Loosing voltage

motoddrob

motoddrob

Hero member
Location
S/W Australia
On going battery issues with the Motodd. Seems the battery is loosing voltage when sitting in the bike. Recharged it on the bench and 4 days later it's only dropped 0.1 volts. So wondering if the bike is draining power when sitting idle. Is there a way to check if the electrics are draining the battery when parked up.
 
If it's leaking via the battery earth there will be an indication if you connect a metre between the battery and the earth connection with the key off. It should read nothing if correct. Don't ask me what setting on the metre, I am an idiot that bearly knows the basics BTW that's the easy bit, finding the source of the parasitic leak is the hard bit. The key should kill it, check there. This is from someone who had to keep a battery disconnected for years just because of this pain in the arse but that was years back and I don't remember what bike it was
 
If you suspect that your bike is draining power, it's simple enough to check. Leave the ignition switch off. Disconnect the battery then temporarily re-connect via a multi-meter on an Amp scale in between the battery cable and terminal, so it's in series with the battery. On most meters, you just turn the rotary dial to select the lower (milliamp) scales. If it has a 10A scale, you have to stick the banana plug for the positive lead in a different hole. For your rate of leakage, it's only milliamps so you won't need to swap the plug to the 10A connection. Just start with the meter on the highest amp scale on the rotary dial switch (Usually 200mA. Maybe 600mA on a higher spec meter) and switch to lower scales if necessary to get a sensible reading.

Most meters won't zero perfectly so you'll probably get some sort of reading. Note what the reading is (if any) when the meter is disconnected. That's your base reference. connect it and note any change in reading. If it does change, the difference between readings is what your bike is sucking out. If you find there is a bit of current leakage, it could be a bit of conductive muck in a switch, or a faulty diode in the R/R.

Ammeters are easy to kill if you pull too much current through them. Amp scales are pretty much zero resistance through the meter. Any half decent meter will have fuse protection, but a cheapo meter perhaps not. You don't want the hassle of replacing fuses in your meter anyway. So don't switch the ignition on with the meter connected on a milliamp scale (the coils will draw a few amps). The 10A scale goes through a bigger fuse (hence the different plug-hole). If you're curious about how much current the coils draw, stick it on the 10A scale before switching the ignition on, but FFS don't hit the starter button!

Bear in mind that batteries lose voltage over time even if they're not connected to anything. That's why they should be recharged periodically when not being used.

A new lead-acid battery (that includes AGM and gel types) will lose voltage at a constant rate of around 3% per month. So over 4 days you can expect a drop of 0.05V. That's about half the loss rate that you're getting, but that's for a brand new battery in tip-top condition. If it's been used and recharged its performance will drop off a bit. I wouldn't be too concerned about a loss of 0.1V over 4 days. That's not bad for a used battery in average condition.

I dunno much about lithium batteries. I believe they have a longer shelf life, which I presume means a lower rate of voltage loss.
 
It takes very little constant drain to empty a bike battery. The rated amperage - not the cca - is what it is pulling from. So 0.1amps drain will take an amp after ten hours, and over a few days something like a 14amp battery won't have much left. I don't know how lithium batteries are rated.
 
If you measure current flow from the battery and the key is off and and everything else is off including the brake light. The first suspect is going to be the voltage regulator. Disconnect it and measure the currrent again. It is normal for the regulator to draw a very small amount of current back from the battery but not enought to kill the battery in a few days.
 
I had that problem and put the amp meter between the earth on the battery and the various sub circuits from the fuse box.
It could simply be a dead battery.

Paul
 
Tippie said:
It takes very little constant drain to empty a bike battery. The rated amperage amp-hour rating- not the cca - is what it is pulling from. So 0.1amp drain will take an amp-hour after ten hours, and over a few days something like a 14amp-hour battery won't have much left. I don't know how lithium batteries are rated.
Click to expand...
Electrical units sorted.

Mr Pedantic ;)
 
My Pan has a tiny batterry around the size of three fag packets (remember its an 1100cc 300 kilo four) and the fuel gauge is never "off" so a draw is always present, the astounding thing is it can sit for months, six even and still crank the engine, and after this long sit it needs a lot of cranking to refill the evaporated carbs, before you get a fire, the fuel pump is electronic, but the fuel tap (a safety item realy) is vacuum operated, and is higher than the tank anyway, the electronics control the speed of the electric fuel pump (its submersed inside the tank) according to revs, low revs (EG cranking) equal slow pump speed, flat out equals max pump speed, and if there is a fault, no spark, because the bike has crashed and is on its side, engine stopped, the pump stops, all clever stuff with a potential to go wrong but so far it hasnt. Its queer to me how this tiny battery can suffer such abuse (not connected to trickle charger) and still get you going with four dry carbs and a slow pump speed, several minutes of cranking might be needed, never failed me yet.
Laverda twins and triples have gi-normous batteries, my Egli started and ran well with a tiny battery from a 400/4, every one I spoke to said it would not be up to the job, but oh yes it was
CLEM
 
Rob, what instruments are you running on the Motodd?
If they are modern, ie electronic they may have a memory that may need a small amount of power to keep it going?
 
Unless you have a clock attached there should be no voltage leakage. Easiest way to check is disconnect the battery and attach an ohmmeter between the the + and - leads. Reading should be 1 Megohm or higher. If you get a low reading remove each fuse one by one to see if goes up, and start tracing from there.
 
This from above poster...well spotted.
"Some regulator /rectifier with battery voltage sensing have a permanent live drain, Electrex one for example".

Most ND RR ( non FET ) also have sense wire, about 1-2mA if fixed connection to battery, ie not through ignition switch. Small drain for regular riding, can sort of be a problem if connected for many weeks without charging... as Cam says you can measure the drain with careful test connections. Always good practice to disconnect a battery for stored sessions. HTH Rob...j.
 
Thanks all,
Pretty sure it's the battery. Loosing voltage sitting on the bench
It's a SSB Lithium 12 months old and has been working fine always starting the bike.
Month or so ago I turned on the ign and nothing, not even the neutral light, the battery has a cutout switch when volts drop it seems 12v.
Measure with meter 11.9v. Jump started from the BM and ran it into town. Went to start again and the battery switched off again.
Restarted using a battery pack and rode home. Put on charger and it came up to 12.8 volts which should start a warm bike but just dies.
Replaced the RR as I was suss about that. Over about a week the battery slowly dropped voltage, why I ask about voltage leaks in the circuitry.
It has 2 years warranty so will send it back. Think Ill go back to AGM.
 
Q, this battery is a warranty replacement from the one I brought just over a year ago. There seems to be 2 series of SSB lithium.
LF........ 12 months warranty, charge with any conventional charger and fitted to the BM for 7 years and never been a problem
LH........ 2 years warranty, charge with a lithium specific charger, has a flash push button voltage readout. Both been a problem.
The Motodd had a LF series fitted for several years, Slow to start but start it did. Probably on the too small size and eventually failed hence the replacement.
 
motoddrob said:
Q, this battery is a warranty replacement from the one I brought just over a year ago. There seems to be 2 series of SSB lithium.
LF........ 12 months warranty, charge with any conventional charger and fitted to the BM for 7 years and never been a problem
LH........ 2 years warranty, charge with a lithium specific charger, has a flash push button voltage readout. Both been a problem.
The Motodd had a LF series fitted for several years, Slow to start but start it did. Probably on the too small size and eventually failed hence the replacement.
Click to expand...
I had a LH SSB Lithium battery fitted to the Benelli when I bought it, it was nothing but a pain in the backside, always loosing charge and going flat if left for 3 or 4 days without running the bike. It was less than 2 years old and still within warranty. The bike is fitted with an immobiliser that does draw continuously on the battery granted. Starting the bike on a cold day was a very hit and miss affair with the battery loosing voltage when cold and would only coax the engine into life after 4 or 5 tries, each failed attempt warmed the battery a little thus enabling a higher cranking voltage.
Not a confidence inspiring experience. In the end I replaced it with an AGM battery, no further issues. I couldn't see the point of replacing it under warranty. Talking with others who have SSB batteries it would appear that the newer ones are of a lesser quality than the originals.
 
Have a LHZ14-S that is about 6 years old and keeps full charge but I do remove it from the bike when it is not going to be used for a while. I still don't know why the new LH9B-4 dropped it's guts but it has been holding it's charge ever since the battery techs gave it a check up. I still like them, light and powerful start.

SSB will want you to return the battery to where you bought it or take to their local agents for checking before replacement.
 
Interesting thread!
I now have LiFePO4 batteries on 6 of my 10 rideable bikes.
They overwinter much better than gel batteries, due to the very low self-discharge rate.
The one bike I have to watch is my modern Triumph TTSE, which will drain the battery if left connected for long enough.
I suspect this is due to the immobilizer, clock etc., which never completely go to sleep.
The Laverdas don’t seem to have this issue.
Steve
 
You must log in or register to reply here.
Back
Top