I just bought a refurbished Delta Pro at a substantial discount. I cannot distinguish it from new. Not a scratch on it I can see. Even the wheels are pristine. As far as I can tell looking at the case, it is the same as a new unit.
As this is my first unit, I am having trouble finding out some of the finer info about the device. I have written Ecoflow customer service and the are good about replying but don't give me the detail I would prefer.
The Delta Pro arrived just after Xmas. At the moment the detached, unheated, stand alone garage it is in is quite cold (outside temps -7°C / 19°F). I placed a small 10w heating pad under the case. I was worried it would get too cold and not charge (LiFePo4 shouldn't charge below freezing) in the sunny winter daylight. The pad was 11w AC but was showing a draw of 17w. After 10 hours the Delta Pro was down by 15%. This should be equivalent to about 500w. More than the 200w I expected. At this point the battery was at 9°C. During the day it dropped to 6°C. I decided to not heat the battery and see how cold it got. I would check it early the next morning and if it was too cold, turn on the heating pad before sun up.
The next morning it was at 4°C and increased when charging through the day back up to 6°C. The battery temperature never dropped below freezing despite the constant subzero temps.
I know that some Chinese batteries have small heating elements built in to keep them at charging temperatures. Could this be the case with the Delta Pro or is the temperature inside my garage just higher than I thought?