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Author Topic: Slow speed alternative fuel engine + battery bank = powerful option  (Read 1608 times)

Tanman

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So I've been on a learning journey of alternative power for a few years now. That is what lead me to this forum. Through my research I have found a theme of "fandom" of alternative energy ie solar, wind ect. however, for a lot of people these types of power producers are not practical. For example, I live in a residential neighborhood with lots of trees so wind and solar on my house would be an absolute joke. Hydro is not an option either (as it is for most people). That left me with one choice a backup generator. I scored a 5kw diesel Yanmar L100 engine about 2 years ago for $400 with 1 hour on it (retails for 4-6k). After the fact I started to do the math of how many gallons of fuel I would go through to keep that sucker running in a power outage, I was quickly discouraged and realized I could only keep it running for a couple days at most with my on hand fuel supply. This lead me to do a lot more research and I discovered an old gem, the Delco-light farm power plant. This has to be one of the oldest commercially sold home power systems. At that time (1920s) there was no PV or wind generators to slap on your roof. But there were good old lead acid batteries and engines with generators/alternators. These systems were solid and gave many years of useful service. This concept seems to be the best option for long term (1 week +) power outages. Pick the fuel efficient generator of your choice coupled with an inverter-charger, batter bank, inverter charger, and a transfer switch and you have a pretty simple and solid backup power system. I figure for $1.5k you can get a fair amount of 6v golf cart batteries, another $1k for a good inverter-charger, hook that to a manual transfer switch ($200) and a generator that needs a little work can be picked up very cheap. You will have a system that will kick the shorts out of just a plain backup generator or a PV/wind system (depending on location). All for the cost of a good new generator at retail price. So I'm planning on selling a few of my generators I have and putting those funds in to a battery bank and inverter-charger. I would love any input, comments, or rebuttals on this style of system so I can improve my plan.
« Last Edit: March 27, 2020, 06:54:33 PM by Tanman »
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broncodriver99

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Re: Slow speed alternative fuel engine + battery bank = powerful option
« Reply #1 on: March 27, 2020, 09:06:07 PM »
I have been on the lookout for one of those myself. Kohler made them as well in both AC and DC variants. I have come to the same conclusion as you. While I do intend to have enough solar to carry the constant loads and offset some of the evening/night and seasonal loads a good back up generator has always been in my plans. The weather here is just too unpredictable to rely solely on solar. I like that those little light plant sets range from 1-2kw. Seems they would be pretty efficient if one had to run it for a couple of hours a day.

The only drawback I can think of is that one is stuck storing Gasoline. Diesel is much easier to store long term and Propane stores pretty much forever. I plan to have a couple of options as far as a back up generator. I have several diesel gen sets and a couple that are Gasoline/Nat Gas/Propane capable. I don't want to limit myself to one fuel. Plus a back up for a back up is just, well, ......

Tanman

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Re: Slow speed alternative fuel engine + battery bank = powerful option
« Reply #2 on: March 27, 2020, 11:53:05 PM »
Thanks glort, I'm sure I could get away with a few panels on the roof. I do have a lot of shade and trees but some used panels are available. I'm defiantly going to do a diesel generator, currently building a Kubota EA300 geny right now. As far as voltage I saw leaning towards 48v but am defiantly open to 24v. I'm not familiar with buck converters at all, if those are really good I'll have to think about using those. As far as charging the battery bank with a generator I liked the idea of an all in one inverter charger, but if you used buck converters you would need a separate 24v inverter and a separate Ac to DC charger to charge the bank with a regular 110v/220v generator.
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Tanman

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Re: Slow speed alternative fuel engine + battery bank = powerful option
« Reply #3 on: March 28, 2020, 03:03:27 PM »
It seems that diesel isn't dropping as fast as gasoline. I wonder why, isn't it all based off the price of crude oil?

Anyways, here is one of the units I was looking at to be the "brain" of the system:

 https://www.ebay.com/itm/110Vac-2400w-24V-Solar-Power-inverter-80a-MPPT-solar-charger-60a-battery-charger/131951259033?hash=item1eb8e86d99%3Ag%3AkWUAAOSwKetbKG%7EE&LH_ItemCondition=3

It will charge that bank with PV and or 110v AC power from a generator or the grid and has 110v output from a built in inverter. This seems to be the most straight forward option, and it would do everything you would need the system to do.
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Tanman

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Re: Slow speed alternative fuel engine + battery bank = powerful option
« Reply #4 on: March 29, 2020, 04:47:31 AM »
Thatís a good idea to stock up. There is actually a business where my family is from where you can buy as much fuel as you want at todays price and use it over time. You basically pay for it in advance and come get it with a card as you need it.

There are also more expensive and better built ďpipísĒ/inverter chargers available from companies like Magnum. But they are typically $1700 US for the unit. 2-3kw of solar would not be possible in my location, small suburban lot, not a ton of good roof space, my roof has 4 planes, so only one small section faces south. Iíll do some research on the Taiwanese units and maybe pick up a big drum and fill it up with fuel!
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mike90045

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Re: Slow speed alternative fuel engine + battery bank = powerful option
« Reply #5 on: March 30, 2020, 04:28:39 AM »
Battery bank voltage is determined by the AC system load.
1kw = 12V
2kw = 24V
+2kw = 48V.
 
This is because of the DC amps thru cables to power the inverter.  12v into a 3KW load needs massive cables to carry 250amps, and if you really believe the inverter has heavy enough cables inside to not burn up in 10 minutes, have fun with it.  (only 62A at 48V battery)

If your loads are only a couple hundred watts, 12V and a small 500w inverter would be fine.

Welderherup

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Re: Slow speed alternative fuel engine + battery bank = powerful option
« Reply #6 on: October 24, 2021, 07:29:19 PM »
Hi, this is exactly what Iím doing. I bought 2 130ah 12v batteries and a £120 4000w inverter. Hooked them up and they run my freezer for about 2 days. Then I fire up the genny and charge the batteries. This worked the first time but on test number 2 I ran into problems. Genny only making 70v. Fettled it today and got her up to 230v but she still seems low on grunt to me. Iím new to all this kaper so Iím learning as I go. I am in Ireland. I have an LT1 genny.

mihit

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Re: Slow speed alternative fuel engine + battery bank = powerful option
« Reply #7 on: October 26, 2021, 07:45:44 AM »
Batteries are the weakest link in any off-grid system. Ideally you generate what you use, as you use it. Run the washing machine in the middle of the day, etc.

Batteries are ultimately consumable. But you also have a wasteful double conversion of energy, and storage loss.

You yanks are unfortunate with the 110V systems, as pointed out above, lower voltage demands higher current. 240 is way cooler.
24V would be the minimum bank voltage I'd consider. 36, 48 or 72 even better if you can find the gear (inverter etc) to run with it. Telco backup suppliers would be the people to contact.

The less conversion of energy, the better. You have a rotating engine, first look should be what can you spin straight off that (compressor, lathe, drill press)
Then if you need to charge batteries, a DC generator head (rather than generating 110 to feed a charger, to rectify and transform it to LVDC to go into the batteries, to be drawn out, inverted and feed the house...)

Diesel engines beat petrol IMO. Both for fuel storage, and tolerance. They'll generally run on any cleaned oil, waste motor oil, veg oil etc.
Petrols can be run on gassified wood, LPG/CNG, methanol, so there's a bit of resilience there but not as straight forward.

mobile_bob

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Re: Slow speed alternative fuel engine + battery bank = powerful option
« Reply #8 on: October 26, 2021, 10:36:34 PM »
"Batteries are the weakest link in any off-grid system." 
+1

i couldn't agree more!

years ago, on this very forum, and on the sister forum we got into the weeds on this topic and i among others sang the song over and over again

"if" one is in the planning stages, of house and power system, and "if" one is flexible to changing his/her lifestyle to one that is more frugal the options widen dramatically.

anyone starting out with a clean sheet paper approach to home and power system design he could do far worse than learning from the yachting and nasa boys. 

learn how to limit your needs, and control those needs, and the cost of success goes down to something quite manageable.

producing power to charge a battery bank to use later to convert via an inverter to supply poorly managed loads, gets spendy in a hurry.  far better to use the power as it is generated than to go through various stages of conversion, let alone the cost of the battery bank.

every watt saved or trimmed from the need column is a watt you don't have to generate, and probably more like 2 or more watts if you plan on storage and conversion.

that is the main reason the whole tiny house movement has captured my imagination, if there was ever a way to make a very efficient offgrid power system, starting with a well designed tiny home makes things very easy.

bob g

 

otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

mikenash

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Re: Slow speed alternative fuel engine + battery bank = powerful option
« Reply #9 on: October 27, 2021, 06:51:32 AM »
"Batteries are the weakest link in any off-grid system." 
+1

i couldn't agree more!

years ago, on this very forum, and on the sister forum we got into the weeds on this topic and i among others sang the song over and over again

"if" one is in the planning stages, of house and power system, and "if" one is flexible to changing his/her lifestyle to one that is more frugal the options widen dramatically.

anyone starting out with a clean sheet paper approach to home and power system design he could do far worse than learning from the yachting and nasa boys. 

learn how to limit your needs, and control those needs, and the cost of success goes down to something quite manageable.

producing power to charge a battery bank to use later to convert via an inverter to supply poorly managed loads, gets spendy in a hurry.  far better to use the power as it is generated than to go through various stages of conversion, let alone the cost of the battery bank.

every watt saved or trimmed from the need column is a watt you don't have to generate, and probably more like 2 or more watts if you plan on storage and conversion.

that is the main reason the whole tiny house movement has captured my imagination, if there was ever a way to make a very efficient offgrid power system, starting with a well designed tiny home makes things very easy.

bob g

Interesting you say that Bob.  I recently moved from where I lived for the last five or so years - sharing a 130-year-old, timber-framed, high-ceilinged, half-insulated, drafty 5-bedroom farmhouse with an old friend - to a professionally-built "tiny-ish" house made from two insulated containers with a whole bunch of sun-trap glass areas.  Can't believe how little energy it takes to heat the place.  Something of a revelation :)

Tanman

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Re: Slow speed alternative fuel engine + battery bank = powerful option
« Reply #10 on: December 04, 2021, 05:05:52 AM »
This is a dumb question, but what does that switch on most st-type generators do?
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mobile_bob

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Re: Slow speed alternative fuel engine + battery bank = powerful option
« Reply #11 on: December 04, 2021, 06:10:27 PM »
on the st heads i have seen it is used to turn off the voltmeter

which never made any sense to me at all,  its not like the voltmeter is going to last any longer whether off or on, if there is much vibration it is still going to die eventually anyway.

bob g
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