Day: September 28, 2018

The Home Depot near us advertised a small 600W (860VA) generator for $165 and some change.

Now I won’t go into a lot of useless details except to say it’s got a very small 4 cycle 40cc engine and just as small .4 gallon gas tank. (ESI860i) It is advertised that it will provide 50% load (350W) for “Up To” 3 hours. (I did not want to mix oil with the fuel so 2cycle was not an option.) Still this generator comes in at a measly 25Lbs!

My intent for this generator was to power a full size refrigerator that draws about 175W and maybe a little more during a defrost cycle. (But certainly much less than the 600W rating of the generator.)

I ordered one from THD and picked it up a couple weeks later. To my surprise it looked like they threw it off the truck. The box was heavily damaged when I received it.

Still, the generator appeared to suffer minor damage and did run for the first couple days. (I found out later that the oil level sensor was permanently damaged by the rough handling and had to be bypassed.)

I tried to break in the generator by running it at idle for an hour or so then at high idle for another hour. I put a light 60W load on it and ran it for two more hours. I filled the gas tank and hooked it up to 300W load and ran it for maybe 3 tanks about 10 hours before changing the oil.

I was happy enough with the performance to purchase two more generators while they were still on sale @ 30% off. I ran the generator as much as I could during the next few days with the 300 W load and it seemed to provide it with moderate difficulty. The generator eventually refused to run and the low oil light could not be extinguished.

The two additional generators arrived and I performed the same break-in routine I did with the first one. One of the generators was having great difficulty providing the 350W load and would trip offline at about 450 watts. (Much less than the rated 600W) So with three generators at my feet, one refused to run, one couldn’t provide much more than half its rated power and the third seemed to be running ok. The reliability was not as good as I had hoped. (My coworker had warned me about buying these cheep generators.)

The generator that performed the best still could not support a 600W load, it would trip offline about 450W. (I think the advertised capability was stretched a little with the “Up To” caveat.) After hours of research the efficiency was not as good as I had hoped, a 2200W generator could run about as long on a gallon of gasoline as this 600W one. (Which would be MUCH more desirable to have the additional surge capability.) Further, the Yamaha had a 1.1Gallon tank so it would run 10 hours without needing to be fueled or needing oil! (The surge capability would eliminate the need for a UPS to supply the additional current needed to start the fridge.)

I am still on the fence about getting a Propane powered generator, they burn a LOT of propane!

I disassembled the generator that refused to run and the oil sensor was indeed stuck, I pushed the pin out of the connector to regain use of the first generator that produced much more power then generator #3. The only major problem with #1 is that there’s something wrong with the fuel pump. It stops running at about half a tank. LIFAN sent me two fuel pumps, neither of them fit my generator. What I did learn when I attempted to replace the fuel pump was that the vacuum side was full of fuel. I dumped the fuel out and reassembled the generator with a repaired (Frankenstein) inverter module and it ran fine for several tanks of fuel.

Generator #1 and Generator #2 I am almost happy with their performance. They consume enough oil to need replenishment after 6 hours at 300W. A full tank might last three hours before running out of gasoline. (There is no sight glass, the only way to see the fuel is to take off the gas cap.) I am rather surprised at the poor performance of generator #3, I changed out the inverter module and that didn’t help anything. (I assume at this point that the alternator itself is not as efficient and cannot supply the power as the other two that seem to be able to without difficulty.)

I bought a forth generator when they went on sale again. I ran it though the same break-in process that I did with the first three. When I finally put a load on the generator it had no guts at all and tripped offline. Further research over the next couple days revealed that the exhaust had a constriction of some sort and the engine backpressure caused the engine to loose most of it’s torque.

LIFAN didn’t want me to return it to THD even though I’ve only had it for 5 days. They are sending a UPS pickup to repair the generator under warranty. So if you’ve managed to follow this, I have two running and one limping generator in the garage with a fourth being repaired under warranty. After two weeks they said there was nothing wrong with the generator and wanted a credit card to ship the unit back. $30 and three days later I found out that the generator still would cave in at 350W. (Not sure how they managed to get it to support 550W.)

LIFAN shipping came through with a new generator to replace #4 with the bad exhaust after I told them it still wasn’t fixed. (Keep in mind that I could have returned it to THD since it was only 4 days old at that point.) The new generator arrived and I didn’t like the choke lever sticking out of the box.

I pulled the maintenance cover and the air filter cover to take a look at the choke vane in the carburetor. The vane was not inserted properly and prevented the lever from rotating all the way.

I pushed the vane as far as I could and it allowed the lever to operate almost normally. The load tests on the generator passed with flying colors. The one remaining problem child was generator #4, I got out a drill and punched a very small hole into the exhaust manifold. Cranked up the generator and that hole along with the exhaust port was sufficient for the engine to run properly under heavy load.

If you’ve been keeping up, I now have FIVE running generators!

For comparison I looked online for the “Best” generator for fuel efficiency. The Yamaha 2200VA generator makes about 4KWH out of a gallon of fuel. The LIFAN ESI 860i makes only 2KWH from a gallon of gas and has severe limitations because of the small engine size. The assumption at this point is that the sales department stretched the specifications to the limits of the engineering to make it look better. Then when we (The customers) bought the generator and realized the number of shortfalls we would bring it back and buy a more expensive generator at the same store. (Using the credit from the ESI 860i)

I’ve learned a lot over the last several weeks. The last small engine I owned was a gasoline lawn mower. I don’t remember changing that oil more than once per year. This generator’s oil gets fairly dirty after 4 tanks of gasoline, say 10-12 hours. Not to mention oil had to be added at 6 hours or it would not start at 9 hours. I ran 5W20 oil in Generator #1 for about three hours with 60W load in an attempt to clean the engine since being my first of the four, it was run so long without changing the oil. The 5W20 oil wasn’t real dirty, but it was too risky to keep running the generator at such a lightweight oil.

Over the last month I’ve enjoyed playing with these generators. I had long forgotten the pleasure of working on mechanical things. In many ways they are simpler than the computers and electronics that I spend most of my working hours trying to coax them into doing what we need them to do.

Generators have always fascinated me, they can run for insanely amounts of time without needing replacement parts or adjustments. Feed them their fluids and they run most of the time. These LIFAN generators caught me off guard, I hadn’t planned on disassembling them to do simple maintenance. Normally, easy access is granted for things like the air filter. The air filter on these tiny generators requires the generator case be split in two and the motor removed from the plastic enclosure to clean the air filter! When I was talking to LIFAN, they talked as though breaking down the plastic enclosure was something they planned on the average consumer to do. I cannot imagine my daughter (who is quite talented), taking these generators apart in her apartment. (Neither of us have a useable garage for this sort of maintenance.) Being in the military I am used to having well written service manuals, LIFAN has a TERRIBLE manual. There’s NO way that these generators should run 90 hours without an oil change. I also had not counted on how finicky the output power was. They are “Rated” at 600W, but they often cave in at 540W and drop the output until the generator is shut down and restarted. All I really needed was 175W, they were rated at 600W. Where is the math on that one.

When I was a teenager I bought solar cells from a catalog and mounted them on top of my portable radio.  It worked pretty well and was popular on the beach.  I ended up in the middle of the dessert with a dead cell phone battery and had to use a 60KW generator to charge my Cell phone.  I bought and carried a USB solar panel with me after that.  Over the years those USB panels got a little bit bigger and a lot more efficient to where they’d push a couple amps so I gave them to my siblings for emergencies.  The bigger panels 80-100W were getting reasonably priced so a couple years ago (2012 ish) I started buying them a couple at a time until I had twelve of them in storage.  When I quit my full time job in 2017 I laid one of them on the roof in the winter for a couple days to gather some data.  One of my requirements is to provide 200WH of power for my CPAP.   I have enough battery for a couple days, but going without it is not an option.  After a couple days I found out that one panel in the winter sun was not going to provide enough power.  I grabbed a second panel and bolted them together making a 200W 36V array that should provide approximately 360WH of power per day in December. (The worst month.)  Since I sleep at night the power has to make a round trip into and out of a battery which has a significant cost.  But I can also live on six hours of sleep if I have to.  During the summer months those two panels produce almost 900WH/Day which can keep our refrigerator powered and have enough left over for Cell Phones and charging lanterns for the evening.  It is my opinion that all homes aught to have these two panels to provide USB power for the occupants during an emergency.  If your a bit of a Macguyver, 200WH is enough power to make a pot of coffee, toast a couple bagels or thaw waffles with a microwave.

One benefit of living in the same house for 30 years is having the knowledge gained from being there.  Our little home looses power momentarily several times a month.  Longer outages (like an hour) happen very infrequently and are usually related to a violent storm moving through our area.  Maybe twice since we’ve lived here did the power fail for more than a day.  So for me, a generator would probably die in storage before it was needed. (I had a 7KVA generator for a while and really loud!  It was also a significant amount of work exercising the engine and maintaining a supply of gasoline, so I gave it away.) 

We have three large banks of batteries in the garage  and they power three UPS units that are designed to be connected to them.   Our highest priority load is the refrigerator. The 1KVA UPS with external battery can maintain operation for about 24 hours and I’ve got two solar panels to extend that into two days with bright sunlight.  A second UPS and battery bank supports all the computers in the house and the emergency lights.  A rather large third unit can make a pot of coffee in the morning or toast a bagel on solar power.  (It also can run the microwave with some adjustments.)

In 2019 I bought a very small generator to extend the runtime of these UPS units, it took months to figure out a reliable way of connecting this tiny generator.  In the end the UPS units could not be directly powered by the generator using their power cords.  What does work well is to use power supplies and charge the batteries with the generator.

One surprising revelation was that these small generators are most efficient at 100% load.  An 860VA generator producing 500W generates about 4.4KW/Gallon of gas.  At 130W that same generator only produces about 1.8KW/Gallon of gas.  With that in mind it made sense to me to intermittently run the generator and use the UPS batteries to support the load.  The charge/discharge battery losses were easily made up with the increased efficiency of the generator at it’s maximum rating.

Using a adjustable current & voltage power supply, the charging currents and full charge voltages can be set for the generator power rating, storage battery size and type.  In my case I have enough battery to consume more charging current than the ESI860 generator can produce.   The ESI860 can run for about a little over 3.5 hours on a tank (.4 Gal) of gasoline at full load of 500W.  12 Amps (About the maximum the ESI860 would support) for 3.5 hours is 54AH at 28Volts (3780WH/Gal) into 200AH of battery.

Looking at the load side of the equation I need to be under 300W average load.  The Fridge is roughly 100W average so everything else should be less than 200W.  I can also run the generator more often or supplement the charging with solar.

My first computers taught me a lot about needing backup power solutions.  I would spend a couple hours writing a program only to have a power glitch evaporate my efforts.   I was lucky to have a computer that ran on 12V, so extending the power running the lights into the closet with the computer was not really difficult.  My next PC had a traditional AC power supply which made things a little more complicated.  I had already built a small UPS for the lights on the fireplace so it wasn’t difficult to build a bigger one that could also support the computer.  (Just more money in parts.)  Lightning struck a tree in my neighbors yard and that fried my home built UPS sitting the garage floor.  I did not like the rather expensive UPS units in the stores, they all had an awfully short run time.  It also didn’t make sense to purchase multiple UPS units because their batteries were a significant long term cost.  I ended up buying two medium sized UPS units and wiring them to rather huge batteries.  (I wasn’t worried about recharge times that would be several days.)  There are too many variables that have to be taken into account and significant risks of modifying a consumer UPS unit to recommend it to anyone.  (FYI, they are designed by cost concerns not the consumer’s needs.  Most of them will approach terminal temperature by the time the battery is exhausted.  So extending the battery yields dangerous amounts of heat and a possible fire…  *Check it out on YouTube.)

I am still fascinated with electricity and all the things it can do.  (Yes, I can still stare at a running 60KW generator in total awe for quite a while.)  Having a home with toddlers in it pressured me into building redundant lighting in my homestead back in the 80’s.  (The kids were not nearly as stressed if the lights managed to stay on during a storm.)  I came up with two solutions.  First I installed 12V “Grain of wheat” lamps in the ceilings of all the rooms and installed 12V powered wall lights over the fireplace. (Hey they were popular in the 80’s)

(It became unnecessary to have a flashlight since every room in the house was always Illuminated.)   The charger and deep cycle batteries were in the garage with a heavy gauge wire run to a closet DC distribution box.

When “Puck” LED lights became popular in the 90’s I changed out the incandescent grain of wheat lamps out with LED ones.  They are quite flat and about 3″ in diameter.

They produced considerably more light and consumed much less power.

The third generation LED lights I installed had a motion sensor in them.  Normally the motion sensor would illuminate the unit for a minute or two.  I soldered a resistor across the switch so that the LED always glowed and would brighten considerably when the motion sensor was activated.  I installed these modified units in the dark areas of the house.  (Bathrooms with no windows and closets)  Further I powered them with a separate 4.5VDC power supply+Battery replenished with a solar panel permanently installed on the roof.

While I was deep into firmware based microprocessor projects Microsoft and IBM released the Personal Computer based on a similar Microprocessor.  From then until now I’ve built many projects that are a simple hardware circuit driven by software. (One of the first solutions was a software thermostat for the house in the late 80’s.)  I have maybe a dozen Raspberry Pi’s that have proven to be extremely reliable considering their low cost.

In the 80’s microprocessors had become mainstream and my curiosity moved from analog hardware solutions to digital ones.  There were several local stores that I could buy 7400 series Integrated Circuits in DIP packages for pennies.  I was fascinated with the ease of building an If/Then digital circuit and tie that to a discrete component to power the action desired.  Darlington transistors, especially PNP ones were terribly easy to interface with an open collector Integrated circuit.  When the Zilog Z80 Microprocessor came out, I moved onto writing machine code into EEPROMS to get the desired results into my If/Then digital circuits I already knew. (I built a firmware based recipe box and a homemade Inverter/Charger that is commonly called a UPS today.)

As a young child of the 1960’s I was fascinated with batteries and electricity.  To feed my curiosity I had an Allied Radio catalog that (much like Amazon today) I could order about anything I could afford and have it delivered to our door.  I spent the next 10 years building small circuits to fit a wide array of purposes.  (I almost always had a solar powered radio in some form.) When I finally went to Junior College I already had a basic understanding of how most things around the house worked.