Would Higher Octane Run the Gen Better? UPDATE

[BFL13]

UPDATE 21 Nov page 5

Ongoing saga with my 1700w (continuous) gen trying to run my 75 amp charger at 75 amps. Briggs and Stratton P2200 gen.

Previously posted that it would not (flashing overload red light), then discovered I still had it choked. Next test was to run it with the batteries full, but with an inverter draw of 127 amps, then turn on the charger, but now with the gen choke in the right place. Amps now -52 so 127 minus 52 = 75 amps from the converter/charger. No flashing overload light on gen. So I reported success.

Just been camping off grid, did a recharge with the gen and the 75 amper. No red light at first. 75 amps to battery bank. Then after a few minutes the red light started flashing but gen kept running.(It can shut off with overload.) Switched to the 55 amp charger and no red light.

We know that running a charger as a power supply is easier than doing an actual battery recharge due to the higher battery resistance. Sometimes it can do its full amps as a power supply, but might not be able to do its full amps on the battery. BUT--I thought that if it did its 75 amps as supply that was the same effort as doing 75 amps on a battery.

Here, 75 amps on battery seems to take more effort from the charger than doing supply, so needs more from the generator? 75 is not the same 75?

Also there is some relationship between the generator engine running and the power output, as seen when it was choked and did less 120v power. I am wondering if the gen would run the 75 amper without the flashing overload light if only the engine ran a little "better" (not sure what I mean by that in what the engine would have to do) More revs?

The manual mentions engine getting bogged down with too much load-I did not hear it running slower.

So finally after all that background--would the engine do "better" if it ran on higher octane gasoline? It has 87 now (regular). And if it did, would that make the difference to output power I need where I am just on the edge for running that 75 amper?

Engine is 6.77 cu-in(111 cc), 4500 revs single-cylinder, revolving field, wants 87 octane minimum below 2500 ft altitude.

I will not have an opportunity to try that for a while, so I am asking here to learn if it is worth trying at all. Thanks.

[SoundGuy]

BFL13 wrote:
As of December 20, 2015, Peninsula Co-op petroleum sites will have the following ethanol contents:
•Regular Gasoline (87 octane) 10% ethanol, known as E10.
•Mid-Grade Gasoline (89 octane) 5% ethanol, known as E5.
•Premium Gasoline (91 octane) will not contain ethanol.
•Marked Mid-grade Gasoline (89 octane) and Diesel will not contain ethanol

You'd have to check in BC but here in Ontario premium grade Shell & Esso fuel is 100% non-ethanol and is what I always used in my EU2000i gensets, eliminating any concern over gumming caused by ethanol. What really made a difference in performance was replacing the dino oil in the crankcase with Mobil 1 synth - with the former, successfully starting a 13.5K BTU A/C with the genset was iffy even near sea level, with synth success under the same conditions was guaranteed. :B

[BFL13]

Does it matter if the gas has some stabilizer in it, as when you don't use the gen much and leave gas in the tank?

[LittleBill]

high octane generally hurts/ doesn't help unless the engine was designed for it. higher octane fuel is actually harder to burn.


so unless it has a computer to adjust for the timing (it doesn't) you won't see a bit of difference except a lighter wallet.

[BFL13]

Chris Bryant wrote:
Pretty easy to test, just sayin'. 😉

Not quite--first have to run the battery bank down to where it will accept 75 amps for a while, swap out the gas in the gen, and try that. I just finished fully recharging the batteries till the next trip, perhaps till January sometime.

I might get the urge to do that test in the back yard anyway. Ambient temps are falling too. Does the generator care if it is cold out?

[Chris_Bryant]

Pretty easy to test, just sayin'. 😉

[BFL13]

I found this on-line for local gasoline. Will check other brand gas stations.

As of December 20, 2015, Peninsula Co-op petroleum sites will have the following ethanol contents:
•Regular Gasoline (87 octane) 10% ethanol, known as E10.
•Mid-Grade Gasoline (89 octane) 5% ethanol, known as E5.
•Premium Gasoline (91 octane) will not contain ethanol.
•Marked Mid-grade Gasoline (89 octane) and Diesel will not contain ethanol

Seems not all are the same for having the higher octane no ethanol, so I will have to look at them on site to get the latest info. They have changed over the years, even since 2015 apparently.

[BFL13]

babock wrote:
10% ethanol fuel has 3% less BTUs...that's it. That would result in the same power loss that an extra 1000 feet of altitude will do.

Speaking of altitude, what altitude are you doing all of this at?

Maybe 100 feet? (Near the beach) Actually the gen manual says above 5000 ft you need a minimum of 85 octane and to adjust the emissions with the kit thing. Don't run it with that high altitude kit at low altitude or you get "decreased performance". Minimum octane under 2500 feet is 87, so higher than at 5000 feet.

Manual says, "Fuel with up to 10% ethanol (gasohol) is acceptable."
I wonder if "acceptable" means the same to them as it does to me!

Can't remember what the ethanol content is in the 87. Says on the gas pump, so I will check that.

[BFL13]

jkwilson wrote:
What exact battery charger are you operating?

The battery resistance is a non-issue. Amps are amps on the DC side of the circuit. What may be happening is that the charger output voltage may be changing which can change power output and requiring more or less input power.

An inverter generator is power limited at reduced RPM. The generator creates DC power that supplies the inverter. Lower RPM means lower generator output power and less power available from the inverter.

It is a PowerMax adjustable voltage. You set your charging voltage at 14.6, say, and it holds that voltage. Very steady. It is current limited at just over 75 amps. (You can usually get a few more than rated amps with any converter if you have short fat wires to the battery)

The Kill-A-Watt shows it is pulling just under 1700VA while it is doing 75 amps when set to 14.6v and the battery voltage is of course rising while the 75 amps keeps going in.

The battery resistance rises as battery voltage climbs and at some point the converter amps start to taper. When they taper, output watts drops and so does input VA required from the gen.

In this case, it only ran for a few minutes with no red light and then it started flashing, so not enough time for battery resistance to climb? The gen would have warmed up some more (I had it running well before loading it though) and the current going through the wires and the battery would warm them up a bit too. Don't know if that would increase the VA required in those few minutes. Something did.

[MEXICOWANDERER]

The last time I checked, a Briggs & Stratton engine had 5.5 to 1 compression ratio.

Ask the US EPA to provide a comprehensive comparison between alcohol as an additive and MTBE, and you will receive nothing but a cold stare. Stations were mandated to require dual lined fuel tanks but other than the implementation the news feed went dead.

Mexico where alcohol is severely restricted my fuel mileage actually increases in the winter when MTBE is mandated.

Pablo's eyebrows shot upward when I penciled $3.45 Costco gasoline was more expensive to run than $3.73 US refined Mexican BP gasoline. It's all about corruption and using food for fuel for profiteering.

[babock]

10% ethanol fuel has 3% less BTUs...that's it. That would result in the same power loss that an extra 1000 feet of altitude will do.

Speaking of altitude, what altitude are you doing all of this at?

[BFL13]

Is it higher revs I want for that "revolving field" and would lower ethanol gas make it do that? Or would the better gas just keep the revs at 4500 at the max load?

The flashing red light shows on the Kill-a- Watt as intermittent power but the Trimetric shows a steady 75 amps. I think that is just the Trimetric where it has a built in slow reaction it mentions in its manual.

The red light shows that 120v is off, no load light goes out, and then comes right back on with load still there, all very rapid on-off. It doesn't get to where the 120v reset button is needed or conk out the engine.

Same way the inverter shuts off at low DC voltage. It shuts off, then comes right back on, then shuts off. You have to reduce the 120v load to let the "loaded voltage" be higher so it stays on.

I don't think the converter/charger would like that intermittent 120v input for very long, so I don't keep that going.

[RCMAN46]

I have found that my Honda 2000I runs much smoother when I use ethanol free gasoline.

[Dennis12]

what does the manufacturer recommend ? Go by it

[jkwilson]

What exact battery charger are you operating?

The battery resistance is a non-issue. Amps are amps on the DC side of the circuit. What may be happening is that the charger output voltage may be changing which can change power output and requiring more or less input power.

An inverter generator is power limited at reduced RPM. The generator creates DC power that supplies the inverter. Lower RPM means lower generator output power and less power available from the inverter.

[naturist]

It should be noted that ethanol provides an octane boost along with an energy density loss to any gasoline mix. I don't expect that merely higher octane fuel would offer an improvement, but a no-ethanol gas might. I don't know about BC, but here in the states, at least on the East Coast, no-ethanol gas is available, but you have to search for it. It is not usually needed for cars, but small engines often do better with it.