Battery drain???

[28hodge]

Bugger,

Charged the battery Thursday night and left it off the bike to see if it went flat or not, was away all friday so went to pick the bike up on sat morn put it back together and head off to the dyno, battery back o and the bike started straight up, so the battery is holding charge and is still good by the looks of things.

Left the battery on the bike all day sat, then went to it on the sunday afternoon the play with the carbs after the dyno run, ad once again it was completely flat, so i have a drain somewhere, god knows where or how tho, the bike has no ignition barrel, lights or anything electrical on it other than a starter motor!!

I genuinely hate and do not really understand electrics all that well, i will do the tests above and report back, thats if i can even find the bloody multimeter!!

[magg]

The rect/reg is permanently connected to the battery. I assume you use the engine kill switch as the only on/off control of the electrical power, normal ignition switch is bypassed. You will need to find your multimeter and monitor the battery voltage when it is under load starting the bike to really prove that the battery is ok. Then set your multimeter to low amps range and check that there is no current flowing from the battery when you have the engine kill switch in the off position.

[28hodge]

Ok found my multimeter, battery has been off the bike for a week and is holding 11.8v across the terminals, fitted the battery onto the bike and it's turning over and working fine, disconnected the earth and checked between the earth mounting point and the end of the earth and the multimeter is showing 11.8v here too, it's not showing anything with the multimeter on amps setting tho, I've left it connected and will re test in an hour or so to see if it's draining the battery, I think it will be as its flowing 11.8v to earth I think!! Or is that wrong?

Yeah I just use the on off switch as the ignition switch why would I have a drain the earth, I really am clueless when it comes to electrics!

[28hodge]

Started it up off and checked the charge at 5500rpm, all good it's generating 14.60v which is fine according the ricks elec checklist in the document library, left the battery connected will see if it drains it again over night, did find a frayed wire which I re-insulated, think its a oil presure sensor though, right hand side of the bike off the lower of the crankcase round the back of the engine and into the loom on the just above the clutch casing.

[magg]

A fully charged good battery should be over 12 volts, close to 12.8 volts. Yours is a bit low. On which amp range range did you set your multimeter? How much of the original electrical system have you retained on the bike eg are the neutral/oil pressure lights still functional? Did you simply bridge out the original ignition switch?

Zero current is the correct result when measuring between the end of the battery earth lead and the chassis with the multimeter set to current (multimeter probes moved to current measurement positions on the multimeter, not voltage measurement positions). Battery voltage level is the correct reading when measuring between the end of the battery earth lead and chassis when multimeter is set to DC volts.

[28hodge]

I charged it a while ago and it's been sat so that may account for the slightly low reading across the battery.

Left everything connected last night after running the bike up to temp to check the charging reading, came back to it this morn an flat as a pancake so whipped it off an checked it with the multimeter it's reading 4.2 after being connected all night, I've put it on charge an will leave it to see if it's reading 12.8 fully charged.

I'm completely unsure about the loom on the bike it's as it came to me, so I'm gonna be pretty useless trying to explain what's what with it, as far as I can tell its running the bare minimum, starter motor and charging circuit and that's it, I have no neutral or oil pressure lights all I have is temp gauge and rev counter. There are alot of connectors loose down the right hand side of the bike mind, was gonna cut these all off and tape them up as its never gonna go back on the road.

Cheers for the help mags massively appreciated as im a bit lost in this area. I'll charge the bat an then reconnect it and try the amp reading with the multi probes set to dc as I hadn't done that! Told you I was electrically clueless!!!

[Neosophist]

Battery sounds knackered.

Below 12v is completely flat.

http://www.mmbalmainauto.com.au/PDF/Sta ... teries.pdf

See this chart for approx state of charge on a battery/

All you need to do is test for current drain on the bike.

With the bike switched off.

Set your multimeter to current (amps)

Disconnect the earth lead and put the one lead to the earth strap and the other to the battery.. this bridges the gap.

You should have 0 or very close to it on your multimeter.

If it's anything higher then there is a drain on the bike, if not the battery is suspect (I suspect it already)

[magg]

A 4 volt battery is a dud. When checking the current flow between the battery earth lead and chassis the multimeter has to be setup to read amps, this is a different setup for reading volts. How long have you had this problem? Does the temperature gauge work? How do you isolate the battery when not running the bike? If the temperature gauge still functions and you have no other power switch other than the handlebar mounted ignition kill switch, then the battery will discharge through the temperature gauge.

[28hodge]

Charged the battery all day when I left it was reading 12.6, left it off overnight and will check it again tomo, it was at 4v after being left on the bike all last night so it ran down from 11.6vish to 4 over night, but has charged back up to 12.6 today.

Yep temp gauge works and I don't isolate the battery overnight or when not in use, and yep just using the handlebar off switch as a ignition on off. I have only used the bike twice, it's purely a track bike the battery will sit off the bike for a couple of days hold charge and then start the bike once re fitted onto it, and once on will charge and work the bike all day at a trackday, I'm right in thinking that if I just leave the earth lead disconnected when not in use will that solve the drain issue from the temp gauge

[magg]

Yes, disconnecting the battery earth lead at the conclusion of each race meeting is the best solution. While ever the battery is connected the temperature gauge or any other electrical unit still connected will discharge it.

A battery that has discharged as low as 4 volts will never be much good no matter how many times it is recharged. The open circuit voltage measurement is meaningless and IMO any significant electrical load will cause it to go flat again.