The Classic Machinery Network

The battery is being "cooked" with a voltage reading of 18v measured at the battery terminals when running. I assume it is a fault with the voltage regulator not working correctly. Can anyone advise where it is located on the JCB 801 digger.
Any suggestion where I couild buy a replacement or is this a JCB dealer item only?

Rom the battery voltage regulator is usually part of the alternator; it should be possible to find a company that will be able to repair your alternator or offer you a re-con job.

Jeremy

There is a seperate regulator on the 801. I think it's up high on the rhs of the engine and bolted to the back of the engine compartment. I done away with mine a good few years ago when getting a new altenator.

Thanks guys for the advice I will get out on site and investigate . I have ordered a regulator on spec from Holt JCB will let you know

Fitted the new regulator still the same problem 18volts on the battery when running.
Has anyone got a electrical drawing for the regulator and alternator? Or can you advise on how to locate the fault any help will be appreciated.

Bivvysenior wrote:Fitted the new regulator still the same problem 18volts on the battery when running.
Has anyone got a electrical drawing for the regulator and alternator? Or can you advise on how to locate the fault any help will be appreciated.

I can't help you with a wiring diagram but I would suggest checking all of the terminals on the alternator and the regulator; you really need an vehicle sparky to sort this kind of problem unless your very adept at using a multimeter.

Jeremy

Hi Jeremy
I am Ok with the use of a multi meter, My problem is to try to get access to a electrical drawing to see what is missing. As there is a 18v reading on the battery when running the engine I am assuming that the regulator is not latching one of the relays to reduce the output.

Bivvysenior wrote:Hi Jeremy
I am Ok with the use of a multi meter, My problem is to try to get access to a electrical drawing to see what is missing. As there is a 18v reading on the battery when running the engine I am assuming that the regulator is not latching one of the relays to reduce the output.

Ok Rom I hope that somebody on here can provide you with the circuit drawing.

Jeremy

OK I have a service manual that seems to have an extensive section on electrics, if you send me a PM with your email I will send you a copy.
Pete

Thank you Pete for the pdf manual for the JCB 801 The manual quite doesn't cover my machine as it is older. However, it more than explained the electrics bar a few diodes in circuit I can say it is almost identical.

So armed with the information I discovered
1. What I thought was an alternator light was in fact the oil pressure warning light fitted to wrong socket in the panel I had assumed this was telling me the alternator was OK .
2. When I put the oil warning light in the correct socket, and a working bulb in the altenator warning light socket the alternator warning light was found to be permanently on.
Therfore the relay in the regulator was not being latched to extinguish the light when running, it identified that no 5volt voltage was coming from a tap winding in the alternator. A routine continuity of the wiring found no faults
Checked with JCB and found that two types of alternator available a 35amp or 40amp. My machine being the older model was no longer subject to service exchange and therefore commanded a higher trade price of £243 . The reason for the price difference they could not get spares to refurbish the older faulty units.
Took a leap of faith and ordered a alternator to fit.
Will fit when it arrives .