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.

[BFL13]

MrWizard wrote:
that flashing light, says don't add anymore load 🙂

individual item efficiency, only means something, IF there is a way to improve it

over all Efficiency is the end result of the assembled system

and we are not that far apart 0.5% the use of different meters and batteries can account for that easily, or even the mfg tolerances of the parts in the converter

Yes, it all comes out even when you use your "gross efficiency" idea.

So do you think that red flashing light is like the "low voltage alarm" on an inverter, where the inverter keeps running until the voltage gets even lower and the inverter shuts off the 120v ?

EDIT easy to ignore the gen one when there is no noise maker along with the red flashing light! 🙂
-------------------

Thanks Gdetrailer, good info and suggestions.

[Gdetrailer]

BFL13 wrote:

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Looking at Mr Wiz's numbers and mine I can't get the efficiencies to match, but we have the same converter/chargers (75 amp adjustable voltage)

I need to get this straight for calculating whether I can run the 75 if only I dial down the set voltage so the battery voltage can't rise above that and add more to the "output watts". That way maybe I can limit the VA required to under what sets off the red flashing light.


Mr Wiz got:

113v, 15.03a, 1350w, 1698VA, 0.79PF, output 13.2 x 80.5 = 1063w
So efficiency there is 1063/1350 = 79%

I got:

118v, 14.49a, 1247w, 1715VA, 0.73PF, output 14.2 x 75 = 1065w
So efficiency there is 1065/1247 = 85%

If we use the "gross efficiencies" including PF, it is

1063/1698 = 62.6% vs 1065/1715 = 62.1%

So if I set 14.1v on the charger (the AGM spec is 14.1 to 14.4) then at 75a, output watts will be 1058.

Using "gross efficiency" of 62.1% that would be 1703VA

If I use "efficiency" then input watts is 1058/86 = 1230 and my PF of 0.73, then VA is 1685

That flashing red light was not on when VA was 1625 but was on at 1715VA. The 15/20 receptacle is whatever limit a 15/20 has, but the gen limit is 14.2a at 120v. (except for a "surge" being higher limit) The 120v circuit breaker does not pop while the red light is flashing so power keeps flowing and the engine does not slow down any (by ear--no rev counter)

I would like to just ignore that flashing red light and go by the circuit breaker popping and see a steady red light as my overload limit, but I don't know the actual risk if any.

Very tempted to set that charger to 14.1v and pretend I can't see the flashing red light!

You do realize that Wizard's gen IS an "old school" non inverter gen..

Yours is an Inverter gen.

The two different "technologies" often handle things much differently.

Most likely Wizards gen is able to deal better with variable PFs and loads than an inverter type gen..

I think you will find that most inverter gens may not have quite as much "head room" for overloads or not be able to deal with non linear reactive loads as well as the old school gen heads.

Cost also comes into effect, I would not place any "Briggs and Stratton" gen as a "premium" Inverter brand by any means and I am suspicious that the output waveform of it is a bit closer to MSW than PSW..

Switching power supplies also have two different ways of dealing with PFC (Power Factor Correction)..

Passive and active.

Passive is less efficient but more "forgiving" of the input waveform.

Active PFC is more efficient but does not play well with MSW or poorly formed waveforms..

Inverter gens have much less "spinning mass" than a non inverter gen, that spinning mass helps non inverter gens deal with different loads much better.

Personally, I suspect that your "test results" are highly flawed due to too many unaccountable "variables". You are using a lot of highly variable loads which potentially can skew your results.

Batteries present highly variability as does your inverter load on the battery.

I think you need to place a "known" resistive load on the output of the converter/power supply to see if the gen will operate the converter at the current level you want.

This will remove a lot of variables like battery voltage, battery resistance, current absorption, ect.

Something else to consider, you may need to place a small resistive load on the inverter gen, something like an incadescent light. This may help smooth out the waveform from the gen by absorbing some of the reactive load/ spikes that the switching power supply may be presenting to the gen inverter.

When troubleshooting, you always want to try to remove all the variables you can.. Then one by one add in the "variables" as you get things figured out.

[MrWizard]

that flashing light, says don't add anymore load 🙂

individual item efficiency, only means something, IF there is a way to improve it

over all Efficiency is the end result of the assembled system

and we are not that far apart 0.5% the use of different meters and batteries can account for that easily, or even the mfg tolerances of the parts in the converter

[BFL13]

Thanks about the alcohol definition.
---------------

EDIT--I ran the gen to see how the overload circuit breaker works. Plugged the RV into the gen, turned on the MW, no red light, turned on the fridge with 120v and red light started to flash, ran ok, same as when I was doing the 75 charger, turned on a kettle and red light went steady and just after that the gen went burp and stopped the 120v and also the engine slowed down a little but kept running nicely.(eco was off for all this) I unplugged the cord, pushed the circuit breaker reset button, and the engine speeded up again and the green light came on for 120 output. All back to normal.
----------
Looking at Mr Wiz's numbers and mine I can't get the efficiencies to match, but we have the same converter/chargers (75 amp adjustable voltage)

I need to get this straight for calculating whether I can run the 75 if only I dial down the set voltage so the battery voltage can't rise above that and add more to the "output watts". That way maybe I can limit the VA required to under what sets off the red flashing light.


Mr Wiz got:

113v, 15.03a, 1350w, 1698VA, 0.79PF, output 13.2 x 80.5 = 1063w
So efficiency there is 1063/1350 = 79%

I got:

118v, 14.49a, 1247w, 1715VA, 0.73PF, output 14.2 x 75 = 1065w
So efficiency there is 1065/1247 = 85%

If we use the "gross efficiencies" including PF, it is

1063/1698 = 62.6% vs 1065/1715 = 62.1%

So if I set 14.1v on the charger (the AGM spec is 14.1 to 14.4) then at 75a, output watts will be 1058.

Using "gross efficiency" of 62.1% that would be 1703VA

If I use "efficiency" then input watts is 1058/86 = 1230 and my PF of 0.73, then VA is 1685

That flashing red light was not on when VA was 1625 but was on at 1715VA. The 15/20 receptacle is whatever limit a 15/20 has, but the gen limit is 14.2a at 120v. (except for a "surge" being higher limit) The 120v circuit breaker does not pop while the red light is flashing so power keeps flowing and the engine does not slow down any (by ear--no rev counter)

I would like to just ignore that flashing red light and go by the circuit breaker popping and see a steady red light as my overload limit, but I don't know the actual risk if any.

Very tempted to set that charger to 14.1v and pretend I can't see the flashing red light!

[drsteve]

BFL13 wrote:

MEXICOWANDERER wrote:
Yea or no alcohol matters.

You could run 115/145 octane av gas and it wouldn't do squat versus alcohol-free 87 octane gasoline.

I completely don't understand "ethanol(gasohol)" vs "alcohol". What's with that?

Ethanol = ethyl alcohol. Gasohol = gasoline with ethyl alcohol added.

[MrWizard]

this is a 5kw onan
and unloaded voltage is 119-120vac

[BFL13]

Interesting how with the same 75 amp converter/charger you get a better PF at 0.79 than I do at 0.7ish. Your efficiency percentage is the same at about 78%.

Your loaded voltage is lower than what I got 114 vs my 118 , but that depends on the generator. When on the Honda 3000, I got a higher loaded voltage than with this little guy because the Honda unloaded was 126.8v while this one is 124 so loaded voltage is lower too.

Another thing on that is the Honda 3000 dropped from 127 to 124 , 3 volts while this little gen went from 124 to 118 , 6 volts when hit by the same 75 amper.

Must have something to do with the size of the engine wrt the "120v" output.

Anyway, just noting that all generators are not created equal in how they handle a particular charger

[MrWizard]

NEW QUICK TEST

volts at battery 13.2, converter amps 80.5

power meter
1350.0 watts

113.0v * 15.03 amps = 1698.39va

PF 0.794

video frame image

[BFL13]

MrWizard wrote:
i won't debate Pd versus other converters

BUT you can't have BOTH constant amps and constant voltage

to have constant amps voltage has to rise ''probably to a dangerous level'

you have a set constant voltage and amps will taper as the battery charges

Yes, that is what I like. Set 14.8v on the charger. Constant amps while battery voltage rises to some level (14.2 say) then amps taper. Battery voltage continues to rise as amps taper till battery voltage is close to the set converter voltage of 14.8 and amps have tapered to near zero. Now reset the converter to 13.x voltage depending on the temperature. (13.2 for 80F , 13.8 for 50F, etc)

EDIT, you can also set that initial voltage per temperature. EG, if the battery spec wants 14.8 at 80F, then set 15.2 if it is 35F and the batts are "outside" ( not AGMs inside where it is warm).

[MrWizard]

i won't debate Pd versus other converters

BUT you can't have BOTH constant amps and constant voltage

to have constant amps voltage has to rise ''probably to a dangerous level'

you have a set constant voltage and amps will taper as the battery charges

[BFL13]

MrWizard wrote:
its normally stored away, i keep it as a tester, normally for A/C season
i hooked it up for this test, will leave it in place and maybe get a 'high' amps reading thurs or fri

i have seen the converter charge meter, read 80 amps
maybe i can get a power meter reading, with an 80amp charge reading

one more test you might try
do the MW/inverter operation test
then turn off the inverter while leaving the genny and converter on
see if it stays running and what the load is

I did that. Was 119v, 13.65a, 1137w, 1635VA (no red light) shut off the inverter running the MW (load first of course) then saw:

117v, 14.49a, 1241w, 1714VA, PF 0.7 with flashing red light coming on (seems to come on when VA gets over its rated 1700w) but kept running the converter at 75 amps ok.

Yes, 80 amps is possible. I got 103a from my 100 and time2roll got 60 from his 55 WFCO. I got 62 from my 55 Parallax 4455 with short fat wires. You should get a little more than rated max amps (current limited) from your converter if you have short fat wires to the battery.

Unfortunately, PDs even with Charge Wizard don't seem to act that way from most reports. (some exceptions) On start-up they lose about 5 amps , straggle on at not quite constant amps losing some, then dip a bit more (all during the bulk stage when they should be at full rated amps constant, and then--they do the big tapering swan dive like the others do at the start of absorption stage, except from the lower amps they were at by then in the bulk stage.

I could not live with that-- I demand my constant rated or better amps all through the bulk stage. But folks on here with PDs have amazing loyalty to them. People are just weird. 🙂

[MrWizard]

its normally stored away, i keep it as a tester, normally for A/C season
i hooked it up for this test, will leave it in place and maybe get a 'high' amps reading thurs or fri

i have seen the converter charge meter, read 80 amps
maybe i can get a power meter reading, with an 80amp charge reading

one more test you might try
do the MW/inverter operation test
then turn off the inverter while leaving the genny and converter on
see if it stays running and what the load is

[MEXICOWANDERER]

0.00000000% alcohol means alcohol free. Pure gasoline.

Gasohol is the buzzword for alcohol contaminated gasoline, be it 3%, 5%, 10%, 15%

If mileage loss is linear with power loss, using alcohol free gasoline just might be enough to push that generator hard enough for 75 amps. It costs peanuts to try.

When Canadian Club starts adding gasoline I'll consider gasohol.

[BFL13]

Gottaluvit! I like that some folks keep track of things like I try to do, but I don't always do so well. Good going Mr Wiz!

[MrWizard]

the green display can show either...watts, Kw Hrs , COSINE/PF

the two red displays, always show volts on the left 114.0
and amps on the right 12.90

the green meter at the bottom is showing converter output amps 67.2