
Depends how many accessories you're using; the heater fan, radio, heated seats/windscreen, wipers, lights all take power. If you're not using any of these, then the alternator will charge the battery even at town speeds.
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19 years ago
Bob,
Certainly the statement that town driving is no good for recharging the battery is bogus.
Modern cars have alternators that produce substantial output at engine idle speeds and achieve their rated output and speeds just a little above idle and certainly by about 1800 RPM or so.
Whether a battery charges or discharges at idle or in low speed driving depends on whether total electrical load exceeds the alternator's capacity. High-beam lights, heater/AC high-fan speed, and rear-window defogger are the main high electrical load items. If most or all such high-load functions are ON at the same time, the battery may discharge at idle or in stop-and-go driving. You can probably observe this by noting whether your head lights dim at idle with the heater and defogger ON and that the lights brighten as soon as the car begins to move.
The real questions should be what problems are you having with your car and have they been properly diagnosed? A quality garage should have the equipment to load test your battery and measure the current the charging system can deliver to the battery.
Ed P
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19 years ago
Ed P This is what I thought,I remember from way back that the principle advantage of the altenator over the dynamo, was that the former delivered its max output at low revs. The whole story is that we were woken @ 2 am with the car alarm waking the dead! The main battery had gone down and the alarm sensed this as a problem and kicked in, I had only had the vehicle [new] 8weeks and was in a real sweat. The alarm manual tells you how to over-ride the alarm, what it FAILS to tell you is that you must enter the over-ride code with all the doors and windows closed!! So it was a case of put the earplugs in and wait for the call out guy ,[the neighbours love me] NB The BS about the charging was from Subaru UK