Gillig 30ft Low Floor - the journey starts

[Bert06840]

An antenna from Amazon

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And another stubby one. Both are crap.

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If anyone is interested in the designs, let me know.

The DIY ones are made to cover the T-Mobile, AT&T and Verizon bands as well as I could.

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Finnie shows a major dip around 2150MHz.



I also did measurements from 600 to 900MHz, to cover the frequencies used in rural areas. Particularly T-Mobile uses low frequencies, the lowest of all, starting at 617MHz - the famous Band 71.

The preliminary conclusion is that my own DIY designs seem to perform quite a lot better than the sub-$100 antennas from Amazon.

I'm trained in radio engineering so this is perhaps rather obscure stuff for many, but since internet-on-the-go is an essential part of the skoolie thing, I thought it to be appropriate to share it here, and perhaps I can help out some people with what I have learned.

[Bert06840]

The $399 inverter showed up so I did some quick tests.

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Idle current at 22.5V

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Idle current at 26.5V

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Idle current at 28.5V

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Unloaded waveform

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Does not automatically recover from an under voltage condition. That’s annoying.

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Load on the power supply at 22.5V with a 100W lightbulb that draws pretty much exactly 100W on the AC side.

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With median input voltage

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At the maximum input voltage

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Finally, a higher current load test. My big LiFePO4 batteries are in the bus, far away from here, so I rigged up a few NMC cells for a higher current test. These 8Ah cells can do 25C continuously, so running the heater at 1.5kW doesn’t impress them much.

The interconnections won’t win prizes, but I just wanted to see the waveform.

[Bert06840]

At 1.5kW, the THD went down, interestingly enough.

Alright, that’s all I had time for, it’ll go into the bus next weekend.

Conclusion:
- Idle current (at room temperature) runs between 17 and 23W
- does not recover automatically from a low-voltage shutdown. A bone piercing shriek makes sure everyone within half a mile will know about it.
- the loaded efficiency at 100W seems good, if you accept the ~20W quiescent draw
- the waveform is pretty ugly at idle and low draws, but improves at kilowatt-level loads.

[joeblack5]

Thanks for doing the measurements ... I settled a couple of years ago on that brand.. mainly because it is a modular design and relative easy to get to the components to repair...the power components are on the outside of the heatsink.....I blew one up after messing with the current regulation in an attempt to eek another 300 watt out of it... Company sent me free MOSFETs or igbt's..I forgot...and a free oscillator control board.

Johan

[Bert06840]

I had to open the inverter already because the display had popped out. Hot glue isn’t quite the high grade mounting system I would have gone for…

[Bert06840]

Apart from that, it looks like you would expect. But there’s no way that this thing can put out 5kW for any length of time. 800w each trough those tiny E-cores?



It works fine though. Starts my miter saw without complaints.

[Bert06840]

I did some fresh water tank puzzling, and cut some XPS panels too.

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Since I’m doing my conversion off grid, I needed to lay out the panels.