Converting an Ebike to 12 Volt Battery Charger

[Alastor]

Hey ,

I am trying to find a way to charge my 12Volt Solar System with my Ebike in order to do some workout while inside my house when i cant go outside for a ride and also having an alternative way to charge my battery bank when the weather is not good.

To the point now.In most of the ebikes out there if you don't have a battery pack connected and pedal you will see that your CA will come back and it will read some Voltage.I did this ones and i want to check it out and test it thoroughly and build a cheap generator.

I am using an MPPT controller as a battery charger for my 12 Volt bank and i was wondering if i can just connect the + and negative from my controller to it pedal and charge the battery.The controller can handle up to 24 Volts with no issue and it has a blocking sock diodes in the leads so its safe to connect the terminals in theory.

I am thinking on buying a heavy duty steel rear wheel stand that will enable me to pedal inside my house and ofc do the necessary cable arrangements.

Anyone done something like that ? having any tips or what not to do or anything ?

P.S.
I might also consider on taking one of this things if you think it will be safer.I can use the 24 volt as well http://viewitem.eim.ebay.gr/BATTERY-CHARGER-48V-to-12V-STEP-DOWN-DCDC-10AMP--120W/230619561393/item

Thanks mates

 

[tony67]

I was wondering about this myself, whether a motorcycle regulator/rectifier could be attached to the phase wires of a hub motor and the pos neg to a 12V battery. I know the final output would be quite low but if the gearing were right you could get some kind of output while the reg/rec would take care of any over-voltage issues.

Possible? --- I think yes
Practical power? --- Probably not.
Tony.

 

[migueralliart]

Even if you pedal for 5 hours you won't be able to charge much into the battery.

TEXT BOOK HAMSTER IN THE WHEEL

 

[Alastor]

By lurking to the internet i found out that an ebike motor can provide up to 100 watt of pedal power with little effort.This means aprox 8A to a 12v system -20% efficiency button line if i see 5-6 amps going to the battery i will be very happy.Don't get this wrong because there will be no load so the system will work without the pedaling getting heavier like most of the videos out there.It will have to do with your effort only.
The next days i hope i find a nice steel rear stand or something to test this out.Perhaps it will be easier to test this with the bicycle up side down.Pedaling with my hands till i get some results.I will have to make a new PP75 connector so there is fun involved .I also wanted to test out the regen but its high voltage and resistance might need more effort in order to pedal.I want to believe that is possible just to extracting the voltage out of the controller without halving to unplug the phase wires.I have some ideas on how to get the voltage out of my system from the CA to the controller even the phase wires ! So more fun.

I just hope i get some results because there are a lot of applications on a system like that.You might be able in an emergency to charge your own batteries by pedaling,phone,laptop you name it if you can get 100 watts with some effort.I know it will take hours but if its possible it should have its uses for sure.What if we all learned how hard it is to create energy ?i think it could change the way we see things.....ok ok it carried me away from the point but you know what i wana say

 

[Alastor]

Well it was easier than i expected after all .I managed to light a 50 Watt light bolt with only one hand.I got some interesting results.All that out of the controller i did no wiring at all.

1.With no load : The regen on and enabled i manage to do 50 Volts with one hand - Same with regen off.
2.With load : I manage to light up the 50 watt bolt for some seconds it was hard to pedal with the load.The Cycle Analyst indicated -70 watts and the voltage was at 15 volts.

So the only thing i need is just a battery charger (24 volt to 12 volt battery charger)? with adjustable amperage output.I think of a lot of useful things someone can do.I will have to test this out with different loads and watts to see how the voltage drop each time.That will help me choose the chargers input voltage.