DC-only generator/chargers

[John61CT]

Looking for a DC-only genset, to be used for charging battery banks only, supplementing solar. Not interested in AC usage at all, want to maximize efficiency, so avoiding inverter-based charging.

Would prefer an off-the-shelf unit with direct drive, but otherwise perhaps the power head is just HO automotive alternators?

Ideally low-rpm heavy-duty engine designed for quiet and long-term reliability like the old Listers, but smaller and lighter for mobile use.

If the engine can't be robust at a reasonable cost/weight, it must be capable of being made quiet.

Any suggestions welcome.

 

[Optimistic Paranoid]

I've never seen what you are asking for, I doubt if there is much demand for such an item.  You would probably have to build your own from an alternator and lawn mower engine.

 

[highdesertranger]

those used to be more common.  in fact I sold one last year as part of my downsizing.  I sold it to a car restorer,  he restored it an now displays it with his old cars.  here's some pics,






sorry this one is a little blurry,  notice the amp gauge next to it is a dial you can crank up or down the output.





the guy that bought it said that after he restored it worked like a champ.   highdesertranger

 

[highdesertranger]

I don't know the exact history. I remember grandpa using it to jump start the Lima bean harvester. it very well could have been surplus grandpa had a lot of surplus. highdesertranger

 

[SternWake]

Looks like the linked retail options are significantly more expensive than a honda 1000 new.

Saw this linked in one of those links:

http://theepicenter.com/blog/generator-lawn-mower-vertical/

I think If I wanted a portable generator I'd get the Honda eu1000i and use it to power my Meanwell power supply at 40 amps.  

I figure they engineered it well for minimal noise and fuel usage.

NOw if i had the parts laying around to make a dc generator that is a different story.

 

[ArtW]

Don't most gensets come with 12 or 110 outlets? The few I have seen seem to have them

 

[SternWake]

I think the 12vDC output on a honda is only 8 amps max, and is unregulated. With enough time on a depleted battery, I believe it will get upto and perhaps over 16 volts.

Don;t know about other gensets

 

[Mobilesport]

Looks like the linked retail options are significantly more expensive than a honda 1000 new.

Saw this linked in one of those links:

http://theepicenter.com/blog/generator-lawn-mower-vertical/

I think If I wanted a portable generator I'd get the Honda eu1000i and use it to power my Meanwell power supply at 40 amps.  

I figure they engineered it well for minimal noise and fuel usage.

NOw if i had the parts laying around to make a dc generator that is a different story.

I was looking into getting a Honda 1000i but after looking at the specs the honda 2000i is quieter and only takes up a little more space.
The specs are kinda decieving because they say something like
Honda 1000  is  63db @1/4 load
Honda 2000 is  63db @ 1/4 load 
The decieving part is 
Honda 1000 is 250 watts @ 1/4 load
Honda 2000 is 500 watts @ 1/4 load
If you run a 5000 btu ac with the honda 1000 it takes more then a 1/4 load to
run it which would not be in ecomode so louder.

If you run a 5000 btu ac with a honda 2000i it would run on 1/4 of its load ( 1/4 of its
load is 500 watts (eco throttle ) quiet

I'm just using the air conditioner as a example to show the 2000 is quieter

 

[jimindenver]

I use to have a 50a car starter made by Generac I believe. worked great but loud. I'll take the mini charger on the mini inverter generator any day. The purr is worth the inefficiency if it is to be worried about.

 

[jimindenver]

MS, I'm not a Honda fan but those numbers look off by 10 db.

 

[eDJ_]

One of my Uncles built a metal frame and used a horizontal gasoline motor mounted in it with a large Alternator from a Truck connected to it.  I think it was directly driven.   I don't remember a battery being part of it though.

I think it was coupled with one of these.

The red part is a hard rubber material to absorb the shock pulses.

When installed it looks like this

I don't remember seeing him use it, but he built it for a Camp Cottage he purchased at the edge of a lake.
He had acquired several 55 gallon blue plastic rain barrels for cistern water supply,  a couple bottles of propane for a small 22" stove/oven,  and he was describing a box  the generator would be in outside the cottage.
I'm assuming he had some batteries and a 115 vac inverter to run his TV,  electric razor, water pump etc with.

 

[John61CT]

I used the Google to find these.
http://www.altendc.com/
https://www.macfarlanegenerators.com.au/products/c113/Outback-Battery-Chargers
http://toolmonger.com/2009/09/22/gas-powered-battery-charger/
http://www.portacharger.com/12v-dc-portable-generators

Guy

Thanks, interesting!

keywords:

portable DC gas OR petrol OR diesel

combined with

batteries solar OR renewable

and

generator OR charger OR alternator

other search criteria suggestions welcome

 

[John61CT]

those used to be more common.  in fact I sold one last year as part of my downsizing.  I sold it to a car restorer,  he restored it an now displays it with his old cars.  here's some pics,

sorry this one is a little blurry,  notice the amp gauge next to it is a dial you can crank up or down the output.

the guy that bought it said that after he restored it worked like a champ.   highdesertranger

Wow, very cool.

Was that a DIY project or off the shelf?

Was the variable output electronic, or just change the motor RPM?

DIY the electronics would be the biggest challenge, charging output management, proper bank maintenance. Deep cycle batteries need different charge rates depending on their current state , generally slower is better but obviously you don't want to run the gennie all day long.

After that the mechanical coupling, machining solid but flexible mount options.

There's such a huge cost differential between quality and cheap Chinese knock-offs in small portable engines, I would probably start with the latter for one or $200 and see how they go before looking at the thousand dollar Plus Subaru Robin and Honda options.

The alternator market seems pretty straightforward at least

 

[John61CT]

Don't most gensets come with 12 or 110 outlets? The few I have seen seem to have them

The standard portable generators supply only a very small fraction of their output to be available to the DC option when it is there.

I want to have all of the available energy output put into the batteries, the conversion to AC and then going back to DC with a charger is very wasteful.

 

[John61CT]

One of my Uncles built a metal frame and used a horizontal gasoline motor mounted in it with a large Alternator from a Truck connected to it.  I think it was directly driven.   I don't remember a battery being part of it though.

For a really small setup you could just use the battery out of your own vehicle , would shorten its life a bit but definitely a cheap way to go.


>I think it was coupled with one of these.

Probably easier to set it up using a pulley system, you need to optimize the RPM for the alternator separately from the best speed for the motor. Not to mention easier and cheaper.

> inverter to run his TV,  electric razor, water pump etc with.

Yes running the inverter can be required for some electronics, but it is much more efficient and cheaper to go for native 12-volt appliances as much as possible.

You'll notice with even a lot of fancy solid state stuff, the power award actually delivers DC, so as long as you have a well regulated clean supply from your battery bank, you can usually avoid the very expensive huge inverters needed.

Personally I am very willing to forgo many mod cons Americans would consider essential, have lived off the grid in rural Australia for decades, got used to a very simple lifestyle.

 

[ArtW]

I did not know that, thanks for clarifying

 

[lmlisak]

Looking for a DC-only genset, to be used for charging battery banks only, supplementing solar. Not interested in AC usage at all, want to maximize efficiency, so avoiding inverter-based charging

[quote pid='249925' dateline='1482333065']
Hello John
 personally am looking for the same thing... So I would buy the  "off the shelf" generator, and buy a switch mode power supply for the battery... You can pm me for  my ideas.
Thanks. 
L
[/quote]

 

[highdesertranger]

that connector eDJ showed is called a Lovejoy if anyone is interested. http://www.lovejoy-inc.com/ . highdesertranger

 

[Mobilesport]

MS, I'm not a Honda fan but those numbers look off by 10 db.

Yea i guessed at the db level , just trying to show that the db spec for the 1000 and 2000 generator they have is the same for both generators however the 2000 is quieter , i'll look up te exact db and post

 

[Mobilesport]

The Honda 1000 and honda 2000 are both 53db @ 1/4 load but the 2000 is quieter