Best way to charge batteries with small engine/alternator

[crazycal]

Originally Posted by Kubla

Car alternators use a wound rotar in which the limiting factor is cooling so the output is limited so they don't overheat and they are actually too small for their rated output because car engineers realize that they are going to run 95% of the time at less than half their rating so they save weight by making it smaller. If you look at a semi truck alternator of the same rating, it will be 4 times the size because it runs at about 90 % of its rated capacity when the trucks lights are on so get a good honda generator and a good 13.6 volt inverter/power supply for a motor home, my bluebird wanderlodge has a 76 amp inverter for 12 volt power, it also charges the batteries when it operates

That may be but it is an easy and cheap(easy and cheap are very important to me) way to charge batteries.

[nat_ster]

I like where this thread is going.

A small diesel powered Air conditioning system would be a god send for many off grid skoolies.

Nat

[Vlad]

Let't talk about cost effectiveness.

I believe that cost effectiveness must be a key factor in most projects (unless it is an educational or fun project).

You can build great powerful battery charger almost for free or almost for free.

You will need:
1. Small (4-5 HP) engine. It can be a lawn mower engine, or ex pressure washer, or ex generator engine. You can find one for $ 50 or even find it for free(just dig dipper in your garage ).

2. Car alternator. Again you can find one for $20 or for free....

3. A bunch of 2x4, some plywood, couple angle iron pieces, some foam, etc

4. One weekend of fun and you have your charger...

Now let's see how you are going to use it:

1. You use it occasionally for a few hours over weekend.

2. You use it 8-10 hours a day every day.

#1 is a great use and there is no point to spend hundreds of dollars to get more efficient unit

#2 is a financial disaster.

Here is a fuel consumption number for a small yanmar diesel engine L70

L70 takes 270 gram of fuel per KW/H.

You use 50% efficient (yes this car alternators is a waste of energy) car alternator.

1. 50% efficiency: 12Vx100amp=1200 Watt. But you use 1200 Watt x 100/50 =2400 Watt from engine.

2. 70% efficiency: 12Vx100amp=1200 Watt. But you use 1200 Watt x 100/70 =1700 Watt from engine.

1. 50% efficiency 2.4 Kw x 270 gram x 10 hours = about 6.5 litres

1. 70% efficiency 1.7 Kw x 270 gram x 10 hours = about 4.5 litres

So, you are going to pay for extra 2 litres of fuel every day you use it.

Now I took efficient Yanmar diesel engine and 2 different alternators.

If you compare gas lawnmower engine with 50% efficient alternator to Yanmar diesel engine with 70% efficient PMA (permanent magnet alternator) you will be surprised how much more cheap or even free unit will cost you on fuel.

My guess top number is going to be 10-12 litres of gas instead of 4.5 litres of diesel

This is very rough comparison but gives me idea what way to go.

[Vlad]

Originally Posted by nat_ster

I like where this thread is going.

A small diesel powered Air conditioning system would be a god send for many off grid skoolies.

Nat

Diesel engines become most efficient when loaded 3/4 to a full load. This is why I want to load up my power unit with charging batteries and A/C compressor at the same time. When batteries are full I will shut it down and use them to power electric A/C. As soon as batteries are low (safe low) cycle will start over. Even if your batteries are not a monsters you can still use this idea but you will cycle more often. I do plan to start thread for lithium batteries. I do have some great ideas to share....

If I don't need A/C but batteries are low the power unit will charge batteries at higher rate(safe for batteries) but A/C will be disconnected by it's clutch.

BTW you can use heating oil, WVO , used engine oil, used transmission oil, used hydraulic oil to power your small diesel engie. In this case you will get your power virtually for free.

[superdave]

www.mikeswindmillshop/com i have been using his wind gen. for 4 years now, would love to take his class. he makes a generator to hook up to a small motor for charging. great people check it out. http://www.mikeswindmillshop.com/pro...ick-charge-pma

[crazycal]

Originally Posted by superdave

www.mikeswindmillshop/com i have been using his wind gen. for 4 years now, would love to take his class. he makes a generator to hook up to a small motor for charging. great people check it out. Quick Charge PMA - Mike's Windmill Shop

Your first link doesn't work.

[Vlad]

Here is another looks like good PMA.

http://www.windbluepower.com/Wind_Bl...r_p/dc-500.htm

It is specifically designed to run with engine. It's power curve looks very promising...

Also they sell parts to make your own PMA. If you have an old one and some time/skills it will save couple $$:

http://www.windbluepower.com/category_s/27.htm

I contacted them and here is our conversation:

--------------------------------------------------------------
Me:

Hi, I am looking for a PMA which I want to connect to 12 HP 2 cylinder diesel engine.

My goal is to charge 10 KW/H lithium battery bank in 6-10 hours. I am thinking about using 24 V system.

The PMA must be capable of charging 24 V battery bank at 50-80 amp (charging voltage will be 30+ volt).

I will use pulley/belt system to connect PMA to engine, so RPM is not a problem. Also engine RPM will be electronically monitored and controlled according to voltage/ amperage.

I found info about your DC-500 Motor Driven Permanent Magnet Alternator

Here are 2 questions:

1. Is your PMA DC-500 capable to provide 50-80 amp of charging for 24 V battery bank? I can set any RPM you suggest.

2. If for whatever reason I need more amps can I connect 2 PMS's to get more amps(both PMS will be on the same output shaft)?
-------------------------------------------------------------

Here is an answer:

-------------------------------------------------------------
Hello,

Yes, our DC-500 will produce 60 amps at around 2,000 rpm. You can connect 2 PMA’s together but I don’t think it will be necessary in your situation.

Thank you for your interest in WindBlue Power and please do not hesitate to contact me if you have any other questions.

Donna
--------------------------------------------------------------

I tried to contact Missouri Wind and Solar before. I asked simple question about their PMA power output and their answer was just plain and stupid.... it looks like all info they posted on their website is made up......

[nat_ster]

The guy at Missouri Wind and Solar is a drug addict.

Look him up on you tube. A few years ago there was a ton of f$cked up videos on there.

No way I would send them money.

Nat

[Vlad]

I was thinking the same about the owner of Missouri Wind and Solar...... Youtube is full of negative videos about him and his products....

[Vlad]

I was thinking about using PMA as alternator for producing 12V or 24V. The problems are a few with PMA:

1. Most PMAs are modified car alternators.

2. I couldn't find a good professionally designed PMA under $500 USD

3. People who build PMAs make performance claims without any proof, making this claims just a blah blah blah. As a matter of fact most power, voltage, rpm etc claims are pure BS in most cases.

4. Even considering all above and finding some "good" ones the power output is very limited.

5. PMAs produce unregulated power and in order to keep power in usable and efficient range (volts, amps) engine speed must be controlled very closely.


So, after some research I decided to find a good reliable high perfomance high efficiency car alternator. I was lucky enough and found this guy:

American Power Systems 55i 200ACT 28J Alternator T33418 | eBay

It is made by American Power Systems and the model is 55i-200ACT-28J

Here some specs of this great unit:

http://www.americanpowerinc.com/imag...20shaft%20.pdf

The APS Brute series alternator delivers 6.3 kW of clean, regulated DC power in a ruggedly built chassis designed to meet the rigors of military use. This alternator is designed to meet military standards and multiple units can be paralleled for additional power.

ELECTRICAL SPECIFICATIONS:

Rated Power: 6.3 kW

Rated Voltage: 28 VDC nominal

Rotation: CW

Output Current: 225a nominal

Charge voltage setpoint: 28.2 V

Recommeded Pulley Ratio: 2:5

Output at engine idle see curve

Plug Interface: Direct OE compatible

++++++++++++++++++++++++++++++++++++

Love this one:

Efficiency: 87% typical.

Not bad compare to 55% efficiency of a regular car alternator.
++++++++++++++++++++++++++++++++++++

MECHANICAL SPECIFICATIONS:

Diameter: 7.5”.

Mount: Wide Pad or J180

Weight: 35 lbs.

Cooling: External fans

And after all I paid $ 400 USD for it which is not bad at all for a new alternator like this....

[Vlad]

I was thinking about water heater for our skoolie when time comes to install one and found that even 6 gall units consider to be a luxury water heater. 6 gall is not much at all.

Then, since my small diesel engine for battery charging/AC unit is water cooled I can use hot coolant to heat up water for free.... and I mean a lot of hot water.....

I will use heat exchanger and probably Propylene Glycol coolant to be more safe.

This is another reason to build a good unit and use water cooled engine to charge batteries.

[Vlad]

I plan to have full size washer and dryer. Dryer is a big energy hog. While you are hooked up it is OK you can use shore power, but what to do when you are not?

Why not to use a small radiator connected to cooling system to supply heat to dryer? Instead of energising electric heat element energise solenoid to open coolant circuit to dryer radiator... I think this is possible.....

[taskswap]

This is a common project for wood boiler folks (which, in case it wasn't obvious from other posts, I am one). It's not terribly difficult. Usually you use something along the size of a standard oil cooler - whatever fits in the dryer - and you mount it in the internal air duct the dryer has to pass air over its own heating element.

Couple challenges: when doing this you sometimes need to expand the duct in back with some sheet metal, because it's not very big. Electrical elements are very small compared to water-to-air exchangers. Not a biggie in a house, but in a bus you might need to be clever about space usage.

Also, this works best with older units, the ones still controlled by relays. They're pretty dumb and have no idea you've cut the heating element circuit. Some new units are computer-controlled like cars and shut down when this happens. Mostly the high-end LG's and such - probably not what you'd be converting, just pointing it out.

Finally, be prepared for the cycle to take a lot longer. Electrical elements can transfer heat quickly. Water-to-air units can transfer a lot of heat, but it takes more time to do it in small units. Unless you want to install a giant radiator in there...

Note: it still takes several amps to run the drum motor. Wet clothes are heavy and hard to move.

[Vlad]

Originally Posted by taskswap

This is a common project for wood boiler folks (which, in case it wasn't obvious from other posts, I am one). It's not terribly difficult. Usually you use something along the size of a standard oil cooler - whatever fits in the dryer - and you mount it in the internal air duct the dryer has to pass air over its own heating element.

Couple challenges: when doing this you sometimes need to expand the duct in back with some sheet metal, because it's not very big. Electrical elements are very small compared to water-to-air exchangers. Not a biggie in a house, but in a bus you might need to be clever about space usage.

Also, this works best with older units, the ones still controlled by relays. They're pretty dumb and have no idea you've cut the heating element circuit. Some new units are computer-controlled like cars and shut down when this happens. Mostly the high-end LG's and such - probably not what you'd be converting, just pointing it out.

Finally, be prepared for the cycle to take a lot longer. Electrical elements can transfer heat quickly. Water-to-air units can transfer a lot of heat, but it takes more time to do it in small units. Unless you want to install a giant radiator in there...

Note: it still takes several amps to run the drum motor. Wet clothes are heavy and hard to move.

After researching dryers for some time I was surprised. In house you choose gas or electric depends what power you have. Also you can get electric ventless unit.

It is clear how gas and electric units work. Ventless are not so clear for many people. Ventless units use cold water to condense moisture extracted by hot air from clothes, hence you don't need to blow it outside.

I prefer gas dryer in house because it is much more powerful, cheaper to operate. It is a super efficient because all heat including exhaust goes though clothes.

Now let's see what is used in RV and what is practical to use in RV application.

1.Most RV dryers are ventless. Ventless unit is horrible by it's nature. It wastes tons of fresh water in dry cycle. You simply dump warmed up clean water in rv park sewer system which in most cases a septic tank/field. Also this units are electric and require a lot of amps to heat up air.

2.The rest of dryers used in RV are just vented electric units.

You can also buy a compact electric vented unit and use it in RV.

The strange thing is I couldn't find compact (24"x24") gas dryer. This would be ideal for RV application.

I also noticed most if not all dryers that come gas or electric use bottom space for gas furnace and rear for electric heating element. I started to think to combine gas and electric in one unit. When shore power is available use it when not use propane. This can be done. The problem is I can't find 24"x24" gas dryer...... GGGRRRRR.

But yesterday I got another idea why not to get 24"x24" electric dryer (tons of them cheap and even cheaper used ones), add water/air radiator and this is all....

Here are benefits:

1. available size (24"x24") unit on market
2. cheap to buy new and even cheaper used ones. Can be mech or digitally controlled.
3. can be used as electric when shore power is available
4. easy to add water/air radiator. There is a ton of space on the bottom under the drum
5. free very hot water. Diesel engine run almost at boiling temperatures giving a lot of very hot water.

Now here is why gas unit is more powerful:

Typical house unit has 3 KW heating element. 1 KW =3412 BTU, 3 KW =10000 BTU.

My typical house gas dryer is 20000 BTU which is 2 tmes more.

Even a small water/air radiator can easily give 20000 BTU.

[nat_ster]

Here in Canada, all residential dryers are electric.

Only commercial dryers are gas.

A good old wash board and cloths line take up much less space, and energy.

Nat

[Vlad]

Originally Posted by nat_ster

Here in Canada, all residential dryers are electric.

Only commercial dryers are gas.

A good old wash board and cloths line take up much less space, and energy.

Nat

I bought our gas dryer which is whirlpool residential unit about 5-6 year ago locally in Canada. It works great since. I could buy electric one but loved gas idea.

We have a lot of them in HD:

SEARCH - gas+dryer - Home Improvement, Home Renovation, Tools, & Hardware | Home Depot Canada

[nat_ster]

Originally Posted by Vlad

I bought our gas dryer which is whirlpool residential unit about 5-6 year ago locally in Canada. It works great since. I could buy electric one but loved gas idea.

We have a lot of them in HD:

SEARCH - gas+dryer - Home Improvement, Home Renovation, Tools, & Hardware | Home Depot Canada

My bad, around here I can't get them without special ordering.

Anyone convert one to propane?

Nat

[taskswap]

I had a neighbor who did that in the last town I lived in. They didn't have piping for natural gas but all the dryers were sold for it. Home Depot sold him the dryer and the conversion kit. I remember it clearly because he was bitching about it all weekend - it was like $80 for basically a brass fitting with a different-sized orifice and a couple of bits to install it. It was like the most overpriced thing I've ever seen. Installed in like 5 minutes.

Vlad, I'm curious what "ventless" unit you're talking about. I actually bought one about 10 years ago when I lived in a house that had the laundry in the basement. We were looking for an option to do small loads without having to truck the laundry up and down 2 flights of stairs all the time. I bought it because I didn't want to have to install 50A service and dryer venting to the closet I put it in - I pulled the water/drainage from a bathroom that shared a wall with the unit.

Anyway, long story short, this unit definitely did NOT use cold water to condense the dryer exhaust. I would have known because I had a boost pump in the basement that was on its way out and everybody in the house knew when a faucet was on. Instead, it used a small A/C condenser built into the back. You could even hear it kick on.

I still hate these units - I would never recommend one after my own experience with it. But it didn't waste water - at least not that model.

[Vlad]

Originally Posted by taskswap

I had a neighbor who did that in the last town I lived in. They didn't have piping for natural gas but all the dryers were sold for it. Home Depot sold him the dryer and the conversion kit. I remember it clearly because he was bitching about it all weekend - it was like $80 for basically a brass fitting with a different-sized orifice and a couple of bits to install it. It was like the most overpriced thing I've ever seen. Installed in like 5 minutes.

Vlad, I'm curious what "ventless" unit you're talking about. I actually bought one about 10 years ago when I lived in a house that had the laundry in the basement. We were looking for an option to do small loads without having to truck the laundry up and down 2 flights of stairs all the time. I bought it because I didn't want to have to install 50A service and dryer venting to the closet I put it in - I pulled the water/drainage from a bathroom that shared a wall with the unit.

Anyway, long story short, this unit definitely did NOT use cold water to condense the dryer exhaust. I would have known because I had a boost pump in the basement that was on its way out and everybody in the house knew when a faucet was on. Instead, it used a small A/C condenser built into the back. You could even hear it kick on.

I still hate these units - I would never recommend one after my own experience with it. But it didn't waste water - at least not that model.

You are right, to make gas appliance designed for natural gas work on propane you need to replace jets with smaller size. Propane has a higher energy density. The same way natural gas boilers, stoves, ranges, heaters can be converted to run on propane.

Here is a gas/propane chart:

http://www.joppaglass.com/burner/lowp_chrt.html

Here is a good explanation how ventless dryers work:

How Do Ventless Clothes Dryers Work?

Some small dryers can be vented indoor just by installing lint trap. This dryers will increase moisture level indoor......

[jazty]

Originally Posted by nat_ster

Here in Canada, all residential dryers are electric.

Only commercial dryers are gas.

A good old wash board and cloths line take up much less space, and energy.

Nat

Around here I'd say that gas is the more popular choice than electric when purchasing a new dryer. It's rare to find a house built in the past 30 years that doesn't have a gas hook-up. Even the small communities (400+ people) around here have access to natural gas.

+1 for the clothesline. I'd like to see a number amount of how much energy is used nationally to dry clothes in a year.. I bet it isn't pretty. Especially when 80% of the year you can dry clothes for free outside!