Which engine should i get ?

[craigcurtin]

Guys,

I am looking at purchasing an engine in the very near future and am undecided on an 8/1 or a 12/2. I have a base load of 3KW constant and then additional loads i can cycle in and out to bring the load upto between 4.5 and 5KW (i can cycle it less than that if required)

I am pretty sure i am going to be over the limit for a 6/1 so the question is as a newbie am i better off with a twin or a single.

I know that with a diesel i need to keep the load up to it - the numbers people seem to say is that 80% load is a good number to look for ?

If so based on a rough rule of 2HP for KW then i am looking at just fitting in to a 8/1 but with not much wiggle room.

What do the experts think ?

I will be running this on Vegoil which i have in plentiful supply so actual running costs is not an issue.

Craig

[mobile_bob]

i am of the opinion that running these engines at 90%+ of rated load is most desirable from an efficiency
standpoint, right up to where the engine starts to make some darker grey smoke is about where things get
really good from an efficiency standpoint, somewhere between no smoke and where it starts to chug black smoke
is about right in my opinion.

running at this level may require a bit more attention to details such as the cooling system, thermal siphon becomes
a bit sketchy on some engine's at this level of power output, the changfa's benefit from a closed and pressurized system
circulated by a waterpump and controlled by a thermostat in order to control the heat well.

the 8/1 i think is a nice compromise in simplicity and power between the 6/1 and 12/2, and depending on flywheels it comes
with you might be able to tweak it to run a bit faster for a bit more power if needed. the twins can be good engines, but will
be no where near the efficiency of an 8/1 produceing an average of 3kwatts electrical, there is just about twice the frictional
losses in the twin to overcome and that forms the baseline fuel consumption at no load which will be significantly higher than
the 8/1 at no load.

the baseline consumption gets divided into each kwatt generated, so i would expect for example:

if te baseline of the 8/1 turning a 5kwatt head is about 600gr/hr, then the 12/2 might be 1200gr/hr (actually it won't be that high
i don't think, maybe 1000gr/hr is more realistic) any we will use the 1200 for the sake of arguement.

so the first kwatt produced has to burn enough fuel to make the kwatt of power, plus all of the baseline consumption
the second kwatt produced has to burn enough fuel to make the 2kwatts, plus half of the baseline can be distributed to each
kwatt produced, and the third kwatt gets one third of the baseline etc.

so basically at 3kwatts the 8/1 probably will burn  about 2/3's of the fuel the 12/2 will burn at that load level, and you will only be loading
the 12/2 to about half capacity.

having stated all of that, it would appear that the 8/1 is a more appropriate match to what you describe as your needs, however

it all depends on your total system, and how the engine/generator fits into the scheme of things, and also how you will be using it.

if for instance you will be producing all of your power with the engine, and not storing in batteries, or using an inverter and have
no desire to schedule loads or manage your loads, you likely should probably step up to the 12/2 because you will need the added
capacity on an intermittent basis. i am not at all in favor of that approach but i recognize this is the reality  for some installations.

on the other hand if you can schedule your loads, manage them either manually or by automation, plan on intergrating batteries and inverters, or other power production means your horizon will definetely broaden significantly.

under such a setup you might run the engine at full capacity or 4kwatts, using the 3kwatts as your continuous load supply (which is
really high on a continous basis in my opinion ) and use the excess 1 kwatt (plus any excess from the 3kwatts) to charge batteries
to power an inverter with enough surge capacity to do everything a 12/2 could surge to anyway. the result would be a fully loaded engine
that might not have to run as many hours per day as the prior example would. the end result would be less fuel consumption, better waveform, lower distortion, dead on voltage, no flicker and all that depending on the quality of inverter used, a simpler and as some might attest to as a more reliable single cylinder engine.

that is a lot to think about, and there is not clear cut answer to your question  without knowing more about what your end goals are
and what the total system plan is to look like, and what components are you planning to work with in the system.

hope that helps

bob g

[mobile_bob]

i just assumed he only had access to either an 8/1 or a 12/2

all things considered, i would opt for a 10/1 myself if i could get one, and couple it with an st 7.5
or maybe a 6kw pm head when they become available. 

and depending on whether or not batteries and inverters were to be a part of the system, i might
forego both st or the pm head in favor of a 48 volt project X alternator which would be a nice match
for a 10/1.

that is if i were to want a listeriod to start with 

personally i think he would be far better served with a changfa S195m IDI, or maybe the DI variant



ducking and running now...

bob g

[craigcurtin]

GUys,

Thanks for the information and the things to think about. A bit more info as background.

We live in a normal residential neighbourhood and have grid power. We are looking to reduce our carbon footprint and looking to the future with a MicroCHP setup. As we have a small business working with computers that we run from home we have a fair number of PCs that are constantly on and are powered by UPS's.

Our plan is to in the first instance to create a small subboard from our main switchboard - on this we will move all loads that are OK to disconnect from the mains power through a series of interlocks and relays under automation control. We will also move all the PCs to this same board on their UPS's.

Due to time of day billing that we have for mains electricity in Australia it is very economically viable to run the generator from 7AM in the morning to 10PM in the evening.

I will then sequence loads during these hours of operation to provide a load over and above that from the PCs which currently pull approximately 1.5KW. We have things such as pool pumps, solar pumps for swimming pool heating, an outdoor jacuzzi, Hot Water heater etc.

Initially there will be no battery storage etc, but i do have plans longer term to add storage and alternators.

However i am also fascinated by home and process automation and once i have a handle on the system would love to consider runnign this 24/7 - as there appears to be many stories on the net of people running for months at a time 24/7.

Out of interest why would you say the changfa is better ? Who could i source one through (or getting initial pricing for comparison to the Lister) - What is the longevity of a Changfa in comparison to a Lister and would they be suitable for 24/7 operation ?

I have started a number of other threads in relation to cooling and oil filtration.

regards

Craig

[mobile_bob]

the choice between a listeroid and a changfa is a personal thing for me

certainly a listeroid can be made to run very long hours if you take the time up front to properly
go through it and prepare it to do so.

the changfa's are "generally" of higher initial/"out of the crate" quality in my opinion than the typical
listeroid by quite a stretch, having a full pressure lube system and generally an electric start for about
1/3 to 1/2 of the initial price of a listeroid is attractive as well.

i think as long as you know what you are getting into, and are not afraid to properly go through a listeroid
before placing into service there is no reason for it not to run a very long time with minor maintenance along
the way.

if i were you i would certainly read Quinn's 3 part series on utterpower.com, quiz folks like JohnF, CaptFred
and others that have logged many thousands of hours and learn how they manage to get such good performance
from their engine's.  They get thousands of hours of relative trouble free operation based on a common theme
and not on the original indian quality of product.

based on your further info regarding your computer needs and the fact you are useing ups systems, have you
considered that you are using batteries and inverters already? it certainly would be an easy step from all the seperate
ups' to going to a single battery bank and a larger redundant ups system such as the exeltech mx series.

one of the problems with the listeroid will be your choice of genhead, and how you are going to manage voltage
and hz stability sufficient to be acceptable to your ups'. a lot of folks report issues with st power and being able to make
it clean enough to be acceptable to their ups systems.

something to consider

bob g

[bschwartz]

mobil_bob, the 6.5K PM heads are currently available!  I'm VERY HAPPILY running one from Tom Osborne now.  My 6/1 is pushing 3.3 KW at 4200 ft.  Very stable voltages, and although I don't have a O-scope, the waveform seems better based on my microwave not moaning near as much as it did on the ST-5.

[veggie]

Jens,

Regarding your poll on how many people were running Listeroids for extended periods:
It could be that there simply wasn't enough members in the forum at the time you posted it.
Try that again in 6 or 8 months and I think the results will be significantly different.

Cheers,
Veggie

[veggie]

I think all of Bob's points about the Changfa's and the Listeroids are good ones.
Both engines are excellent workhorses.
I must however bring up the subject of sound levels.
If you are planning on residing in a residential area, you should do some research on the noise levels of both engines.
It may or may not be an issue for you, but there is a considerable difference between the two.
I have recently taken readings on both my engines (Changfa S195 and Listeroid 6/1) with the following results.

Changfa @ 1700rpm = 93 dba
Listeroid @ 650rpm = 66 dba

Readings were take at a 3 meter distance and both engines had stock mufflers.

I was able to get the Changfa down to 89 dba by adding an automotive muffler.

Good luck with your selection,
Cheers mate!
Veggie

[BruceM]

Great sound data, Veggie.  A kind soul sent me an audio file of a Changfa before I purchased one.  That convinced me to go Listeroid 6/1, despite the their quality issues.  It's so quiet with a good auto muffler that I can't hear it from my shop or house.

I know Bob had done some work with sound isolation enclosure on the Changfa, and in some cases that might do the trick. 

[craigcurtin]

Guys,

Thanks once again for all the info. I was definitely cognizant of the engine noise level and the running speed of the changfas - which is why i was so attracted to the lister.

I will be building a purpose built shed for the lister so the noise levels will be contained.

I intend to initially go for a 44 gallon drum as the expansion chamber external to the shed, If that proves to be too noisy, i was then thinking of placing a 15 gallon drum inside that surrounded by Sand to further deaden the pulses.

I have already done lots of reading over at utteropower and intend to do lots more.

Yeah i know i already have lots of Batteries and Inverters, I also have access to a couple of large APC 3000XL units with dead batteries - these make fantastic inverters, not so sure about their treatment of their battery charging though.

However they have a DC input voltage of 96v so this would mean i would have to get 8 very large 12v cells to get a decent runtime. That is not in the budget at this time.

I am aware of the power stability issues with the ST heads, can someone give me a source for the PM Generators in the 6Kw range ?

regards

Craig

[mike90045]

I am aware of the power stability issues with the ST heads, can someone give me a source for the PM Generators in the 6Kw range ?

If all you are doing is charging batteries, ST should be fine for that, no need for a PM till the ST gives out

[Henry W]

Veggie, Did you think of putting a muffler on the S195's Intake?
I an curious how much it will help.

Henry

[JohnF]

Jens;

Didn't see your poll.  BUT, one 6/1 with 25,000 hours plus, the other with 14,000 plus.  Yes, I've done some work on them (the "more experienced" engine now has a new camshaft) but I'm pretty happy with the results.

P.S., For those running the twins, I'm working on a better camshaft (IMHO, the absolute main reason for twin failure) that will be North Ameri9can produced.  I've done the stats, the comparison between an Indian camshaft and an OEM one is frightening - no wonder the Indian ones fail.  I expect to have some solid numbers to post in the near future.

[lowspeedlife]

Hi Craig & welcome,
George a utterpower sells a PM genertor, not sure but I think his is only 3 KW. One of our members, Central Georgia Generators, Is selling them also. I heard a rumor that he has one thats 8KW. He's listed in the Dealers Registry area of the forum near the bottom of the home page.  Lots of great people & info here to help you & Don't forget to post pictures!!!


   Scott R.

[bschwartz]

I am currently running one of Tom Osborne (of Central Georgia Generators)'s  6.5K PM generator heads and love it compared to the ST-5 I started with.