Hi all,
My grey cab 1990 3CX runs fine but over time battery loses charge. Battery will take charge from charger and tests out ok so i suspect the alternator.
measuring voltage across battery and on 2 main connections on back of alternator at rest gives 13.35V which mildly surprises me. Battery has just been on charger over past 24hrs. When running all 3 measure 13.04v, so does that mean running is draining battery and alternator not charging?
Why is fresh battery showing 13.35V? Is this normal?
Any help/advice much appreciated.
Greg
Grey Cab Electrics
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Re: Grey Cab Electrics
Hi Greg I would have thought perhaps a 14v output from the alternator would be more like it? Does the battery go flat if you disconnect it because you may have something slowly draining the battery, if you look on YouTube there are great videos on how to check out both batteries and alternators plus locate a battery drain. Hope that helps.
Jeremy
Jeremy
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Re: Grey Cab Electrics
Thanks Jeremy, the thing I find most confusing is the lower voltage when engine running which suggests current drain to run engine and no charge from alternator. Hopefully an electrics expert will comment.
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Re: Grey Cab Electrics
Don't know if I should call myself an expert, but yes, if the voltage is lower with the engine running than when stopped, the alternater is definetly not charging, or at least not delivering enough current for the load.
I would say that about 13V on freshly charged battery in good condition is normal, if slightly on the high side. Maybe your charger has a somewhat high output voltage?
Charging voltage should be at least 13.8V. "Intelligent" charging systems may apply slightly higher voltages, up to about 14.5V, depending on circumstances. (13.8V is generally quoted as "float" or "maintenance" charge at 20°C. Cold weather allows for higher charging voltage, and temporary "boost" charge right after starting is sometimes applied.)
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Best regards, Kári.
I would say that about 13V on freshly charged battery in good condition is normal, if slightly on the high side. Maybe your charger has a somewhat high output voltage?
Charging voltage should be at least 13.8V. "Intelligent" charging systems may apply slightly higher voltages, up to about 14.5V, depending on circumstances. (13.8V is generally quoted as "float" or "maintenance" charge at 20°C. Cold weather allows for higher charging voltage, and temporary "boost" charge right after starting is sometimes applied.)
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Best regards, Kári.
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Re: Grey Cab Electrics
I think I may be being a dumb ****. Having replaced the alternator to no good effect I have just twigged that the indicator light never comes on. I have tried shorting the small connection on the connector block on the back of the alternator to earth with ignition switch in the on position which I believe should light up indicator light if it works. No joy, so how do I get at bulb to replace, and any ideas on source for bulb would be good. Am I finally heading in the right direction?
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Re: Grey Cab Electrics
Hmm , I'm not sure what the light actually does , connecting it to earth should replicate a bulb , does it charge when you do that ?
I had a look on youtube there but didn't see anything worth watching !
Press the lamp test button on the LH side of the steering column , just in case your charge light does work .
The manual should have the info on replacing the bulbs , you can download it on this site for free .
My Grey cab has a buzzer that also goes off when the battery isn't charging .
Bit of a pain as I need to give it quite a few revs when stone cold to stop my ears being battered .
I had a look on youtube there but didn't see anything worth watching !
Press the lamp test button on the LH side of the steering column , just in case your charge light does work .
The manual should have the info on replacing the bulbs , you can download it on this site for free .
My Grey cab has a buzzer that also goes off when the battery isn't charging .
Bit of a pain as I need to give it quite a few revs when stone cold to stop my ears being battered .
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