We have had a query from an RM owner in France about their batteries not getting a charge. I think they have RM 552. As far as we know its an original Leyland engine.

They have done a test and found there is no charge coming to charge the batteries and they are being drained and need constant recharging. They say they have tested the alternator and its outputs and that is apparently producing a good charge and the bus starts and everything runs OK lights heater works etc. We have suggested a check and clean of all terminals and wires, we don't think it has an isolating switch but will check, but anyone any other ideas? TIA

My bus number (if any): RMC 1485 and RTL 960 plus loads of RTs

Recent checks on our RM765 (Simms electrical system) showed no charge received at the battery. A friend who is pretty well clued up stated the alternater needed a small voltage fed from the Simms control box (easily measured at the alternator end)to excite it into producing alternating courrent. A spare Simms control box was fitted and around 27 volts duly arrived at the battery. We found that with the alternator off the vehicle and its contacts shorted out it would be extremely difficult to rotate the unit by hand thus proving output was available. AC current after leaving the alternator passes to the rectifier thus changing to DC output; I wonder if there is a problem there? Or a control box problem? If no isolating switch is fitted then it smacks of a faulty control box. I have some service sheets and diagrams kindly sent by Chris Sullivan if a copy of these would help! Regards Ian.

My bus number (if any): rm765, rm446

Thanks Ian that is really helpful. I don't know if its a Simms or CAV system although being a Leyland engine suggests its Simms. I have told them to check all the terminals in the control box so maybe that will find the problem. If not we will have to get another control panel or try a control box from one of our RMs and see if this has the same problem.

Regards

Brian

My bus number (if any): RMC 1485 and RTL 960 plus loads of RTs

It mustn't be pulling the contact in in the control box (paddle thing on end of a coil) (weak field? on F wire)- the tension spring on this is adjustable and it might be as well to carefully clean the contacts on this with very fine grade emery/wet & dry.
Or to check without doing any adjusting, with the engine running on fast tick over press the paddle contact home and if all is well it will stay home, it might drop out on tickover but should drop out on shut down which is important to check that it does if you adjust the tensioning spring so the pull off is not as strong.
Might be as well getting the batteries load tested once they have been charged up as well as checking leads for chaffing, good connections at terminals and connections (including the one behind the ROS bench seat back as as been suggested

HTH

Mark

My bus number (if any): RM1414 sort of

After ongoing hassles with the ageing coils and relays in the control panel in the box to the right of the drivers seat I've replaced the voltage regulators on 2213 & 238 with a CAV equivalent 440D solid state unit, cost about £25.00. RM 471 already had this unit fitted. I'll get a picture, instructions and wiring diagram on the ROOF website as soon as I get time. Has anyone got details of how to wire a relay to power the cab heater and other accessories when the alternator is charging?

My bus number (if any): RMs 238, 471 & 2213