Lucas A127

[buggsy]

Hi,

 

I have had a quich search and have not found the answer to my problem so here goes. I have a Lucas A127 70 amp alternator fitted to my boat with 3 leisure batteries and 1 start battery also i have a durite 180 amp split charge relay fitted.

 

This weekend whilst out cruising for two long days i have noticed that the volt meter has not risen like normal and my batteries appear low. I have checked the alternator output with one of the led testers that you can buy in the local motor factors and it says that the alternator output is weak!

 

I will check all connections tommorrow but is it time to take it to a professional for repair?

 

cheers,

 

Steve

[Guest]

Did you check the output before or after the relay? Those particular relays are not my favourite.

 

This is what I have found on more than one occasion:

 

Edited October 12, 2008 by Guest

[buggsy]

Hi Catweasel,

 

i connected the tester as the instructions stated on the neg and the positive of the alternator and reved the engine quite hard.

 

cheers

 

Steve

[Tony Brooks]

Hi,

 

I have had a quich search and have not found the answer to my problem so here goes. I have a Lucas A127 70 amp alternator fitted to my boat with 3 leisure batteries and 1 start battery also i have a durite 180 amp split charge relay fitted.

 

This weekend whilst out cruising for two long days i have noticed that the volt meter has not risen like normal and my batteries appear low. I have checked the alternator output with one of the led testers that you can buy in the local motor factors and it says that the alternator output is weak!

 

I will check all connections tommorrow but is it time to take it to a professional for repair?

 

cheers,

 

Steve

 

 

I would say that its time to buy a decent voltmeter so you can tell us what readings you are getting.

 

First of all make sure the drive belt is well tensioned, then, if all the connections are in good order you have two possibilities.

 

1. A very high alternator load automatically depressing the voltage (flat of faulty batteries perhaps).

 

2. AS you say , a faulty alternator.

 

To do a proper diagnosis we need the voltage reading with less than 10 amps of charge flowing because the batteries are well charged and NOT because you have let the revs drop.

[Allan(nb Albert)]

Hi,

 

I have had a quich search and have not found the answer to my problem so here goes. I have a Lucas A127 70 amp alternator fitted to my boat with 3 leisure batteries and 1 start battery also i have a durite 180 amp split charge relay fitted.

 

This weekend whilst out cruising for two long days i have noticed that the volt meter has not risen like normal and my batteries appear low. I have checked the alternator output with one of the led testers that you can buy in the local motor factors and it says that the alternator output is weak!

 

I will check all connections tommorrow but is it time to take it to a professional for repair?

 

cheers,

 

Steve

 

I had a similar problem earlier this year with my Thorneycroft 108 (i.e. BMC 1.8 with A127 Altenator) and durite split charge relay - my voltmeter which fitted in one of the (cabin battery) lighting circuits rather than the more normal ignition circuit was only displaying about 12.5v with the engine running. Normally it would display over 13 volts after startup rising to 14 volts with batteries fully charged.

 

With my digital multimeter the problem was diagnosed as a poor earth connection between the A127 Alternator and the earth strap on the starter motor solenoid. The problem was sorted by earthing the alternator directly to the earth strap on the starter solenoid.

 

As I removed and refitted both starter motor and alternator last winter, I imagine that I somehow introduced a dirty contact between altenator and engine block or starter motor and engine block. However, as the new direct earth connection between alternator and starter solenoid works my intention is not to investigate.

 

Hope this helps rather than hinders!

 

Allan

[chris w]

Steve

 

Is the red charging light staying ON after starting the engine?

 

Chris

[buggsy]

Hi,

 

thanks for the replies but i think the "muppet of the week award" goes to me. When i checked the alternator belt today it was loose and thinking back i have not rechecked it since replacing it earlier this year. Another peace of useful information is when attending one of Tony's excellent boat maintenance courses, remember to consult the notes before asking for help on the forum!!!!

 

Anyway i have checked the output of the alternator today and battery voltage is 12.82 and rising, so i have decided to bring all the batteries home for a full charge and will recheck at the weekend and report back.

 

cheers

 

Steve

[buggsy]

Quick update,

 

i charged my batterries at home all week and yesterday fitted them back too the boat and all is back too normal, so the problem was purely the slack alternator belt.

 

One thing i did learn when searching on the net from QA a company supplying patent parts, fitting a new alternator with flat batteries will ruin the alternator.

 

Once again thanks for the replies and i wonder what the next problem will be!!!!!

 

cheers,

 

Steve