Off Grid which generator to chose 10 kVA to 15kVA

richardimorse
richardimorse Registered Users Posts: 98 ✭✭
edited November 2018 in Solar Beginners Corner #1
Just finished getting pricing for Commercial grade generator systems, in the 10 to 15 kVA range

The YangDong YD485D generator  is rated as 17kVA 13kW Standby and 15kVA 12kW Prime
The YangDong YD480D generator is rated as 14kVA 11kW Standby and 13kVA 10kW Prime
The YangDong YD385D generator is rated as 12kVA 10kW Standby and 11kVA 9kW Prime
The YangDong YD380D generator is rated as 11kVA 9kW Standby and 10kVA 8kW Prime

The 4xx models are 4 cylinder the 3xx models 3 cylinder

They cost exactly the same

Which is a good thing, as price shouldn't be the selection criteria, so how to select, lots of advice say 2* your inverter size, but my 9kVA inverter system has 3kVA headroom for instant power, i.e. all those devices you shouldn't be using, like kettle for 3 minutes, power tool for 10 minutes, hairdryer for 5 minutes, microwave for 5 minutes, to allow for those I have a "headroom inverter" which supplies the power hungry users.

I have a constant power budget of around 3kVA and time of day dependent users which can take that up to 5.5kVA when the 2.5 kVA ironing session starts for 2 hours
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So what size generator, here looking at what three FXR3048E inverters can pull to charge batteries, the max battery recharge current they draw is 10 Aac each to charge with 40Adc each, so 30 Amps at 220V is 6.6 kVA
 
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The headroom inverter is catered for already because the inverters will just reduce power for charging the batteries for a few minutes OR draw from the "temporary use" generator standby power rating while users are reaching for the kettle and hairdryer 

===

It comes down to

1) not oversizing and causing generator damage from insufficient load levels e.g. 40% vs 70% etc
2) fuel consumption (operating cost, smaller engine lower costs)
3) 3 cylinder vs 4 cylinder (I am trying not to think of this as my "new car" which is making me want to go 4 cylinder)
4) spare parts availability and service repairs which are fine with all 4 generators

===
I know one thing, that when I need to run the generator it is because the batteries need charging (Dark days or failures or undersizing)
So being able to run load and charging is important, which in my case is 6.6 kVA plus 3kVA load plus 2.5kVA for ironing = 12kVA

The ironing won't always take place so when it doesn't I get 9.6 kVA loading = 60%, 70%, 80% and 90% loading on each of the four generators 
===

One scenario is for emergencies if I have to bypass the inverters and there is no battery charging at all while the generator runs, this will not work well for any generator, but would be worse for the larger ones, however, I have a 5kVA generator for backup to power smaller loads only, without any battery charging.  I will arrange a transfer switch for that as well in emergencies, just in case the whole system gets struck by lightning, stranger things have happened, however I can't rely on the backup generator for long usage periods and will need to use the new generator as well in the event of a total disaster.

Which of the four generators should I choose, they all cost the same, I am thinking the 480D

Here is a video of the generator https://www.youtube.com/watch?v=1KQsMRrXoak

Comments

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    Based on one factor alone, personally I would go with a 4 cylinder, 3 cylinder engines are inherently unbalanced, the choice would then be narrowed to 2, all things being equal the obvious choice would be the YD485D, because it could do everything the YD480Dwith some reserve capacity, the difference is most likely the alternator, having a higher rating, with the addition of a turbo perhaps on the diesel to get the additional output , a wild guess.

    Whichever is selected be sure to rodent proof the housing, they love to strip the sound deadening foam which plugs everything once running, radiators alternator cooling slots, you name it, not to mention chewing the insulation off wires, this is based on experience. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    The YD485D has no turbo, but what is interesting is the fuel per KW is better for the 4 cylinder.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • richardimorse
    richardimorse Registered Users Posts: 98 ✭✭
    mcgivor said:
    The YD485D has no turbo, but what is interesting is the fuel per KW is better for the 4 cylinder.
    I am pretty much sold on the 4 cylinder, the difference between the two is the cylinder bore size, 80mm in one and 85mm in the other, hence the model numbers. one has a 1.8 L engine and the other a 2.1 L engine, Manufacturers recommend that a generator has to be run at 75% of prime power at least 2 hours in every 100 operating hours, if this is not available then a load bank must be created which artificially adds this load to the generator, I can think of a good use case for that, charging the the old 12V battery bank once a month at the same time as the new battery bank,  but would need more generator connected chargers for the 2nd battery bank, I could even use them as emergency batteries in permanent standby mode with a selector switch like this.
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,730 ✭✭✭✭✭✭
    That switch is dangerous if you have uninformed users. Any diesel that has a turbo for offgrid is another bad choice in my opinion.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    A couple points which you may already know:

    Check the PF on the chargers.  I think they're PF corrected, but this may influence the 6.6kva estimate (ie 6.6kw might be 7.x kva).

    I think the chargers can be set for a max generator draw, so charging gets throttled if need be for loads.  This lets you set a limit in the "sweet spot" (~75%) generator loading without having to worry about loads (within reason).  This feature, if used, could influence ideal generator size.

    FWIW 

    As an aside, @mcgivor why is a 3cyl engine (assuming inline, as I think most are) inherently unbalanced?  The crank would be 120° apart.  4cyl at 90° apart might be slightly smoother, but ... ?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    > three FXR3048E inverters can pull to charge batteries

    But note that as the batteries reach absorb, charge rate will drop and you will be operating at much less than 50% load.   This isn't great for a diesel - so I'd lean towards the YD385D.

    >  I will arrange a transfer switch for that as well in emergencies

    A friend had lighting jump the transfer switch gap, causing great damage to the generator controls.  He would have been better off with a manual plug in cable.

    My understanding is that cold diesel generators benefit from 5 minutes of warm-up before load.

    I am available for custom hardware/firmware development

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    I think that the question of 3 cylinder is that the cylinders do not fire in even power strokes per revolution (something like 2 pulses in one revolution, 1 pulse in the second revolution). Can cause harmonic/twisting issues in the motor/generator drive system... Possibly even seeing the small RPM variation in the lighting (pulsing lighting from variable voltage).

    4 cylinder fire every 1/2 revolution of the crank.

    For "naturally balanced" engines, a V8 is harmonically balanced for the first harmonic (second harmonics are smaller but present).

    4 cylinder motors can be harmonically balanced with a weighted shaft that turns (as I recall) at 2x the crank RPM. At least, decades ago, this was not common practice.

    I don't have any (long term) experience with gensets (or with larger gensets)--So I cannot really help with choices here...

    Many inexpensive (and some expensive) gensets (diesel motors and otherwise) can shake themselves apart... Checking customer references on gensets with lots of run time on them would be a good idea (also their experiences with repairs and part availability).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • richardimorse
    richardimorse Registered Users Posts: 98 ✭✭
    Good point about that switch, the 1+2 option is a very bad idea anyway, that combines 2 battery banks of uneven Ah together, the 1 or 2 is also a bad idea as the inverters and chargers should be permanently connected to the battery bank they are charging and the generator can feed the live input busbar anyway for multiple chargers and inverters as needed.
  • richardimorse
    richardimorse Registered Users Posts: 98 ✭✭
    jonr said:
    >But note that as the batteries reach absorb, charge rate will drop and you will be operating at much less than 50% load.   This isn't great for a diesel - so I'd lean towards the YD385D.

    In my case we intend to implement AGS 2-wire start-stop control so options exist to stop the generator automatically, however, for non AGS implementations this is quite important, in terms of running generators underpowered, I found this from CAT https://forums.cat.com/t5/BLOG-Power-Perspectives/The-Impact-of-Generator-Set-Underloading/ba-p/69719

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    The marine transfer switches... Don't switch under load (arcing contacts), support the cables (switch plastic is not very strong), and have spares:

    https://www.thehulltruth.com/boating-forum/853223-blue-sea-battery-switch-failure.html
    https://www.mastercraft.com/teamtalk/showthread.php?t=42800
    https://www.thehulltruth.com/boating-forum/692733-battery-switches-prone-failure-2.html
    https://keywestboatsforum.com/battery-switch-broke-t3568.html
    https://www.thehulltruth.com/boating-forum/739622-battery-switch-doh.html

    Bluesea (mfg) apparently had some issues in ~2006 and again in ~2017 (fixed?)...

    Perko is, (I guess), a popular but less rugged mfg.

    I don't know what happened--These searches used to deliver quite a few posts about marine disconnect switch (A/B 1/2) switch failures...

    I can't even find my post(s) on this forum... Perhaps, I am getting old and forgetting????

    Today, almost nothing.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited November 2018 #12
    we intend to implement AGS 2-wire start-stop control so options exist to stop the generator automatically
     
    Not going through absorb is usually bad for batteries.

    I understand the concern, but if there any data showing that a well designed 3 cyl has more wear than a well designed 4 cyl?  Or is this just Internet speculation?

    I am available for custom hardware/firmware development

  • mcnutt13579
    mcnutt13579 Registered Users Posts: 111 ✭✭✭
    We have lots of customers running 3 and 4 cylinder diesels at < 50% load for thousands of hours with very little problems.

    But where are you going to get service for that turkey?  Get something assembled in the USA that you know who the dealer is and the engine builder is a recognizable name.  We have seen too many boat anchors because one little part failed or was NLA.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Go with the larger system.  Any loads with poor power factor (most battery chargers, AC pumps) will eat up your extra capacity quickly.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    We have lots of customers running 3 and 4 cylinder diesels at < 50% load for thousands of hours with very little problems.

    But where are you going to get service for that turkey?  Get something assembled in the USA that you know who the dealer is and the engine builder is a recognizable name.  We have seen too many boat anchors because one little part failed or was NLA.
    In Mozambique I'd bet the service and parts availability are more readily available than an assembled in USA unit, different market.. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • mcnutt13579
    mcnutt13579 Registered Users Posts: 111 ✭✭✭
    The OP is in Mozambique?
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    The OP is in Mozambique?
    Yes Mozambique 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,730 ✭✭✭✭✭✭
    BB. said:
    The marine transfer switches... Don't switch under load (arcing contacts), support the cables (switch plastic is not very strong), and have spares:

    https://www.thehulltruth.com/boating-forum/853223-blue-sea-battery-switch-failure.html
    https://www.mastercraft.com/teamtalk/showthread.php?t=42800
    https://www.thehulltruth.com/boating-forum/692733-battery-switches-prone-failure-2.html
    https://keywestboatsforum.com/battery-switch-broke-t3568.html
    https://www.thehulltruth.com/boating-forum/739622-battery-switch-doh.html

    Bluesea (mfg) apparently had some issues in ~2006 and again in ~2017 (fixed?)...

    Perko is, (I guess), a popular but less rugged mfg.

    I don't know what happened--These searches used to deliver quite a few posts about marine disconnect switch (A/B 1/2) switch failures...

    I can't even find my post(s) on this forum... Perhaps, I am getting old and forgetting????

    Today, almost nothing.

    -Bill
    I only use what Schneider and Outback use in their distribution panels because it is reliable, tested by engineering, and if I have an issue, customer service/support can't blame someone else. I would think that Richard, in the business, would want to do the best for his client.

    All of those Marine battery switches are pretty much junk.  When I was out Sailing the world there were better makes and they cost more than 100 dollars in the 90's. The ones with an off position can do alot of damage and should not be used.

    Schneider has really improved their support and Outback is having some Mate3 issues that I think they should have solved in a timely fashion.

    This is not just my opinion BTW.

    Naw your not getting old :)
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • richardimorse
    richardimorse Registered Users Posts: 98 ✭✭
    mcgivor said:
    We have lots of customers running 3 and 4 cylinder diesels at < 50% load for thousands of hours with very little problems.

    But where are you going to get service for that turkey?  Get something assembled in the USA that you know who the dealer is and the engine builder is a recognizable name.  We have seen too many boat anchors because one little part failed or was NLA.
    In Mozambique I'd bet the service and parts availability are more readily available than an assembled in USA unit, different market.. 

    Just about everyone has home generators that you buy in the DIY store that are 3kVA or below

    The Chinese give you an option on engines to use global brands like Perkins or Cummins instead of YangDong and on alternators to use Stamford and UK made DSE controllers or Chinese Smartgen or Czech ComAp, but these all do the same and no-one is complaining about their Chinese Apple iPhone.

    Service and parts is an issue everywhere in Africa, you have to be able to maintain your own generators using local labour because transportation is always long distance, nearly everyone who doesn't have a DIY store generator has a Chinese made 2-cylinder 5kVA generator like this, some USA companies sell the same generator under a USA brand, you might recognise the configuration.


    For sure the YangDong 485 engine and the 385 engine are the choice for parts availability, so I have decided to go for the 485 which gives the extra headroom, AGS 2-wire control can be used to take maximum system load capacity up to 15kW in case we have a construction party with power tools going off all over the place 
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited November 2018 #20
    Spitting immage of the one I now have, comes within a multitude of names and colours, often store branded, all appear the same, the price varies, most expensive is branded Hyundai, twice the cost of my 5kw Mitsu named, all have a single cylinder air cooled Yanmar diesel clone, It actually works extremely well in a backup application, in my case for welding and occasional battery charging, but definitely not a prime unit.

    Think you made the right decision going with the larger unit.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.