Best way to charge batteries with small engine/alternator

[Vlad]

Let's discuss the the best, most efficient, cheapest way to charge batteries using engine (gas, diesel, propane). Solar, wind water mills camp power etc are all great options but let's see what we can get from engines.


Here are some options:

1. Engine---Gnerator(110v/220v)---Battery charger---Battery

2. Engine---Inverter(110v/220v)---Battery charger---Battery

3. Engine---Alternator(12v/24v)---Battery

#1 and #2 ave well discovered and discussed all over, but how about charging batteries using alternator?

Here is the math 12V system @ 100 Amp will only need 12 x 100=1200 Watt. So I personally think that run you huge V8 or huge diesel and use 2 HP out of it is not the best economical way to charge your batteries. The small engine can change this picture.

I was reading about some small diesel engines and found that small single cylinder Yanmar diesel L70 uses only 270 g/kW-hr which is 2 times better than Honda EU inverters.

This engine is rated for Net Continuous 5.8hp [4.3kW]/3600rpm. We only need half of this power to get over 100 Amp charge. In this case we can slow down engine to get better service life, better fuel economy and less noise.

Here I can see 3 areas we need to discuss:

1. Engine Gas or Diesel or Propane.... size, model price etc

2. Alternator 12V, 24V, output, model, price etc

3. Noise reduction, sound dampening. Any engine must be as quiet as possible. Engine enclosure construction, materials, sound dampening materials, etc

[somewhereinusa]

I haven't gotten it built yet, but have all the pieces.
With the bad luck I've had with Onan generators I have a couple of perfectly good Kubota diesels laying around
with relatively low hours. I have a friend in the automotive alternator rebuilding business that built me a 320A 12v
alternator, it uses the same mount as a semi, (also same mount as my bus) just a bit longer out the back. I already
have an inverter and house battery bank. That will be enough amperage to run everything I have. I was originally going to
mount the generator in the engine compartment right in front of the house battery bank. My plans have changed a bit I decided
not to use the factory air due to the fact you have to run the engine. The area where the factory condenser was is big enough for
the generator and is just on the other side of the engine. I use 00 cable for all of my house battery cables and 5 feet is well
within the specs for cable length. Exhaust will run up through the engine compartment using a venturi pipe out through the roof.
I've also thought about adding a second smaller alternator 120A or so to the system to charge the start batteries, but that's probably
too much redundancy. I will use the start batteries to start the generator. I already have a way to connect the two battery systems
together in an emergency.
At the present time I have a 1000w inverter. On the plus side putting this type of system is when one part goes bad you don't have
to replace the whole darn thing. I'm sure someone is going to jump in here and tell me how inefficient the set up is, or that it won't work. I'm not all that concerned about it. The last thing you want to tell me is that it won't work.
about it. I have the parts

[Vlad]

Originally Posted by somewhereinusa

...... I'm sure someone is going to jump in here and tell me how inefficient the set up is, or that it won't work. I'm not all that concerned about it. The last thing you want to tell me is that it won't work.
about it. I have the parts

When you look at convenient system engine/ generator/ charger/battery. There are 4 steps and each one has loses. Alternator system has only 3 steps engine/alternator/battery.

If we compare apples to apples we will see that in both cases engines are the same, generator and alternator are almost the same devices. Alternator is actually 3 phase generator.

This system can be very universal when it comes to components. It can be expensive if you buy all new top top or it can cost you next to nothing because we all have stuff laying around.

My goal is to build efficient, easy to build, off shelf parts etc system. Everyone can choose what engine and alternator to choose.

Also #3 in original post: "Noise reduction, sound dampening. Any engine must be as quiet as possible. Engine enclosure construction, materials, sound dampening materials, etc" can be very helpful because you can use it to make cheap genset and have happy neighbors...

[Vlad]

I can see one of the biggest challenges is noise. If somebody have some experience please share. I found some good info here some links:

http://www.rv.net/forum/index.cfm/fusea ... m#20415669

http://www.dieselserviceandsupply.com/S ... ators.aspx

http://www.earsc.com/pdfs/StandbyGenera ... ePaper.pdf

https://www.youtube.com/watch?v=Ytx0M8fDpGo

http://home.comcast.net/~prestondrake/S ... lencer.htm

http://www.acoustiblok.com/PDF/resident ... system.pdf

[Vlad]

I have some experience with Arduino board and want to use it to control battery charge and engine side: RPM, temperature, oil alarm, start, stop etc.
I know alternator charge depends on exciter coil voltage/amperage. We can control charging voltage/ amperage using Arduino. This will give us very accurate charging profile especially if we decide to use Lithium batteries. Also we can have custom charging levels like quick charge or just slow/eco...which can be used when noise is an issue.

Off topic: I built torque converter lock for my Ram truck using Arduino. It cost me under $10 and works exactly the way I want.

[Vlad]

I found very interesting info about permanent magnet generators PMG or PMA. They mast be much mo efficient compare to regular car alternator. Some of them are converted car alternators like Delco Modified alternator and some are specifically designed to be PMG from ground up. You can find both on eBay.

I do like this ones:
http://store.mwands.com/permanent-magne ... s-pma/pmg/

They do cost a bit more but considering zero maintenance down the road I think this can be a good deal. Also they sell chargers and other things to make generator/solar/battery/grid connections easier.
I sent them email with few questions let's see what they tell us

As an engine option I am thinking about this eBay deal:

http://www.ebay.com/itm/Yanmar-L70AE-L7 ... 338f2544ff

This looks like a good deal.

One open question is how to make it as silent as possible. Please share your info and experience. Together we will find the best way to overcome most of the problems.

[somewhereinusa]

Just a few thoughts from some quick look ups.

Those brushless alternators are pretty low amp, the most expensive one from that link looks to be about 125 A at 12V, that's too low, at least for my installation where I will at times be using the setup as a power source, not to just charge batteries. And, they are expensive. The alternators that are used in modern over the road trucks last for thousands of miles with no maintenance. My 320A alternator with brushes cost about the same but produces 3840 watts at 12V. At the rate I will be using mine that translates to years. I probably won't live that long besides, I can change a lot of brushes for that kind of money.

It looks like your 125A is going to take about 2HP witch is well within the range of that little diesel, that seems to be about 5 HP.

They have a 24V starter, tapered output shaft, preheaters, air filter. They are complete based on external inspection, rotate 360 degrees, and have compression. Although these are used engines, they appear to be low hour and in decent condition We don't know internal condition or if they run

Anything air cooled is going to much noisier than water cooled. When you build an enclosure the air cooled will need much more air circulation to keep it cool thus, letting more "noise" out. Air cooled WILL be a much easier installation.

[Vlad]

Originally Posted by somewhereinusa

Just a few thoughts from some quick look ups.

Those brushless alternators are pretty low amp, the most expensive one from that link looks to be about 125 A at 12V, that's too low, at least for my installation where I will at times be using the setup as a power source, not to just charge batteries. And, they are expensive. The alternators that are used in modern over the road trucks last for thousands of miles with no maintenance. My 320A alternator with brushes cost about the same but produces 3840 watts at 12V. At the rate I will be using mine that translates to years. I probably won't live that long besides, I can change a lot of brushes for that kind of money.

It looks like your 125A is going to take about 2HP witch is well within the range of that little diesel, that seems to be about 5 HP.

Anything air cooled is going to much noisier than water cooled. When you build an enclosure the air cooled will need much more air circulation to keep it cool thus, letting more "noise" out. Air cooled WILL be a much easier installation.

The problem with car alternators is not maintenance. They do last 100K+ miles in car application and change brushes is not a big deal. The problem is they are very low efficient. They are in 50-60% range. I will try to get more details about PMG and share it. Also Freedom II Hydro PMG dual rotor produces 2800 watt which is not bad at all it is more like 120A @ 24V.

The noise is an issue This is why I want to run it @ 1800-2000 RPM max. I might try to find 10HP Yanmar diesel and keep RPM even lower. There is also an option to add AC compressor and get a very efficient AC.

[bansil]

Years ago we had a lawn mower engine with a pully on shaft, that had a 12v alt mounted to it with a belt...
We used it to keep drag car batteries charged between rounds , we couldn't afford a gennie in high school

[Vlad]

Does somebody have experience with Permanent magnet generators/alternators (PMA PMG)? They suppose to be more efficient and require no maintenance. It all sounds great but would be nice to hear and discuss REAL EXPERIENCE. It doesn't have to be exactly engine/generator/alternator. If you have any PMG PMA experience wind turbine or hydro please share..... We need more info and input.

I tried contacting Missouri Wind and Solar company but it looks like they have no info about their own product... This looks very strange. They claim 2800 watt power but after getting rpm/ power output I can only see 1100 watt @ 780 rpm. This is just a false claim unless I get better explanation how they got 2800 watt.... It looks like a bunch of ignorant clowns are trying to make a power revolution......

[bansil]

Originally Posted by Vlad

........... It looks like a bunch of ignorant clowns are trying to make a power revolution......

I see what you did there

Bansil approves

[Vlad]

Originally Posted by bansil

I see what you did there

Bansil approves

This is a very strange situation. I wanted to see a Power/ RPM data but I only could find meaningless wind speed/power graph . I contacted this company and asked this very basic simple question. But guess what?.... no answer. OK no answer is nothing for me I called them and asked the same. They told me that all they have is wind/power graph. After some pressure they sent me power/rpm table. The maximum value in the table was 1108 Watt which is much much lower than 1500 Watt and even lower than 2800 Watt they claim.

How do you call people who designed and built from scratch a generator and they don't even have power/rpm data? I call this people clowns... Also they say their generator is revolutionary great unit this is why I called them "clowns are trying to make a power revolution....."

I would buy their generator and I don't mind to pay $500+ if it guarantee can produce at least 1500 Watt and be efficient.

[opus]

[Redbear]

Running the small diesel and generating DC directly is a solid idea. You may have some difficulty reducing the RPM, though, depending on how the engine is controlled.

3600 RPM to me sounds like it was designed for AC generator service:
60 Hz = 60 R/second x 60 seconds = 3600 RPM.
If an electronic speed controller operates based on the frequency it sees, it may take some engineering to slow the RPM.

If the RPM control is mechanical, then an "Appalachian American" solution should suffice.

[Vlad]

Originally Posted by Redbear

Running the small diesel and generating DC directly is a solid idea. You may have some difficulty reducing the RPM, though, depending on how the engine is controlled.

3600 RPM to me sounds like it was designed for AC generator service:
60 Hz = 60 R/second x 60 seconds = 3600 RPM.
If an electronic speed controller operates based on the frequency it sees, it may take some engineering to slow the RPM.

If the RPM control is mechanical, then an "Appalachian American" solution should suffice.

This is the point of getting DC and charge batteries directly. Most if not all DC alternators are 3 phase AC alternators, then AC is converted to DC via 3 pairs of diodes and rectified to get charging voltage 14... or exciter coil is controlling output voltage. It doesn't matter what RPM the engine is running.

The problem (may be not a problem at all) is car alternators are low efficient by their nature. This is why I was thinking of using wind turbine PMA/PMG.

[Vlad]

I got a diesel engine from semi APU (axillary power unit). It used to be a Rig Master APU. My plan is to use engine, ac compressor and add 24V alternator to charge batteries

The engine is 2 cylinder liquid cooled Perkins /CAT





The engine is rusty but hardly used. I bypassed controls and started it up. It runs very good.

I am thinking about using bus cooling system and completely enclose the engine to help to make it as silent as possible.

The engine is 500cc 2 cylinder 12HP @ 2800 RPM I am thinking about lowering RPM below 2000 RPM (to reduce noise level) but I will lose some power. I might be end up adding a turbocharger....

[charles_m]

Looks like you've already got something worked out, but I love these:

https://www.youtube.com/watch?v=ntdCHjxh3Sc

If I was building a cabin I'd go for a setup like this. I think they are handsome and brutally simple. Quite efficient and people claim 100,000hrs of service life if maintained properly which is crazy. Then again, the model I like tops out at about 700 rpm and is built like a tank.

[Vlad]

Originally Posted by charles_m

Looks like you've already got something worked out, but I love these:

If I was building a cabin I'd go for a setup like this. I think they are handsome and brutally simple. Quite efficient and people claim 100,000hrs of service life if maintained properly which is crazy. Then again, the model I like tops out at about 700 rpm and is built like a tank.

The key word in your post is "CABIN"....

If I were to use it stationary for sure, but in mobile application it is too bulky, too heavy and not enough power.

My plan is to use AC compressor and alternator at the same time. It will look like this:

1. The power unit will start in the morning or when batteries are too low.

2. Charging system will start will start.

3. If AC is required, AC compressor will start/ stop.

4. When batteries are full power unit will stop.

5. Electric AC will kick in using batteries/inverter.

I do plan to have 10-12 KW/H lithium battery pack.

6. I will make sure batteries are full in the evening and they will provide power during night time.

This is the plan. I am busy with my bus conversion but will slowly work on this power unit project.


BTW I found this great article about alternators efficiency:

http://delcoremy.com/documents/high-...ite-paper.aspx


Very interesting and very fundamental material to read.

[crazycal]

I'm too tired to read this thread,

but go here====> https://theepicenter.com/cgi/order.c....html&cart_id=



and scroll down to this.

BUILD YOUR OWN GENERATOR - DIY Parts & Accessories

[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