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Can batteries used in electric tricycle be charged by pedaling? Answered

Can batteries used in electric tricycle be charged by pedaling?
we requires to provide adequate gear ratio to increase the speed so as to generate voltage as much of 24v or more in order to charge a 24 v battery pack
.And another thing i believe we can use the same pmdc motor used in driving for generation purpose also by rotating it at a higher speed!
correct me if i am wrong!


Of course Yes. If you are ready to spare 6 to 8 hours for peddling daily ! If you do not have that time a big No.

The reason is that charging requires longer time then discharging. Batteries are charged at a particular rate as per their design. If you go faster then that, the battery life will be affected & you will " kill" the battery in process.

Also, please note that when you are converting one kind of energy ( in our case mechanical) to another kind of energy ( in our case electrical) there is always loss. The output will be very less then the input. So you have to always find out the system where this loss is bare minimum then only that solution will be a viable one.

so what about using lithium polymer batteries!
i believe There exists e cycles which can charge their batteries while on board!

i was referring to this one!

but i guess it only does the boosting purpose!

I was not able to have any technical information regarding the same so no comments. If you have any just let me know.

In addition to that, As far as movement goes, the human body is very inefficient.
Only about 35% of the energy we take in goes into movement. The rest is wasted keeping us at 98.6 F and keeping our brains running.
The amount of energy humans take in varies with food, and food varies in price.
But I do know that the base amount of energy you'd need to use would be higher when peddling than with something else like an adapter. Not necessarily more expensive, but higher nonetheless.

And on top of all that, you said in the comments below that you need to charge a 35Ah battery at 24 volts. That's 840 watt-hours my friend. It's quite a sizable chunk of energy. That energy also needs to be exerted over a period of time to avoid destroying the battery. As if to put the nail in the coffin, 840 watt-hours would only charge a battery that charges at 100% efficiency! And a battery like that simply doesn't exist.

It might have the tiniest chance of being feasible, but it definitely isn't practical.

You are dead right tylervitale ! It is much better to supply that energy to our brain rather than to use it for pedaling. That will give much better & smart output.

As with all these ideas then extra weight soon overcomes any advantage there may be.

Lightness and simplicity will be far more use then complex and expensive.

the battery capacity is 35 AH ,And im bit confused about using the motor for trike as generator also! I HAVE FOUND ONE PLANETARY GEAR 24 v pmdc motor for the purpose.That provide enough speed by its gear ratio!
I do find some electric trikes using the pmdc in the motor assist mode to recharge the batteries by pedaling the motor shaft also.so thought of doing so.

NOTE: A lead acid battery is a slow charge device - It should take several hours to fully charge so the level of return your going to get from regenerative charging is VERY small (if anything).

Charging quickly is a road to short battery life, (believe me), and as the battery set is one of the biggest expenses you need to take care of them.

Look carefully at what I said before - 1/2 hp isn't a lot of power. 346 watts at 24 volts that's potentially 14 amps BUT nothing is that efficient so say1/10 or less of that will actually be available.

I am not saying it can't be done, I am not saying it won't work and will not charge the battery BUT realistically in electric cars weight is everything.

The equipment, gears train, etc is dead weight and WILL affect the over all performance - Importantly in mostly it affects the range you will get.

With your 35Ah battery Roughly speaking your going to be able to run your 500 watt motor for perhaps a hour, ( I like to be optimistic), under ideal load conditions (on the flat, motor running at optimum RPM, minimum weight load)

I strongly doubt you will add much to that with regenerative charging (unless you live in a VERY hilly place, and you have to go up as well as down). I think you will add more by setting up a peddling assist system to drive the wheels in addition to the motor and use your human 1/2 hp in it's most effective way.

Bear in mind that your battery will not charge unless the regenerative voltage exceeds the battery terminal voltage. You don't have a tonne or so of momentum to push the car/generator along and so getting this state will be very hard (Hard means equipment and equipment means weight).

so what about using lithium ion batteries!?
i believe they offer better performance

Correct as I said they are lighter charge faster and are more robust than a lead acid set up BUT they COST!

i am struggling to find lithium ion batteries (24 or 48 v 35 ah)!
can u suggest some sites where we can order these batteries.I haven't ordered from Internet before.
I BELIEVE TO RUN A 24 V motor 24 v battery is enough or is it a mistake?

24 volt motor - 24 volt battery

Where to get them - I really don't know - I don't know where you are and if I did I still couldn't help any better then a web search.

One thing I can tell you it will need to be made up as a battery pack from smaller batteries and it will not be cheap.

I am seriously worried for you because of your evident inexperience with electrical matters.

high currents even at 24 volts can be - are a danger to the user for all sorts of reasons that you don't appear to be aware of.

Look at some of the links gives in answer to your other posts they may well help you.



6 years ago

Every motor can operate as a generator which can recharge a battery.
Leaving aside the electronics of how the motor is powered.

When generating, there are electronics that can convert the generated
energy ( lower voltage ) to a level that charges the battery pack at any pedaling speed.
The electronics also allows the adjusting of how much charge is
delivered which relates directly how hard it is to pedal.  
This means that down hill runs can be selectively brake adjusted at
your handle bars.


Is the battery pack a single 24V battery or a pair of 12V? Maybe its several smaller voltage batteries. At any rate the charging system doesn't have to charge the batteries as a single unit. If, for example, you have a pair of 12V batteries then a generator that can crank out 13V or more can be connected to each battery in parallel for charging. So you won't need the larger and heavier 24V generator but it will take longer to charge the batteries since they will be receiving half the current.

I guess so. You should try this. Stick a DC ammeter in series with your battery and your motor, and then see if you can pedal hard enough to make the current flow backwards.


the average human can output about 1/2 hp say 370 watts of energy (for a while)

A GOOD fit cyclist may be able to output 1 hp 756 watts for an hour or so.

Knowing what power is available work out how much your battery charger is going to take and you can see this isn't much of an option - at any speed/usage rate your going to use up the battery faster than you can replenish it

Far more efficient to peddle directly.

It also takes quite a lot longer o recharge the battery than to discharge it (generally). That's why electric cars use LIon battery packs they are lighter for a given energy density and charge faster.

You can indeed harvest energy to recharge the battery down hill or under braking although the systems to do this are quite complex;.

F! cars have a 80K watt motor for the KERs system. This acts to recharge a LIon battery pack to a fairly high voltage. some 300+ volts apparently. The battery pack is more or less drained in 6 seconds.