Hi all,
I have a 1985 ex Dutch army v50 Nato and have been riding it around London for a while now. I rode it on Saturday, started no problem, no issues during the ride. On Sunday I was going to go for another ride and it wouldn’t start: flat battery! When I checked it was down to 11.4V. As far as I could tell I had not left any lights on, so not sure why the battery was flat.
I should add that I do not ride this bike every day, in fact before I rode it on Saturday I had not ridden it for 3-4 weeks. But you’d expect it not to start on the first day if the charge was an issue.
Charged the battery overnight and read 12.8V when I put it in. Put my multimeter on the battery and started the bike. No issues starting it. this time and under revving the Voltage spiked to 13.7V. Although I expected a little bit more of a charge, it does seem to be charging. So I am a tad puzzled and open to any ideas.
In the meantime I will monitor the battery.
Thanks!
OK - so the charge light is on when you switch on and then goes out once the engine is running? Along with your check with the meter do you see the lights brighten at all between tick over and reasonable revs? I’m not familiar with the Nato version but I’d imagine that there should be no drain when the ignition is switched off. My UK civilian version will start up happily after being left for months. Do you know the history of the battery? Maybe its time has come.
a fully charged 12 volt battery should read 14.4 volts under full charge.
If yours is reading 13.7v it may be on its way out.
Check the mains connecter to the alternator though. Mine went high resistance and I am now told this is not uncommon.
Thanks for your input guys.
To answer some of your questions:
Yes, the charge light does come on when switched on and goes off once the engine runs. I did not see a noticable change in light levels between the bike being off, ticking over or revving, but wasn’t particularly paying attention to that, so can be checked again.
The battery is indeed old and ready 12.7V when the charger said it was fully charged. Under revving (at standstill) the charge went up to about 13.7V, but not higher than that. I agree that it should read more, but suspected that that was more the charging system of the bike instead of the battery. So it seems the charging systems does charge, but not sufficiently?
I will check the mains connector…
Are you sure it was the battery causing the problems and not the old click no crank issue with the starter relay?
Did you just get a click from the starter relay?
I’m pretty sure that is was the battery as it did try and start and just slowly died. Once the battery was charged it started up no problem.
The thing that stumps me is that it was fine on one day and dead the next. It’s a tad odd.
That does sound like a flat battery
How old is the battery? Could just be dying of old age.They start to not hold max A/hr charge and after taking the charger off when it read OK, Voltage has dropped off by the next day, or few days.
if you are running about in town at low speed with the engine just above tickover, and you have the lights on you will drain the battery
Yes. Modern vehicles cope better I think since can’t turn lights off on them.
used to have the same problem with my R80RT
did a trip to London, then rode across the city and out to Dorking to see a relative, came out and flat battery
bumped it and the bike started
when I got home fully charged
riding with the lights on was the problem, so I fitted a police issue regulator and a halogen sidelight
also check that some silly sod has not fitted a headlamp bulb of a higher wattage
Yes I had same problem with my Spada, going to Motomecca in Clapham one Saturday, accidentally had my lights on but didn’t know it. Then started hesitating at idle at traffic lights etc., realised what I’d done, turned lights off, normal idle restored!