disappointing DC conversion...

[byron]

just finished a DC conversion following the useful advice on here & LCGB.

BGM 120W stator, modified coils
one of those ebay single phase rectifier units from ebay
7.2 Ah sealed lead battery
standard series II lighting with 35/35W headlamp
2x pathfinders with 48W bulbs

fitted an Indian igntion key to switch the standard lights on
the spotlamp comes on with high beam, via a relay
modifed the handlebar switch to switch power to a relay to turn the foglamp on

fitting an ammeter between the rectifier & battery, it reads around 0 with standard lights on, and goes -ve with either on the Pathfinders on, and of course more so with both.
So the battery isn't getting enough to keep the lights running...
Measuring the volts across the battery it does rise to 13/14 v with the engine running.

I'm guessing the total wattage is too great...

Anyone got same setup and measured the current with all lights on ?
Does it matter that the battery is on its end, with the terminals at the top ?
Or can sealed lead batteries be fitted anyway up ?
What's the choice of Pathfinder bulbs...?
Does it matter which way round the two yellow wires from the rectifier are connected to the stator ? I wouldn't have thought so...

Anything else i should check ?
I think all my wiring is ok, earths are fine, and everything works as planned connected a battery charger to the lighting circuits.

It may just be as simple as lowering the wattage, trying some leds perhaps, but would be good to know as i have a few more of these conversions planned...

thanks.

[minotaur]

about to do the same myself over the next two weeks although sourced a 9amp sealed alarm battery, i will run an led rear, eliminate the festoon 35w headlight, with either 35w or 20w in the pathfinders, lth in germany do a conversion ring for the 20w bulb, i expect this to work ok, soulsurfer is the authority on this...........

[soulsurfer]

Yep, I use the 35watt halogens in the pathfinders, but I would assume that you wouldn't have these on all the time, giving the stator a breather a chance to charge the battery when off. The 20 watt bulbs are for show and not very bright.

Deffo fit led rear light, have a look at the BGM option

If it's a sealed alarm type battery, then orientation isn't an issue.

The yellow wires can connect either way.

I just think your trying to power too much, but as I'm continually saying, I have no idea what makes it a 120 watt stator as the regulator you're using is rated 120w too, I reckon 90w is it's limit

Hope this helps

[byron]

I just think your trying to power too much

yes, very likely. will look into lower wattage bulbs for the Pathfinders.

Hope this helps

yes it does, thanks

Have you measured the current on yours with just the standard lights on ?

[soulsurfer]

Here's the bulb details...
http://www.forums.ilambretta.com/viewto ... er#p151302

Cant remember what the current was but it wasn't an issue, certainly with standard light with rear led. There is a drain on the battery with the spots on, this is because the stator can't generate enough power for all of them, this is the weak link. With your bulbs sorted you'll be able to run your lights without issue, which will be bright and stable, and have plenty of time with spots on before the battery drains. When the battery gets low, the lights will dim, turn the spots off and your headlamp will be as normal i.e. bright and stable and your battery will begin to charge again.

BTW I'm using a 5Ah battery.

[byron]

thanks again, I was about to look for your post on alternative bulbs

[byron]

[thanks to the generosity of goldeneye, cheers mate, it's karma] I am going to try a split system using a Cosa regulator unit. Running the standard lights AC and just using the battery for the lamps & horn...
The owner of the scoot i have done is worried that he'll be left with no lights at all, probably not true, but still worth doing something to try and avoid...
And I want to be able to fulfill my talk of riding in a parade of light....
[for longer than ½hr]

[coaster]

Hi Jarv, I replied to your other post on the LCGB site saying pretty much the same as Soulsurfer. There SHOULD be more than enough power from the DC set up to run your lights without a battery. In my case I have a 55/60 watt xenon headlam and a LED rear. I haven't tried it without the 7.2 Ah battery but would expect that the lights would dim at low revs in the same way as the AC ones did. |The battery is having the effect of smoothing out the feed for the lights but I would imagine that if I were to ride it around town for a few hours at low reves then the battery would run down and the lights would dim at low revs just like an AC system, so no problem there really. In reality, that scenario is never likely to occur but if doing lots of town ridding then a weekly top up from a battery charger miight be in order or some long runs

You can only get so much power from a stator and I wouldn't have thought that splitting it would make any difference. If I get a chance later |I'll stich the ammeter in circuit and see what the current consumption is like. Don't give up yet, I certainly won't be going back to the old set up

[byron]

cheers Colin, I was hoping you'd read this and reply.
Be interesting to hear what the actual current reading is.
Nobody seems to have measured it, or done much in the way of long term, long distance riding.
The idea behind using AC for some lights is to not demand so much from the battery, and avoid the lights going so dim as to be useless....
I just don't like things fitted to scooters that don't work properly
Now waiting for a cosa unit to test.

[soulsurfer]

The idea behind using AC for some lights is to not demand so much from the battery, and avoid the lights going so dim as to be useless....
I just don't like things fitted to scooters that don't work properly
Now waiting for a cosa unit to test.

The lights won't become useless, if wired correctly they will just revert to being powered from the stator and that's only if you're using the spots (both of them) for extended periods.

I don't like things fitted to scooters that don't work properly either, that's why I fitted this system