Flat Battery mystery

[Mick Taylor]

Bit of a shock this afternoon, the previously superb AGM battery on my Classic was near flat for no aparrent reason; a bump start got her running and after a few miles the electric start etc was back in service so no problems with the charging system. I am an epic dullwit when it comes to electrics so please excuse any mistakes in the following. I still needed to find out what had drained the battery despite being useless with electrics.....however following an online tutorial I connected my digital multimeter in series via the negative terminal of the battery and on the 20u/10 DC Amps scale I got a reading of -0.03; all other DCA scales showed zero. I found out that the 'u' symbol means microamps but I have no clue what /10 means.Disconnecting the fuses one at a time did nothing.....except when I disconnected both the Alternator and Auxiliary fuses at the same time and the reading changed to -0.01. Disconnecting the alternator leads alone did nothing....still -0.03.Going through the electrics disconnecting various components did nothing until I came to the starter solenoid....removing the large spade connector immediately resulted in a drop back to -0.01 (on the 20u/10 DCA scale)Can anyone enlighten me please? Have I found the likely source of the problem in the starter solenoid? I sincerely hope so as I happen to have a brand new spare, but before I swap it I'd really like to know what may have gone wrong and whether I am barking up the wrong tree. Is a drain of -0.01 still too much?Mick.

[Howell]

Hi Mick,The test you have performed appears to show minimal drain when the bike is stopped. If you set your multimeter to "DC Volts", 20, and start the bike you should show between 13.5 to 14.5 Volts if you connect across the battery terminals. This shows if you are indeed charging the battery.Regards,Howell

[Mick Taylor]

Thank you for that, my knowledge of vehicle electrics is so basic that I have no idea whether a discharge rate of -0.03 on the 20u/10 DC Amps scale is normal, reasonable or totally unacceptable...as I haven't a clue what 20u/10 really means. I looked on t'interweb before asking here, but pretty much everything I can find is couched in language that assumes a level of knowledge of terminology and processes that I just dont have. I guess every battery has a natural discharge rate, but can anyone perhaps educate me a little as to what I'm looking at and what it means?The battery in question is one of the MotoBatt yellow absorbed glass mat batteries and until this weekend I have had nothing but good things to say about it.....it's about one year old.Mick.

[Richard Negus]

Hi Mick,My meter has two position options for the red cable in the DC amps mode, either 0 - 10 amps or 0 - 200 milli-amps (mA). Your meter sound like it has similar options, either 20 micro-amps or 10 amps.I've just tried to measure the battery discharge rate on a Commander, which only has the clock in circuit when the ignition is 'OFF'. It's too small to measure on my meter.On my fake Classic, with Sparkrite regulator, the reading is again less than 1 mA or zero - can't say.I suggest you perform your test again with the dc side of the Boyer Powerbox disconnected from the harness, similarly disconnect the 6-way plug from the ignition unit.If the battery has gone flat within a matter of a few days, then I would suspect an internal fault there.

[Mick Taylor]

Hi Richard, many thanks for that....my meter is seemingly vastly cleverer than I am...the fused DCA scale runs from 200u (200 microamps?) through 2m, (2 milliamps?) 20m, 200m, 2 (Amps?) up to 20u/10. There is also an unfused 10A option in a seperate port.Assuming the settings run from low to high as shown above, 20u/10 is the highest setting on this scale, higher than 2 (Amps?) so I guess the /10 is some sort of multiplier.I know where the ignition box is and I can get at that connection easily enough, I did try disconnecting each part individually, but possibly not both at the same time. The boyer powerbox however..... was slightly battered (cracked) when I got the bike and I replaced it with the customary solid state finned alloy R/R unit (three yellow alternator leads and a single red and single black lead) which has been working perfectly for the last year....see photo. I still have the powerbox though.Is it likely this new R/R could have gone t*ts up? I notice the replacement R/R now listed by Startright looks quite different and comes with original type connectors. If the ignition box is found wanting....is there a plug and play replacement available? I'm sure I recall some discussion about these being a problem.Best.............Mick.

[johnbirchjar]

Hi Mike,for years now I've had a "battery drain" problem with my Classic,especial in the winter when I don't get to use the old girl much,so if I know that I am not going to ride the bike within the next four or five days I just disconnect the positive side,problem solved ,she fires up even after standing for long periods. I think I read (or was told)that the electrics were always "live" on the air-cooled rotaries,even with the ignition off and the key out,so there is always a drain,hence the reason I disconnect,rgds,J.B.

[Mick Taylor]

Hi John, thank you for that.....well if that is true that there is a permanent 'live' element then I guess some sort of draw should be expected, but for the life of me, in the absence of a clock or computer etc I can't imagine what would do this.The other thing that bugs me is that it hasn't done this before. It has crossed my mind that the battery itself could be the problem, but at little over a year old it shouldn't be.As it happens I have made some progress of sorts....after disconnecting and re fitting most of the accessible electrics, following Richard's suggestion (disconnecting the DC feed to the R/R made an instant difference....dropped to -0.01) and fiddling about with the usual suspect....the wiring around the headstock at the back of the headlamp.....the drain shown on the meter (with everything connected) suddenly dropped from -0.03 to -0.01 and there it has stayed; no amount of tinkering seems to make any difference.So, seemingly a considerable improvement then...but why?..... I have no idea and I still don't know what the 20u/10 scale on the meter actually means, or whether my much reduced draw of -0.01 is a lot or insignificant.....time will tell I guess.Mick.

[Howell]

Hi Mick, 0.01 or 0.03 mA is so small a current, it may be discounted, I would not class this as a dischrgrge.If your battery is 14 Amp/hours, it would take 14/0.00003 hours to discharge - 466,000 hours!

[Mick Taylor]

Hi Howell, thank you for that, much appreciated, however I really do wish I could read and understand the scale on the meter....every reference I have found thus far assumes basic knowledge that I dont have so I have no idea if I'm reading it correctly or not.The fused DCA scale on my meter runs from 200u (200 microamps?) through 2m, (2 milliamps?) 20m, 200m, 2 (Amps?) up to 20u/10.20u/10 is at the top end of the scale....above 2 Amps.....from that I guessed (no better word for it) that the /10 is a multiplier, but I have no clue how that works, so I'm quite unsure whether my -0.01 draw represents 0.01 of an already tiny amount or 0.01 of a significant current which could in itself still be sufficient to drain the battery over a typical period of inactivity.The handbook with the meter offers no explanation of any of the symbols on the device!.....I guess I need another book....Multimeters for dummies.Next step is to reconnect the battery, test the voltage and see what a week or two does for it. Thank you for the input.Mick.

[FloridaMike]

Typical causes of flat battery include normal sitting discharge of a non-used battery. Keeping the battery topped off with a trickle charger or on a battery maintainer will help. Cold temperatures are not kind to batteries either. One thing you might want to be sure of is that the terminals and the area around them are quite clean (no road crud, oil, etc.) because in high humidity conditions, that goo is slightly conductive and over time, will drain the battery. Letting a discharged or almost discharged battery freeze will kill it, so if you are not using the bike over the winter, take the battery into the house or put it someplace warm(er) where it can't freeze.If it is a standard wet cell battery (filler caps), if the level is low, add ONLY distilled water, NEVER add acid. If you use tap water with any significant mineral content, you can very easily destroy the battery - don't ask me how I learned this.When a sealed (AGM) battery dies, if it won't hold a charge, it is time to replace it.Charge a wet-cell battery at 1/10 the ampere hour rating marked on the battery. A 12 AH battery gets charged at 1.2 AH, no more, if it gets hot, or worse, boils, you need a lower charge rate. Be gentle, these are chemical reactions and sometimes they are not fast and cannot be rushed. That's why using jumper cables from a car's battery to start your bike can easily result in exploding (!) your bike battery - don't do it!!!! And of course, you're out in the boonies somewhere and have no running water available to wash the acid out of your eyes. As Mr. Orwell said, double plus ungood.More usual causes are something pulling current even when the bike is parked. As an example, if one of the diodes in the alternator (or AC generator) has some leakage, the battery will be drained. These diodes are supposed to measure zero ohms in one direction, infinity in the other, but in fact, they are never quite infinity - this is "back leakage". You can test this by turning everything off, putting a milli-amp meter in series with the battery lead and measuring the drain current with the rectifier (diode assembly) connected and disconnected. If there is a jump in the drain with the rectifier connected, there's your problem.The various aftermarket electronic ignitions can also have this problem. Basically, keep disconnecting stuff until the drain disappears - and you've isolated the problem. I've also seen electric clocks do this, as well as on-board alarm systems. If you have an alarm system, be sure to dig out the documentation to reset it because if may either not work or think it has been stolen and not shut up when reconnected. (Always fun if you are working on the bike at 11:30 PM in an otherwise quiet neighborhood . . . )Motorcycles are not very gentle environments for batteries. Extreme temperature changes, lots of vibration, long periods of inactivity, all of these shorten battery life. Generally, if the battery lasts two to three years, you've done fine, longer than that is wonderful. About the only worse vehicular environments for batteries are lawn/garden tractors and light aircraft. Even big aircraft are not immune, see "Dreamliner".Best Regards,FloridaMike

[johnbirchjar]

Hi Mike,In all my years of messing about with cars,bikes,trucks,construction plant,ect;I have never had a battery explode using jumper leads,(I supose this could happen if one connected a 24v from a truck to a 12v car or bike,but I expect a lot would bepend on how long they were connected )rgds,J.B.

[Richard Negus]

I don't see why motorcycle batteries shouldn't last as long as normal automotive batteries, where five years is considered the norm.My US-made AGM battery, fitted 15 months ago at a cost of £99, has just failed over a matter of days. No amount of charging off the bike made any difference and | got quite adept at push starting.The saving grace is that the supplier replaced it without a quibble, even though, technically, it was out of warranty. But what happens if the replacement also fails after fifteen months? That size of battery, B14L, is used on many different makes and models and is probably made by the hundreds of thousands, if not millions, per year.A quality AGM battery for my car, replaced at 5 years when that too suddenly wouldn't turn the engine, cost £20 less, weighed four (?) times as much and had ten times the capacity.

[johnbirchjar]

I pay about £30-00 for my lead acid batteries,(allways the same make)and they last about three years.I purchased my car (new) in 1999,and replaced the battery 2 winters ago(12 years )is this some sort of record , it definatly is for me,I tried to re-place it with the same make as was fitted originaly,but the company don't make lead acid batteries any more,(I only fit lead acid batts,don't like gells,when they go flat,thats it ,they can't be re-charge)The battery for the car was about eighty quid.If anybody wants to know the name of my bike battery I'll make note and report back,rgds,J.B.

[Dell Boy]

Varta batteries on my Commanders last about five years now I am not using the bikes all the time, I use the Dommie mostly now.Varta batteries are what I use, lead acid. Just have to be carefull not to be riding with a defective voltage regulator which will boil them. I have a voltmeter fitted now. Best £5.00 I have ever spent.I have a Motobatt on the Egli which hardly gets used but turns the electric start fine when I do use it.Derek F.

[Robert14]

I do use a Motobatt MBTX14AU on my classic and I`m very satisfied

[mutley]

I pay about £30-00 for my lead acid batteries,(allways the same make)and they last about three years.I purchased my car (new) in 1999,and replaced the battery 2 winters ago(12 years )is this some sort of record , it definatly is for me,I tried to re-place it with the same make as was fitted originaly,but the company don't make lead acid batteries any more,(I only fit lead acid batts,don't like gells,when they go flat,thats it ,they can't be re-charge),rgds,J.B.

Hi guys, this is my first post, just picking up on johns comment that you cannot recharge a gel battery, i have recharged them, they do contain acid and providing the battery is not damaged carefully remove the top, if you have a cell or two a bit dry top up as normal with distilled water, charge for about 15 hours and check the voltage which should be be about 14 volts. Leave it for a couple of days and recheck the the voltage, anything over 12.6 volts battery is ok, anything less you need a new battery. Hope this is of help in saving a few pounds Regards Ivor

[Joe]

Hello Mick,If your still having problems with your bike I'd be happy to run parallel tests on my Classic with you over the phone or I could pop over to you as you aren't too far from me in Essex. I'm busy this week but I'm sure I'm off shift next week so any time for me would be good.My Classic is a replica but 100% correct using new old stock parts about 20 years ago so should be OK for the comparison tests it only lacks the LE chassis and engine No. because I couldn't find an original bike when I wanted one so I built my own, LE 106 maybe? I even have the correct Norton Classic log book too.Buy the way, I have just purchased a Motobatt for one of my other bikes on the day you posted your original message, I hope I haven't just wasted £80.00. It claims to have 20% better cranking power so I thought I would try it out as it's a big lump to turn over and so far so good....... This is my first experience with a gel battery, I always use lead acid (from the ROC) and change them every two years whether they are good or not, perhaps this seems a bit wasteful but this is only for my every day bike because I need it to be reliable and with 186,00 miles showing on the speedo it's been just that. Some of my less used bikes though do have 5 or 6 years old lead acid batteries and they also seem to be OK. Let me know if I can help.Kind regards, Joe.

[johnbirchjar]

Thanks for that Ivor,one of my favorite maxims "Life is a learning curve" and so it is ,J.B.

[FloridaMike]

Hi Mike,In all my years of messing about with cars,bikes,trucks,construction plant,ect;I have never had a battery explode using jumper leads,(I supose this could happen if one connected a 24v from a truck to a 12v car or bike,but I expect a lot would bepend on how long they were connected )rgds,J.B.

I've seen it three times - twice on motorcycles and once in an airplane. Makes an unholy mess and is *very* exciting! All 12 volt to 12 volt systems, one I know was connected backwards (owner told me so), the other two were "correct". All three blew almost immediately once the jumpers were connected. The side blew out on the battery of the bike that was connected correctly, fortunately the owner was standing to one side, not directly next to the battery. On the airplane, the top blew off, and while the unhappy owner was frantically washing his hands and arms, battery acid got all over the inside of the cowling, and made a mess of all the expensive aluminum parts . . . several thousand dollars in repairs before the airplane was airworthy again.I think what happens is that if the subject battery has gone dead because it has a shorted cell, when you dump 600+ amps of cranking power into that low resistance, kaboom. With a battery that is discharged but otherwise OK (someone left the lights on), you *MAY* be able to get away with it. I'd prefer to err on the side of caution.You're right, it is not common at all, but it does happen so keep it in mind before attaching the jumper cables.With best regards,FloridaMike

[Dell Boy]

I have blown up one large car battery whilst I had it on charge on the garage floor being charged.I was welding & was too close to it & the vapours from the battery ignited & blew the top of the battery.Big wake up call when you are cocooned in a welding mask & out of the blue KABOOM!!!Derek F.

[Richard Negus]

I was once sitting on a boat in a marina talking to the guy next door working on his engine. There was a small bang, he popped up like a Jack-in-the-Box and jumped straight in the water!He explained later that he'd got his battery on charge and had decided to turn his engine by shorting the solenoid terminals there rather than using the push-button up in the wheelhouse - big mistake! After returning from A&E, he spent the rest of the day washing sulphuric acid out of the engine bay.

[johnbirchjar]

Dell Boy ,It can only happen to you ,rgds,J.B.

[johnbirchjar]

Changing tack a bit,Joe, your Classic,186,000miles ?how many engine rebuilds?(and gear boxes)J.B.

[Joe]

Hello JB, No, it's my Commander with 186,000 miles. I'm not sure what my Classic has covered as I rarely use it which is a shame as it's a lovely bike to ride and one of my favorites along with my DKW. Regards, Joe.

[Joe]

Hello JB, Sorry I forgot to add this detail.1 new rotor housing after the plating lifted, 1 complete set of seals and I have had to recover the shaft bearings twice on both ends which just involves machining down the shaft journal (or removing the old recovered bearing) and press fitting the inner part of the bearing onto the new surface bringing the shaft dimensions back to normal. Both occasions were after I'd run low but not out of oil during a tour....Could be a coincidence?..... Not sure if my shaft will take another go though. I'm sorry that my description isn't more technical but I'm sure you get the gist...... The gearbox hasn't been touched yet but it's getting noisey in 3rd and 4th so it's on the list and I'm now also in the process of replacing the chain gaiters but still on the original chain. 1 new set of clutch cush drive rubbers and I have had to re-solder the nipple back onto the clutch cable twice. Also, over the years I've had a few pairs of fork seals and 2 water pump rebuilds but the first was when I purchased the bike at 33,000 miles just in case it needed it. My other Commander which I've had from new now with 67,000 miles has had 5 water pump rebuilds. Just checked the MOT's for the mileage on the Classic and Deek which is 2599 and 5579 respectively. I thought they were much higher. Regards, Joe.

[johnbirchjar]

Thanks for that Joe,I had been hoping to speak to the owner of an aircooled that had done all sorts of high milage so I could pick his brains to find out what the secret is to get high milage out of mine after the re-build, (mine has only done 57,000 miles and is due for a re-build ,)It was mollied and rebuilt at Shenstone after having only covered 625 miles , but that,as they say,is another story ,ride safe,J.B.

[Mick Taylor]

Hello Mick,If your still having problems with your bike I'd be happy to run parallel tests on my Classic with you over the phone or I could pop over to you as you aren't too far from me in Essex. I'm busy this week but I'm sure I'm off shift next week so any time for me would be good.

Hi Joe, thank you for the offer, much appreciated.......if you have a multimeter, perhaps we could do an initial comparison over the phone? As it happens I have been away for a few days, so I left the battery connected and tested the voltage at 12.75 before I left. Today I tested it again and it's now 12.69.I'm in two minds as to whether it's the battery or the bike electrics at fault. I have found that the current drain I first measured at 0.03, which then dropped to 0.01 for no aparrent reason has now increased to 0.9 which is a huge increase.I have also found that the figure fluctuates when the steering is turned or I tamper with the wiring around the steering head.The bike has done only 4,000m and the general condition of the electrics is commensurate with that mileage although clearly, age hasn't done it any favours. I'm going to look very carefully at the wiring around the steering head and see what If anything I can find.This is my first motobatt AGM battery and I have been really happy with it until now....and it may not be the battery at fault of course.Anyone looking for a decent branded lead acid battery, try these people; MDS Batteries, free delivery, super fast, pukka Yuasa batteries at really good prices.....just remember to include the acid in the order.http://www.mdsbattery.co.uk/departments ... .kettle738

[Richard Negus]

I have also found that the figure fluctuates when the steering is turned or I tamper with the wiring around the steering head.

That sounds very much like corrosion at the two nine-pin connectors from the harness into the instrument binnacle. Easy to get the binnacle off and clean/grease the terminals, but a pig to get the connectors back into place as the loom has very little slack in it.

[Mick Taylor]

Thanks Richard, you are a star......as usual.......that gives me a proper starting point, which is priceless as I truly hate electrical issues.I will update as and when I get round to tampering with it.Mick..........kettle738.

[andy588tt]

Hello Mick,If your still having problems with your bike I'd be happy to run parallel tests on my Classic with you over the phone or I could pop over to you as you aren't too far from me in Essex. I'm busy this week but I'm sure I'm off shift next week so any time for me would be good.

Hi Joe, thank you for the offer, much appreciated.......if you have a multimeter, perhaps we could do an initial comparison over the phone? As it happens I have been away for a few days, so I left the battery connected and tested the voltage at 12.75 before I left. Today I tested it again and it's now 12.69.I'm in two minds as to whether it's the battery or the bike electrics at fault. I have found that the current drain I first measured at 0.03, which then dropped to 0.01 for no aparrent reason has now increased to 0.9 which is a huge increase.I have also found that the figure fluctuates when the steering is turned or I tamper with the wiring around the steering head.The bike has done only 4,000m and the general condition of the electrics is commensurate with that mileage although clearly, age hasn't done it any favours. I'm going to look very carefully at the wiring around the steering head and see what If anything I can find.This is my first motobatt AGM battery and I have been really happy with it until now....and it may not be the battery at fault of course.Anyone looking for a decent branded lead acid battery, try these people; MDS Batteries, free delivery, super fast, pukka Yuasa batteries at really good prices.....just remember to include the acid in the order.http://www.mdsbattery.co.uk/departments ... .kettle738

Hi Mick I use Odyssey batteries no acid bigger umph and after 6 years still no problem I relocated it behind the seat hump of my F1, I got fed up with boiling the battery in the normal place I fitted a wiring harness with a rubber plug over the terminal block so a charger could be connected without removing the bodywork.Ride safeAndy