My Lister running in full CHP with video - cross posted from VOD

[julesandtash]

Right, time for an update.....

Rossey very kindly sourced me some new batteries for the APC SURT6000xli 6KVA online UPS which made their way down here courtesy of Hifly and Mark230678
Clearly they were better than the old ones as these had a terminal voltage just over 100V DC each whereas the old ones were less than 12V !!
As soon as I put them into the UPS and connected the power back up, away it went happily.

Here is the waveform on the output with no load, very nice pure sine wave


Here it is in with mains input (not lister power) on the top trace and ups output at the bottom. Notice the UPS output is more pure sine than the mains which has flattened peaks.  This is with 1.5KW of load connected as well. The cutoff trace is just down to the timing of the camera shutter, it was a full trace on the scope screen


This is with the Lister powering the UPS and almost no load on (just the scope and UPS battery charging). I dont think I need to mention that the Lister output is the top trace.


And here is the same with a 1.5KW of load connected to the UPS


It bolsters the voltage nicely too.
With the 1.5KW of load connected, UPS input voltage from the Lister was just under 215V as below


but the output was a rock steady 230V


Just to prove it was happy on the messy generator power, here is the front panel. Battery charging and no error lights..


I have tested the Actifry which now runs perfectly on UPS power.
Now to build a cradle for the UPS, test the earthing arrangements and RCD operation now I know it works and connect it up more permanently.

[Julian]

Wouldn't it have been easier just to go down to the chippy for the chips ... or am I missing the point!

[julesandtash]

The whole point is that I want the off-grid power to be as good as the mains so I know that I can use absolutely anything without problems.
Even though other items ran OK, I suspect that they will be healthier and happier on quality power

[Julian]

He, he!

[therecklessengineer]

Looks great Jules.

I tried the similar with an old 3kVA unit. It did not appreciate trying to boil the kettle and resulted in 'letting the smoke out'. It also took aaaaages to charge the batteries.

[julesandtash]

This one is 6KVA so should handle things like the kettle OK (I hope) - it's rated for 4.2KW.

I've got some steel fabricating to do for it's mounting now, then some proper cabling of the UPS into the control panel.
After that I should be good to see how it goes in full service

[julianf]

Jules,

Im interested in somthing ive not mentioned before -

How does the engine now track the load?

My main concern with an off-grid setup was that it would be possible to stall the engine if too much was switched on (you say that does not happen anyhow) but with the ups, i can see that its now possible to temporarily draw more than the engine produces - which is great.

But then is the engine then separated from the load?  Ie when you put the kettle on, how does the engine track this?

As you know that was one of my stumbling blocks with grid tie, but im now wondering if, with a ups, my engine could eventually be usefull to me?

[julesandtash]

The engine seems to track the load when the load is within the range that the engine can power. When I had 1.5KW of load connected the to the UPS I was seeing 7 amps from the alternator to the UPS input which is about right.

I do want to load the UPS to near it's maximum of 4KW, which is more than the engine can produce and see what happens in that scenario but I need to get the wiring done properly before I test it at that kind of current.

[julesandtash]

Right, the UPS is now connected properly and the house is running in pure sine UPS power. No flicker at all in any lights, actifry and washing machine work fine and the UPS batteries are charging on genny power.

Here is the steel frame with UPS on top. Cover the alternator nicely and will make it easy to put some weldmesh in front of the belt and flywheel too


closeup view of the UPS. The plug in the metalclad socket is nothing to do with the UPS, that is the central heating pump that circulates engine heated water to the thermal store


The load on the UPS (and the lister) is 6A at 230V at this point. Only one LED on the UPS load bargraph illuminated, batteries charging and engine supplying all the power
Here is a view of the control panel and alternator isolator. The values shown on the LED panel meter are downstream of the UPS (ie what the house is drawing)



UPS, Lister and panel all visible in this one.


The engine tracks the load nicely and supplies the load up to it's maximum output (which is about 13 to 14A).
I have had 18A of load connected (4.1KW) and at that point the engine would initially supply it but start to slow down. As it slowed and the voltage fell below the UPS input threshold, the UPS switched immediately to batteries, still supplying the load and the engine the sped up as it was unloaded due to the UPS switching to batteries. As the voltage climbed,  the UPS switched back to generator and teh cycle repeated.
This was a slow repeating process, around 30secs on the engine, switching to batteries for 15secs or so then back to the engine.

As such, the system seems to be just as expected now, it supplies pure sinewave power up to full output of the Lister with no drain on the batteries and can support loads in excess of what the Lister can managed for short durations (like boiling the kettle) with some help from the batteries.