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dc conversion
Posted: Sun Jan 10, 2010 1:11 am
by mnpes
trying out something on the lammy at the moment....concerning a dc conversion ...
got the bgm 120watt ... converted it to full-wave ....
replaced the standard regulator/rectifier with a honda 3-phase one ....
but only using one phase ....
no problem dumping any excess unused wattage the stator produces....
(if the bgm unit could put out 120watts)...more like 90 watts
the honda unit as a built in circuit which automatically adjusts the charge rate...
unlike the standard regulator/rectifiers constant trickle charge...
( remembering the current the stator produces is only minimal anyway )
this is done via a sensor wire connected to a permanent live
ie.. rear brake switch....
not having enough positions on the ignition switch for my accessories...
a master swich isolates the circuits from the battery...
when the weather changes ..... will set the multimeter up onboard .....
can get some readings out on the road then ....
if it"s okay will keep you informed
if not .... win some lose some ....
safe riding
loved the post on the crankcase induction ts barrel ....
topman ... (darren) .... scotty
a pleasure to know the man .... always got time for you ....
Re: dc conversion
Posted: Sun Jan 10, 2010 8:22 am
by soulsurfer
Please post your findings either way.
How much does this Honda jobbie cost?
Have you seen the other PODtronics/Wassell conversions on here,
the stator is always the limiting factor regrding charging?
Re: dc conversion
Posted: Sun Jan 10, 2010 9:41 am
by coaster
What he said, always room for new ideas

Re: dc conversion
Posted: Sun Jan 10, 2010 11:51 am
by firekdp
Trailtech have a regulator worth looking at as well. These are 150W single phase with a current limiter for smaller Ah batteries (under 4Ah). These have an extra wire that connects to the battery negative so that you do not have to fit an isolator like the positive connected type. These may be better for the small sealed type batteries that are only designed to be trickle charged. For larger batteries the extra wire is simply not used as the they will handle the higher charge.
The standard Vespa battery charging regulator also has the capability of having a controllable output but again an isolator would need to be fitted.
Re: dc conversion
Posted: Sun Jan 10, 2010 1:05 pm
by byron
firekdp wrote: The standard Vespa battery charging regulator also has the capability of having a controllable output but again an isolator would need to be fitted.
I have just fitted a vespa unit to my bike, is that what the "unused" terminal [next to the earth] on the rectifier is for ? what do you mean by an isolator ? My battery is 1.2Ah, just using it to run the horn and have fitted a socket for phone charger and other accessories like maybe a soldering iron for roadside repairs.
I have fitted a zenor diode to cap the voltage, but do I need something else ??
Re: dc conversion
Posted: Sun Jan 10, 2010 1:32 pm
by firekdp
byron wrote: I have just fitted a vespa unit to my bike, is that what the "unused" terminal [next to the earth] on the rectifier is for ? what do you mean by an isolator ? My battery is 1.2Ah, just using it to run the horn and have fitted a socket for phone charger and other accessories like maybe a soldering iron for roadside repairs.
I have fitted a zenor diode to cap the voltage, but do I need something else ??
Yes, the unused terminal marked "C" on a PX type needs to be connected to a battery supply/+ve via a switch. When the scoot is not running the switch is to isolate the power from the reg to prevent the battery discharging through it. Using this connection the charge through B+ should then be regulated according to the battery voltage, not full charge at all times as when the "C" is not connected. Try it, you may then be able to dispense with the zener.
As I said in another post a scootrs switch would be the one to use with any system needing battery circuit isolation.
Re: dc conversion
Posted: Sun Jan 10, 2010 2:12 pm
by byron
thanks, that's excellent information as always.
I'll give it a go.
I have been using a ScootRS switch for the last three years, shame I trimmed the appropriate wires right back as I didn't need them, until now...
Re: dc conversion
Posted: Sun Jan 10, 2010 3:56 pm
by byron
yep, that works a treat, and no need for the zenor diode.
top tip
shame I spent some time yesterday making a heatsink for the diode out of a piece of pushbike crank...
until i sort out my ignition switch;
if i connect this to control the voltage, the battery could go flat when the engine is not running...?
will the battery go flat if i don't connect this for now, and use the zenor diode ?
sorry for slight thread drift mnpes, but it's all relevant stuff, and yes, do let us know the results of your conversion, good or bad.
Re: dc conversion
Posted: Sun Jan 10, 2010 4:06 pm
by firekdp
byron wrote:yep, that works a treat, and no need for the zenor diode.
Excellent.
byron wrote:if i connect this to control the voltage, the battery could go flat when the engine is not running...?
will the battery go flat if i don't connect this for now, and use the zenor diode ?
If the battery is left connected to the C connector then the battery will go flat over a period of a few days. With only the B+ connector used you won't have that problem.
Re: dc conversion
Posted: Sun Jan 10, 2010 4:57 pm
by byron
firekdp wrote:[If the battery is left connected to the C connector then the battery will go flat over a period of a few days. With only the B+ connector used you won't have that problem.
thanks again, I'll go with the zenor diode for now, until I strip the headset down again