Hybrid Electric/ICE Project- Please pick holes in my plan :)

Hello,

So the plan is to use a very small, efficient (honda gx25) 4-stroke engine that I have, to turn a Permanent Magnet DC alternator designed for wind turbines. The engine puts out about 1hp or 720 watts and the alternator ( i am yet to purchase this but have been in contact with the manufacturers ) I am told will run anything up to 40 amps at 60v at 5000rpm. Together the engine and generator weigh about 7kg. I will go into more detail about the generator in a minute...

The basic concept is to have the generator built into an air-cooled, sound insulated backpack (preferred) or towed on a small trailer (i hate trailers) supplying power to my ebike. The engine will burn between 300 and 500ml of fuel per hour depending on revs.

I am undecided upon weather to have a small battery to store charge and possibly work as a buffer to smooth the power from the alternator or to have the engine running constantly. This is quite an exciting plan for me as I am a range addict who can't handle waiting for batteries to charge and can't be bothered with loud thirsty motorcycles any more. I'm dreaming of 200-300mpg figures.... 300ml of fuel for 1hr at an average of 15mph is about 50 miles per litre so maybe 200mpg without even adding a battery to store and release charge as a more advanced hybrid could....


The bits i'm stuck on are some of the more advanced electrical concepts like......

If the alternator is running at say 2500rpm and giving 20amps. could a controller be connected directly to it and just draw as much current as it needed? And if it wanted more than the alternator was supplying would the undervolt protection just kick in? would there be any risk to the alternator?

If this is not possible and i need to use a battery as a store and to provide cleaner DC, am I limited to lead acid or is there a way to charge lithium batteries safely from a source that may have slightly fluctuating current and voltage?


If anyone else can see any potential challenges or has any bright ideas i'd love to hear what you think....

I'd guess you'd not like to wear an ICE generator on your back, but the GX25 sounds like its sized for the task.

Can you post the specifications or schematic of your Permanent Magnet DC alternator's power output circuit?

[EDIT] You had a lot of helpful guys reply in a previous thread that you subsequently abandoned. People may be hesitant to invest their time here as a result.

Subject: Deductive thinkers needed!! Confusing problem

No schematic but here is the product listing:

http://www.ebay.co.uk/itm/331366277595?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

It has a built in rectifier but no regulator so will put out more volts and amps the faster you turn it.....

And i'm planning on modifying the exhaust to be quieter and to exit at the bottom of the pack... May well end up with a simple ducting system and fan to draw air in at the top and exit at the bottom/rear to keep warm air heading away from me and cool the engine and alternator. I know it's going to be a crazy device but if i can get it quiet enough it could be a great adventure machine

[EDIT] You had a lot of helpful guys reply in a previous thread that you subsequently abandoned. People may be hesitant to invest their time here as a result.


Wow, offending behaviour duly noted! Apologies to anyone who was disappointed by my lack of response I spent 2 weeks waiting for a new Multimeter to show up and probably would have checked in again if my van hadn't developed an unfindable diesel leak...

I think i understand the etiquette a bit clearer now.

Yikes. I guess newbies don't get a second chance around here.

I was hoping you'd update that first thread so that others could learn from your experience.

The generator question is one that's been thrashed out in previous threads. There may be technically sophisticated solutions, but separate batteries charging off the generator while you use one conventionally should work. With the price of batteries continually decreasing, a generator solution is increasingly less useful.

What is it you seek to gain from the generator?

Most of us here at some point used ICE, and the greatest part of going electric is never having to see touch hear or smell the foul nasty things again.

[youtube]kxRX6LXDpWs[/youtube]

Hahaha! I was waiting for that . To explain what i hope to achieve with the generator.... I like the idea of never having to stop or plan too carefully my journey. I did eventually figure out that i had a dodgy cell in my 20ah pack and after replacing it with a £30 ebay jobby it's been running fine since (testing each individual cell under load turned out to be a serious mission) with a decent 30 mile range the way i ride. The thing i can't stand is having to constantly worry about how much juice i have left and where i'm going to charge if i don't just turn back home. With a generator i just have to find a petrol station and on i go. The main issue i guess, is that carrying camping gear (even really minimal stuff) is gonna be tough without space in the backpack... I'm gonna have a search for the other threads mentioned.... thanks for your replies! Oh, and does anyone know if the dc from the alternator i plan to use will be ok to power the controller directly or charge a lifepo4/lipo directly?

Disadvantages:

Noise
vibration
smell
inability to use cycle lanes, parks, nature trails etc
Advertises illegality of machine

It'd be a close call for me on whether I'd rather have an engine doing 5000rpm strapped to my back or walk.

With the right batteries you could be looking at a 10 minute recharge, probably with a portable charger weighing less then an engine/alternator/fuel tank.

BTW, that alternator on ebay looks awful - no specification whatsoever.

Noonoos said:

Hahaha! I was waiting for that . To explain what i hope to achieve with the generator.... I like the idea of never having to stop or plan too carefully my journey. I did eventually figure out that i had a dodgy cell in my 20ah pack and after replacing it with a £30 ebay jobby it's been running fine since (testing each individual cell under load turned out to be a serious mission) with a decent 30 mile range the way i ride. The thing i can't stand is having to constantly worry about how much juice i have left and where i'm going to charge if i don't just turn back home. With a generator i just have to find a petrol station and on i go. The main issue i guess, is that carrying camping gear (even really minimal stuff) is gonna be tough without space in the backpack... I'm gonna have a search for the other threads mentioned.... thanks for your replies! Oh, and does anyone know if the dc from the alternator i plan to use will be ok to power the controller directly or charge a lifepo4/lipo directly?

Click to expand...

Make a pack that suits your needs. Perhaps consider something like a meanwell RSP3000 for a charger. Range anxiety vanishes, and it doesn't require spraying carcinogens into the air we all breath and paying evil folks to invade peoples countries and murder them.

liveforphysics said:

Noonoos said:

Hahaha! I was waiting for that . To explain what i hope to achieve with the generator.... I like the idea of never having to stop or plan too carefully my journey. I did eventually figure out that i had a dodgy cell in my 20ah pack and after replacing it with a £30 ebay jobby it's been running fine since (testing each individual cell under load turned out to be a serious mission) with a decent 30 mile range the way i ride. The thing i can't stand is having to constantly worry about how much juice i have left and where i'm going to charge if i don't just turn back home. With a generator i just have to find a petrol station and on i go. The main issue i guess, is that carrying camping gear (even really minimal stuff) is gonna be tough without space in the backpack... I'm gonna have a search for the other threads mentioned.... thanks for your replies! Oh, and does anyone know if the dc from the alternator i plan to use will be ok to power the controller directly or charge a lifepo4/lipo directly?

Click to expand...

Make a pack that suits your needs. Perhaps consider something like a meanwell RSP3000 for a charger. Range anxiety vanishes, and it doesn't require spraying carcinogens into the air we all breath and paying evil folks to invade peoples countries and murder them.

Click to expand...

Not to mention that the ICE is maybe 1/3 efficient so you waste 2/3rds of the energy carried, and with all that heat closing it up in a box isn't going to work.

Hey, thanks for the input... I'm very excited about the prospect of a decent sized pack that could charge in minutes! What kind of pack is this? I know Graphene super-capacitors and the likes are just round the corner but i didn't know there was anything that could charge that quick available at the moment (sorry if that's ignorant). I know that the generator would attract attention to my currently illegal ebike but i'd even considered a legal 250w build with this in mind. The other reason i'd planned to build the generator was to hook up to the electric quad i'm building. It's a beast with crazy torque and 4 lead acid batteries to keep topped up when dragging stuff around on the farm. I just really like the idea of a good ultra small generator for all kinds of tasks. And i totally get the 'boo carcinogens and the oil industry' vibe which is why i'm so intrigued by ebikes and 200mpg figures in the first place. I did notice the awful listing of that alternator but was encouraged when the seller gave me such detailed feedback and didn't just try and sell me the thing... Ho hum.. Doesn't seem like anyone's too impressed with my plans but thanks for the feedback

Maybe do it with an existing automotive voltage regulator that is tuned to your desired voltage?

For fast charging batteries, any lifepo4 from A123 or RC lipo (LiCo) especially Turnigy nanotech.

There are also some "power" 18650 cells that take high charge rates, I'm sure others could give detailed recommendations if you went that route.

A limiting factor may be how much power you can pull from a wall socket.

The hybrid system sounds better suited to your quad...

Is this the kind of pack you mean?

http://www.hobbyking.co.uk/hobbyking/store/__49509__Turnigy_nano_tech_Ultimate_7500mah_2S2P_90C_Hardcase_Lipo_Pack_ROAR_Approved_.html

what kind of charger/BMS set up would i need to charge 6 or 12 of them (44.4 volts) as fast as possible?

Is the Meanwell charger suggested previously the right kind of thing and are there other options?

This is outside my experience, but I know others here have experimented with fast charging. The 90C nanotechs are the ones, just look at the maximum charge rate when comparing the different batteries. The largest RC chargers I have seen are 2000W. If you want more power then a Meanwell (or similar) switchmode power supply offer the best power for a given size and weight.

The other altenantve, often discussed and sometimes done, is to supplement your wattage with a solar panel. 100w of solar can be carried on a trailer, and if you are traveling slow, it could double your range.

The starting point, as always, is get a really big battery to start with. When I tour with camping gear, I pack 48v 48 ah. Some of it old and funky, but I get about 35 ah of real usable battery. About 1800 watt hours. Typical bike batteries are 500wh. I charge with two 250w chargers, so 4-5 hours to charge, generally at a camp site where I can buy a spot with a plug. Or along the way, I can find a free plug and stop for an hour here, two hours there.

Wow 48ah! That's a lot of battery. Must be pretty heavy?? 25kg? I love the idea of solar and i'm starting to think about where you could strategically place a small array of panels.. What is your range like with your full setup?

Hmmm, I guess you lot are still pretty unresponsive even though i've been on best behaviour and checked for replies every day!...

Well here's an update anyway. I'm really excited about solar and wondered if I should continue on this thread or start another?? The Hybrid quad is taking shape and I think the engine is much better suited to this task. You hear that!? You were right!!!

So solar.. Do i need a charge controller? or if i chain them in series up to about 54v is there a clever way to just wire them in with diodes or something similar so they are contributing to movement when im moving and charging the (48v) battery when i'm not? Any ideas or other threads you could point me at? I did a quick search but couldn't find anything relevant..

Noonoos said:

Hmmm, I guess you lot are still pretty unresponsive even though i've been on best behaviour and checked for replies every day!...

Click to expand...

Remember, people are not always on, some only visit once a month, some even less, some more often. Even then, this isn't the only discussion going on, and they may have limited time to spend when they are on. So you would want to be patient and give people time.

Plus, not everyone is interested in every project. I get very few replies to any of my project threads, but a lot of poeple read them. It's just how life works.

I'm really excited about solar and wondered if I should continue on this thread or start another??

Click to expand...

If it's part of the same project, you're much better off to keep the same thread, otherwise those following the project or trying to help you may not see (or care to dig thru) another thread about it. And those seeing the new thread trying to help you there may not know about the previous one, and you will end up having to repost things you asked, answered, etc., from one thread into another. Better to keep it as one.

Any ideas or other threads you could point me at? I did a quick search but couldn't find anything relevant..

Click to expand...

There's quite a few discussions about solar charging, or even running motors direct off the solar panels, but no perfect way of finding them, other than simply searching on "solar" and skimming thru the threads / posts to see what's relevant to you.

It depends on how people worded their thoughts as to how easy it will be for you to find.

If you like, when you do find the info you need, you could add it to the ES wiki for future searchers to find.