Battery flat in a day but no current drain ???

[cliverlong]

Hi

Newbie here. Looking for help and suggestions.

I have a 1995 250 Virago I use for commuting in London (probably won't pass the ULEZ requirements in October 2021). I would like to keep the bike on the road to the summer.

I have had regulators/rectifiers fail , both cheap Chinese imports through EBay and a £70 Electrex (?) one. I need to fit my 4th reg/rec.

However the problem I need help with is the battery goes flat in a day when on the bike. When off the bike the battery can show and keep 12.8V for a week, just standing. The obvious cause of battery discharge is a current leak. However, when I connect the multimeter in series with the battery, the multimeter shows no current even when set to measure 20mA. Could I be doing something wrong when trying to measure current? If I can't measure a current drain when the battery is on the bike but the ignition is off I can't think how I can work out why the battery is discharging.

Any suggestions what to test would be appreciated.

Clive

[Riejufixing]

Hm, tricky. Either:

o - Your meter is borkeded.
o - You are misusing your meter.
o - Something's touching the non-earthed battery terminal when it's connected and whatever cover is in place.
o - When the battery's connected, physical strain on the wire causes some unintended connection somewhere.
o - When the battery's connected and the machine run, it's OK, but when it's switched off, something remains connected until you disconnectt the battery.

Can't think of anything else.

[WD Forte]

Voltage alone can indicate but by no means prove
a battery is healthy.
I've had plenty that showed good voltage but failed to do some work
or hold a charge.

Without knowing what, where and how you're testing in detail
plus the contextual stuff you've omitted makes it guessing game.

The many regulators fitted makes me wonder what's been going on with the bike.
____________________
bikers smell of wee

[oilyrag]

Is the fuse blown in your meter?

[steve the grease]

They just go- especially at this time of year. Voltage reads Ok , but when you ask it to do any work there is nothing there. To test try getting an old headlamp bulb. Wire it up to the battery and check the voltage, I bet its low.
2 weeks ago we ended up stuck in the car park in town waiting for the recovery bloke less than 24 hours after charging my Mrs battery up all afternoon. Even after a 20 mile run when we came back to the car- totally dead. With a jump started fine. Started fine for a day or 2. Took it for MOT and got the bloke to do a heavy discharge test > result :22% of the CCA ( cold cranking amps) that explains a lot. New battery ( cant have her breaking down) spins over twice as fast and always starts.

Just get a new battery mate.
____________________
All the above is my personal opinion, you can see my lips move, but I'm talking out of my arse.
I've been riding, and fixing , bikes for 50 years, in that time the more I learn, the less I am absolutely sure of.....

[MCN]

Halfords can do a High Rate Discharge Test on the battery for you. Or of there's a bike shop or other automotive service place. (May be a charge with a pun included.)
The only way to thoroughly test a battery is to put a heavy load on it and measure voltage drop.
A healthy battery should be able to hold voltage whol the load is applied.

Batteries that have been abused are very easily permanently damaged. Poor maintenance chemically changes the plates surfaces. Very little can be done to resurrect a neglected battery.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[Lone-Wolf]

[MCN]

OP joins, posts and then 'apparently' loses the web address for bcf.

'kin' Millenials. 🙄
____________________
Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[cliverlong]

A small update.

As suggested above, I realise I had been using the multimeter incorrectly. There were sockets from the probe leads I should have been using for measuring current - but I wasn't . The simplest tips can be the most helpful.

Now using the meter correctly (again) (and assuming I'm reading the thing correctly) - with the meter in series, and ignition switched off, the ammeter reads 64 microamps (which seems too small!) When I switch on the ignition I read 4 amps and rising . I think there is a problem. So what do I disconnect to try to isolate the problem? Relays? If someone knows of a reliable , systematic fault diagnosis weblink , I will be vary grateful if you can post that and I will follow the steps.

And the statement that I didn't give contextual information may be valid, but not very helpful. I thought I had written what was relevant - but maybe incomplete - so how about indicating some key information I had left out in my post? I recognise people are giving their time freely to help me and I appreciate that. The fact I am posting here indicates I need to and am willing to learn.

Thanks

[Easy-X]

It looks (from the circuit diagrams I'm browsing) that with the ignition off only the rectifier is in-circuit so teeny-weeny current drain sounds about right. Once you turn the switch though all sorts of stuff is powered up. Lighting circuit, indicators, CDI... everything really. I don't think the various functions have individual fuses.

I think you'll have to start disconnecting things (take notes/photos as you go.) I had a similar problem on the ol' DT. Turned out to be the noise-suppressor in the flasher relay had degraded and was shorting to ground.
____________________
Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[jeffyjeff]

[MCN]

If you have replaced several regulators then it's a strong possibility that they overcharged the battery.
They should limit output to 14 volts for a 12v battery.
And a handful of amps.
If it's a sealed (vented) battery then electrolyte can be boiled off and there is no easy way to determine where the level of electrolyte is.

Of course if you replaced the battery then that changes the facts.
____________________
Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[oilyrag]

I think they have an electric carb heater that comes on when you turn the key. That would explain the 4A when you turn the key on. You could try unplugging the carb heater and see if the 4 amps goes. If it is the carb heater that's taking the 4A it's not a problem. 64 microamps, if that is correct it's nothing and won't drain a battery.

[cliverlong]

Thank-you for all the feedback and suggestions.

The current draw of the carb heater when I switch on the ignition makes sense.

I have fitted a new regulator/rectifier and it is delivering about 14V DC to the battery.

A mechanic looked at the bike and he said if the old reg-rec had failed that might have caused a short. He said the reg-rec on the bike always "sees" voltage even when the engine is switched off. A failed, shorting reg-rec might explain the lack of charging of the battery and the battery discharging overnight. The mechanic suggested fitting a waterproof isolation switch - capacity about 10 amps - and fitting it either between the battery and the rest of the bike so the battery is disconnected when not running - a "cut-off switch" I guess. Or fitting the switch between the reg-rec and the battery. Then refit the voltmeter across the battery, that clips on the handlebar, to ensure I can see the battery is getting some recharge voltage when running. I suppose the risk of putting the switch between the reg-rec and the battery is I forget to switch it on and the bike starts but the battery isn't recharged.

I hope the above makes sense.

I will update this thread in a few weeks.

Thanks again.

[jeffyjeff]

[Scrap]

[cliverlong]

[quote="Scrap"]

[oilyrag]

The regulator rectifier should be fine the way it is without a switch but it's a bit odd that so many of them have failed. Has the bike's electrics been modified in any way? Like LEDs, or different stator or rotor? Damaged battery or the wrong battery in it? Just trying to think of things that could be taking out regulator rectifiers.

If you decide to isolate the regulator rectifier you could use a relay, with the control side powered by a switched 12V from the ignition so it would close automatically when the key was on. That way you would never ride away with the switch off. Or you could simply disconnect the negative cable at the battery when you park it.

On your meter you did it right by starting at the highest range going down. I don't follow your units though. Can you put up a picture of the meter or a link to it?

[cliverlong]

[Lone-Wolf]

[cliverlong]

[WD Forte]

IF true, 64 microamps (uA) is fuck all leakage
what's the fuss?

1A =1.000
64mA =0.064
64uA =0.000064 or 64-100000ths of an Amp

I doubt that shitty little £2.99 meter can be trusted at such fine resolution anyway.
It could be current going through your body if you're touching the probes or internal leakage
in the meter itself.

RRs can cause problems if the rectifying diodes start to break down
and leak reverse current, but I dont see any diode test mentioned here.
leakage from the sense wire isnt usually a problem on a good RR.
I've had mine permanently connected to battery live for years without parasitic drain issues.

An isolator switch is only useful for a bike/car left standing for extended periods where
alarms, immobilisers etc will pull it down over weeks.

Do proper testing, buy decent battery, service and maintain bike correctly.
____________________
bikers smell of wee

[Kawasaki Jimbo]

[oilyrag]

If you put the meter to 20m, that means 20mA max range and it shows close to 0 you're good. On that bike when the key is off everything turns off. Nothing draws current, unless you have added after market stuff or have a problem. On more modern bikes a reading in the mA range when the key is off is normal.

With regards to your meter. It most likely isn't accurate in the mircoAmp range but for this application it doesn't have to be. Put it to 20mA range, that is low enough. When you lower the range on the meter the display moves the decimal point to the right. If you took a measurement that was 64 micro Amp and the meter was on a 1A range the meter would read 0.000 064. If you put the meter to a 1mA range and took the same reading, 1mA is 1000 times smaller than 1A so the meter moves the decimal point three places right so it would now display 0.064. If you put the meter to microamp range that's 1000 times smaller again so the meter would move the decimal three places right again so it would display 64

[WD Forte]