Alternator or battery prob?

Post by **southerly95** » Sun Jan 27, 2008 2:57 pm

Sorry this may be a duplicate posting but can't trace what should have been the original.

I fitted an alternator last Sept bought from a well known MM spares dealer and about 6 weeks after fitting it the battery failed being badly distorted, hot and hissing with the pressure.

Nor sure if the battery was at fault or the alternator, how can I test the latter please? New battery bought and using the dynamo at the moment. Many thanks, John

Post by **Orkney** » Sun Jan 27, 2008 3:27 pm

Guess the proper and definative way to get an alternator tested is to send it to a place that refurbs them - that or send it back from whence it came with an polite explanitory note and asking them to look at it.

Batteries are fickle things, so could well be the one that was used to the alternator was past its best & the higher charge cycles from the alt just finished it off.
Hot & hissing could be low on electrolyte, damaged / crudded plates or overcharging.
6 weeks though sounds like the battery was on its way out.

Reckon either way your doing the wise thing and not risking a new battery on.

Try going into some detail with the supplier - if its who I use they wouldn't even think about it and just send you a replacement provided your detailed in your approach to them.

Post by **bigginger** » Sun Jan 27, 2008 3:54 pm

Did you rewire for the alternator, bypassing the voltage regulator on the bulkhead? The alternator has one built in, and doesn't need that one. The fact that you've swapped back to dynamo suggests not, and you may have blown the one in the alternator - they're fickle things.
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Post by **Orkney** » Sun Jan 27, 2008 3:59 pm

Nice one BG - would that be symptomatic over that time period? would account for it frying the battery wouldnt it?

Post by **bigginger** » Sun Jan 27, 2008 4:01 pm

Dunno about the time lapse - I've never tried it, but it's a certainty for frying the alternator

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Post by **bmcecosse** » Sun Jan 27, 2008 5:57 pm

If directly connected to the dynamo wiring - the regulator would put limited volts to the sensor connection on the alternator and make it run 'flat out' - which would soon fry the battery. The alternator may still be ok. It must be connected correctly!

Post by **southerly95** » Sun Jan 27, 2008 7:10 pm

bigginger wrote:Did you rewire for the alternator, bypassing the voltage regulator on the bulkhead? The alternator has one built in, and doesn't need that one. The fact that you've swapped back to dynamo suggests not, and you may have blown the one in the alternator - they're fickle things.
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I installed precisely as per instructions (BM supplied). Probably best that I email them, thanks for advice, John

Post by **bigginger** » Sun Jan 27, 2008 7:25 pm

Fair enough - just a thought

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Post by **bmcecosse** » Sun Jan 27, 2008 9:38 pm

Did the lights seem very bright when running on this alternator ?

Post by **southerly95** » Sun Jan 27, 2008 10:04 pm

bmcecosse wrote:Did the lights seem very bright when running on this alternator ?

I had just installed Wipac halogens and was also having serious misfire prob's due to 3 coil failures in 3 months discussed on threads elsewhere on Forum so it is difficult to say. I think that's a prob with refurbing a car when you are upgrading so much at the same time especially if things don't settle down well on install.

The car, a 65 convertible has settled down now and running beautifully with the exception of periodic red light syndrome which is partly why I got the alternator.