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Dc electrics

Technical help for Series one, two and three Lambrettas. Models include the Li, Li Special, TV, SX, GP, Serveta and API/SIL models

Dc electrics

Postby ULC Soulagent » Mon Oct 21, 2019 3:06 pm

Hi all :D
This has got me stumped so I’m putting it out there for the lecy boffins as it doing my nut in.
Basically I’ve a mb simple loom and converted over too dc, Stator, podtronics wassel, dc junction box and battery 7amp.
Fitted it while following the mb instruction on his site which went ok, no issues there.
I have led side and rear taillight and normal 35/35 watt headlight bulb. Also run dc for my twat nav and phone.
My problem arrives when I switch on my headlight and within 15 mins my battery has drained :evil:
Now I’ve measured the voltage coming out of the Stator( both Yellows) and it’s 12v and no more. Same with the red leaving the wassel into the Dc Juction box. Should it be more than 12v too keep topping up the battery or do I have a bigger problem than that :? Hate electrical
Many thanks
Shane
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Re: Dc electrics

Postby Meds » Mon Oct 21, 2019 5:02 pm

If you break it down it could be any one of 4 things
1. The stator is failing- giving low volts
2. The battery is failing and drawing a load of power - causing low voltage.
3. The DC converter is faulty and dumps a load of power
4. Your lighting system has a fault causing a big draw draw dropping the voltage

I’d start by removing all the lamps and see if the problem goes away.- if it does then replace the lamps one at a time till the fault returns
If you can - try charging the battery on its own and seeing if it takes and holds a charge - that should let you know that the battery is not at fault.
Beyond that - it’s time to start isolating parts of the electrical system to try and identify the fault


To try and help you identify the problem
Find out if the stator is ok by removing the 2 yellows and measuring the unloaded stator output - this should be around 14v AC.
Find out If the battery is at fault - Measure the voltage across the unloaded battery - that should be above 12.5v and about 14v for a fully charged battery.
If both of these are ok - restore the yellow wires -
Try and identify a faulty regulator rectifier - disconnect all of the outgoing circuit wires and measure the DC output of the regulator(with the battery connected - it should read battery voltage) then get the bike running and measure the output with the engine running and the battery charging ( this should be a bit higher ) that will let you know the DC output is ok and the battery is charging - if your rectifier/regulator is dumping loads of power it should get hot
Next
take all your bulbs out and measure the regulator output voltage Energising one circuit at a time - this will tell you if you have a circuit with a fault.
Next replace the all the lamps one at a time.
If this is ok the. It’s a bulb- replace the bulbs one at a time.

edit on 23/10/19 in red
Last edited by Meds on Wed Oct 23, 2019 10:55 am, edited 2 times in total.
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Re: Dc electrics

Postby ULC Soulagent » Mon Oct 21, 2019 6:58 pm

Cheers Meds
I’ll give that a bash :lol: hopefully not with a hammer
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Re: Dc electrics

Postby Knowledge » Mon Oct 21, 2019 8:37 pm

Hi Marty.

I have recently fitted one of these to my mate’s scooter.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F223652877350

It presents two USB sockets and a digital read out of the voltage. When you switch the scooter on and bring the battery to life, it reads about 12v, but once the engine is running, it shows a healthy 14.4v.

If you can find a good place to mount it (top of a leg shield tool box), then it will tell you all you need to know about your system.

I’ve now bought one for myself.

PS. I don’t think you get a meaningful reading if you connect across the two yellow wires of a DC stator. You need to go through the Wassell and have a bit of load on the red side.
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Re: Dc electrics

Postby Toddy » Tue Oct 22, 2019 5:51 am

I had that issue coming back from a rally late at Night , lights drained battery on DC set up leving me unable to see the road :shock: Mine was the Wassell unit , changed it and been good since
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Re: Dc electrics

Postby ULC Soulagent » Tue Oct 22, 2019 8:30 am

Knowledge wrote:Hi Marty.

I have recently fitted one of these to my mate’s scooter.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F223652877350

It presents two USB sockets and a digital read out of the voltage. When you switch the scooter on and bring the battery to life, it reads about 12v, but once the engine is running, it shows a healthy 14.4v.

If you can find a good place to mount it (top of a leg shield tool box), then it will tell you all you need to know about your system.

I’ve now bought one for myself.

PS. I don’t think you get a meaningful reading if you connect across the two yellow wires of a DC stator. You need to go through the Wassell and have a bit of load on the red side.

Cheers Martin, I’ll look into that
Regards
Shane ;)
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Re: Dc electrics

Postby ULC Soulagent » Tue Oct 22, 2019 8:31 am

Toddy wrote:I had that issue coming back from a rally late at Night , lights drained battery on DC set up leving me unable to see the road :shock: Mine was the Wassell unit , changed it and been good since

Cheers Toddy,
I’m sure I’ll get too the bottom of It somehow :D
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Re: Dc electrics

Postby coaster » Wed Oct 23, 2019 9:57 am

Reading the advice above, some of it might be a bit misleading :? The regulator works by shorting excess voltage to earth and needs a load attached to give a meaningful reading (same with the AC regulators). A fully charged battery will show around 13.5 volts which should rise to 14.2 or thereabouts when the engine is revved over around 3-4k RPM. The voltage straight out of the stator on the 2 yellows (disconnected) will rise to 20-30 volts AC maybe more depending on revs.

It sounds like the battery isn't charging, I have found both my installations prone to high resistances in spade connectors which look fine but on close inspection have slightly corroded. The connections on alarm type batteries seem very prone to this, I now use bike batteries with screw terminals. Also bare in mind that if you ride with the lights on, you wont put much (if any) charge into the battery if riding round town, especially if using a high wattage headlamp bulb, Martins suggestion of a volt gauge is a good one so you can keep an eye on the charging is a good one.
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Re: Dc electrics

Postby ULC Soulagent » Wed Oct 23, 2019 11:20 pm

coaster wrote:Reading the advice above, some of it might be a bit misleading :? The regulator works by shorting excess voltage to earth and needs a load attached to give a meaningful reading (same with the AC regulators). A fully charged battery will show around 13.5 volts which should rise to 14.2 or thereabouts when the engine is revved over around 3-4k RPM. The voltage straight out of the stator on the 2 yellows (disconnected) will rise to 20-30 volts AC maybe more depending on revs.

It sounds like the battery isn't charging, I have found both my installations prone to high resistances in spade connectors which look fine but on close inspection have slightly corroded. The connections on alarm type batteries seem very prone to this, I now use bike batteries with screw terminals. Also bare in mind that if you ride with the lights on, you wont put much (if any) charge into the battery if riding round town, especially if using a high wattage headlamp bulb, Martins suggestion of a volt gauge is a good one so you can keep an eye on the charging is a good one.

Cheers Coaster,
I’ve ordered a few bits on Martin's suggestions so just waiting on them turning up. In the meantime my bgm clubby has decided too crack along the tailpipe section going into the box part :evil: bloody things
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Re: Dc electrics

Postby Fast n Furious » Thu Oct 24, 2019 1:29 am

The open circuit output voltage from some Indian stator / flywheel combinations can get as high as 150 volts. This is 'open circuit' AC voltage of course. So, make sure your mutlimeter is set to AC200V range when measuring the stator output. Rectify this voltage to DC and you've got over 200V. This a big ask for any regulator to control this down to the circa 14VDC charging level.
Fortunately, this voltage drops dramatically as soon as there is some electrical load placed upon it such as, charging a battery or running with the main lights on. The more electrical load you apply, the more the stator's AC voltage will drop and so the 'shunt type' regulator has less work to do.
Always make sure that the connections from the regulator to the battery are the best you can make and maintain. As Coaster pointed out- a high resistance here will unload the regulator. In this situation,the regulator now has to deal with clamping a lot of high incoming voltage. This makes the regulator run very hot when touring for hours on end, especially on hot summer days. Consequently, the regulator will burn out, leading to potential battery damage and blown bulbs. This is a common situation with a lot of motorcycles. it's not just a Lammy quirk.
Running with the headlamps on all the time is the kindest way to treat the regulator. It's also the kindest way to prevent your battery from overcharging and it's a safer way to ride!
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Re: Dc electrics

Postby ULC Soulagent » Thu Oct 24, 2019 7:45 am

Fast n Furious wrote:The open circuit output voltage from some Indian stator / flywheel combinations can get as high as 150 volts. This is 'open circuit' AC voltage of course. So, make sure your mutlimeter is set to AC200V range when measuring the stator output. Rectify this voltage to DC and you've got over 200V. This a big ask for any regulator to control this down to the circa 14VDC charging level.
Fortunately, this voltage drops dramatically as soon as there is some electrical load placed upon it such as, charging a battery or running with the main lights on. The more electrical load you apply, the more the stator's AC voltage will drop and so the 'shunt type' regulator has less work to do.
Always make sure that the connections from the regulator to the battery are the best you can make and maintain. As Coaster pointed out- a high resistance here will unload the regulator. In this situation,the regulator now has to deal with clamping a lot of high incoming voltage. This makes the regulator run very hot when touring for hours on end, especially on hot summer days. Consequently, the regulator will burn out, leading to potential battery damage and blown bulbs. This is a common situation with a lot of motorcycles. it's not just a Lammy quirk.
Running with the headlamps on all the time is the kindest way to treat the regulator. It's also the kindest way to prevent your battery from overcharging and it's a safer way to ride!

Food for thought FnF, my battery is of the spade connector so I’ll check everything over :D
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Re: Dc electrics

Postby Meds » Thu Oct 24, 2019 9:28 am

Are you getting anywhere with the fault
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Re: Dc electrics

Postby ULC Soulagent » Thu Oct 24, 2019 11:30 am

Meds wrote:Are you getting anywhere with the fault

Just working on it now Meds :?
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Re: Dc electrics

Postby Fast n Furious » Sat Nov 02, 2019 11:45 pm

ULC Soulagent wrote:
Fast n Furious wrote:

Food for thought FnF, my battery is of the spade connector so I’ll check everything over :D


Do you mean it's a "Gell type" battery like those used in alarm panels?
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Re: Dc electrics

Postby ULC Soulagent » Sun Nov 03, 2019 9:36 am

Fast n Furious wrote:
ULC Soulagent wrote:
Fast n Furious wrote:

Food for thought FnF, my battery is of the spade connector so I’ll check everything over :D


Do you mean it's a "Gell type" battery like those used in alarm panels?

Yes FnF,
Got the bits that Martin recommend but interestingly when I hook one up it reads 12.7 on the battery yet the other one reads 13.0 :lol:
Going too have another tinker today as I’ve got. A fecking bad cold which has knocked me sidewards over the last 10 days and only picked up my repaired Bgm zorst yesterday.
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Re: Dc electrics

Postby Fast n Furious » Sun Nov 03, 2019 2:30 pm

Do you mean it's a "Gell type" battery like those used in alarm panels?[/quote]
Yes FnF,
Got the bits that Martin recommend but interestingly when I hook one up it reads 12.7 on the battery yet the other one reads 13.0 :lol:
Going too have another tinker today as I’ve got. A fecking bad cold which has knocked me sidewards over the last 10 days and only picked up my repaired Bgm zorst yesterday.[/quote]

I use these battery's with great success. The advantage is that you can mount them in any position except upside down which is especially useful on scoots with no battery tray. ( a battery mounted directly above a hot engine is a bad idea anyway)
If it reads above 13.5V then it is charged.
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Re: Dc electrics

Postby ULC Soulagent » Sun Nov 03, 2019 3:57 pm

Right here goes
Battery fully charged was 12.9 and stayed like that when reved
Led side and tail lights it dropped to 12.8 and stayed there,
Main headlight and it dived like a u-boat under attack to 12.4
Went out for a 25 mile spin with headlight on and it was 11.6 when back home :(
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Re: Dc electrics

Postby Fast n Furious » Sun Nov 03, 2019 4:21 pm

its not charging. charge voltage should read between 13.5-14.0 volts.
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Re: Dc electrics

Postby ULC Soulagent » Sun Nov 03, 2019 4:23 pm

So either Stator or wassel at fault ?
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Re: Dc electrics

Postby Toddy » Sun Nov 03, 2019 4:31 pm

Try another Wassell first ;)
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