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Another 12 volt thread!!!
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cocorico
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January 11, 2020 - 9:36 am
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14.5V is right for a standard 12Vrec/reg. 5 wire connection like this:

recregsignalwires.jpg

A decent workshop charger will control the current as well, high current to start, tapering off to a lower maintenance current when fully charged. AGM batteries are unsuited to high voltages, but 14.5 is still OK. 'Wet' batteries can stand some overvolts as the boiled off water can be replaced. All batteries need to be treated properly to obtain maximum life.

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SpacedMarine
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January 21, 2020 - 11:55 am
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Ok so fitted a new battery.Well charged.Fitted it.Giving 12.5v.Turn ignition on drops to about 11.75.(coil I'm assuming).Start up idles at 14.5.Turn lights on idles at 12.5.Rev it up gives 15+ at the battery terminals regardless of whether lights are on or not.

Spoke to Rex last week he says fine to attach black and red together.

Is the rectifier just duff or is Mike's theory about the black wire meaning it doesn't regulate properly as it isn't sensing any voltage drop due to not being hooked in after the ignition?

Dont want to knacker another battery is all.

I guess the only way to know is to try it?

What's 7/16 in mm again?

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cocorico
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January 21, 2020 - 12:38 pm
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SpacedMarine said
...gives 15+ at the battery terminals regardless of whether lights are on or not.

Spoke to Rex last week he says fine to attach black and red together.

When you switch the ignition on, the voltage should not drop (other than for an ign light, maybe, which shouldn't be pulling 750mA) unless you happen to be at a 'points closed' position of the crank, try rotating it to 'points open'. When you say 15+ do you have a more precise reading, and how is it measured? A DMM can be somewhat innacurate on motorcycle electrics. I presume the black wire referred to is not the negative output? Looking at the diagram I attached above, the only way I can see the 'black' or sense lead having any effect is if it is a controlled regulator. Without knowing what's inside the regulator it's not possible to say. I do know that the regulator on a Moto Morini relies on a signal from a good battery to achieve the correct output - won't work at all if the battery is low. But if Rex says it's OK, I would accept what he says, he knows about Bantams and what he sells. You could run the engine on battery only for a while. Stick a headlamp bulb across the battery output and monitor the regulator output voltage at different rpm, you could also monitor the ac input to see what you are getting from the generator.

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SpacedMarine
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January 21, 2020 - 12:47 pm
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Ok so with the sensor wire connected through the ignition and back to the live battery terminal it's a little better but I can still get a steady 15 volts if I hold the throttle open which is too much 🤔🤔🤔🤔

The bike is wired negative earth and there are no voltage drops getting battery voltage +ve terminal to the frame and 0v -ve to the frame it must be duff!

What's 7/16 in mm again?

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SpacedMarine
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January 21, 2020 - 3:05 pm
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Sorry coco missed your post.The black wire on this rectifier is the sensor wire the negative is green.Im guessing I was at "points closed" otherwise my wiring isn't right 🤣🤣🤣.The 15volts is across the battery with the engine running.

When I wired the "sense" wire the voltage did come down a bit at idle but give the throttle a bit and it shoots up i dare say if I was doing 60 down a dual carriageway I would be getting 15 volts.

What's 7/16 in mm again?

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mikef
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January 21, 2020 - 3:23 pm
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Hi SM.
      I would say that 15V when revving the engine is OK. As has been said before, a digital multimeter "doesn't like" the spiky waveform and noise from a motorcycle electrical system so can be a bit error prone. The voltage seems to level out at 15V as indicated by the meter so that shows that the regulator is regulating. The sense wire on many regulators is internally connected via a resistor to the output so that the regulator will still work if the sense wire is not connected externally. Not sure about this regulator though.
I think your system is working as it should.
Mike.

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SpacedMarine
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January 21, 2020 - 3:38 pm
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Thanks mike im just really concerned about wrecking another battery as this will be the 4th one in about 12 months. Part of the reason I went 12v.

What's 7/16 in mm again?

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cocorico
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January 21, 2020 - 4:18 pm
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SpacedMarine said
...When I wired the "sense" wire the voltage did come down a bit at idle but give the throttle a bit and it shoots up i dare say if I was doing 60 down a dual carriageway I would be getting 15 volts.  

Ah - but have you actually measured it going up to 15V when revved?

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SpacedMarine
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January 21, 2020 - 5:09 pm
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Yes coco across the battery terminals it goes up to about 15 volts when you rev and hold I did take some footage but it's a bit wobbly as I only have 2 hands🤣

That's without the sensor wire fitted but to be honest it's not much better with it fitted

What's 7/16 in mm again?

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nickjaxe
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January 21, 2020 - 5:16 pm
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James my cheapo multi tester reads erratically if near the running engine...I hook up to temp 3 feel long extension leads to the voltmeter to get the meter away from the engine a bit...much more stable then.

Nick.

My Bantam video              https://www.you.....jpOFmzRZRI

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mike p5xbx
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January 21, 2020 - 5:17 pm
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still maintain that 15volt is too much for a Sealed battery
at that voltage it will be gassing
at 10c this starts happening at 14.82volts
at 20c its 14.49V
they do have a vent but if it cant vent quickly enough it will bend the plates and short out internally, = dead battery
SLA charge voltage should be 14.2-14.7v Max

D? - D10- D14 Bantams 350 AJS -500 Triumph http://bsanotru.....lfire.com/

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SpacedMarine
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January 21, 2020 - 5:20 pm
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mike p5xbx said
still maintain that 15volt is too much for a Sealed battery
at that voltage it will be gassing
at 10c this starts happening at 14.82volts
at 20c its 14.49V
they do have a vent but if it cant vent quickly enough it will bend the plates and short out internally, = dead battery
SLA charge voltage should be 14.2-14.7v Max  

Yes I got a agm fitted so it's far too much surely?Gotta be a duff regulator?

Gonna try an Ebay special at £4 what could go wrong?

 

Anyway it's not getting ridden again till I'm happy with it as the new battery wasnt cheap!

What's 7/16 in mm again?

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Lone Wolf
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January 21, 2020 - 7:21 pm
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SpacedMarine said
Thanks mike im just really concerned about wrecking another battery as this will be the 4th one in about 12 months. Part of the reason I went 12v.  

Wotcha.

Four batteries in one year - change the regulator/rectifier.   I had the same happen on my Enfield - going as high as 16.2volts.   New reg/rec fitted and it stays below 14.8 now.

^..^

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cocorico
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January 21, 2020 - 8:23 pm
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Worth a punt? ** Please log in to view **

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SpacedMarine
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January 21, 2020 - 9:37 pm
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cocorico said
Worth a punt? ** Please log in to view **

That's the kind of thing I'm looking at.They look exactly the same as the one I got .

Lone Wolf said

Wotcha.

Four batteries in one year - change the regulator/rectifier.   I had the same happen on my Enfield - going as high as 16.2volts.   New reg/rec fitted and it stays below 14.8 now.  

Yup.Started with a new square rectifier fried 2 6 volt batteries.changed to 12 volt reg/rec boiled one battery dont want to do another👍🏼

What's 7/16 in mm again?

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mike p5xbx
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January 21, 2020 - 11:29 pm
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SpacedMarine said
Gonna try an Ebay special at £4 what could go wrong?

Out of the Frying Pan>>Firecant-look
you can use them on the D1>D7
I have done it
but D14 has twice the power output and will cook them within a few miles
have tried one on a C15>12volt Zzzzzzzap
re-read post 12 for a R/R that works
 

D? - D10- D14 Bantams 350 AJS -500 Triumph http://bsanotru.....lfire.com/

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SpacedMarine
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January 22, 2020 - 12:37 am
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Ta Mike £38 for piece of mind seems like a fair price dont think I can put up with anymore electrical gremlins 👍🏼

What's 7/16 in mm again?

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cocorico
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January 22, 2020 - 8:13 am
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Good to hear that the GY6 one is OK for D1 to D7 as I have one for D3! The AO one referred to by Mike seems similar to the Boyer Power Boxes I have used over many years - but much cheaper (makes mental note...). Must admit I had thought that 4A output from the GY6 type would be adequate for a 175cc engine, but then running with improved lighting on a 12V system I suppose you are pulling well over 48W!

Hope it works - be quicker delivery anyway!

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SpacedMarine
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January 22, 2020 - 10:01 am
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I think my headlight alone is 45 watts coco 🤣🤣🤣

What's 7/16 in mm again?

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mike p5xbx
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January 22, 2020 - 5:19 pm
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the D14 type alternator can put out almost 100watts at 4000rpm when wired as 12volt
that’s around 7.5amps so the cheap ebays ones don’t stand much chance if only rated a 4amp max
that's the first time I have seen an output quoted for the GY6 regulator
but is ok for the D1-D7 bikes

D? - D10- D14 Bantams 350 AJS -500 Triumph http://bsanotru.....lfire.com/

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