Charge Control Configuration Help Needed Badly [CLOSED]

[electricpedals]

Hi, we are currently attempting to boil a 2kw kettle using Human Power in the form of people pedaling bicycles, where each generator will be a 24v / 250w MY1016 DC motors that when pedaled under load will produce about 100watts at 12-15v. The kit we intend to use is:

17. -20 bikes generating ~2kw
    
3. ?x Morningstar TS-60 controllers
   
1. x 500F UltraCapacitor (effectively acting as a battery)
   
1. x Victron Phoenix 2000/12 Inverter
   
   

We really need your help!

1.    We know that 2kw is being produced, but at the same time it takes time to charge the UltraCapacitor (UC). So what happens in the meantime, say when the UC is at say 5v? Is the amps then 400? How does the charge controller respond?

So during normal operate the system generates 2kw @ 12v how many of the 60A charge controllers will we need? 3?

2.    Next part is about load dump. I've read so many comments on load dump but I really don't understand. I do know that you can parallel TriStars in diversion mode. However, each TriStar must have its own diversion load and the diversion voltage setpoints should be staggered. For example, if you have two diversion controllers, you will want one to be at say 14V; while the other is set to 14.1V. When the first controller has diverted all the power it can to its diversion load, the voltage will continue to rise on the UCs. Eventually, the voltage will reach the second TriStar's setpoint of 14.1V and it will start to divert power.

It is important that each TS have its own diversion load which is unable to draw more than the TriStar's rated 60A. If you were to have a diversion load that can draw more than this, the controller will go into overcurrent protection, shut off the diversion load, and you will risk severely overcharging your capacitors.

Could someone please help me spec out the load dump?

3.    Finally, can the load dump be used to discharge the UC for safe handling? If so how?

I appreciate that these are complicated problems, well certainly for me. Really, appreciate your help.

Colin

[Flux]

This seems a bit crazy. If you want to boil water then the smallest number of stages of conversion you use the less loss you will have.

If each generator dumped directly to a heater it would make more sense.

I have no idea how an inverter will perform when connected to a capacitor instead of a battery but I suspect not very well. Capacitors have very different characteristics from batteries and the inverter will have been designed for a battery. To produce heat I can't see why you even want charge controllers.

The whole thing seems to be geared to cost a fortune and do the job in the most complicated way. I personally have no desire to expend energy to pedal anything and if I did I would want every available watt to go into the water.

Flux

[electricpedals]

Ok for the sake of clarity, can we please assume the we just need to produce >2Kw of AC to power numerous appliances!  

[electronbaby]

If you are using a battery based inverter, then you will need to use a battery. If you do not have a battery of sufficient size, you are asking to ruin equipment.

Yes, capacitors are very different than batteries.

Yes, this seems like a waste of energy. It would be more efficient to run the generating source directly to the heating element because it does not care about voltage fluctuations.

If you want to power >2k of load, then you need to make sure your source or supply is >2kw and stays there. If you cant do this, then you will need a bigger battery acting as a buffer.

[Blutoy]

I would like to know who we are and why boil water. Is this a frat thing?

[Opera House]

Rectify each bike and put them in series.  Have a big meter or light bulb that everyone can see to regulate voltage.

[Ekij]

If you're charging a capacitor rather than a battery you don't need a charge controller, just rectify the AC to DC and drop it into the capacitor. Some form of protection to ensure you don't over-voltage the capacitor would do.

However the obvious question is why do you want to boil water using a 2kW AC kettle?

There are many devices out there for boiling smaller quantities of water using the "cigarette lighter" output of a car. ~12V 10A.

Much simpler.

(If you've got 24V just wire two in series)

[zap]

David Butcher has used ultra capacitors for his pedal generator for quite a while now and maybe electricpedals got the idea from his work?

http://www.los-gatos.ca.us/davidbu/pedgen/ultimate_pedal_tv.html

Does the Unite motor make a good generator?

[electricpedals]

Guys thanks for your comments.

Firstly to answer the question about why would we want to boil a kettle? Well firstly for education, we do quite a bit of work in schools/festivals highlighting energy usage; and having 10 or 11 people pedaling to boil a cup of water is a really effective way of demonstrating the shear amount of energy required to boil a single cup of water. Secondly, we are currently contracted to a television documentary company in the UK who are making a major science programme for the BBC to highlight energy use in the home. Their plan is to remove a family home from the mains electricity system for 12 hours and instead use human powered devices (e.g. bicycles, rowing machines etc) to provide their electricity. The aim is to show in tangible, human terms, how much electricity each device in the household uses - and how they can be used more efficiently to save money and reduce environmental impact. It will be a high-profile programme and should generate a great deal of interest. We are also currently in discussion to make versions in other parts of the world.

Further, as was pointed out in a later post, much of what we do is an evolution of concept created by David Butcher (http://www.los-gatos.ca.us/davidbu/pedgen.html) many years ago.

So we are faced with a significant challenge as I am sure you can appreciate.  100 cyclists pedaling to produce a household demand profile that could reach up to 10kw. Perhaps I should have made this clear in my first post, but I did not wish to muddy the waters discussing the entire project, rather I am interesting in advice on some of the smaller problems. We plan to complete a 2kw test in a couple of weeks. The setup is simple:

20. bicycle generators producing an average of 90kw per person
    
3. x Tristar 60A charge controllers in parallel
   
1. x Maxwell 500F Ultra Capacitor
   
1. x Phoenix Inverter C 12/2000 - 230V
   
   

Our only really issue at this point is what to do with the surplus power? Given that potentially 2kw can be produced I assume that we would need to load dump that can easily dissipate 2kw? What are my options? Any ideas?

[electricpedals]

Yeah the unite generators are quality. The only issue for us here in the UK is getting our hands on 80 of them! If you are in the US and need a contact, I have found a few people that stock them for a reasonable price. Colin.

[RandomJoe]

I remember as a kid one of the more entertaining exhibits at the science museum was an exercise bike wired to a series of 100W light bulbs.  Get on and start pedaling, as you produced more power a bulb would glow brighter, then the next one would switch in and glow, so on.  Of course, only true he-men would ever get all the bulbs to light at all - let alone for any length of time!

How about feeding the power through a power meter (even a standard residential one, if you wind up using AC) so you can show after all their exertions they produced a whopping 1 kWh - which could be purchased from the grid for 9 cents!  (Or whatever the local cost is.)

Dang it, now I'm thinking about how to convert my bicycle resistance trainer into a power generator again! :p

[zap]

I have some Currie ebike stuff... I think the Unite are a close match, I've just never tried to spin any of them up to make power and was wondering how well they perform in that duty.

[zap]

Since you have probably been looking into this problem further, you've probably also realized the Maxwell isn't the perfect storage system when used with a variable input supply.  A battery will attempt to clamp the voltage and probably take more abuse than the supercap would and at a much easier price.

From what I've read, the supercap's voltage range is +-16.8v on the high end... most of the inverters I have experience with trip on an over voltage of +-15v.  Your Phoenix looks like it might have a variable over voltage protection which you can change so over voltage may not be an issue in this case.

I'll assume you're sticking with the supercap because of it's gee-wizardry.

Are using a BMOD0500-P016?  It has a built in "dump" feature which can be used to control the charger in a high voltage event.  In your case can you use it to control a dump load instead?

From the BMOD0500-P016's data sheet:

"The output of Pin 2 (wrt Pin 1, GRND) is normally close to 0V when the voltage management circuit is inactive. However, in order to use the signal, the user needs to connect a pull-up resistor (typically 1kΩ) to Pin 2 and a 5V supply. In this configuration, the voltage at Pin 2 will be ~ 5V when the circuit is not active. When a cell in the module goes into over voltage condition (>2.7V), the voltage management circuit becomes active and tries to discharge the cell to bring its voltage

below the threshold."

If the BMOD0500-P016's control feature can be used (and tweaked to work at a voltage lower than 15v) as a dump load controller then all that's required is a dump load of sufficient size to handle the wattage being dumped.

Some of the members here use their excess (dump load)power to heat water... ironic eh?

Other choices would be resistors, nichrome wire (picture the wire in an electric toaster), light bulbs... basically anything that uses power... even a motor.  All can be used to dump power.

Good luck.

[electricpedals]

Thanks Zap,

first I have in my possession 6x BMOD0500-P016 and you are absolutely correct about the 'gee-wizardry'.

Anyway, cut a long story short, we have decided to change the system to 24v (from 12v). Its a long and complicated path, but essentially the idea was to build 5x 2kw 12 circuits (to avoid having to source 750A isolators etc) and link them all together using the Victron Inverter's parallel setup. However, I've since found that the only issue is that each 2k circuit must have the same voltage otherwise the parallel system will 'error' meaning that all five inverter will need to be reset.

So we went back to the drawing board. Now the system is going to be 24v and will be comprised of the following:

100. x Bicycles generating 100W DC Average.
     
7. x 60A Morningstar Tristar Controllers in parallel
   
6. x 16v BMOD0500-P016 UltraCap (UC) (series pairs / 3 parallel groups) giving 2500F @ 24v
   
4. x 24/3000 Victron Inverter in parallel
   
   

This will be one 416A circuit @ 24v.

Load control is interesting. I was unaware of the UCs ability to control load and will need to investigate this further. However, the alternative is to use the Load Control function on the Tristar. The main issue is to ensure that voltage does not exceed say 30v (note the inverters operate 19-33v) to avoid damage. Unlike a standard wind turbine we don't the cyclist to pedal into a load. Rather and perhaps more simply, if the voltage exceeds 30v then all we need todo is effective open the circuit which will reduce the load on the bike's DC generator. Or simply have a large LED display with the voltage that everyone pedalling can see (I would rather it not be 'manual)

Anyway, this is about where we are with the design. Any thoughts on managing the voltage management, correct isolators / fuses, inverter parallel configuration is welcomed!

This will be show on primetime BBC1 (main UK TV channel, 5-10 million viewers) in September so you should be able to see the program on the BBC iplayer!

Thanks

Colin

[DanG]

Seen it done before; WCCO here in Minnesota powered some of their nightly news television broadcasts using human power in a publicity stunt last year at our Minnesota State Fair. Included below are some contacts to perhaps see where they would do it differently the next time, near zero technical info available on web...

http://wcco.com/statefair/we.power.state.2.793382.html

They ended up creating 26.5 KW hours total...

http://wcco.com/statefair/minnesota.state.fair.2.373951.html

Fair goers are invited to visit the WCCO building and be a part of We Power by hopping on one of the eight stationary bicycles. Each of these bicycles is connected to a small generator. The energy each person produces will be stored into batteries and added to the collective energy that is created. When the necessary amount of energy to produce a 30-minute newscast (approximately 10,000 watts) is stored, a "human-powered� newscast will be possible by using an uninterruptible power supply (UPS) to convert battery power into electricity. During a human-powered newscast, all of the equipment, lights, cameras, mics and monitors on the WCCO stage, will be powered by this bike-generated, We Power source.(TVNewsday)

http://green.yahoo.com/blog/ecogeek/89/how-many-corndogs-does-it-take-to-power-a-tv-broadcast.html

Sponsors included:

http://www.res-americas.com/

http://www.eriksbikeshop.com/ride/

http://www.fresh-energy.org/media_center/news_releases/2007-08-22_state_fair.htm

[ghurd]

"if the voltage exceeds 30v then all we need todo is effective open the circuit which will reduce the load on the bike's DC generator"

Looks good on paper.

So 20 people, pedaling their butts off, into a load,

Suddenly go open circuit???

Tchaikovsky's Nutcracker Symphony?

All I want for Christmas is my two front teeth?

"voltage management"?  Are you trying to make voltage, or power to boil water?

"inverter parallel configuration"?

Did you read Flux's reply?  It was the first one.

The conceptual design parameter is to make a lot of power?  To boil water?

Think about it.  2,000W to boil a kettle of water.  Now check how many watts your kettle uses.

The design is flawed at the most elementary levels.

G-

[electricpedals]

ghurd your comments are flawed on every level. Try to understand the problem better with constructive questions, rather than idiotic assumptions.

[TomW]

pedals;

Excuse Me.

Glen has been providing top notch help here for a very long time.

You have no credibility to talk trash to anyone here and certainly not Glen!

If you want to continue getting help here you better get your arse wired straight.

Apologize and hope he accepts.

Being a young punk, know it all you should have a LOT better grasp of this than you actually have.

Thats my opinion this is your one and only chance to square yourself.

Tom

[wdyasq]

So, why does the truth upset you? THAT is the first question you need to ask yourself.

Ron

[rossw]

Wow, you been reading that book "How to win friends and influence people"?

I agree with Tom. I think you're waaaay too low on cred to start slagging off those who have lost more than you're likely to ever earn.

[behoof]

Wow electricpedals,

Why on earth would you come into a forum to ask for help and information and then slam the very people you are asking for help??? This logic baffles me totally.

IMO you really need to back off and rethink your position.

Perhaps you might do as TomW has suggested and apologize. Maybe you were just a bit hasty in your remark, that being the case, now while the iron is hot would be the best time IMHO to right a wrong and perhaps gain a bit of credibility and standing amongst the people you thought highly enough of to bring your ideas and questions to??

But on the other hand, where I'm more inclined to reside, I probably just need to make you my very first person on here that will never be seen again.

As with all things when we screw up and have a chance to fix it, don't wait too long, people tend to act accordingly when slammed,  "The ball is in your court!"

behoof

[zap]

Colin,

You see the effects of slamming ghurd.  If more "regulars" on this site read the newbie posts, I have no doubt you'd see a few hundred people jumping in to back him up.  No telling how many people he's helped out of a pickle and that's just on this site alone.  I wouldn't doubt the number would rise into hundreds, if not thousands, of those who've been saved from getting into a pickle in the first place simply from reading his posts and replies, not to mention emails when he personally responds privately.

I count Glen as a friend and I too, along with others, feel you owe him an apology.

If I know Glen like I think I do, your comments will roll off him like water off a duck's back... trouble is, he's not the only one reading this post.




Now to the business at hand.

ghurd was spot on with his assessment of going open circuit on your set up.  I have a pedal generator and can attest to the effects of pedaling hard and suddenly losing the load you're pedaling against.

Most have seen at least some of the amazing wrecks every year on the nightly news for the past few decades during the Tour de France.  Tone the worst of those wrecks down some and that's what you face if you continue your "open circuit" plan.

Imagine grunting you way up a 10% slope on your bike, with everything you've got then either throwing a chain or breaking one.

You won't have as much road rash to deal with but you could easily have injuries not to mention grumpy power producers... like I said... ghurd was spot on!

Last night I had an idea how you could control the voltage on each bike cheaply but a late phone call and a few hours of sleep has wiped the idea away.

The person you slammed is one of the better ones with real world experience in this area.  I don't know how many dump load controllers he's sold or how many times his design has been copied but it is popular.

Of cource 100 voltage regulators will have a worse reliability factor.

If I were you, I'd set the TriStars in diversion mode then look into the supercap's own control abilities as a backup to the TriStar's.

You may still want to consider some type of output display for each of the 3 parallel groups of peddlers to give each group a heads up as to whether their power is going towards the goal or is being dumped.

Chances are you'll have a lot more hot water than you'll need... and you could probably produce enough extra power to run the production company's on-site video efforts.

It's none of my business but it appears you have some decent funds to throw at this project... maybe it's time to consider tossing some towards an electrical engineer?  I have no problem believing you could find a few dozen who would do it for free as long as they could see their name scrolling by on the credits.

 

[electricpedals]

Thanks Zap,

you are absolutely correct about the open circuit issue. This is where I am:

Setup:

1. x Morningstar Tristar C60
   
2. x UltraCaps (UC) in series (24v)
   
1. x Victron Inverter (24v/3000)
   
   

The Tristar is set to diversion.

Although I have only tried this with a single generator (this setup should support about 30 riders), once the Tristar reaches its diversion point, if there is no load on the diversion circuit and I keep pedalling, the voltage continues to rise and the load remains. (Interesting to see how this behaves when 30 people pedal). This is understandable since the diversion configuration dictates that the load is on the same circuit as the UCs. Conclusion is that I will need a load dump for a worse case scenario.

So having charged the UCs to around 29v, I then experimented to see how long a 3kw would boil for. In the absence of a capacitor discharge algorithm I found that between 29-18v (i.e. when the inverter shut down) gave me about 20 seconds. Given that I have 6 of these, we should get a whole minute buffer which is great news.

I thought I'd record the kettle boil for posterity! Check it out:

http://www.youtube.com/watch?v=5RWaCE_SW8w

With regard Glens comments and my response, I'll apologise when an apology is warranted, in other words I'm not going to say it until I mean it. I'd happily receive his comments if they are useful. Anyway, how we get to that point, well time will tell. In the meantime, irrespective of the criticism I will continue. Perhaps this is a crazy project but a brief is a brief and this is what the client wants. This project is so unusual that it is difficult to find with the understanding. I have a document with at least 40/50 people all over the world who were contacted about the project. It's very difficult to find an expert.

[electricpedals]

> "if the voltage exceeds 30v then all we need todo is effective open the circuit which will reduce the load on the bike's DC generator"

Looks good on paper.

> So 20 people, pedaling their butts off, into a load,

> Suddenly go open circuit???

> Tchaikovsky's Nutcracker Symphony?

> All I want for Christmas is my two front teeth?

> "voltage management"?  Are you trying to make voltage, or power to boil water?

> "inverter parallel configuration"?

> Did you read Flux's reply?  It was the first one.

>The conceptual design parameter is to make a lot of power?  To boil water?

Think about it.  2,000W to boil a kettle of water.  Now check how many watts your kettle uses.

> The design is flawed at the most elementary levels.

> G-

Look you pissed me off with that last comment, that is the long and the short of it. I can't change that it is done. If Anyway, if you are not interested in discussing this with me further, then that's cool, there is no love lost!

Anyway, incase you are remotely interested. To try to answer your question: The simple idea is to produce 10kw of power as real time as possible, hence why we are not simply charging a battery bank. A family will live in a standard house for 14 hours, unaware of the human power station outside. A group of which will be pedalling 'baseload', fridge, lights etc.

So say someone in the house switches on the 3kw kettle - the ultracaps will provide about 60secs (assuming no other significant load). However, groups of cyclists will be on standby to replace the lost energy. So although we will have a extensive realtime human control, ultimately we can't exceed the UCs ceiling threshold of 16v. The answer your comment about 'parallel configuration' -  Victron inverts support a parallel configuration to allow for higher output.

Well Glen .. your move! ( sorry cough)

[rossw]

I'll apologise when an apology is warranted,

I'd say one is overdue already.

Keep in mind that sarcastic and cynical comments that you might make in person  often appear to be very rude on a discussion board.

<sarcasm>Not that you'd ever do that of course. </sarcasm>

If you had adequately explained the situation in the first case, rather than just pissing on everyone, you MAY have received a more politely worded version of "you're going about it the wrong way".

For my money though, you can FOAD, come back when you've learned some manners and humility. Of course, this isn't MY site (if it was, you'd likely have been removed already), and others may not agree with my apraisal of the situation. I can think of several ways to achieve what I think you're after (I have 35 odd years background in industrial/commercial R&D), but stuffed if I'm going to bother detailing it, or going out of my way to assist you. I suspect many others will be in the same boat.

As for your quip "Well Glen .. your move!" - I hope he treats your response with the ignore it deserves.

[wdyasq]

Now Ross,

Be careful, you may hurt the young man's ego. You do realize egos are more important than the truth!?

Although many might have methods that have the possibility to work, unless they fall under the 'make my ideas work no matter how stupid it may be', I doubt it would be used.

35 years experience .... you should go to school and learn something!

Ron

[TomW]

Mister pedals;

You arrogant pissant this thread is closed. I doubt anyone will help the likes of you now anyway.

If you were in my physical proximity we would have gone behind the woodshed for a chat by now.

You are the type that ruin sites like this pissing on the good folks that try to help you.

You will probably scam your way to riches pimping green power but not with help from here.

Tom