Running the generator

Started by clint7434, August 20, 2016, 08:32:49 AM

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clint7434


So, what triggers me to start my generator?  What piece of data (and there is a LOT!) do I look at to tell me that I need to supplement my PV system with some generator-produced power?  It is a 24-volt battery bank.
And, just as importantly, what piece of data tells me that the generator has run long enough and I can turn it off?  I must start the generator manually, as it sits in an enclosed shed. 

I have a fairly new system, just commissioned this summer, and we have had a great amount of solar input.  But the summer is winding down, and I need to be able to understand my system as the sun arcs lower and lower. 

In advance, thanks for your help!

grgdgreek

Hello,
Could you please give us a rundown of your system:-)?
P.s. welcome 2 the forum :-)
Home:6*135w mitsu.10*175w shuko. 2* cl150.3*D400 turbines.
Rolls18*4v series 5000 545ah*3 .2*Victron 3000 multiplus inv/chg. 24v. Shop:28*185w shuko. Sunny island. Sunnyboy.Rolls 40*s530.48volt.Sunny web box.

clint7434

Here is a list of the "primary" components of my system...

4   Trina 255W Solar Modules
1   Classic 200 Charge Controller
2   MidNite MESPD300 Lightning Arrestors
1   Magnum MS4024 20000W 24VDC Inverter
1   Magnum Control ME-ARC50
12   Trojan T105  Batteries

Westbranch

So, what triggers me to start my generator?

well if I got down to 50% DoD , or SoC , (take your pick) , in one day , everyday, AND my Solar could not get me to FLOAT at least every other day (min once per week) I would be BULKing up with the gen set  in the mornings...

Sorry it isn't an exact number but it is location and needs dependent... as well as how your system works over time.


hth
KID FW1811 560W >C&D 24V 900Ah AGM
CL150 29032 FW V.2126-NW2097-GP2133 175A E-Panel WBjr, 3Px4s 140W > 24V 900Ah AGM,
2 Cisco WRT54GL i/c DD-WRT Rtr, NetGr DS104Hub
Cotek ST1500 Inv  want a 24V  ROSIE Inverter
OmniCharge3024  Eu1/2/3000iGens
West Chilcotin 1680+W to come

TomW

Quote from: clint7434 on August 20, 2016, 11:07:07 AM

1   Magnum MS4024 20000W 24VDC Inverter

I suspect this is a typo?

20 KW @ 24 volts would be 800 plus amps and seems a bit much.

When I had an active system using Outback inverters, I set the inverters to charge from the grid if below a specific voltage for X time. That was before the WizzBang JR was available to count amps in and out of a system using a  Classic. Relatively the same as "time to fire up the generator". You are aware some generators can be remote started?

As WB noted, it is system and location / usage dependent.


Just from here.

Tom

Do NOT mistake me for any kind of "expert".

( ͡° ͜ʖ ͡°)


24 Trina 310 watt modules, SMA SunnyBoy 7.7 KW Grid Tie inverter.

I thought that they were angels, but much to my surprise, We climbed aboard their starship and headed for the skies

clint7434

you are right... it is a typo.

about the generator... it is enclosed in an old shed that has 3 sets of doors -- left, right, and 2 in the front.  They all have to be opened (manually) in order for the generator to exhaust properly.  So, I bought a generator that does NOT have auto-starting capability. 

We are located in northern NY -- Adirondack Mountains (~43 degrees lat).  And there is about 4-6 hours of good direct sunlight during the summer each day, sometimes more.  We have a 3 bedroom, 2 bath cabin, 1400 sq ft.  So our power consumption is pretty strong at times. 

mike90045

Quote from: clint7434 on August 20, 2016, 05:24:22 PM
.......  We have a 3 bedroom, 2 bath cabin, 1400 sq ft.  So our power consumption is pretty strong at times.

Strong, as in Air Conditioning, or electric baseboard heat in the winter ?

Generally, you want to trigger starting the generator on either of 2 things.  High power draw or Low battery voltage

But first, what sort of loads are you expecting the batteries to be carrying ? (numbers, not guesses)
Historically, have you been able to get to float at least 3 times a week on solar ?

Winter with shorter days, do your loads decrease?  Can you expect solar to power things in good weather, or are you going to have to supplement the solar with generator every day ?
http://tinyurl.com/LMR-Solar

Classic 200| 2Kw PV, 160Voc | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph )| Listeroid 6/1, st5 gen head | XW6048 inverter/chgr | midnight ePanel & 4 SPDs | 48V, 800A NiFe battery bank | MS-TS-MPPT60 w/3Kw PV

clint7434

Well, now you are asking the questions I need to address... but the system is new, and we will not be spending the winter there, but will retreat to Virginia (winters are NOT hard here.) So, the place will sit with virtually no load all winter. 

But to address other questions (and sorry, I don't have a lot of data yet... I've been gathering it for a couple of weeks, that's all.) Main appliances are a small electric refrigerator (365 kw-hours per year estimated), baseboard heat (but not electric, just the pumps), a small clothes washer and a propane dryer (although we hang clothes outside most of the time.)  Microwave (900 watts) that is used for about 2 minutes a day.  All LED lighting.  And the usual assortment of occasional power tool usage, vacuum cleaner, ... here's some numbers, based on 34 days of data taken in July and August... averages,

Hi VPV = 138.46 
Hi VBatt = 27.7 
KW hours = 2.62 
Float time per day = 99.57 minutes.  Note there was 20 days when float time was 0, and 14 that were NOT 0, and it was these that were used to develop the 99.57 minutes average flat time.
Hi Power = 0.930 KW

So, does this make sense? 


Westbranch

well, based om your current use, you have a balanced system....  keep track of when you cease to get any float, that is the time to use some fossil fuel...

however that 90 or so minutes of float is still significant. 

The next piece of data is what are your charge parameters? and how are you determining the end point for Absorb?  Do you have a WBjr?
KID FW1811 560W >C&D 24V 900Ah AGM
CL150 29032 FW V.2126-NW2097-GP2133 175A E-Panel WBjr, 3Px4s 140W > 24V 900Ah AGM,
2 Cisco WRT54GL i/c DD-WRT Rtr, NetGr DS104Hub
Cotek ST1500 Inv  want a 24V  ROSIE Inverter
OmniCharge3024  Eu1/2/3000iGens
West Chilcotin 1680+W to come

RossW

Quote from: clint7434 on August 20, 2016, 08:32:49 AM

So, what triggers me to start my generator?

I've only been living (and running two businesses) completely off-grid for 12 years, so a "n00b", but I've made my share of mistakes and live with them.

I run the generator on what superficially seems to be a complex set of conditions, but isn't really as bad as it looks.
I used to have 48V/1500AH (then 1000AH, then 500AH) AGM lead-acid, but changed a couple of years ago to 300AH LFP (and wish I'd done it earlier, and wish I'd got 600AH).

My generator is home-made, and auto-start/auto-stop. It starts if the battery volts are too low, or the load is too high, or if the SoC is too low, or if the time of day is (x) and the SoC is below (y), or once every (n) days just to exercise the generator.

With the LFP cells, I'm able to go to 85% DoD (although I have the genset autostart at 75% during the day, or if it falls to 80% SoC regardless of the time), and that means that I get the same "usable watt-hours" out of a 300AH LFP bank as I got from my 1000AH AGM bank. The LFP are also way stiffer than the AGMs ever were.
3600W on 6 tracking arrays.
7200W on 2 fixed array.
Midnite Classic 150
Outback Flexmax FM80
16 x LiFePO4 600AH cells
16 x LiFePO4 300AH cells
Selectronics SP-PRO 481 5kW inverter
Fronius 6kW AC coupled inverter
Home-brew 4-cyl propane powered 14kVa genset
2kW wind turbine