HF Predator Inverter Generators.

[sajohnson]

Originally Posted by Keyair

Same Guy... 3500w starving for air solution...

Great videos -- love the intro with the ducks!

That is one of the best things about the Internet -- it allows people to share tips, advice, instructions, etc.

I'm not in the market for a generator, have no connection to any of the mfrs, and do not care what people buy.

That said, as a technician I am interested in generators, inverters, solar panels, batteries, etc. I did notice a few things in this video that I thought I'd point out:

1) All the vacuum testing was done at idle, with no load. Under load, the vacuum would be even greater.

2) Even with six (6) 1" vents and the engine at idle, there was still enough vacuum to keep the door pulled shut. That indicates that there is still not enough airflow.

3) The foam inserts will immediately begin to become obstructed with dust, insects, and debris -- so the airflow will be progressively less over time.

4) This is clearly a Homer Simpson level "D'oh!" design flaw. Owners should not have to a) purchase a replacement door, or b) modify the existing door. It is the mfr's responsibility to make this right. They should provide a replacement door -- or some other solution -- free of charge. End of story. It's bad enough that they made a mistake like this, the least they can do is correct it.

Call me cynical, but I'm gonna go out on a limb and say that ain't gonna happen.

In that case I would search for other solutions. For example, while I get the appeal of working on a door panel that can be removed and placed on a bench -- is there a reason a vent(s) cannot be installed elsewhere on the case?

One dilemma is the conflicting goals of reducing noise & keeping the interior clean vs allowing air in. Maybe a compact air filter assy, mounted (ideally) inside the case, or externally?

[bigredandoldblue]

I paid an additional $130 for the extended warranty that is hassle free. I called the home office and they said they use to send them to small motor shops for repair, but it is cheaper for them to just replace it with a new one. The CATCH is three years on original purchase date, so if it fails the warranty does not roll over.

Drawing power at 2200 watts was the refrigerator, a/c, two 120v lamps, radio 120v, 2 phone chargers, 2 tv, microwave. I'm going, to do some more testing.

[EarStreaming]

Glad you created this thread as I'm interested on this alternative to the higher prices ones. I prefer the propane over gas and would love to get updates from folks here that have converted to propane and their experiences.

[rmkrum]

Hm. Interesting. There is obviously something going on here with carburetor air flow in these inexpensive inverter generator sets. Just the slight change in engine tone at idle with the door open or shut is interesting.

A handful of additional thoughts:

This is the Predator from Harbor freight, but I bet most of the inexpensive inverter sets are similar. Cooling air for the engine has to come from somewhere. It has to be drawn into the enclosure, circulated over the engine, and has to flow out somewhere. I assume a heavily baffled intake and outlet grill to keep the noise inside. The carburetor air intake and its filter is probably also deep inside the enclosure. So what air the carburetor gets is coming from inside the enclosure. The exhaust discharges outside the enclosure through the muffler assembly. That's the basic air flow for these things.

The oil change door being sucked and held in place, to me, indicates that the engine cooling fan is doing most of the sucking. Its a high volume fan that needs to keep the engine cool. Using the door as an indicator of proper air flow to the carburetor is a bit misleading, because the air flow through the carburetor is very much smaller than the big cooling fan air flow.

A much better way to characterize the engine combustion air starvation problem would be to tap a suitable water column manometer into the air filter assembly on the carburetor intake side of the filter (Manifold vacuum in the carburetor would be even better). Then you can see the carburetor intake air vacuum changes in real time under varying loads and easily determine what is really going on.

I'm not saying adding more air vents is not a good idea. My suspicion is that just the 5-6 added one inch vents may not be anywhere near enough when the engine is running at full speed under heavy load, and trying to suck a much higher volume of air through the baffles in the enclosure. Then you will possibly be seeing real carburetor air starvation. Running this test at idle, without carburetor air intake vacuum instrumentation is not going to prove much. I want to test this at full load, on a hot day, at altitude, running on propane. (grin)

I'm sticking my nose in here because this is a good demonstration of potential problems. I would bet my 3400 watt Champion Dual fuel Inverter will exhibit similar issues, assuming it's engine air intake is from inside the enclosure as the Predator apparently is. So from that point of view, this subject "needs more research" and a bit better instrumentation. I do know that the Champion has a much larger oil change access door, so there is room for a lot more ventilation if I need it. I need to look into the subject when I have time.

Until we get more experience with these generators, and some quantitative measurements, this may also be a nice solution in search of a real problem...

Sorry for the not so brief diversion...from the "Department of Overkill Engineering".

[Keyair]

This appears to be a problem on the 3500w version.
The 2000w unit does not have the oil door, as the whole side panel comes off, so it would be difficult to assess if there is an issue.

[rmkrum]

Originally Posted by Keyair

This appears to be a problem on the 3500w version.
The 2000w unit does not have the oil door, as the whole side panel comes off, so it would be difficult to assess if there is an issue.

Yeah, that situation would only be evaluated with the manometer setup--and looking at difference in carburetor input vacuum with door on or off, assuming one can snake the manometer tube connection into the enclosure in a viable way to get good measurements.

Another suspicion is that the engine cooling fan probabably sucks air OUT of the housing, rather than blowing it in--based on the door being sucked into place. There is potentially a lot of suction possible at high RPM and with potentially increasingly dirty baffles on the inlet side of the case, this may get worse...I suspect a lot of the 'quiet' in these things is a lot of sound suppressing construction, and dirt-trapping foam materials, as well as the obvious soft rubber mounts for the moving parts to keep the noises inside the box. I bet the 2000 is really loud with the side panel off!

It's one of those problems that are "interesting, in the Spockian sense". But, as I always point out, if you can't measure it, you can't really understand what is going on...

[HiHoAgRV]

Agree, the fans on these usually blow air out of the case. The inlets are placed to force incoming air across the various parts that need cooling. By adding a new vent, less air will enter the original inlets and cross the cooling fins and possibly create an over heating issue

[rmkrum]

Originally Posted by HiHoAgRV

Agree, the fans on these usually blow air out of the case. The inlets are placed to force incoming air across the various parts that need cooling. By adding a new vent, less air will enter the original inlets and cross the cooling fins and possibly create an over heating issue

Really good point! That's why the need to measure what is really going on at the carburetor air intake, instead of arbitrarily punching extra holes in things...I need to take a close look inside my Champion with a view to airflow, and someone with a HF Predator needs to do the same and report here...time to dig out the borescope camera and poke into the inner recesses...

[Keyair]

2000w unit is again $449 with the coupon I got via email again today. [emoji3]

[UnklJoe]

I know this is about Harbor Frieght inverter generators, but I mentioned I bought two remarkably similar Wen 2000W inverter generators from woot.com a while back. And, they're back on sale at woot.com today for $384.99 each. I also found a gas tank cap that is like the ones used on Yamaha generators that can be adapted for extra gas tanks (on ebay) so if I were using gasoline I could make up my own extra tank so it could run all night long without getting up to add fuel (using a outboard engine fuel tank). And, the magnetic dipsticks, too (also on ebay).

[Keyair]

The billet fuel cap that allows an external tank, makes sense, and they are out there.
I think I’m going with the Propane conversion, but want to make the regulator easily removable or even mount it on the propane tank if possible.

[sajohnson]

Originally Posted by hamboneto

I paid an additional $130 for the extended warranty that is hassle free. I called the home office and they said they use to send them to small motor shops for repair, but it is cheaper for them to just replace it with a new one. The CATCH is three years on original purchase date, so if it fails the warranty does not roll over.

Drawing power at 2200 watts was the refrigerator, a/c, two 120v lamps, radio 120v, 2 phone chargers, 2 tv, microwave. I'm going, to do some more testing.

Thanks hamboneto!

2200 watts is good (low) for all those loads together.

Our microwave alone is ~1825 watts. The rooftop A/C unit (13.5KBtu Coleman) uses ~1400 watts (running). The fridge is another ~300 watts. So that's 3500W right there, plus the smaller stuff.

The QD3200 WGO installed is really undersized. We have to watch what we turn on.

I'd be interested in any further testing you do.

[Keyair]

My magnetic dipstick and fill/drain tube arrived.
Very nice parts!
Happy!

[AFTER TAXES]

Originally Posted by Keyair

So, let me start.

HF 2000w Unit.
Bought 6/17/2018, here in CA.
Fathers Day Coupon, $449, plus we bought the 2 year warrantee @99.99.
Added a 2 gallon fuel can and some Stabil 360 fuel treatment, Tax, and we were about $600 out the door.

First impressions were good.
Unit was well packaged, came with a small tool kit in a pouch(Spark plug wrench, open ended wrench, and a screwdriver).

I added the 10/30 oil they suggest, which was not included, but I had some to hand(10/30 Synthetic Diesel oil).
There was some oil evident in the crankcase, so the unit was probably test run during production, and drained for shipping.

Filled it with oil, and gas(with Stabil 360 added), and opened the gas tank vent.
Then pulled the starter cord maybe 5/10x with the start switch in OFF to prime the gas into the carb, and oil into the engine.
I noted the pull starter is very light, and easy to pull for me, at 6' 4" and 240lb.... ish...

Flipped the switch to START and pulled again... the unit fired and ran before I was maybe 1/3 into the stroke with a puff of blue smoke, but after 5 seconds I flipped the switch to RUN and the unit purred into a steady gait.

I weighed it and it came in just under 55 lb full of oil and fuel.

My GF was able to start it no problem, and she is half my size or less. I'm sure she could pick it up, but it would be a struggle.

are u saying it beats a honda .........? only money

[Keyair]

Nope, and that’s not what this thread is about.

Now go back and read the opener, especially the bit in bold.

[Keyair]

HF has a super coupon I got via email for the 3500, @ $699.99, valid thru 8/15.

[AFTER TAXES]

sounds and reads, has a lot too do with money........
but only Alumaholic knows !!!!!!

[Keyair]

Update...
Magnetic dipstick added and fill/drain tube tested.

[ROBERTSUNRUS]

Originally Posted by Keyair

The billet fuel cap that allows an external tank, makes sense, and they are out there.
I think I’m going with the Propane conversion, but want to make the regulator easily removable or even mount it on the propane tank if possible.

Hi, I think that I like the idea of mounting the propane regulator on the propane tank. I'm sure that you will post pictures of it and report how well it works.

[rmkrum]

Test carefully. I know on the 3400 Champion dual fuel inverter the regulator hose length from engine to the low pressure regulator is designed to work just right. Can’t extend it any and be sure it will still run correctly. This regulator precisely controls fuel flow based on engine vacuum.