Go-kart engine to charge electrical system?

[ganchan]

I never heard of this before. A guy commenting on someone's blog described his power system thus:

My power system is totally portable, and not connected to the van’s wiring at all. It consists of a small go cart engine hooked up to a car alternator, which charges a $20 battery exchange deep cycle RV battery housed in a plastic case with 4 fused 12v cig lighter outlets mounted inside the battery box also. Gives me all the 12v I need to run this laptop, my 12v electric blankets, lights, water pump for luxurious showers, for about a week between 15-20 minute long recharges. If I’m running my AC constantly, I need to recharge every 2-3 days. Total cost for all of the electric I need or want averages about $4 a month for one gallon of gas.

I wonder where all this stuff is positioned in his van. It's hard for me to picture it. But I'm still totally new to all this....

 

[Reducto]

He made a generator. What do alternators max out at these days, about 80 amps? That's around 1000 watts. You can get a cheap 2000 watt generator that will take up less space and likely be more reliable for a couple hundred dollars. A few hundred more will get you a nice Honda or Yamaha.

If you happen to have a go kart engine laying around and like tinkering then go for it, but I fail to see how this would actually be better than an off the shelf generator.

 

[SternWake]

Internet claims. Bah.

My favorite are the MPG claims of some.

One can certainly charge a battery with a separate engine spinning an alternator,

And if it is a high amp alternator, spinning fast, it can indeed charge the battery back upto the 80% charged range fairly quickly. Each 25 amps an alternator produces consumes ~ 1 HP, and a depleted battery can easily ask for 75 amps.

However, Lead acid batteries require being fully charged every so many cycles. If they are not returned to 100% every 15 Deep cycles, then they walk down in capacity, and the more they walk down, the harder they are to get back to where they started walking down from.

Walkdown in capacity actually begins at cycle 1 but is not really noticeable by most until cycle 15, unless they watch their voltmeter like a hawk and take notes during discharge.

The biggest issue with lead acid batteries it the all important 80% to 100% recharge, and this takes many hours no matter the charging source.

So do you want to listen to a go cart engine for 8 hours?

Solar is good for that last 20%. The alternator is good for getting it to 80%, and the earlier in the day 80% SOC is achieved, the better, so that the solar can finish off the job.

As that lead acid battery gets all petulant if it does not get that full charge as often as possible, and as soon as possible after being discharged.

 

[RogueRV2]

It is hard for me to believe he can run all that and use only one gallon of gas. Sounds fantastical. These type of generators might be efficient as they loose no power to a transformer, but it not as good as he says. Using a 1985 Honda EM500 and a 20 amp battery charger to replace 50 amps each and every day from 210aH battery bank, I estimate it will cost me $50 per month in fuel should the price return to $4/gallon. At $2 bucks, the 12 gallons needed would only cost $25. Run time would need to be about 2 to 3 hours day, using 1/4+ gallons per day for 30 days. The EM500 generator with a 60cc motor is rated for only 400 watts continuous, and the charger consumes a bit more than 300 watts when it is producing a full 20 amps @14.5vdc into thirsty batteries at a fuel consumption rate of about 0.1 gallon/hr. With his 12vdc generator run at 2,000+ rpm by 5hp lawn mower motor ( larger than 60cc in displacement), his might be producing as much as 40 to 50 amps, but more likely only 20 to 30 amps if a common one wire GM alternator is being used. Remember he is using only one 12vdc deep cycle battery. Even if his fuel consumption were the same as a 60cc Honda motor run at an optimal and low speed, or he used only 20 amps per day just to run an electric blanket during the night, his fuel bill would be at least $25 bucks per month. At the time of his post, fuel was at $4/gal. I don't know how much an electric blanket uses, but it produces heat in a similar way a coffee pot, hair drier, or electric heater does, and therefore must use gobs of power to do so.

If one is pinching pennies, this kind of generator, if the parts are found for next to nothing, can be an effective and efficient rig. Get an old motor, 5hp or more, plywood, board, a pully and belt, and a standard GM alternator, and it will work. It could be done for under $100 bucks. However to generate 20+ amps it will need to be run fast. GM alternators do not produce much until 1,500 to 2,000 rpm.

 

[LeeRevell]

You can find instructions and videos for home-made alternator 'generators' on any prepper site and on Youtube. Easy enough to do. Tends to be bulkier and less efficient than a factory designed unit, but it does work.
Used cheap lawnmowers are a popular starting point.
Not everybody can afford the nifty neato Honda genny.

 

[jimindenver]

I use to pull the engines off of reel mowers and do stuff , one was a generator as described. In the 80's I was given a Generac 50a 12v car starter. It worked much better than what I built. I had the plans to build a 120v generator out of a washing machine motor but then saw a barely used Coleman powermate 2500 on CL for $50 and thought what's the point. The 2500 is a B&S 5.5 hp engine sitting on a alternator and was very compact for a generator of that wattage. Unfortunately it was also loud enough to wake the dead, so I sold it for 3x what I paid and bought a larger, quieter generator.

As for the rest of the claims.... I agree. Electric blankets, air conditioner, pump, those all take lots of power. Your basic B&S engine is not even close to efficient at lower speed and guzzles gas under a load so I can't see the charge regiment or the gas usage as feasible.

Of the generators I know of others using, the inverter generators with eco switches can use less gas when running smaller loads. The little 2 stroke generators from harbor freight are suppose to sip the gas although their voltage isn't well regulated. Honda use to have the EX series and the ex650 was suppose to be 54 DB and good on gas. Heck even our 3500/4000 isn't too bad when just charging us up a few hours a day, we'd use less than 5 gal in two weeks. On the other hand, turn on the air conditioner and it will guzzle a gallon a hour.

So like Rogue said, if yo have all the parts and need a project, great. Otherwise it's cheaper and with better results to seek out a proper generator. Depending on where you are they can be cheap on CL, maybe not right after a disaster but give it a few months and people will start dumping the ones they bought for said disaster. The best deal new I have gotten was a 3000w open frame for $200 from Home Depot. Kind of hard to buy everything needed to build one for $200.

 

[jimindenver]

I know huh. I thried to run the window shaker we have without the solar assist. Even with a 8-D and the unit running on 400w, the starting surge sagged the battery to the point the inverter shut off. A 8-D has 250 ah so I can't see a smaller battery doing it for days. lol

 

[minimotos95]

Since I picked up a coleman generator that wasn't putting out any power on either AC or DC, my plans are to tear the B&S motor out of it and hook it to the powerstroke alternator that's been collecting dust or to a factory 75amp alternator for my van(so I have a spare handy).
It's a quick and dirty way to get power. By no means comparable to modern portable generators.

 

[ganchan]

Any other options for charging/recharging a house battery, preferably while driving? Sounds like you'd need to sink a lot of money into solar panels to get much juice from that department....and as for charging off the vehicle alternator, I might only drive a couple hours a day, which wouldn't help much either.

 

[SternWake]

House battery charging from the alternator can be effective if large copper cabling is used between alternator, isolation device, and house battery.

Also how it is wired can make a difference, and the device used.

Diode based isolation devices drop voltage 0.7v and can severely limit recharging.

Simple or Smart solenoid systems allow more voltages.

Another variable is the voltage regulator in the vehicle. Some only allow 14.2, or perhaps even less. The lower the voltage, the lower the electrical pressure and the slower the recharging.

Mine happens to allow a nice pleasing 14.9v, but then will revert to a 13.7 or 13.9v well before my depleted battery would choose.

Taking power for the house battery from the fully charged starter battery can fool the voltage regulator into reverting to a 13.x voltage earlier. I instead recommend taking power for isolation device right from alternator(+) so that the circuit is not only shorter, but the voltage regulator can better "see" the depleted battery and allow the alternator to stay up in the 14's for longer, which increases charging amperage.

But the 80% issue still applies. Once a battery gets in the 80% range the amps it can accept diminish and it still takes many hours to reach a true full charge.

That being said getting the battery to 85% when driving is 10x better than getting it only to 75% when driving, and thick copper cabling in the house battery alternator circuit can make that difference, and significantly extend battery longevity and performance.

There are also DC to DC devices made to take the alternator juice and change the voltages so that the battery sees 14.x volts for longer. Sterling is one such company, and for vehicles whose regulators do not allow at least mid 14's these are a good option. Those which do allow 14.4+V might not benefit from such a product.

So when looking to charge a house battery via alternator, buy more copper now, or buy a heck of a lot more lead later.

 

[jimindenver]

Any other options for charging/recharging a house battery, preferably while driving? Sounds like you'd need to sink a lot of money into solar panels to get much juice from that department....and as for charging off the vehicle alternator, I might only drive a couple hours a day, which wouldn't help much either.

Not saying this is enough or not enough but solar doesn't have to cost you a arm and a leg. A 200w kit can be had for $300 or less shipped to the states. It will include the panels, wiring, mounts and controller.

 

[ganchan]

Not saying this is enough or not enough but solar doesn't have to cost you a arm and a leg. A 200w kit can be had for $300 or less shipped to the states. It will include the panels, wiring, mounts and controller.

Well, that would be enough to recharge little devices, etc. And the electricity itself would be free, so it's a one-time cost.

What I don't understand is all the accounts i've heard of people keeping their house batteries in the passenger floorboard, under their bed, etc. Aren't these things supposed to be a little on the dangerous side for that (hydrogen outgassing, explosion risk etc)?

In my fantasy world, every device I need could be powered by good old 9-volt Ray-O-Vacs....

 

[SternWake]

In summertime 200 watts of solar is more than enough to power my laptop for several hours each day, run my fans, and my compressor fridge, all my lighting and still have a bit of a surplus, but I am in a sunny environment.

In winter I fall a bit short due to the laptop usage and longer nights.

Alkaline batteries are junky wasteful environment destroyers. You'd spend way more on 9v ray o vacs in a year than recharging a 12v lead acid battery with solar, so your fantasy world, would be my H#ll.

Yes, flooded batteries should be in a sealed, vented to the exterior, box. Fact is they only offgas when being charged and are in the 75% or more charged area. So in daytime with windows open and vehicle moving, the risk is reduced, and at night time, under discharge, there is no offgassing.

Many who choose to place their batteries in their living quarters go with an Sealed Valve regulated AGM battery( VRLA). These only offgas if severely overcharged, and overcharging is much much much less common than chronic undercharging.

 

[jimindenver]

230w is more than enough to keep our trailer going and we usually see clouds by mid day as the weather compresses over the peaks. That's without a huge inverter but it's cooler up there. We run the furnace every night and some days too. Add in the exhaust fans, pump, TV, lighting the rig end to end at night and phone charging and we don't really conserve much. All of that is done with a single grp 27, 95 Ah battery too.

the trick is we don't use a lot of power at night. The furnace, the LED lights and the TV/sat is about it. By morning the battery will be between 12.4 and 12.5v. That is brought back up to float pretty early and from then on anything we turn on that does not require a huge inverter just causes the controller to put out enough amps to cover the load. The 230w system is good for 16a at altitude and turning the furnace, 17 LEDs and both fans only comes to 11a. The battery never knows they are running. We can run the big inverter on the bigger bank and let the panel replace the power as most of the time we don't use what is readily available. It takes about a half hour or so to get the 8-D back up to float after running the microwave. Two panels replace even more of the power as the microwave is in use, meaning that less has to be replace at twice the rate, float comes in 10 mins.

Combined I use my three systems as a single real world 600w+ generator. What they can't power on their own, they assist in running and replace what was taken afterwards.

Gassing is a issue for non sealed batteries. They should be outside or in a ventilated box. The gas is corrosive and can be explosive. There are various sealed batteries that can be used in a non ventilated situation such as AGM or Gel.

 

[grummy]

I LOVE it when a guy like RougeRV2 throws us the REAL MATH on these projects. Bottom line is indeed, its not the best option...... not at first glance in the traditional sense. But there could be an option out there that is not quite so grim if one has the room for it, and it could be done rather inexpensively... certainly under the price of a fancy honda or yamaha gen set.

For many years, I had on a shelf, an old military issue Deco, Cast iron 4hp engine. My goal was to build said DIY generator, but add fully automatic control to the scheme, such that the system could be put into "auto mode", then start and stop whenever it wanted to in order to maintain my electrical needs. Because I have spent my share of time in automation, motion control and simple logic circuits, this really would not be all that hard to accomplish.... it actually has become fairly easy with multi-function electronic relay devices that are sub $100 these days (think simple PLC). Obviously, the 4hp would limit my choices on the alternator side, but I was thinking "compact"......

I never got around to finding the time to build this system, but the dream has never really left my brain, and here is why.

At the time, I was not thinking of the much better engine options available... Since I have a step van, I have enough room to use something much larger as long as it perhaps did a lot more than just provide electricity. because I am a gear head, I at some point found myself with a 22hp Kawasaki liquid cooled V-twin. Thought I would use it on one of my garden tractor resto-mod projects.

When I fired it up on the bench, I was shocked to HEAR how quiet that engine was, and how vibration free it was. After I researched the model number, I found the engine to have a 20 amp charging circuit. A 20 amp charging circuit is slightly less common, but most have by default, a 15 amp system. I found that the engine was actually able to deliver 20 amps of charging already by 1/3 throttle. (I used an Amp/clamp meter on the battery feed, but then loaded the battery incrementally with a battery load tester).

Now personally, 20 amps is 20 amps..... I could live with that real easy. But this dream gets better. As I was researching the engine, I came across a manufacturer that used or uses that engine for all in one, self contained "carpet cleaning" systems that get mounted inside vans. It's primary purpose is to pump/circulate water via tubes dragged into the house and connected to the working end of the machines.

Its SECOND purpose is the one I got real interested in, because they also self create the HOT WATER with that same engines exhaust gas via purpose built heat exchanger. Now I chased the thought of scavenging heat from a small engines exhaust gasses some years ago in another forum, and the guys who had the mind to do the math always told me it could not be done.... and I left it at that for a while.

In later years, I started to wonder why a person couldn't create/use a small catalytic converter on the small engine to create more heat from teh unburned fuel no different than your car..... And years later than that, I read articles where BMW had actually used catalytic converters under their test cars to create pressurized STEAM to actually assist the engine via small turbine. I know, crazy stuff, but hey......

Now, I dont think the carpet machines use platinum in a cat at all. I think their engines are just plain large enough to create the btu they need to make the hot water.... but its not just warm water according to them.... It actually has to be controlled so it does not produce steam.

So, what is the bottom line ? These days, you can find quite a few VERTICAL shaft, V-Twin 14+ HP engines for CHEAP from crapped out zero turn lawn mowers (Horizontals always cost a lot more). A vertical shaft V-Twin is a bit more compact than the horizontal in some cases.

They have electric start, they have 15 to 20 amp charging circuits. They have HOT enough exhaust to create steam via heat exchanger.

To me, this sounds a LOT better than the Honda EU2000 that I DID buy just to save time and have power when I need it. I traded that particular engine away for something else along the way, but I wish now I would have at least hung it on the receiver hitch while running so I could make a decibel level and vibration comparison...... While my on-board underhood mounted honda is certainly quiet and fairly smooth, there is a good chance that the V-twin could have matched it.

The good news is, I'm not dead yet (My wife keeps reminding me of that when I sluff off not taking on another dream), I still trade tractors and engines.... I have room to do it..... and the Honda wouldn't really go to waste just because I pulled it out of the truck.

I'm done now....

 

[highdesertranger]

grummy as far the water heater off the exhaust on small engines, been done for years. you have to search for wet suit heater for gold dredgers. many homebuilt systems. strapp mining had a store bought one for b&s and Honda engines. although out of production for awhile I heard though the grape vine that they are back. as far as building your own generator, while it can be done I believe you are better off just getting a store bought one. highdesertranger

 

[RogueRV2]

If in Phoenix, and can't afford one of those really nice Honda's, this can do the job and only for $150 bucks. I have two, one for parts if need be, to back up the solar system. I suspect that they will last for years and years. If one is living with a solar system, how often do they need 1000 watts? From time to time, I find these for sale even up in a remote part of Montana at this price.

http://phoenix.craigslist.org/evl/tls/4838454202.html

 

[akrvbob]

Before the current Inverter Generators from Honda, they made a really great series of Generators that were 500-650 watts. You can commonly find them for a few hundred dollars and they have the typical great Honda quality and reliability and parts are still commonly available. If money were tight, that's what I'd buy. A freind got one off ebay for $150, rebuilt the carb and it's the perfect generator.
Bob

 

[RogueRV2]

....And If one is concerned about long term reliability, these old Honda generators, by the fact that they still run good after all these decades, have proven to be very reliable. There are of course pros and cons to consider, yet as a survivalist-guy, these are proven to be reliable, are ruggedly built, simple enough for anyone to work on, quiet, compact, and inexpensive enough that one can afford a spare that can also be used to generate the extra power if needed. I also believe they are more resistant to EMP. The Honda 2000i gen-verter type does produce 'cleaner' power, and is about twice as efficient, however, with the huge difference in price, one can purchase the fuel to run the old 1985 Honda EM500. At $2 bucks a gallon, if it requires $25 a month in fuel to power my MH each month, the difference in price means that the first two years of fuel is essentially FREE. Or I can by a complete new 200 watt solar system, including batteries. How often will one have to have 2000 watts of power? I would seldom use more than a few hundred watts at any given time. If I needed some thing to run a skill saw or other power tools, I'd get a cheap used, noisy, and big 3000+ watt generator. The skill saw is my most useful power tool. A Honda 2000i will not run even the lightest weight 1/2hp skill saw, and I doubt it would power, but the smallest window mounted 5,000btu A/C unit. Of course, if you've got the bucks, go for it!

 

[CityWoman]

Came across this old thread while doing a search.  Interesting how everyone assumed the person quoted was a man.

The quote comes from a blog by Sharon, AKA TinyCamper, in a post she wrote about her sister Gail's camper van conversion.  It's a very nice article which shares a lot of details on how her sis converted a van very simply, attractively, and affordably.  It became so popular and got so many questions that Sharon made a permanent link to it from her home page. Although Sharon hasn't updated her blog in over a year, I have that article bookmarked and refer to it for ideas as I am doing my research.

The sentence quoted by the OP here was written by Gail, AKA Happy Camper, while she was answering questions in the comments.  Gail wasn't living in her van F/T, but apparently camped and traveled quite a bit in it.  I don't know if she is still using the van; I recall she was trying to sell it at some point.  

Scroll down to Gail/Happy Camper's comment of March 7, 2014 over at Cargo Van to Camper Van to see the quote.  I recommend the article, too, if you want to keep things simple.