Using a hub motor and solar panels to charge batteries

[sophocha]

Hi there folks. I'm pretty sure this was asked before a million times but I need to get my ideas out there just for the sake of arguing....

I have build a 1000w/72v bike with the hub motor at the back. I have no pedals. I have a 10ah lipo battery (two 5ah 4s packs in parallel....range around 40km). My idea is this: I'm planning of getting another hub motor and install it at the front wheel so that I can use that as a hub generator (I know I have to convert AC to DC through a 3 phase rectifier.....i do not want to use the regen function of the hub). That goes through a sort of controller that charges two or three 12v 18ah lead batteries. While doing that, I will install two 100w solar panels as well , also getting some energy to the lead acid batteries. The plan is to drive 20km with the 5ah lipo pack while the other 5ah pack is being charged with a big 20a lipo charger connected to the lead acid battery that is being charged with the solar+hub generator....when one of the packs is depleted, I switch wires so that I charge the other pack while I drive with the other, and so forth.....how feasible is this? How efficient would this design be?

 

[amberwolf]

Using the motor as generator while rolling will just use up your power faster, not get you more of it.

Plus all the conversions are hugely lossy.

You might as well just tie all the motors and lead batteries to the bike's frame by a rope and drag them behind you while you pedal, for all the good it will do you.

This thread:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=78660
probably has enough to show you the problems.

The solar might give you some charge while rolling (there's a lot of threads about that, too), but there's drawbacks to it (see the existing threads, alternative energy area as one place to start).

 

[sophocha]

I'm going to use a second motor at the front wheel to generate the power (not use the same one) plus i won't be using its regen function so it won't be dragging me down so much. I have space on my frame for all these.....my bike use to be 40kg more in weight (6 lead acid batteries!) but it coped fine at 78km/h....I need to start reading more to see if any of these wild ideas could be possible....I just want to squeeze more range out of it, not that 40-50km is not good but more is better.

Using the motor as generator while rolling will just use up your power faster, not get you more of it.

Plus all the conversions are hugely lossy.

You might as well just tie all the motors and lead batteries to the bike's frame by a rope and drag them behind you while you pedal, for all the good it will do you.

This thread:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=78660
probably has enough to show you the problems.

The solar might give you some charge while rolling (there's a lot of threads about that, too), but there's drawbacks to it (see the existing threads, alternative energy area as one place to start).

 

[amberwolf]

I'm going to use a second motor at the front wheel to generate the power (not use the same one) plus i won't be using its regen function so it won't be dragging me down so much.

It is exactly the same thing as far as what you are trying to do is concerned.

Read the thread I linked.

.I just want to squeeze more range out of it,

You will get LESS range doing that.

 

[sophocha]

Here is the rough idea....has anybody actually tried this in real life? I'm not after overunity here, it seems like a good idea to charge the lead acid batteries while you are out so you can charge the second lipo pack while you drive ( over here its sunny 300 days a year) plus use the extra juice from the second motor...

 

[amberwolf]

I give up.

Build it, try it, report back here when it doesn't do what you want.

 

[sophocha]

Well, I have the extra motor sitting here (its for a customer) so I might as well do it and report back my failure rather than have these questions float in my head

I give up.

Build it, try it, report back here when it doesn't do what you want.

 

[amberwolf]

Make sure you put wattmeters on everything so you can see how much is being used, and how much is being put back, etc. Otherwise you won't really know exactly what is going on in there.

 

[sophocha]

That is a good idea. I have a watt meter on my lcd3 display....if I sustain 400-500w on my drive (maybe around 30km/h), have a 200w solar panel and see how much I can squeeze from the second motor (maybe 200w?) it might work....have to experiment more and report back

Make sure you put wattmeters on everything so you can see how much is being used, and how much is being put back, etc. Otherwise you won't really know exactly what is going on in there.

 

[amberwolf]

I mean wattmeters like the hobby RC type (or cycle analyst, watts up, etc), that measure wh and ah passing thru them and "log" it (at least until power is cut). Just search for "wattmeter" here on ES and you'll see lots of examples.

Just seeing instantaneous wattage doesn't measure what you need to measure to show you what's actually happening. (it changes too fast to keep track of on multiple displays at the same time, which is what you'd have to do).

And you still need to read the thread I linked you to, which will explain (numerous times and ways) why what you want to do won't do what you want.

 

[sophocha]

Will do. Thanks

I mean wattmeters like the hobby RC type (or cycle analyst, watts up, etc), that measure wh and ah passing thru them and "log" it (at least until power is cut). Just search for "wattmeter" here on ES and you'll see lots of examples.

Just seeing instantaneous wattage doesn't measure what you need to measure to show you what's actually happening. (it changes too fast to keep track of on multiple displays at the same time, which is what you'd have to do).

And you still need to read the thread I linked you to, which will explain (numerous times and ways) why what you want to do won't do what you want.

 

[sophocha]

This guy has done the test for me It was much harder to spin a 350w motor by hand but much easier on a 1000w motor. He said max out (pedaling) he was pushing around 30v.

https://www.youtube.com/watch?v=weQxnPz0Ow0

 

[sophocha]

How about this PMA instead of the hub motor? Looks really interesting

http://www.windbluepower.com/Permanent_Magnet_Alternator_Wind_Blue_Low_Wind_p/dc-540.htm

 

[dogman dan]

There is no extra energy from the second motor, only extra heating, which will use up more energy.

Just use regen on your rear motor, when its coasting down a hill. Anything else, like pushing one motor with another is the same thing as driving around in your car after you poked a hole in your gas tank. Hmmm,, why did my mpg just get cut in half? Hmmm.

Go ahead and try it if it amuses and educates you. You will find that the efficiency of using a hub motor to make power is about 10% or less. in fact, about 3% back is typical when using regent stop. It depends on things like the weight and the height of a hill when using regen to get power back from a hill.

But the inescapable thing is one motor wastes 25% or so making heat, then the other will waste just as much into heat making that same motion back into electricity. Hubbies generally operate no more efficient than 75% at the rpm a bike moves much of the time, so losing 25% to warming one motor is bad enough, add another motor as a generator, and lose another 25% at least. That's just not going to gain you anything, cutting your efficiency to 50% from 75%.

The watt meter will not lie. You will see much more power going in one end, than you see coming back through the other motor on the bike. In fact, you can prove it without a watt meter. Hook a full battery to your motor, Hook an identical battery to your hub motor generator. Ride till the battery is empty without pedaling. Now see with a voltmeter how full your generator battery is. See how little is put back? It won't be full, or even close to it. The amount missing will not be same as the amount it would take to ride a bike as fast as you went. You will have simply heated up two motors with the energy, and you can't get that back.

Ride on one battery while another solar charges is not a bad idea. But once you start discharging at more than 100w,, no reason to charge a separate battery. You can ride around all day on one 5 ah battery, and enough panel. I just built a trailer big enough to be able to carry up to 200w. but no money to buy the panels.

Solar charging your bike can work, though it does take a lot of panel to go far or fast. Perpetual energy,, no,,, that does not work, never has, but it can be known to sell good to some people. I suggest you start by trying to sell it to members of a fringe religious cult they have just proved they are gullible and will buy shit on faith.

 

[sophocha]

Allright, I'm convinced that an extra hub motor will not work....I might as well use my 200w solar panels to charge my extra battery on the go.....

Quick question.......how about hooking up a PMA (permanent magnet alternator) instead of a hub motor to charge the second battery? Would that change the efficiency rating or its going to be the same thing as using a hub motor? or maybe use some big fan blades on the alternator to harness wind power on the go?

http://www.windbluepower.com/Permanent_Magnet_Alternator_Wind_Blue_Motor_Wind_p/dc-512.htm

 

[dustNbone]

You're still trying to achieve the same thing, a windmill is going to create wind drag, which is something you aim to avoid on a bicycle (or any vehicle really, but think about why cyclists "tuck" themselves out of the wind). This additional drag needs to be overcome by another force, either your pedaling or by the motor converting (stored) electrical energy into mechanical energy.

The most efficient way to convert human muscle power into mechanical energy (or very close to it) is to connect pedals to a wheel with a chain and some gears. Any conversions in between are going to lower the efficiency quite drastically.

 

[Chalo]

If you attempt to use a vehicle's forward motion to somehow power the vehicle-- no matter the system you choose-- the result will be consuming more energy to make less forward motion.

Solar cells can potentially extend range, if they don't cost more as drag than they contribute as electricity. But this works because solar energy isn't energy you already put into the system with a motor, so harvesting some of it adds to your total energy. The same goes for a sail; it extracts energy that comes from elsewhere, instead of draining kinetic energy from your vehicle.

 

[amberwolf]

This is why I pointed him to that thread, so you all won't have to waste your time saying the same things that have already been said a bajillion times.

He needs to just go read that thread, and do the tests himself, and we should all leave this thread alone until he does that.

 

[sophocha]

I read it, but it doesn't hurt to ask some questions....

Solar panels it is then! I'm forgetting the wild ideas about wind turbines and hub generators ...or maybe a sail bike....ehehe

This is why I pointed him to that thread, so you all won't have to waste your time saying the same things that have already been said a bajillion times.

He needs to just go read that thread, and do the tests himself, and we should all leave this thread alone until he does that.

 

[st35326]

I read it, but it doesn't hurt to ask some questions....

Solar panels it is then! I'm forgetting the wild ideas about wind turbines and hub generators ...or maybe a sail bike....ehehe

This is why I pointed him to that thread, so you all won't have to waste your time saying the same things that have already been said a bajillion times.

He needs to just go read that thread, and do the tests himself, and we should all leave this thread alone until he does that.

A 100 watt Solar Panel is large, a 200 watt panel is massive to put anywhere on a bike. Why not just build a stationary charger with a few solar panels, batteries and a charge controller?

This setup was designed to just charge 3-5 ebikes, but after that video I kept adding panels and batteries so it also works as a power generator for brownouts. Its gotten to the point now where the my batteries reach "float" (full), before noon so I end up feeding a bit of 120v power back into my house.

The charger that came with my Stealth Bomber draws 550-600 watts which means you need AT LEAST 3 of those 200 watt panels.

https://www.youtube.com/watch?v=TRnkC41b-Hc

 

[craneplaneguy]

Grid tied solar is many times more cost effective and long term then small off grid solar systems, just saying. You never waste a watt when grid tied, either you use it directly or it turns your meter backwards, to be used later. I used 1500 KWH last month, and still have a 10,000 KWH credit with my utility. Having been off grid for years, 28, earlier, I'd never mess with batteries again if I could help it. Except for ebike batteries of course!

 

[st35326]

Grid tied solar is many times more cost effective and long term then small off grid solar systems, just saying. You never waste a watt when grid tied, either you use it directly or it turns your meter backwards, to be used later. I used 1500 KWH last month, and still have a 10,000 KWH credit with my utility. Having been off grid for years, 28, earlier, I'd never mess with batteries again if I could help it. Except for ebike batteries of course!

News flash ..... If you don't have batteries you ARE NOT OFF GRID. Just saying, you draw from the grid nightly. In fact when the grid goes down you are every bit as powerless as people without solar (even in summer sunlight). Federal law mandates all grid tied systems must completely shut down when main power is lost. Whats the point of having solar if you can't use it when the power goes out?!

Power companies in the U.S have caught on to the fact that net metering is starting to heavily cut into their profit margins and they are committed to get rid of it. Many states (most recently Nevada) have already passed legislation allowing utilities to purchase solar energy at half the rate they charge you to use it. This is why Tesla, Solar City and many others have went to battery storage vs grid feed. All my batteries get charged first to 100% SOC then and only then do I feed back into my home. Im not into playing kissy face with power companies here in SoCal that charge people nearly half a dollar per kWh but subject their customers to rolling brownouts (the longest I recently recall lasting 18 hours).



https://www.greentechmedia.com/articles/read/why-is-net-metering-under-attack
http://www.ases.org/2013/03/solar-rights-net-metering-under-attack/
http://www.solaramerica.org/2014/06/23/utility-net-metering-under-attack-in-arizona-and-cali-why-should-you-care/

I'm in the process of converting my system over to complete TESLA Model S battery modules as seen here...

https://teslamotorsclub.com/tmc/threads/plan-off-grid-solar-with-a-model-s-battery-pack-at-the-heart.34531/page-5

 

[Matador]

There is no extra energy from the second motor, only extra heating, which will use up more energy.

Go ahead and try it if it amuses and educates you. You will find that the efficiency of using a hub motor to make power is about 10% or less. in fact, about 3% back is typical when using regent stop. It depends on things like the weight and the height of a hill when using regen to get power back from a hill.

But the inescapable thing is one motor wastes 25% or so making heat, then the other will waste just as much into heat making that same motion back into electricity. Hubbies generally operate no more efficient than 75% at the rpm a bike moves much of the time, so losing 25% to warming one motor is bad enough, add another motor as a generator, and lose another 25% at least. That's just not going to gain you anything, cutting your efficiency to 50% from 75%.
[...]
Perpetual energy,, no,,, that does not work, never has, but it can be known to sell good to some people. I suggest you start by trying to sell it to members of a fringe religious cult they have just proved they are gullible and will buy shit on faith.

My physics courses are far far away, But...

There is that clever guy who once said... What was his name again? Oh yes, Antoine Lavoisier... Well he said "Nothing is lost, nothing is created, everything is transformed". But the bad new is... With a dual motor, A bigger proportion of the energy is transformed in heat dissipated and lost in the wind... You get more friction from more moving parts to slow you down, etc...

You can't escape Lavoisier's Law of conservation of mass, of which the first Law of thermodynamic is a version adapted to thermodynamic systems...

Quote from a random science wbsite : "The First Law says that the internal energy of a system has to be equal to the work that is being done on the system, plus or minus the heat that flows in or out of the system and any other work that is done on the system," said Saibal Mitra, a professor of physics at Missouri State University. "So, it’s a restatement of conservation of energy." Ref : http://www.livescience.com/50881-first-law-thermodynamics.html

Perpetual motion is not possible in the real world. Free energy is just impossible.

In the same manner,
If you use your car's alternator and battery to generate electricity to electrolyse water into hydrogen and oxygen while planning to run your car on hydrogen and save costs on fuel... Well that alternator will have to generate way more amps than if you did'nt have an HHO system plugged onto your car. That alternator will require more angular force to turn and charge the battery than if it had'nt had the task to refill a huge energy drain from the HHO pulling juice from the battery. In then end, you will not save on fuel... Overcoming that additonnal force and turning the alternator will require your car engine to burn more fuel (less mpg). You will loose more energy form the added strain on the alternator (worst mpg) + heat losses than you would gain from injecting the generated hydrogen to your motor cylinders.... Oh, and that alternator will die much sooner than it should.

There is no such thing as free energy. Energy is conserved (some of it in the form of heat we can't make use of) : First Law of thermodynamic.

 

[amberwolf]

I read it, but it doesn't hurt to ask some questions....

Ah, my apologies then; it seemed from some of the questions that you hadn't yet read it.

 

[sophocha]

https://www.youtube.com/watch?v=3sK9ceGtry8
(In Greek)

https://www.youtube.com/watch?v=8KdcBoo5f0Q
(PBS special in English)

http://www.hellagen.gr/search/label/ΗΛΕΚΤΡΟΦΑΣΜΑΤΙΚΗ ΘΕΩΡΙΑ
(documentation of the device in greek)

Well, there is this guy in Greece (google Petros Zografos) that made a machine that directly splits atoms producing lots of energy and it does not cost more than 80 euros to produce ( and as he says its not against the laws of thermodynamics).....I know about the HHO scams and all, but the panellists that you see in the video are all major physicists in Greece and they were grilling him for 2 hours. They all agreed that his device works!! My physics are not up to par but what I got from the video is that he made a plate with a magma of materials (mostly carbon) that burns out through electrolysis, but the major breakthrough was his electronic device that produces a splitting resonant frequency of the atoms (among its harmonics the most important is the Pythagorean 7th harmonic...without that nothing is working)....what do you think of all this?

There is no extra energy from the second motor, only extra heating, which will use up more energy.

Go ahead and try it if it amuses and educates you. You will find that the efficiency of using a hub motor to make power is about 10% or less. in fact, about 3% back is typical when using regent stop. It depends on things like the weight and the height of a hill when using regen to get power back from a hill.

But the inescapable thing is one motor wastes 25% or so making heat, then the other will waste just as much into heat making that same motion back into electricity. Hubbies generally operate no more efficient than 75% at the rpm a bike moves much of the time, so losing 25% to warming one motor is bad enough, add another motor as a generator, and lose another 25% at least. That's just not going to gain you anything, cutting your efficiency to 50% from 75%.
[...]
Perpetual energy,, no,,, that does not work, never has, but it can be known to sell good to some people. I suggest you start by trying to sell it to members of a fringe religious cult they have just proved they are gullible and will buy shit on faith.

My physics courses are far far away, But...

There is that clever guy who once said... What was his name again? Oh yes, Antoine Lavoisier... Well he said "Nothing is lost, nothing is created, everything is transformed". But the bad new is... With a dual motor, A bigger proportion of the energy is transformed in heat dissipated and lost in the wind... You get more friction from more moving parts to slow you down, etc...

You can't escape Lavoisier's Law of conservation of mass, of which the first Law of thermodynamic is a version adapted to thermodynamic systems...

Quote from a random science wbsite : "The First Law says that the internal energy of a system has to be equal to the work that is being done on the system, plus or minus the heat that flows in or out of the system and any other work that is done on the system," said Saibal Mitra, a professor of physics at Missouri State University. "So, it’s a restatement of conservation of energy." Ref : http://www.livescience.com/50881-first-law-thermodynamics.html

Perpetual motion is not possible in the real world. Free energy is just impossible.

In the same manner,
If you use your car's alternator and battery to generate electricity to electrolyse water into hydrogen and oxygen while planning to run your car on hydrogen and save costs on fuel... Well that alternator will have to generate way more amps than if you did'nt have an HHO system plugged onto your car. That alternator will require more angular force to turn and charge the battery than if it had'nt had the task to refill a huge energy drain from the HHO pulling juice from the battery. In then end, you will not save on fuel... Overcoming that additonnal force and turning the alternator will require your car engine to burn more fuel (less mpg). You will loose more energy form the added strain on the alternator (worst mpg) + heat losses than you would gain from injecting the generated hydrogen to your motor cylinders.... Oh, and that alternator will die much sooner than it should.

There is no such thing as free energy. Energy is conserved (some of it in the form of heat we can't make use of) : First Law of thermodynamic.