Using a hub motor and solar panels to charge batteries

[dogman dan]

I think they are doing a good job selling perpetual motion machine. It's always been a very profitable product to sell.

Back to solar,, 200w is a big panel to carry. The trailer I built to hopefully,, carry 200w of lightweight flexy panels is 26" by 8 feet! The plan is to use four 50w panels that are about 2' square, in series for a 48v output. Hoping to get at least 40w or so of 60v out of it in practice. 400wh a day? Still not much power, but possible to get 15 miles longer range from any size battery per day.


Check out threads by Parajed His solar tadpole trike is the bomb.

 

[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!

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).







News flash? Hardly.You are absolutely correct, but I never claimed to be off the grid as you suggest. While I have NO power when the grid goes down. I don't care if the water is flowing, the wind is blowing, and it's high noon. So what? The advantages of being grid tied, admittingly at least for me and my utility, so far outweigh being off grid, it is a no brainer. The "point" of having solar is to provide all your power, Captain Obvious here. If I get too upset over the very few hours PER YEAR the grid goes down, I could start my welder/generator for a few hours, but even that is too much bother for what is a minor inconvenience. The LAST thing I would do is spoil my system by lowering the efficiency during the 99.999% of the time the grid is UP, by introducing batteries into the equation.

Again, we have different utilities, the power hasn't gone off line here for 18 hours total in the entire time I've been grid tied, 10 years. Still, think of the larger PV system you could have installed, if you'd spent the money for more PV instead of on batteries, charge controllers, load diverters, and their associated wiring, breakers etc. The first time I bid out a grid tied system for a customer, after years of doing off grid installs, I couldn't believe how the parts count, and the labor, went down! For me anyway, the "romance" of being off grid faded long ago, I'm proud to be a Idaho Power customer! The other thing I take comfort in....is IF my utility get's all hinky and starts reaming me out for what I feel is excessive fees for using their system as my power dump, then I'll go off grid, but not before. Most people don't have a clue how large a battery bank it takes to realistically operate their home for any length of time, in the manner that they have grown accustomed to. A few hours here and there of no power, just are not that big a deal compared to the battery based alternative. Tesla can keep their batteries, for now anyway.




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

 

[sophocha]

I think they are doing a good job selling perpetual motion machine. It's always been a very profitable product to sell.

Back to solar,, 200w is a big panel to carry. The trailer I built to hopefully,, carry 200w of lightweight flexy panels is 26" by 8 feet! The plan is to use four 50w panels that are about 2' square, in series for a 48v output. Hoping to get at least 40w or so of 60v out of it in practice. 400wh a day? Still not much power, but possible to get 15 miles longer range from any size battery per day.


Check out threads by Parajed His solar tadpole trike is the bomb.

Great! Will look into it

Sent from my Redmi Note 2 using Tapatalk

 

[craneplaneguy]

I clicked on that Tesla motor club link, and the lengthy list of equipment needed kind of makes my point. Compared to just an array, an inverter, and a couple disconnects. And, when you put one watt into ANY battery, especially if left there any amount of time, you never get that one watt out. A great percentage of it, yes. I get 100% of it back, years later, and my " battery" ( the grid) is of infinite size.

Just playing devils advocate here, carry on! ANYTHING solar is magic.

 

[Choudhary]

Namaste everyone. I am planning to try out a similar solar thing on my bike. I have semi recumbent sort of thing, which gives me enough length to get a 150watts panel.
I have a few questions though
1. In order to charge 25.9v li battery, we use 30v charger. A 24.2 volt solar panel provides : voltage at max power - 24.2 || open circuit voltage - 26.4 volt. So this won't work. I reached out to a lot of vendors, some say I should go with 30volt, some say 36v. How should I find the best solution.
2. Can I charge the battery while discharging? Or should i keep 2 separate batteries - discharge one while solar charge another?

I am highly inspired by the suntrip (https://www.youtube.com/watch?v=C6Xe9M0VcaI) and plan to ride around India on my bike.

 

[dogman dan]

Again,, check out Parajed's setup. He uses a voltage converter to turn panel voltage into pack charging voltage. It's very simple and with some common sense on the users end, should work fine without a lot of wasted energy, like 12v battery to inverter to AC input charger.

It doesn't have to get your pack completely full off the solar either. If full charge is 30v,, 29v from the panels is fine. Soon as you ride a block or two, you will be at below 29v, and power will begin to flow from the panel into the battery. Setting your panel to provide a slight undercharge will make the whole setup safer, no risk of overcharging it while it sits in the sun filling up.

Yes,, you can charge a battery as you ride. If you pull out 300w while putting in 100, the battery just thinks you are pulling out 200w.

 

[dogman dan]

https://endless-sphere.com/forums/viewtopic.php?f=3&t=62700

See how Parajeds solar trike works there.

On a computer that has the pictures today.. This is the trailer I want to cover with 4 12v 50 watt panels.

 

[Choudhary]

https://endless-sphere.com/forums/viewtopic.php?f=3&t=62700

See how Parajeds solar trike works there.

Thanks a lot Dogman. That thread is full of useful information.
I also agree with your suggestion of going with a 24v panel & avoid over charging of the batteries.
Just to clarify, if i use a 24v panel and wire them directly to the batteries, i don't need a booster & a fan setup, right?

 

[dogman dan]

You'd be best off with the voltage converter I'm sure. Dial in your voltage to what you need. the voltage from the panel will vary a lot.

From what I read,, having the panel voltage close to the pack voltage increases the efficiency of the converter, increasing its reliability.

But if the panel voltage could never exceed full pack voltage, you could go that way,, it just would never get the pack completely full. But once your pack voltage drains from riding, current will flow to the pack, if it's lower than what the panel puts out.

But again,, Parajeds method looks so simple and affordable, why skip the voltage converter, unless it's to just use an actual charge controller.

 

[Choudhary]

I completely missed mentioning the charge controller. I thought it is a part of the junction box in every solar panel, hence goes without saying. My bad.
So yes, I will be adding a charge controller with the panel. And I guess with that I can regulate both the voltage (at 29v may be) and current (perhaps at 3-4amp).
Another doubt though. As of now I am using 14ah lead acid (deep cycle) batteries (i will switch to lithium eventually). what max current can i charge it with. While using solar, I am hoping to get it charged as quickly as possible. I am not worried about affecting its life. If I can charge it, say in 3 hours, by reducing its life to half, I am happy with that. I just don't want them to swell up immediately.

Which leads me to another question. In a 24v 14ah setup, is there a limit to the solar power that I can use? If I the highest current that I can use for charging this battery is 4amp. Then its best for me to get a 4 x 24 ~ 100 watt panel. Of course, most of the time, I would be getting ~80% power. But If i am hoping to get a 200watt, then I would be wasting money & power (unless I get a bigger battery. Is that right?

 

[dogman dan]

Depends on your battery. Some have a bms with a 5 amps charge limit. So that would be 5x 28v,, 140 watts. So with that much panel, or a 5 amps charger,, you'd fill a 400 watt hour battery like yours in 2.8 hours.

Or,, while moving,, drain it at 140w slower rate. So say you were going at 300w,, call it 12 mph,, you'd be able to go twice as far before you have to stop and let the solar catch up for a few hours, or find a plug.

With my trailer, if it ever gets its solar,, I'm just figuring on enough panel to limp to the next plug at 200w, So I can ride in the afternoon, more or less empty my battery, but still limp to town for a charge and a fill up of the water in the mid morning. tip the panel east in the am,, grab 200wh, then move on at a slow pace. Or it there is a mountain to climb,, sit till I have enough to climb it. two days in that camp if that is what it takes.

Camp in the boonies, stop at towns for a faster charger off a plug, then not worry so much about it if I run it dry in the afternoon. If towns were not 60 miles apart out here, or more,, I'd just figure on stopping twice a day to charge.

If I had money,, I'd just tour from motel room to motel, and charge each night. I have the battery now for 60- 100 mile range, but I can't afford 60 bucks or more a night for long.

 

[sophocha]

I think I'm getting 7 50w mono solar panels....one at the front, two at top of the bike, two at the back at 90 degrees, and a small trailer for the last two panels as well as hiding my six 12v18ah lead acid batteries in parallel. I have a tristar 45amp solar controller which I'm going to connect to the 6 lead acid batteries.The plan is to have the seven 50w solar panels charging my lead acid batteries on the go. I will have a 5ah 72v lipo pack for my drive pack, while I will have a DC-DC converter to up the voltage to 24v in order to have my ISDT 20A lipo charger charging the second 5ah lipo pack in about an hour. I think it is feasible to travel 50km (I'm not sure at what speed but it has to be dead slow), teach for three hours while having the bike in the sun to charge the lead acid batteries, and do another 50km back. What do you think?

 

[amberwolf]

If there's any way you can make a switch to toggle your SLA pack from 12v 1s6p to 24v 2s3p, while disconnecting it from the solar panels and connecting it to the RC charger, you can skip the DC-DC conversion that will be wasteful of power and save a bit of time as the SLA wont' have to recharge as much.

Just make sure that either the same switch does all of the conversion at once, or that you have a safety mechanical linkage that prevents switching things in an order that could cause fireworks.

 

[amberwolf]

As of now I am using 14ah lead acid (deep cycle) batteries (i will switch to lithium eventually). what max current can i charge it with.

Check the side of the batteries, and they may have the max current rate listed there. If not, you'd need to check the manufacturer spec sheet. They dont' usually accept very high charge currents.

I fried some 7Ah batteries charging them at 0.25C, with DayGlo Avenger, back when I started this whole ebike thing.

I used a 4A charger (almost 0.25C) and later a 5A charger (over 0.25C) on 18Ah SLA and they did fine, though. I don't think I ever tried higher than that on them, though. Long time ago so I cna't remember for sure. It's probabl buried in my CrazyBIke2 thread, in the first couple years' worth of posts.

 

[dogman dan]

Yes,, lead requires a very slow charge, compared to lithium. If you are just riding along as you charge, then of course you can have a fairly high current, and still have none of it going into the batteries. Till you stop,, then whammo. So some kind of switch maybe?

As long as you have lead,, might keep it down to just a few of the 7 panels.

 

[markz]

I wonder what it takes to steal power right off a power line. DMM have them loop hooks clamp style that can measure amperes. Be cool to just climb a pole and throw something around the line, it'd be dangerous too.

What about buying a very flexible roll up type solar panel that you can use and spread out on the ground.
Or a small motor that you can raise and lower to generate power. Say going down a hill you lower a small motor onto the tire, then that generates power. If you have it hooked up all the time I think you defeat the net gain aspect.

 

[amberwolf]

I wonder what it takes to steal power right off a power line. DMM have them loop hooks clamp style that can measure amperes. Be cool to just climb a pole and throw something around the line, it'd be dangerous too.

Aside from escaping from law enforcement if they saw you doiing it, you'd have to carry enough equipment to convert that extremely high voltage into something you can actually use that it'd be kinda pointless; the added weight and volume would use up the power you get from a random tap-in here and there.

Or a small motor that you can raise and lower to generate power. Say going down a hill you lower a small motor onto the tire, then that generates power. If you have it hooked up all the time I think you defeat the net gain aspect.

That's what regen braking on your existing hub is for.

 

[dogman dan]

To carry a large panel to fold out when stopped,, I still liked the idea of those 50w size flex panels. Roughly 2 feet square, so a stack of 8 could be carried for a total of 400w. Possible to carry a stack of those in a pretty small trailer, or the rear deck of any good cargo bike. 400w charging will fill a 1000wh battery in a long lunch break.

But then you get into real money,, they are around 75 bucks each. One option I considered for my trailer, is a folding top so you could have 8 of them. But $$. once you get to the cost of a Honda EU 1000 generator, I start to like just getting one of those. Weight about the same, cost about the same. Cost of gas for it,, not enough to care about much.

 

[sophocha]

http://pesn.com/2011/08/28/9501905_Thane_Heins_Regenerative_Acceleration_Generator/

What about this? Another scam? "Regenerative acceleration generator"

 

[amberwolf]

Scam, idiot that doesn't understand what's going on, doesnt' matter--it amounts to the same thing, in that it can't work.

there is NO way to get more energy out than you put in, and if you take energy out of your motion, you slow down.

Period.

the only way to NOT slow down and not take energy out of your motion is to add energy from some other source onboard your vehicle, or transmitted power from somewhere else (solar, microwave, etc).


Anytime you see "free energy" on a page/site/book/etc you might as well just skip it and go read something useful instead.