Then the experimenting began. Here's what we learned.
All my documentation says we have a 9,000 BTU roof mount air conditioner. Our first test was to try the roof a/c and my 9,000 BTU R2D2 unit on shore power at the same time. After about 30 mins the 20 amp supply breaker in the garage tripped, indicating that we'd need over 20 amps to run both.
We relocated the shore power to a 30 amp circuit in the garage and both air conditioners ran fine, except the 9,000 BTU R2D2 output was very lacking compared to the 9,000 BTU roof mount a/c. And the R2D2 cooling wasn't very satisfying as it tried to cool the helm area. The roof a/c, as usual, did a great job cooling the dinette.
We then tried to run the roof a/c and R2D2 from generator power. We first cut in the roof mount a/c which didn't phase the 3kw unit, then kicked in the 9,000 BTU's of R2D2. The generator immediately overloaded. We then tried running R2D2 first, then bringing in the roof a/c, but the results were the same.
My electrical engineer S-I-L Trey, couldn't believe we were overloading the generator with two 9,000 BTU units, so we tore into the roof a/c to get specs to find out why it was so inefficient and found a plate that said it was designed to draw 14.6 amps running.
This didn't seem right to him for so few BTU's so we dug deeper and got the model number, then went to the Internet. We discovered the roof a/c was not a 9,000 BTU unit, but was in fact a 13,500 BTU unit. This quickly answered our question as to why the R2D2 output seemed so feeble compared to the roof mount unit. But this also negated our potential to significantly increase cooling by going to a 15,000 BTU rooftop unit. And anything over 15,000 BTU would require a generator upgrade.
In conclusion, we decided the R2D2 unit didn't warrant the space it took up for cooling it provided, so it has to go. A high velocity squirrel cage fan can provide marginally acceptable cooling for the helm by blasting the 13,500 BTU air from the dinette forward, but it isn't a permanent solution and probably wouldn't be workable for a scortching hot day especially with the heat generated by extra crew. The challenge now is to somehow make the existing roof mount 13,5000 BTU a/c and EU3000i generator get the job done.
Cover for the 3000i
Some good news. Some bad news. I'm holding my breath.It's nice to have the electric start for the 3KW. But I already have the eu2000 and would only need to add another cheaper eu2kw. Question becomes...how many BTU are required to cool the inside of a SC in 95' Florida?
ReplyDeleteSorry, another thought came to mind. My 28 foot Airstream Would become a meat locker with a roof mounted 13,500. It was a 26 year old unit. The coach was not particularly well insulated. I'm wondering why a newer A/C mounted on a smaller sq ft cabin wouldn't do a better job of cooling. It must all be loss through the glass area?
ReplyDeleteWhat happened to the idea of using Sea/Lake water as a coolant through a radiator; circulating the water, and blowing the Cooled air, with a fan, through-out the boat? I used this principal to cool my house with well water and it worked like a charm. What it lacked was any humidification, which on a boat would be a Good thing.
ReplyDeleteNeed a/c on the trailer too.
Delete