Moped Battery

i plan on putting some 12v accesories on my ped and was wondering if there is any way to use my maxis orignal magneto to recharge a 12v battery.

Re: Moped Battery

you can buy those little motorcycle batteries and i imagine it can be recharged because other mopeds do it!

Re: Moped Battery

The magneto on my Tomos makes about 50 watts of power, the head light stays on automatically and uses up the bulk of it. What i was thinking was to put a switch on the head light so i can charge the battery during the day while im riding. The thing to watchout for would be the fact that the voltage goes up and down with the rpm even though i have a voltage regulator, im just wondering if its safe to put 15 volts of charge into a small battery on a hot summer day?(the voltage may go way over 15 volts speeding down a hill and im concerned that the battery may explode) A new model of Tomos at the local dealer has electrick start on it, it would be interesting to see the set up on it for comparison.

Re: Moped Battery

magnetos produce AC current which is useless when it comes to charging batterys its a pulsating current. and if somehow you rigged it up the voltages would cause the battery to over heat and boil.

good idea tho

Re: Moped Battery

Matthew Libhart /

Your maxi is 6V (did Puch ever make a 12V), so unless you swap out your magneto for a 12V you can't charge a 12V battery. That said, if you want to run a 6V battery it can be done but it required modification to the coils and electrical components. Let me know if you'd like to know how.

Re: Moped Battery

Oh yeah let us know how. Also why should a voltage regulator not do a good enough job of keeping only safe voltages going to the battery?

Re: Moped Battery

Furthermore, cant AC be simply converted to DC by using a diode? So, a 50 cent diode, a 50 cent regulator, some wire, and you have what you need to hook up a battery, which gets charged properly and doesnt recieve too much voltage.

Re: Moped Battery

Matthew Libhart /

That is essentially what it is, the problem is that Puch, in their infinite wisdom or insanity, has one side of the AC grounded to the body of the bike. Also, you have to take into consideration that your lights and everything will take a certain amount of you amperage, and you have to have enough left so that you can in fact get a charging voltage on the battery (at least about 6.8V if not 7.2).

Here's what I did. On the back of the headlight coil you can see that one end of the winding is "glued" to the core which mounts to the frame. Cut this carefully and solder a wire to it. Your headlight and taillight coils now have two independent ends. Not doing this is not an option if you want to run the lights from the battery. Run each of coils' ends to a separate full wave rectifier (radio shack), you'll need two. Take that DC voltage and combine the positive to one terminal in a wiring block. Run that terminal to a large capacitor which has its - end grounded. This filters out the low ends of the AC waves which are still present even though you're rectified. Run a second wire to the capacitor and put that to a power zener diode, 6.8V would do ok, 7.2V would be better. This has to be a good one, at least 10A. This will bleed the extra voltage to ground. Put a second wire to the zener positive and go back to a terminal on the block. This terminal can be used to run lights, charge a battery, and run accessories. It'll only charge the battery though if you can measure at least about 6.8V on it with everything running, lights, accessories, etc but w/o the battery connected. Measuring this would ensure that you've got the voltage to charge the battery if it's connected. If you get that, hook up the battery but go through a fuse. If the battery shorts and you don't have a fuse in there, you'll burn the coil.

This is more complicated than just a regulator and a diode.

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