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Battery discharge.

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Hello all,

My 73 850's wiring harness has had some modification. I discarded the Zener and the rectifier and fitted a ' Wassell black box. I find the battery discharges over time more than it should {the battery is quite new}. I use Oxford battery optimizers for winter battery maintenance on my bikes, the one attached to the Norton tends to 'kick in' more frequently than my other machines. I suspect the wassell black box is draining the battery, on the move the alternator kicks out around ten amps. Has anyone else on the forum had any experience of this problem? 

            An unrelated question! Are Zener diodes still available? I am rewiring a Bonneville at the moment and was thinking of keeping the standard set up, from what I can see positive earth Zeners aren't available although I did see a NOS item that someone wanted fifty quid for. Surely these are a tenners worth tops?

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Don't know how many Podtronics, Powerboxes and other boxes that replaces Zeners are out there. Probably there must be a lot of still working replaced zeners laying in sheds all over the country. Sorry that I will not part from mine until the restauration is finished and I know that the replacement works.

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The way to check is:

1. Disconnect the live battery terminal and connect a multimeter on 10 amp setting between the terminal and the cable. There should be virtually zero reading. If there is an appreciable reading you have current leakage somewhere and the regulator is the most likely culprit - disconnect this and try again.

2. If the reading is very small, set the meter on milliamps and see what the reading is. Anything more than a few milliamps still means leakage and follow as in 1 above.

Both these with a charged battery of course, and if the regulator turns out not to be at fault then progressively disconnect components till the discharge disappears.....

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hello that only way a battery will leak is it going to earth some where  and discharging  So you next have to find and eliminate the leak,     yours  anna j  

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The information above by Ian S to check for leakage is fine. The confusion infered (rubbiosh spefler no spelll chicker) by AJD is to be ignored. An alleged prime cause of leakage can be the 2MC (original Lucas item). One of the problems with Grahams leakage is the 'black box' reg/rect. is that Wassell do not have any technical back up, Podtronics are from USA, While Boyer Power Boxes are very expensive. I sell a reg/rect that is cheaper AND I give a technical back up.

Lucas Zeners, -these were last made in the 1980s. Since then we have had several 'zener diodes' available as new, but none that I have seen have a decent specification (100W) or indeed have any specification. The final voltage of the zener was often a bit variable so you were either a bit over or under charging (the Zener limited the top voltage) But despite all that we have had over 50 years of this device and it is still viable. So don't discard it yet.

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I would certainly follow Ian's and Al's suggestions.

But you might also try, after a nice long ride, when the battery is fully charged, check voltage then try disconnecting it at the terminals.  Check then the voltage again the next day.  

There should not be a significant voltage drop.

If there is a significant voltage drop the battery itself could have an internal fault.

Mike

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I've noticed that immediately after charging voltage is higher than after something like a quarter of an hour. So do as Michael says but with a check after an hour and then next day.

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Yes this is normal, batteries when coming off charge do show a higher than normal voltage but bear in mind this is 'off load' (apart from the multimeter). Put the lights on for 10 mins, this will knock the voltage down. If your motorcycle battery is 9 Ahr then of course you won't 'get' 9A for 1hr but you might get 1A for 9 hours ish. But if you put the bikes lights on (say 4.5A then they should stay 'usable' for 2hrs ish. If you was riding, ignition only, say 2A you should be able to ride for at least 4 hrs, 200 miles or so?

By the way Lucas Zener diodes when last sold where about £30. If you buy second hand one I can test them.  aoservices.co.uk

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Thanks to all for your useful suggestions. There is some useful tips on testing current leakage and I will be trying them out. On the subject of a Zener for my Bonneville I think I should fit a podtronics box and make life easier for myself

Thanks to all.who replied

Graham

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I have been having the same issue with battery draining on my MK2a fitted with 3 phase alternator and Wassell 200W combine rectifier/regulator. Finally got around to testing using a multimeter and the Wassell box was drawing 12 mA. Have replaced it and the new box is drawing 0,25 mA, so looks like they all draw to a certain extent.

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... that even 12 mA would take a loooong time to drain a decent battery. It equates to around 1 amp in 80 hours or so - if you have a 12 Ah battery it should take around a month to go flat. I know all this is a bit hypothetical.....

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I have a 3 phase alternator and black box reg/ rectifier. After a couple of years I found the battery started to go flat after a week or so, but not with the terminals disconnected. I suspected it was the reg/rectifier leaking to earth so I replaced it. Problem solved.

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10AH battery and took 3 weeks to discharge, as it is an AGM it should not need charging that often so the Wassell box is in the bin.

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I have noticed the same problem as Graham did with an A-Reg 3. I've installed a circuit breaker which is also the main fuse.

The white button is the break button.

Don't ask me where I get it from.

Fritz

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Some years ago I had a Velo Viper (later converted to a Venom). The proud PO showed off the Alton generator which was fitted and told me how good it was. I discovered that the pathetic regulator fitted allowed a steady 0.5 amp or so to feed back from the battery so flattening it more or less overnight. Why on earth they didn't just put a diode in the circuit I have no idea.

That combined with the horrendous racket from the straight cut gears made me ditch it very quickly in favour of a Lucas E3L which worked faultlessly.

The silver lining was that I put the Alton up on ebay and got £300 for it - nearly as much as a new one. And the buyer was in France, where Altons come from!

 


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