how do I know the amount of throttle to send to my charger

simagic · September 2011

I've been doing my research and have narrowed it down somewhat.
I'm intending on getting a
Yamaha EF2000iS - 1600 Watt Inverter Generator ...... ... or a .....
Yamaha EF1000iS - 900 Watt Inverter Generator............(link below)

http://www.electricgeneratorsdirect.com/Yamaha-EF1000IS-Portable-Generator/p1205.html ......... or ..........
http://www.electricgeneratorsdirect.com/Yamaha-EF2000IS-Portable-Generator/p2785.html#reviews

in order to charge my 220AH AGM batteries when we have extended cloudy days.
I'm planning (so far) to charge them with this charger .........

http://sterling-power-usa.com/sterlingpowerusaprocharge12volt30ampbatterycharger-pcu1230.aspx.

So I have 3 questions...(Question 1). I'm assuming that if I went with the larger generator that I would have equal results by running the larger one at lower RPM (quieter for my neighbors and less fuel consumption) and the smaller one would have to run at higher RPM. (I would think that would be correct??? Am I right??). (Question #2) Is it "better" to run these at lower RPM or higher RPM for best efficiency??? With that said..(Question #3) is ...how do I know at what RPM to run either of these generators in order to properly "power" the charger and get the intended results.. What am I looking for and where am I looking for it.

PS. At this point I'm intending to getting the LP conversion kit to allow the generator to run on LP gas so as not have to deal with gasoline goo build up in the engine during the off times and not having to store and recycle smelly gasoline.

RCinFLA · September 2011

Re: how do I know the amount of throttle to send to my charger

The Yamaha's are nice quiet generators. I have a EF3000is.

The rpm on eco-mode is automatic based on load.

Turn EC off and it runs at about 3800 rpm constantly. If you need electric motor starting surge current then you may have to turn EC off.

Go for the EF2000is, at least. The sound is low, even at max rpm's.

Seven · September 2011

Re: how do I know the amount of throttle to send to my charger

Is 220ah your string size or single battery? Are you runnin 12v or 24v or????

Typically the lowest RPM that will do the job is the best for fuel econ, but I think you would really need to check the actual output at a specific RPM to know for sure.

You may want to look at a charger from our host.

Cariboocoot · September 2011

Re: how do I know the amount of throttle to send to my charger

Calculate the maximum Watts you'll need for charging and loads (don't forget power factor on charger). That should tell you the generator size you need; it must be able to supply that much power.

As RC said, the eco-throttle takes care of itself and will slow the gen down when less power is required. These are not like the fixed RPM generators where there's an "optimum loading" of the engine (>50% capacity).

simagic · September 2011

Re: how do I know the amount of throttle to send to my charger

To seven......It's 12 volt....you say "you would really need to check the actual output at a specific RPM to know for sure."
How am I checking this output... Where am I attaching a meter.. Do I disconnect the charger and attach the meter to that...Do I attach the meter to the battery. Do I attach the meter to the generator????. What am I looking for and where am I looking for it.

BB. · September 2011

Re: how do I know the amount of throttle to send to my charger

The new Yamaha's are aiming right at the Honda eu line... Competition is nice!

I always suggest the smallest genset that will run your loads--Or even get two, one small/quiet inverter-generator, and a second cheap big old 3-5kW noise maker (and fuel drinker) to run the occasional large tools.

The battery charger you found looks nice (PFC--very nice). You could run this on the 900 watt genset very nicely (at least looking at the specifications).

If you have heavy loads you need to run (say a window A/C system), you may wan to look at the 24000 series Yamaha instead.

What are your planned loads/uses for the genset? Can you go smaller or should you look at a larger unit?

The ECO throttle is to conserve fuel (and reduce noise). Use it unless you have problems starting the load (like an A/C or air compressor).

-Bill

simagic · September 2011

Re: how do I know the amount of throttle to send to my charger

To seven again...It's two 6v batteries equaling one 12v 220 ah battery

simagic · September 2011

Re: how do I know the amount of throttle to send to my charger

Reply to BB.
.Not intending on running any heavy loads. Just lights.....TV.. computer
in an emergency. Basically want to if I should get the smaller Yamaha and run it at High RPM or get the larger Yamaha and run it a lower RPM... And how and where am I checking it's performance

Cariboocoot · September 2011

Re: how do I know the amount of throttle to send to my charger

simagic wrote: »

Reply to BB.
.Not intending on running any heavy loads. Just lights.....TV.. computer
in an emergency. Basically want to if I should get the smaller Yamaha and run it at High RPM or get the larger Yamaha and run it a lower RPM... And how and where am I checking it's performance

There's two throttle settingson an inverter-generator: eco OFF and eco ON. When it's off it runs full speed all the time. This is a waste of gasoline if you're not having to start heavy loads as RC and Bill mentioned. When it's ON it will adjust throttle speed according to the load demands.

As I said, figure out the most power you need and size the generator that way. It doesn't sound like you'll be needing lots (the battery charging looks like <400 Watts max). Add a few lights, TV, computer and you've probably doubled that. So if you had a 1kW generator with eco throttle on it will hum along nicely and consume a minimum amount of fuel.

My concern in a power outage is always keeping the refrigeration going, as I hate to have to toss out expensive quantities of food (and have nothing to eat). That requires a bit more "oomph" in the generator, but I've found the Honda EU2000i can do it. With judicious monitoring I used it to keep 'frige, freezer, and water pump going when we had power out at the old house. Once cooled down, the freezer would last for several hours and the water pump could be run "as needed". Most of the time I kept it hooked to the refrigerator - and the TV, computer, a few lights ...

simagic · September 2011

Re: how do I know the amount of throttle to send to my charger

Ok great.. I didn't know that it was either eco on or eco off and that's it. That kinda makes it a lot clearer. I thought (wrongly so) that if I took eco off, that I would then have to decide how fast to run it. Now I don't decide how fast to make it. It decides for itself. great.. thanx. NOW IT"S CLEAR...Thanx

simagic · September 2011

Re: how do I know the amount of throttle to send to my charger

Am I good with the 30amp charger for my 220 AH battery... it's a little over the 13%. Am I safe with that...Everywhere here it says 5%- 13%...not 5%- 14%. seems like 13% was the number someone came up with as Maximum...14 OK??

BB. · September 2011

Re: how do I know the amount of throttle to send to my charger

For "non-inverter generators", running them below ~1/2 of rated output--for the most part, fuel flow (kWH/gallon of fuel) remains about the same.

For an inverter-generator, I would plan on running about 1/4 of rated load fairly fuel efficiently.

For example, using the Honda eu2000i numbers:

4 hours per tank * 1,600 watts * 1/1.1 gallon fuel tank = 5,818 WH per gallon of fuel = 5.2 kWH per gallon
9.6 hours * 400 watts (quarter load) * 1/1.1 gallons of fuel = 3.491 =WH per gallon

And using Honda eu1000i numbers: Run Time per Tankful 3.8 hrs. @ rated load, 8.3 hrs. @ 1/4 load

3.8 hours * 900 watts / 0.6 gallons = 5,700 WH/gallon
8.3 hours * 225 watts / 0.6 gallons = 3,113 WH/gallon

The Yamaha EF200is at 1/2 load: Run Time (50% Load):8 Hours

8 hours * 800 watts / 1.1 gallon tank = 5,818 WH/Gallon

I don't know if the Yamaha numbers are accurate (the old Honda 1/4 load numbers were 15 hours per tank but now are listed at 9.6 hours per tank), so you will probably have to do your own testing to see what your fuel numbers work out to be.

For solar charging a "generic" Lead Acid Battery bank, we use 5% to 13% as the basic range. Below 5%, there is a combination of not enough current to "mix" a flooded cell battery and not enough energy to both recharge the battery bank and supply a "normal" set of loads (i.e., run risk of "deficit" charging the battery bank). At 13%, that is the normal maximum rate of charge for a flooded cell lead acid battery (they can overheat with more current). Also, works out to be, roughly, the maximum cost effective recharging (solar panels are expensive) as the battery will not accept > 13% for very long before they enter absorb charging (or the battery gets hot and the charge controller rolls back on charging voltage/current).

For AGM batteries, they can go below 5% or above 13%--But the basic recommendation for solar charging (for the above other reasons of minimum load support/wasted $$$) still stand.

For utility/generator chargers, the absolute recommended maximum charging current is probably 25%--usually because there is a lot more "free" power from a utility/generator and over-sizing is less of a cost hit.

Here is a great thread about one person's (SteveK) journey to find the best fit for his generator/battery bank charging (hint, your charger with PFC on a smaller genset looks to be a good fit):

Question about battery charger selection with EU2000 generator

Lots of details (if you are interested).

-Bill

Cariboocoot · September 2011

Re: how do I know the amount of throttle to send to my charger

Don't worry too much about the size of the battery charger. Even though it's 30 Amps, that's its maximum capacity. A regulated charger will not dump a steady 30 Amp load into the batteries until they burn up. The current draw will drop off as the battery charges and its internal resistance increases. Usually the Voltage set points on these chargers is lower than what we'd want for deep cycle too. Not much chance of overcharging from one unless you walk away and forget about it for a day; they aren't designed for that.

RCinFLA · September 2011

Re: how do I know the amount of throttle to send to my charger

Inverter generators have a permanent magnet three phase alternator that has a full wave rectifier to produce high voltge DC voltage.

A permanent magnet alternator's output voltage is a function of rpm and load current. The higher the rpm the higher the voltage for a given load. For the high frequency pulse width modulated AC output inverter, the input DC voltage must be greater then about 175 vdc to prevent the sinewave peaks from clipping. The ECO regulator automatically adjusts engine speed to keep the DC voltage around 180 volts.

Because it take a finite amount of time to speed up the engine, there will be some clipping of the output sinewave for a short period if a sudden increase in AC load is applied.

As to rpm versus output power, typically the engine speed peaks out at about two-thirds of rated power. Although these generators do save fuel by backing down rpm with light load, because of their small size their fuel economy based on kWH's per gallon of gas is rather low, about 4 kWH's per gallon. For propane, they will use slightly more gallons of propane then gallons of gasoline. (4.24 lbs per gallon of propane)

From the EF2000is spec for 400 watt load with EC on, a 20 lbs propane tank will last about 40 hours. Based on my EF3000is, expect about 10% better fuel to kWH's at 75% loading, when using ECO.

mike95490 · September 2011

Re: how do I know the amount of throttle to send to my charger

So, your charger of choice, is listed as being PFC .97 which is good, and efficency is 85%. Their site lists it as needing 450watts from the grid (mains) So, your min genset size would be 500w. After a few minutes of charging, the battery draw, for a smallish bank (220ah) will drop off. At some point, you may want solar to take over the absorb part of the cycle.

But my guess, unless you need to run a lot of loads, is the smallest genset (eu1000) and even it will be below 50% most of the time. Size the inverter so it can start your largest load (fridge?)

simagic · September 2011

Re: how do I know the amount of throttle to send to my charger

Mike....You say. "At some point, you may want solar to take over the absorb part of the cycle." . Why wouldn't I let the charger (which is 3 stage) completely charge my battery. I've seen on other blogs the mention of letting the solar "finish up"---(why?) I'm thinking that's why I'm doing this. The main reason I'm doing this phase of my whole "solar system'' is for when there is no sun to charge the system

Cariboocoot · September 2011

Re: how do I know the amount of throttle to send to my charger

The charging deep cycle batteries thing: http://www.windsun.com/Batteries/Battery_FAQ.htm#Battery%20Charging

When you get in to Absorb and Float the current requirements drop drastically and are more a matter of load needs rather than battery needs. Running a lot of generator (even an inverter type) to supply a couple of Amps doesn't make sense from the economic POV. Even on day when there is "no sun" there often is enough to complete the charge demands or at least contribute to them. If absolutely necessary you can run Bulk & Absorb on the gen (Float is not an "essential" charge stage). It's always best to make the most economical use of power, and in the case of generators that means loading them up. There is a certain minimum amount of fuel they will use whether producing 0 Watts or 30 or 50, et cetera, before the engine starts to rev and use more gas.

simagic · September 2011

Re: how do I know the amount of throttle to send to my charger

Ok, I get it. I don't want to spend $10 for a pound of meat and another $5 for just another ounce. Got it

simagic · September 2011

Re: how do I know the amount of throttle to send to my charger

hey, when you say "It's always best to make the most economical use of power, and in the case of generators that means loading them up. Do I run my "additional items'' from an additional plug (ie octopus plug) run from the generator to these items or do I run my additional items from my inverter getting the juice from the battery which I'm now charging??

Cariboocoot · September 2011

Re: how do I know the amount of throttle to send to my charger

simagic wrote: »

hey, when you say "It's always best to make the most economical use of power, and in the case of generators that means loading them up. Do I run my "additional items'' from an additional plug (ie octopus plug) run from the generator to these items or do I run my additional items from my inverter getting the juice from the battery which I'm now charging??

Consider this:
If you have an inverter with built-in charger, when you apply power to AC IN it switches all loads to that input and changes its function from 'invert' to 'charge'.

When we talk about charging from a solar array we refer to the 'net' charge rate as being the current coming from the charge controller minus the current going out to run loads.

See where this is going?

There's no sense in generating AC, turning it in to DC, then turning it back in to AC to run things if you don't have to. The only exception to this that I can think of is if you have large loads and a small generator, in which case charging the batteries only will allow the loads to use whatever power they need from the batteries while the charger puts out whatever it can - similar to how it would function with the charge coming from solar.

simagic · September 2011

Re: how do I know the amount of throttle to send to my charger

Thanks again for all this info .got it.........That's why they call this "beginners corner"

how do I know the amount of throttle to send to my charger

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