Volts indicator

[nick]

I noticed on my way home last night that the volts indicator was well to the left (low) side. I had the fan, and headlights on. If I add more services the indicator droped into the read. I tighten the alterator belt but there was no change. So I put a volt meter to the battery with the engine running and found that with no services on I was getting 13.55v. If I turned everything on, high beam, fan, door open warning, wipers, hazard lights, the volts at the battery drop to 11.8v, and the volts indicator goes into the red zone. I guess the alt is not able to keep up. Or is this a voltage regulator problem. Anyone have any thoughts?

nick

[gaz]

what are you getting from the battery alone whith nothing runnning and the engine off could be the battery knackered or maybee just wants a good charge ie. off the car and on a charger for a couple of days not just a good drive out and also check your water levels in the battery and top up prior to charging if your only using your car for short trips and using all power heavy gadgets like windscreen wipers fan/blower radio then you will always be taking out more power than your putting in

It rides again

[nick]

Just came off the charger. The battery turns the starter with no problem and the car starts just fine so I doubt that the battery is gone bad. I was a little puzzled by what you said with respect to alternator capacity. You implied that if you run all of the services that the car has the battery has to help the alternator and in time will always run the battery down. Does that mean the alternator is undersized for this car?

nick

[jclay (RIP 2018)]

It is a 65 amp unit (with Air conditioning). What you have to remember is that these cars are getting older and the motors are probably drawing more current than when they were new. I know that my heater fan motor sure does.

Have fun, drive fast & safe, be kewl,

jclay

[Rayjones]

I've had the same thing happen during a very heavy rainstorm, so bad I could not see to drive more than 15mph, with everything electrical on at full blast on the voltmeter was right down the scale, normally though there is no problem, and if conditions had allowed me to drive faster I think the electrical output from the alternator would have kept up.

Ray

1980 UK BRG 2L DHC

[nick]

With my car it makes no difference if the RPM is at 1000 or 3000 the meter goes into the red. The two big draws are the headlights and fan. The wipers draw quite a bit as well.

nick

[FI Spyder]

My volt meter is always steady at 3/4 mark even with lights on even though the alt is early type not the HD one that came with it (A/C type), headlights always work, clock keeps perfect time, no electrical problems, even though the top is original there are no leaks. What's wrong with my car???[:o)]

OK, it was built by rover but still.[:)]

TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra

[black_1980_tr7]

Your volt meter showing low, is similar to my experience
on my own TR7. I ended up replacing the alternator.

My hunch is that 1 or 2 diodes in the alternator's rectifier
have gone bad (common on older alternators).

The remaining alternator diodes and windings are having a hard time
keeping up with the vehicle's electrical needs.

You might want to consider replacing the alternator, but it
sounds like yours does need servicing.

I wrote up a Bosch 96A replacement procedure on this TR7 site some years ago. Since then I've added info, pictures, and other information.

A pdf instruction file can be downloaded from ...
http://www.smallscalerailway.com/tr7_fixes.htm

[:)]