In Bahamas: Is it our Fridge or House Bank... neither good option

[theBigKahuna]

Out the gate, my electrical knowledge base is not the best... I know that's a character flaw for a cruiser! Our situation is our new Vitrigo fridge (replaced in Dec) is showing a low voltage errror (1 red flash every 4 seconds). The quandry I have is at the same time our House bank mulitmeter never reads below 12.4 and the Inverter display not below 12.2. Any ideas / advice appreciated... Being in the Bahamas doesn't make either issue any easier.

Other notables:
- House Bank (3 Odessey Performance 4D-1300 AGMs) replaced 7/2019
- Error goes away when genset is run; but returns after turned off. Big Unless and I'm assuming. It's daylight and probably our solar panels (1500W) nudge things along.
- Error goes away under shore power
- By and large the fridge is keeping everything froze / chilled but we're seeing a bit of defraust melt down from time to time.

Praying not battery bank as we're over here 'till May.

Cheers!

jBrad
sv Fuzzy Logic ('15 Leopard Sailcat)

[ohdrinkboy]

I'm far from an expert at this as I have a simple little boat. My first though is, what is the voltage at your fridge? You could have a voltage drop in the run from your batteries to the fridge.

[Chotu]

That pretty much narrows it down actually.

It can really only be one of two things unless the refrigerator is malfunctioning.

Either you have corrosion between that refrigerator and the batteries, including whatever control panels and breakers you have between them.

OR….

Did you install the refrigerator? Or did a yard do it?

In either case, it sounds like maybe the wiring is too small. That can create a voltage drop as well. To fix the situation, rewire that refrigerator with quite a bit better and larger wires than you currently have. Double check with the manufacturer to see what they require for that wiring. And if it’s a long run, go up a little bit in thickness.


As a sanity check, if you can get in behind the refrigerator and put a voltmeter on the DC wiring that connects to the refrigerator, do that to see what you get and if it is low.

My post assumes that your batteries truly never go below 12.2. Definitely make sure of that. And make sure they’re not going below 12.2 when the refrigerator compressor is on. It doesn’t matter at other times.

[CharlieJ]

OP: While checking for corrosion, undersized wire should be done, my first inclination is a weak house bank. Does the bank voltage increase to about 14.2V when charging and then reduce to about 13.6V?

[theBigKahuna]

Charlie, yes that's how the house bank reacts... currently working it's way up charging from solar (and flash is not occuring). OhDrinkBoy, yes, I'll check the voltage the next time we defrost (WAY more often than on land!!!). But Chotu, you reminded me of our install. The fridge was an 'inkind' swap. But (again, not being an electician) the new wire (12V) appeared larger than the existing and I should have paid attention!

It is funny though! I'd sailed my whole life, 16ft hobies, windsurfers, sunfish, lasers etc and love them all. Moving to a 40' cat didn't really change the sailing technique much. But what I didn't realize was we'd be a late bloomer diesel and 4 stroke mechanic, a PEX plumber and budding novice electrician. As always all you folks's input is always greatly appreciated/respected and we're so glad to have the cruisersforum platform to share knowledge.

Fair winds,
jBrad

[Bill O]

jBrad,
We probably need more info to properly help.

With 1500W of solar you should be able to top off your house batteries daily (house bank = 3x 170ah = 510ah) During the day, what voltage are your batteries? (you mentioned 12.4V) Are you solar panels/chargers working? If so, would expect them to come up to 14.3+V.

How long are you running the gen? Assume the bats are getting charged when on, what bat V are you seeing when gen is on?

Unfortunately, could be the house bats failing after 4 yrs. There is a significant V drop at the fridge compressor when it starts up. If you are see 12.4 (low) on the house bank and have a 3% loss in your wire to the compressor, you could easily see <11.6V at the compressor on start up.

[CharlieJ]

OP: So bank appears to be charging correctly. Next step would be to check the voltage, while the compressor is operating, at the battery terminals and compare it to the voltage reading at the load side of the breaker that serves the reefer and finally at the connection to the compressor.

[Avionics_Joe]

To determine the problem:
1. Measure the battery voltage at the batteries with the low voltage warning going off.
2. Measure the voltage at the compressor with the low voltage warning going off.
If the voltage at the batteries is okay but the voltage at the compressor is low it is wiring, either too small wires or a bad connection. My bet is on a bad connection.

3. Put one probe from the voltmeter on the positive terminal of the battery, put the other probe on the positive post on the compressor. Write down the reading.

4. Put one probe from the voltmeter on the negative terminal of the battery, put the other probe on the negative post on the compressor. Write down the reading.

If the two reading are about the same your wires are too small.
If one number is larger than the other, that is the side with the bad connections.

Also be sure to check the drop across you circuit breaker, they go bad.

[Avionics_Joe]

I am in the Bahamas, take a look at: https://share.garmin.com/seaseeker

And see it I am near you.

Originally Posted by Avionics_Joe

To determine the problem:
1. Measure the battery voltage at the batteries with the low voltage warning going off.
2. Measure the voltage at the compressor with the low voltage warning going off.
If the voltage at the batteries is okay but the voltage at the compressor is low it is wiring, either too small wires or a bad connection. My bet is on a bad connection.

3. Put one probe from the voltmeter on the positive terminal of the battery, put the other probe on the positive post on the compressor. Write down the reading.

4. Put one probe from the voltmeter on the negative terminal of the battery, put the other probe on the negative post on the compressor. Write down the reading.

If the two reading are about the same your wires are too small.
If one number is larger than the other, that is the side with the bad connections.

Also be sure to check the drop across you circuit breaker, they go bad.

[theBigKahuna]

[QUOTE=Bill O;3756495]jBrad,
We probably need more info to properly help.

With 1500W of solar you should be able to top off your house batteries daily (house bank = 3x 170ah = 510ah) During the day, what voltage are your batteries? (you mentioned 12.4V) Are you solar panels/chargers working? If so, would expect them to come up to 14.3+V.

How long are you running the gen? Assume the bats are getting charged when on, what bat V are you seeing when gen is on?

Unfortunately, could be the house bats failing after 4 yrs. There is a significant V drop at the fridge compressor when it starts up. If you are see 12.4 (low) on the house bank and have a 3% loss in your wire to the compressor, you could easily see <11.6V at the compressor on start up.[/QUOTE
Just ran the genset for 1.5 hrs. and meter goes up to 14.31, in the 14s after 45 minutes or so. then down to ~13.65 and actually bouncing up to low 14s (solar is kicking in (The victron solar app is still showing us in Bulk mode though).

TBH, my MAJOR concerrn is the batterys or the Vitrigo fail while here... family visiting etc. So, the hope is we'll make it till June.

Offseason plan is already to replace Inverter and Charger as charger is inadequate (times out after 45-1hr and has to be reset) and battery bank very likely may be long in the tooth... This years boat kitty was pretty much eaten up w/ the solar and water maker, etc.

But, are going thru a bunch of the steps posted here so we can isolate the issue, which could very likely be power loss going to fridge and likely the issue is combination of 'all the above'.

Again, many many thanks and additional insights will definitely be factored in.

Cheers!
jBrad sv Fuzzy Logic

[Bill O]

jBrad,
If you get a chance purchase an inexpensive Watt meter https://www.ebay.com/itm/36404132953...3ABFBMvMzT1t5h
and install just before compressor controller. They are helpful to record the low V when the compressor kicks in, total ah and shows the amp draw when compressor is running (this is helpful when recharging the refrigerant in a capillary system).

When they installed your new Vitrifrigo, did anyone add more refrigerant? If so, it maybe drawing too much current, which could also be part of the problem.

[Captain Bill]

While your battery readings under load are not terribly concerning, I'm a bit concerned about your charging profiles. You said that your batteries went to float voltage after only 45 minutes of charging at absorption voltage. Having Many years of experience with AGMs before switching to LiFePO4 it seems to me that you have virtually no chance of getting your AGMs to 100% in 45 minutes. I'm not surprised the Victron is still reporting that it's in bulk. If you don't get your AGMs to 100% at least once or twice a week you will seriously affect their useful life. AGMs really don't like partial charge. If your routine is to bulk them up with the genset/charger in the mornings and let the solar take them to 100% then I don't see a problem, but on a 510ah bank they should not drop out of absorption until you are down to about 2.5 amps going into the batteries. 1500w of solar should have no trouble holding absorption voltage this time of year in the Bahamas. Except on the rare cloudy days in the Bahamas late winter/spring I was always able to reach absorption voltage by noon on 640w. Quite often it would take until 3:00 or 4:00 before the tailing current got down far enough to drop into float.



Do you get a lot of shadows on your solar array? My experience is that boats at anchor in the Bahamas are almost always facing east and this has a tendency to cast shadows on the solar arrays on the back of the boat until late in the morning even if the panels are mounted well behind the boom. I always pulled my boom well to port to avoid direct shadows on the panels in the morning. It also had the effect of shifting the stern slightly to starboard and causing the mast shadow to miss the solar panels much earlier in the day. It saved a lot of generators running.


Previous contributors have pretty much covered everything I would have to say about possible issues with your fridge.

[hpeer]

Going thru this myself at the moment.

I have wind and solar and all was just fine as long as the winds kept up. The wind genny kept my batteries up all night, no problem.

Then we hit low wind spell and the batteries are WAAAY low in the AM. The wind gunny masked the problem. The deep discharge punctuated it.

Oh the fun of sourcing batteries in Dominica.

GC-2 batteries, French. Last time they died, suddenly puffing up, was in Guadeloupe. I am afraid that during the covid period I was not on top of proper battery charging. So I blame myself for the short life.

Where exactly are you in Bahamas?
I would start calling around to source batteries, just in case. I hear importing takes time.

[chris mac]

Hey fuzzy logic, we have seen you around ( I'm on SV purrfect)
If we share an anchorage I would be happy to come try to help, so keep an eye out for us and I'll do the same. We are heading over to cat in the next day or two, not sure where you are at right now.
In terms of your battery, you mention the victron app. Go on there and check history. Depending on the app it might be a tab labeled "detailed". See what min and max have been on a day to day basis. That should tell us if the batteries are keeping up or not.

[theBigKahuna]

Originally Posted by chris mac

Hey fuzzy logic, we have seen you around ( I'm on SV purrfect)
If we share an anchorage I would be happy to come try to help, so keep an eye out for us and I'll do the same. We are heading over to cat in the next day or two, not sure where you are at right now.
In terms of your battery, you mention the victron app. Go on there and check history. Depending on the app it might be a tab labeled "detailed". See what min and max have been on a day to day basis. That should tell us if the batteries are keeping up or not.

Hah! We, in turn, have been hearing you on the squaker! Yes, we'll keep an eye out for you! We're in Nassau and had been waiting for a window to get up to the Abacos, but Mother Nature is being a %#@$# (no disrespect intended!). Plan B's now heading to Shroud then the Staniel / Black Point Cays to await guests. It'd be outstanding to both run into you and get another set of eyes.

Fair Winds,

Brad sv Fuzzy Logic