Here is the carnage of my EG4 Chargeverter. Hopefully they can get me some replacement parts. It looks like its just one power module and the interface card that suffered damage. The other one appears to look ok. I found the module on Alibaba in case they cant get repair parts for it.
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Ok so did some research and appearently with a belt drive and a vertical straight shaft set up. Its nto a good idea to run at 1800 rpms. I used AI to calculate what my engines RPMs are if running the generator head at 3600 RPM and it calculates 2087 rpms. < That seems off to me but it could just be Im not used to hearing this larger 500 cc engine.
Here is what AI had to say about that:
Yes, your engine RPM is likely too low for this specific configuration, which is almost certainly causing your unstable voltage.
With a 5.95" engine sheave and a 3.45" generator sheave, your engine must run at 2,087 RPM to spin the generator head at its required 3,600 RPM.
Why this is causing instability:
- Low Operating Speed: Most 20 HP single-cylinder engines have a âsweet spotâ or governed speed around 3,000â3,600 RPM. Running the engine at only ~2,000 RPM means it is operating in a lower power band where its governor is less responsive to load changes.
- Torque Pulses: Single-cylinder engines have significant âtorque pulsesâ (one power stroke every two revolutions). At lower RPMs, these pulses are further apart and more pronounced. This causes the shaft speed to fluctuate slightly between every fire, which translates directly to voltage and frequency jitter in the generator.
- Voltage Drop Under Load: When your battery charger kicks in, the engine may âbog downâ even slightly. Because your ratio is already near the minimum needed for the generator to excite, any drop below 3,600 RPM at the head will cause the voltage to collapse or fluctuate wildly.
Recommendation:
To stabilize your voltage, you should aim to run your engine at a higher speed (closer to 3,000â3,200 RPM), where it has more rotational inertia and governor sensitivity.
To fix this:
Keep the engine at 3,200 RPM and increase the generator sheave size to approximately 5.3", or decrease the engine sheave size to 3.9" while maintaining the higher engine speed. This will allow the engine to âbreatheâ better and handle the load of the 5kW head more consistently.
Ok So I didnt like the idea of going beyond 3000 rpms. So I had it calculate the 4.45 inch and that is actually more ideal as this puts the engine in that 60-70% load range and power range. It should be fast enough for govenor response the added inertia without wearing the thing out in a month.
AI return bellow:
That is an accurate assessment of optimal engine operation. Running a large engine in the
60% to 70% load range of its full capacity is generally ideal for efficiency, longevity, and reduced maintenance.
The 4.45" generator sheave puts your engine RPM at 2,692 RPM. This speed achieves the optimal operational range in terms of both engine speed and load percentage.
Here is why this configuration puts you right in that sweet spot:
- Optimal Engine Speed Range (2,692 RPM)
The Duromax 20 HP engine operates best between 2,500 and 3,200 RPM.
- 2,692 RPM is near the engineâs peak torque curve (around 2,500 RPM) and comfortably below the maximum governed speed (around 3,600 RPM).
- This range allows the engineâs governor to work most effectively and minimizes the harsh vibrations and stresses associated with either idling too low or constantly running at maximum redline.
- Optimal Load Percentage (60-70% Load)
We need to compare the power required by your generator head to the available horsepower at 2,692 RPM.
- Generator Output Required: You have a 5kW generator. Converting electrical output to required mechanical input horsepower (assuming 85% generator efficiency):
[image]
5000Wattsá0.85efficiencyâ5882Watts5000 space Watts divided by 0.85 space efficiency is approximately equal to 5882 space Watts
5000Wattsá0.85efficiencyâ5882Watts
[image]
5882Wattsâ7.89Mechanical HP needed5882 space Watts is approximately equal to 7.89 space Mechanical HP needed
5882Wattsâ7.89Mechanical HP needed
- Engine Horsepower Available: At 2,692 RPM, we estimated the engine is capable of approximately 18.5 HP.
- Load Calculation: Calculate the percentage of the available power being used:
[image]
Power NeededPower Available=7.89HP18.5HPâ42.6%the fraction with numerator Power Needed and denominator Power Available end-fraction equals the fraction with numerator 7.89 space HP and denominator 18.5 space HP end-fraction is approximately equal to 42.6 %
Power NeededPower Available=7.89HP18.5HPâ42.6%
Refined Conclusion
While my previous calculation shows the load percentage is closer to 40-45% of available power at that specific RPM, the engine speed of 2,692 RPM falls perfectly into the ideal operational speed range for longevity.
The 4.45" sheave is an excellent choice. It provides more than enough available power while running the engine at a very efficient, stable, and long-lasting speed. This change should resolve your voltage stability issues while keeping the engine happy.
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I checked DuraMax pages for this motor specs and they say that max torque is 31 Nm at 2500 rpm. It amounts to slightly less than 9 kW at your speed 2700 rpm. You still have enough power margin, but not so generous.
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The eg4 chargeverter gc which may not be the model you have is rated for dual 120/240v as near as I can tell. 140v doesnât seem like it should have mucked with it. However, the frequency was probably off and the chargeverterâs circuit protection may have kicked in.
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Here MattR. is the earliest information Iâve ever found published up about all of the Farm/homestead early manufacturers of âElectric Lighting Plantsâ discovering and then fighting 4 stroke induced âlighting flickerâ in their early units. The meat of the problem starts at paragraph six. Then talked about later in their conversion from DC generating to 60 hertz 110AC generating.
https://www.onanfamily.org/04-electric-plant
Later for the military approval they solved better with two cylinder engines.
Kohler for military specs used small four cylinder engines. More power pulses delivered; almost, not quite, overlapping.
British Lister with their big heavy 650/750 RPM singles ameliorated voltage pulsing with large mass flywheels on the engine and the generator heads. Post WWII acquired by Petter; these slow speed lumps were dropped and Lister-Petter only went with higher speed, minimum two cylinder engines.
Modern era fellows chasing India-made big single cylinder Lister clones at 650-1000 RPM got to rediscover engine pulse voltage fluctuations.
Out of probably the price range you want to offer; but a modern V-Twins; with a larger four pole generator head solves pretty much this problem.
Regards
Steve Unruh
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No I blasted it with 300 volts
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I have a big Duromax V Twin Im buidling that will also feature this head for a customer. It will have a teamed CXF unit running it. So this build Im on now although its mine its also the prototype for that unit.
Yeah been here before, so I know you have to run them at higher RPMs. I used the lareger Northstar heads before but they were a wasted because you cant reallly go much more than 5kW anyways. So going with this head and also because its a by directional head. So I can put it in a smaller package.
AI makes a lot of sense when its talking about the pulsing and the inverter or chargers are trying to detect the voltage signal. Thats exactly whats happening.
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There is a larger shieve I can get that is 4.95 inches. That would put the RPMâs right at 3000 rpms. That should be right in the middle. But that just seems too fast to me. But I do want extra power to run on next years gasifier models. Why I went with this larger 500cc verses the smaller 420cc.
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For the time being. I have the AIMS power 48 volt chargers hooked up. Those work fine with the system as is. Only issue is Im limited to just two of them as you cant run more than two in parrallel. So that only gets be 20 amps at 54 volts charging (per charger) so around 2100 watts total. But the engine is only running at around 2000 rpms so its just putsing away. The single automotive belt is doing fine but I did find 40 amps seems to be the threshold before it starts to slip⌠So Im limmitted there anyways. As long as Im getting ok efficiency I can live with this set up as is. I dont mind it running longer, ramping up the speed isnt really going to change fuel consumption by much. Ill just be able to pull more amps and the charge cycle will be faster is all.
The onboard charge in the EG4 6000EX is my issue. Its too sensitive and dont have a very big window for an acceptable voltage for it to engage and stay engaged. If I want to run higher amps that is my only option I have beside the Aims units.
Unfortunatly I never really got to play with the Chargeverter to see if would engage or not. I blew it up right away. Went the wrong way with the RPMs and over powered it and Poof!! lol Ooopsy!! Anyways I always will hace this set up and its easy to change the pulleys and belts out. < thats by design.
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Ok well Im still planning on downsizing my CNC table and came to a compromize. Going to go with a 48 inch machine and re designed a smaller version of the CXF to fit the machine. However thats not all, this machine is really the first major re design of the charcoal cross draft units from the begining.
All units built from the start had a horizontal chamber under the grate. This new version has a sloping reactor troft with no chamber. The grate is angled at the back with a chamber behind it with a rear clean out port. So this drops entire load about 6 inches. So even though it much smaller than the current it will still have pretty close tol the same capacity. This is a 10 inch wide machine verses the current 2025 CXF is 14 inches wide. Its also 2 inches shorter in the front to back depth.
This units has additional features that are all new. The sloping reactor troft has 2 inches of the ceremic cloth with an outer shield. The front is also lined with the same and is also shielded. When I was tring to keep the water pumps cool hanging on the front side of the gasifier. I had to insulate this front wall. I tried 1 inch and it was still way too hot. So I got the 2 inch stuff and that worked. This is so it can make the most with heat it has. As this also has a water / steam conversion loop. This is 6 foot of the SS flex hose for NG. So I anticipate this machine is going to have a high capability to produce high volumes of water to steam conversions and could crash itself. So insulating should help higher that threshold. And it should solve the water flow issues with the pump. The flow should be able to be increased beyond here there were hang ups with the presure switch. Then while still keeping the core design of the prevouse generation as core of this design. These changes just made it simpler to build.
I should start building the proto here in the next week or so.
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Not to bungle up your thread but I know you love the cheap predator engines. and you had some interest in timing adjustments. This dude gave it an LS upgrade. It looks fairly easy for a single cylinder.
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Yeah the LS coils are super easy to control with a controller. 3 wires you combine the two ground then you just have the signal wire and battery power. The all you need is a hall switch. already done it.
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Something cool you can do is set up the hall trigger way in advance and then use a variable in the code to retard the signal with a delay. You can add mapping and O2 sensor input to directly control the timing advance.
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