Random power spike in new Frigoboat

[Bill O]

Just installed a new Capri50F frigoboat for a well insulated 3.5 cu ft freezer. This one has an air cooled condenser and when we get hauled out we will install the keel cooler (with an in line filter/dryer).

The installation was not difficult except, we had a problem w/the Merlin II speed card. The problem with the Merlin II is know and was posted on CF earlier this year https://www.cruisersforum.com/forums...aw-260468.html We had the same symptoms as in post #1 and we returned it to Coastal Climate Control for a refund. While testing the system w/the Merlin II in place we noticed a high amp spike of > 9amps, but didn’t think much of it since I assumed it could have had the compressor at 3500rpm when this happened. (we have a Watt meter before the compressor to constantly monitor power consumption, time, etc.).

We replaced the Merlin II with a manual speed board (from Coastal Climate) and again checked the system to see how much power would be consumed over several days. We left the speed controller on the lowest rpm (2000 rpm) to see how long it would take it to pull the 3.5 cu. ft box down to temperature (10-13F with a digital thermostat with a 3 degree differential). Will say it wasn’t the fastest rpm to pull the box down, but was very frugal on power consumption. Once the box hit temperature and was cycling normally we saw a spike of ~3.5amps when the compressor started then settled into ~2.15amps. This seemed good so we let it run overnight. The next morning we check and observed that we hit a max draw of 8.87amps. This seemed odd, but let it continue to run. All during the day it ran “normal” (3.5 on start then settling to 2.15), until that night we had another power spike of 8.82 amps. No idiot lights were flashing to indicate an error had occurred when I checked the next morning and the power consumption was back to normal.

At this time there is no filter/drier in the system and wasn’t sure it could be some sort of blockage happening increasing pressure causing a higher load on the compressor.

Other than that the high random power spikes, the Frigoboat system works well just with the air cooling w/the compressor running at 2000 rpm. With the lowest compressor speed, we are averaging ~28ah/day with the initial pull down from ambient (~78F) and holding 10-13F on the digital thermostat near the top of the box, while a temp probe near the bottom of the box was 4F.

To me the random high start up spike seems like odd behavior and have had no good explanation from Coastal Climate why these spikes are happening. Anyone have any thoughts why I’m seeing these random high spikes?