Inverter for Residential Fridge

[SLSettles]

I have asked this same question on another forum and have been speaking with another coach owner with a nearly identical setup who also tried the PROwatt 1000 and had very similar experience with it. He is convinced that it was surging just slightly higher than the 9.6 max amps that the inverter is rated for, about 1200 watts of surge. So he got the 2000w version (with a 19a max) and has had no further problems. I'm still a bit irate that Xantrex would even call this a 1000/2000w inverter when it's really a 900w continuous and 1200w surge, but it is what it is, and they have lost whatever "brand-loyalty" I had.  Again, my thanks to those who have been patient and helpful.

[dickandlois]

SLSettles, From your correspondence on the other forum and for your experience with the inveter. It sure sounds like the 1000 watt unit lacked the ability to supply the needed surge current of the required load. The circuit design likely has a watchdog circuit that monitors current and the trigger level is set a little low and will not allow the unit to even reach a current level to supply 1500 watts at startup let alone 2000. This protects components, but also puts the unit specifications in the iffy area. would be nice if this is an issue and they added a asterisk . in the specifications.

Not that the unit can not supply 2000 watts, just not the power required by large inductive startup loads !!!

Thanks for your feedback and information. It helps me to expand my knowledge base and potential pitfalls of manufactures specification sheets. 

Rich. 

[desertdeals69]

7 hours ago, SLSettles said:

First, thanks for the perseverance to read through all this! I did not do any other tests on the inverter, other than to see if it worked on batteries, on shore with the MSW off, on shore with the MSW on, and with the coach running. Once I found that it would not work in two key conditions I called Xantrex and talked with a tech. The result of that call was the suggestion that I try larger cables (which I dismissed out of hand, #1 18" cables do not have significant drop at these loads) or upgrade to a 2000w version. 

As for the fridge, yes, it has had an extended burn-in period... we have used it at home for years. And yes, I have run it with a Kill-A-Watt many times to evaluate it's consumption, including a couple of days right before moving it to the motorhome to confirm that the numbers were in line with what my batteries can provide. 

Thanks again

Did you check the kill-a-watt when it was defrosting?  It probably draws 10 times the current as the running amps on the spec.

[kaypsmith]

SLSettles, I certainly was not trying to attack you personally. I was only trying to sort through the lack knowledge on our end as to why things did not work. Such as the

current called for by the spec., sticker inside the door. If that sticker does say 3.5 amps at 120 volts, or 402 watts, that number does reflect maximum draw, which includes

startup. Yes, in this event the 1000 watt inverter should be sufficient. Now to look for some other variables, of course the inverter could be defective, also there could

be a defective battery in your bank, with 4 six volt batteries, one possibly bad cell in the equation could also cause a problem that would cause "me" some concern,

not for your perspective, but if it were mine that is one place that I would check out. Please don't be offended at us, tell us of your concerns, that is the only way we

can help anybody. Good luck with your project, and it will be a learning experience that you can come back and share with us, so we will be able to help others.

Also on the subject of (PSW vs MSW) inverters, the msw is more forgiving for some inadequacies handed to them, not to be confused with me meaning they are

better for all applications, they certainly are not, but still have their place.