I got a comment the other day on my YouTube channel that reminded me to do a job that I had been long neglecting. I’m glad I did, because it pointed out yet another hole in my preps.
The comment was about my Battery Bank build series of videos, and asked if the 600W inverter would handle the compressor start-up surge for my fridge. Before I built the battery bank, I bought a Kill-A-Watt meter and did a little monitoring of the fridge, and it seemed to me that the startup surge was about 800W, which I felt was well within the limits of the inverter I was looking at. I was never really satisfied with the measurement, though. The Kill-A-Watt display isn’t really responsive – it only updates once a second or so – and it seems like the surge isn’t accurately displayed. But I went ahead with the Samlex 600W pure sine inverter and built the battery bank anyway.
That was my first mistake. My second was never testing the bank for its primary use case – powering the fridge while the generator is off. No excuses – I just kept putting it off in favor of the next thing. To be fair to myself, I have actually at least used the battery bank. There have been a couple of blackouts where I powered a string or two of LED lights, but that’s not a real test of the system. I also had a hint of failure when I was installing my driveway gate and tried to power a hand drill; when I grabbed the keyless chuck to snug up a bit, the inverter shut down. I chalked that up to the stall current putting excessive load on the system, and figured it would be way more of a load than the start-up surge of a fridge compressor.
With a little spare time this morning, I rolled the fridge out from the wall and plugged it into the inverter. I opened the fridge doors, unscrewed the light bulb – that was drawing 40 watts alone – and waited. And waited. And waited some more. Finally, like a half hour later, the fridge kicked on. The inverter kept up with it for a second or two, then dropped out.
So, I screwed up. I need more inverter. And I don’t need pure sine, either, not for a fridge. But again, I don’t have a good idea of the actual surge, since the Kill-A-Watt is somewhat lame for capturing peaks. So I’ll just be guessing again, which didn’t work out well last time. Maybe I’ll just go for a 1000W inverter, like this Cobra CPI1000. Only $80 on Prime; I like that it has a digital voltage display, and the 2000W surge rating should handle the load.
Or will it?