Troubleshoothing help: Can't run appliances

[YoloSF]

Originally Posted by sailorboy1

You better get a book. Based on this thread you have WAY more to learn than what is going to be possible on a forum.

And don't go all nuts on me as just trying to help you.

Books'n'forums! I'm very thankful for the forums

Any particular books your recommend?

[ranger58sb]

Originally Posted by YoloSF

Fischer Panda genset's getting installed back on board next week, so I'll have that power. I just wanted to know the capabilities of the boat without the genset since I'd only like to run it as a back up if possible.

What's the difference between running the engine vs. the genset? Should I get the same results?

Similar results in concept, but not necessarily in quantity. The engine is usually optimized for propulsion but it'll make some electricity along the way... much of which goes to engine devices and the leftover can charge batteries.

The genset is optimized for making electricity, so you'll get quite a lot more out of that than from the engine; very little is needed for the genset motor itself. And genset electricity is device agnostic... so you can charge batteries, run aircons, microwaves, TVs, whatever up to the limit of power the genset can provide.


You'll need to learn how to calculate "electricity math" -- availability and consumption possibilities -- usually expressed in Ampere Hours.

-Chris

[rwidman]

Originally Posted by YoloSF

Hi forum,

I'm a little frustrated and need a bit of help troubleshooting. To keep this to the point, the specs on my boat can be found here:

I'm a little troubled because I just recently installed 3 x 230ah Trojan AGM batteries. They were fully charged and we went for a weekend cruise and the Mastervolt MASS Sine 12/2000 2kW 220V AC Inverter kept on shutting off and couldn't power these two small draw dehumidifier/heaters

I could run a larger heater we had the first night, but not the second night, and I'm just not sure why since I think I have way more battery power than necessary plus we were topping them off all day with 2 x 100W solar panels, plus we ran the engine for an hour, so they had to be charged, right?

Any tips on where to start looking I'd appreciate... Thanks!

It's a bit obvious that you used up enough battery power the first night that there wasn't enough left the second night. Did the inverter shut down with a "low battery" warning?

It's been suggested already but you really need to learn some more about electricity and battery power. Unless you have a genset, once you leave the dock you are dependent of the batteries for power and electric heat consumes a lot of power.

You need to conserve electrical power use and spread it over your entire trip. Also, you say you installed three batteries, did you use the correct sized cables? How about the inverter? Correct sized cable and didn't exceed the maximum distance?

[YoloSF]

Originally Posted by rwidman

It's a bit obvious that you used up enough battery power the first night that there wasn't enough left the second night. Did the inverter shut down with a "low battery" warning?

It's been suggested already but you really need to learn some more about electricity and battery power. Unless you have a genset, once you leave the dock you are dependent of the batteries for power and electric heat consumes a lot of power.

You need to conserve electrical power use and spread it over your entire trip. Also, you say you installed three batteries, did you use the correct sized cables? How about the inverter? Correct sized cable and didn't exceed the maximum distance?

Yes, cabling is the right size and the distance is correct.

Inverter shuts off with a red light and a click and that's it, there's no low battery warning indicator.

Just bought a decent protable catalytic heater so no more electric heaters on our boat!

[rwidman]

Originally Posted by YoloSF

Yes, cabling is the right size and the distance is correct.

Inverter shuts off with a red light and a click and that's it, there's no low battery warning indicator.

Just bought a decent protable catalytic heater so no more electric heaters on our boat!

Do the instructions mention anything about a low voltage shut down?

If you've recharged your batteries and everything works now, it's almost certain that you discharged the batteries too far and that's why the inverter shut down.

You need to be very stingy with electrical power when away from the dock. I wired my boat to exclude the water heater and air conditioner from being powered by the inverter. I can use the microwave and the coffee maker but not at the same time.

[Ex-Calif]

Originally Posted by YoloSF

Books'n'forums! I'm very thankful for the forums

Any particular books your recommend?

There are tons of books but this isn't rocket science or voodoo magic.

Here is a link to the WM energy budget worksheet. Look it over and plug in what you think. Some guys convert it to excel, add systems that are not covered by the worksheet and let excel do the math.

Some guys also make an "on-the hook" version and an "underway" version.

http://newcontent.westmarine.com/con...r/Elecbugt.pdf

Read through it and ask questions...

[YoloSF]

Originally Posted by Ex-Calif

There are tons of books but this isn't rocket science or voodoo magic.

Here is a link to the WM energy budget worksheet. Look it over and plug in what you think. Some guys convert it to excel, add systems that are not covered by the worksheet and let excel do the math.

Some guys also make an "on-the hook" version and an "underway" version.

http://newcontent.westmarine.com/con...r/Elecbugt.pdf

Read through it and ask questions...

The worksheet looks very helpful, thank you!

[MarkSF]

Originally Posted by leftbrainstuff

Many 'land' devices are made cheap and can be really inefficient in terms of startup and thermal efficiency. On land you basically have a big fat elec power source that can tolerate many inefficient devices.

A boat with a 2000W inverter doesnt have the capacity to deal with these inefficiencies. It might not be your batteries or inverter / charger that are the root cause here.

It often takes some experimentation and measurement analysis to determine whether a plugged in device is good enough to be allowed on the boat.

As a rule we dont run persistent high current loads of our inverter. Not because the batteries and inverter can't handle it but because land heaters are mostly poor performing and inefficient. We also like to recharge our batteries using solar. We only use the generator as an exception.

We use a diesel heater off mains supply and we heat our hot water at the same time. Overall system complexity is higher but performance and reliability improves. The metric for this is my wife saying she's comfortable.

Something to think about.


Sent from my SM-N900T using Cruisers Sailing Forum mobile app

All electric heaters are, by definition, 100% efficient. ALL the power consumed is turned into heat. That applies to land-based and marine versions.

[rwidman]

Originally Posted by MarkSF

All electric heaters are, by definition, 100% efficient. ALL the power consumed is turned into heat. That applies to land-based and marine versions.

Yes, but powering a 120 volt AC heater from a 12 volt DC battery and inverter will lose 10% or more (probably more) in the conversion. It's still heat but it's in the inverter and the space the inverter is housed in, not where you want it.

[transmitterdan]

If you are burning some kind of gas (propane?) in a heater please check up on carbon monoxide as well as oxygen depletion of living spaces. The reason many people use diesel heaters is because they can be fitted so as to not use up all the oxygen in the living space and they vent the exhaust gases outside. Running a catalytic heater inside an enclosed space can kill people very easily and painlessly. They just go to sleep and don't wake up.

[rwidman]

Originally Posted by transmitterdan

If you are burning some kind of gas (propane?) in a heater please check up on carbon monoxide as well as oxygen depletion of living spaces. The reason many people use diesel heaters is because they can be fitted so as to not use up all the oxygen in the living space and they vent the exhaust gases outside. Running a catalytic heater inside an enclosed space can kill people very easily and painlessly. They just go to sleep and don't wake up.

Correct. Some people resort to this but it's better to stay home because of the cold than to take a chance on killing yourself.

[Xlantic]

Originally Posted by YoloSF

Any particular books your recommend?

Boatowner's Mechanical and Electrical Manual by Nigel Calder is the classic although in the 10 years since it was published there may have been significant developments in some areas.

[clyde]

go get the 'nigel calder' book! amplepower has one called 'living on 12 volts' that`s pretty good for novices...learn a few 'ohms laws' like 'watts divided by volts, = amps!' never let your batts drop below 50%, ie, 12.2 volts, before recharging!...i never go by amp hrs used, only volts!...i get an average of 10 yrs on my 6, 6v house batts...clyde

[ramblinrod]

Inverters kill exhaust batteries fast. They are best suited for short duration, modest AC loads. For long duration and/or high loads (like resistive heating) you would need a generator RUNNING.


First, you need to consider your heat loss. A Beneteau 423 with an outside temp of 40F is going to need about 1500W to bring the temp up to 68F in the main salon (cooler the further away from the heat source and in lockers).


Then you need to perform an energy audit. How much current are you drawing per day off your batteries?


With a refrigerator and freezer, lighting, electronics, communications, and all the other stuff, you could easily be up to 200 A-hrs/day.


Now add in 1500W of heat for 24 hours, 1500/.85 (inverter eff.) / 120 = 352 A-hrs / day.


This is why nobody heats with electricity, unless one has a 6kW+ generator aboard.


If you have 640 A-hrs of batteries, you can use about 200 A-hrs / day to keep batteries between 50-80% SOC while off the grid.


So before adding electric heat, your daily A-hrs consumed = your daily A-hr usable capacity (assuming you charge 200 A-hrs/day).


So how are your charging when off the grid?


200W of solar panels will give you about 66 A-hrs/day of charge capacity or 1/3 of your necessary charge capability, to keep the batteries from discharging below 50%.


So assuming you don't have a generator, and do have a 100 A alternator, you would have to run your engine about 1.5 hours / day to keep batteries charged WITHOUT using any electric heat. With 1500W of heat running 24/7, you would need to run your engine about 6 hours per day to keep the batteries charged.


So unless you have a generator, or you want to run your engine A LOT, you need to come up with an alternate source of heat, other than electric.


This is why folks have diesel, propane, or wood burning heaters aboard sailboats.


Rod Brandon

[cwyckham]

I agree that you need to do some reading. Nigel Calder's book is great. I also really like Don Casey's books. they are very simple and well illustrated. I'd start there.


I always recommend that any new boat owner buy a battery monitor. This will tell you the actual usage at any time and the state of charge (SOC) of the batteries.


Voltage is next to useless for understanding the health of your batteries because it will drop either because you have a low load and low SOC or because you have a high load and your SOC is fine. You can't tell the difference!


Batteries are expensive and you can kill them quickly by not understanding their SOC. You will spend hours watching the amps in and out of the battery and switching things on and off to understand how much current they actually draw. They're great fun!