Disappointed kinda

[Tim francis]

My new to me 40 ft cruiser had four 6 volt batteries. Two agm and two fla in series. There was only a ten amp charger going to the engine room to charge either the starting battery or bank or both. There’s a battery switch between the engine room and bank. The boat was built for solar power only. I have a Honda 2000 and from yalls advice here bought a Stetson 60 amp charger. So I bought four us battery fla. I run a 5000 watt inverter for tv and apple charging. The reefer is constantly running of course. I’m definitely not an electrical engineer but understand the basics for the most part. I never had good voltage going to the nav station and inverter. With the new batteries and charger hooked up correctly I feel like I’m not getting a good charge. The alarm goes off on the inverter when the voltmeter shows 10.5 believe. The Stetson charger showed 14.7 volts and around 14.7 amps while charging about 11 hours a couple days ago and the voltage went down a lot quicker than I thought it should. Within half a day after that 11 hour charge. The batteries I took out still showed almost six volts each. With the new batteries I’m getting about the same amount of time before low voltage alarm. So my question is with the inverter left on and the reefer running is 12 to 16 hours after a charge of the Honda normal? I know there’s a lot of variables involved. I have 12.7 coming strait into the back off solar. Granted it’s been unusually cloudy and rainy where I’m at on Maui since I put in the new batteries three days ago. I am open to buying a wind generator I could use some more help and I have searched this forum for info and some is confusing to me and a lot was helpful. I feel like I only get 12 hours of use after 10 hours charging. This might be a little premature but this is the average since I bought the boat two months ago. I motorsailed to Maui from Oahu where I bought her and the alternator seems to top off the batteries great. I am trying to achieve a goal of running the reefer unit and inverter along with a norcold freezer full time with using the Honda Stetson combo once every three days or more. Thanks for reading and helping a younger newer cruiser.

[Uncle Bob]

Just a guess, but I would say that the consumption exceeds production. The reffer is a given and should not be a killer however the large inverter, if left running constantly will be. I think I would try switching off the inverter at the source when it is not needed and see if that improves things.

[UFO]

That Big Inverter Freezer etc will suck down the power - What size is the bank? Hard to see from the photos but looks like 232 @ 20 Hours? Which is not huge for running what you are running!

[smac999]

first your battery should not be below 12v.. if you are getting 10.5v you may have already killed the new batteries.

how close to the batteries is the inverter, what size cable, and what draw? a 5000w 12v inverter will need to be within 5 feet of the batteries, with like double 4/0 cable. otherwise you will have huge voltage drop. and the inverter will shut off even if the batteries are good. though you are likly not using anywhere near 5000w. if you were the batteries would only last 30 mins.

get yourself a battery monitor like a victron 712. then you can see your actual usage and charging. and help you learn what you need to do differently.


if your charger is showing 14.7v and 14a. then either the batteries are getting close to full (~90%). (at which point you can shut the gen off and save fuel) or the loss in the cables is too big. you need to measure the voltage right at the batteries while charging and while inverting and compare that to what the charger and inverter is saying. the charger should be within 10' of the batteries and likely with 6 or 4awg wire.

[Chotu]

“I have 12.7 coming straight into the bank off solar" - there is something wrong here.

That's not a normal charging voltage from your solar array.

You should be seeing 14.4, 13.6 etc... From a solar array during the daytime if your batteries are in a low state if charge. 12.7 is about the voltage of a mostly full battery bank with no solar attached at all and a small load on it.

How big is that TV? Those are battery killers if you watch ba couple hours a day on a small bank like that.

Also is the battery switch set to "both" or "all?"

If you are getting to 10.5 volts you are absolutely destroying your new batteries. Killing them.

Time to see what you're using each day first for power and either cut back or get more batteries.

[ramblinrod]

Originally Posted by Tim francis

My new to me 40 ft cruiser had four 6 volt batteries. Two agm and two fla in series. There was only a ten amp charger going to the engine room to charge either the starting battery or bank or both. There’s a battery switch between the engine room and bank. The boat was built for solar power only. I have a Honda 2000 and from yalls advice here bought a Stetson 60 amp charger. So I bought four us battery fla. I run a 5000 watt inverter for tv and apple charging. The reefer is constantly running of course. I’m definitely not an electrical engineer but understand the basics for the most part. I never had good voltage going to the nav station and inverter. With the new batteries and charger hooked up correctly I feel like I’m not getting a good charge. The alarm goes off on the inverter when the voltmeter shows 10.5 believe. The Stetson charger showed 14.7 volts and around 14.7 amps while charging about 11 hours a couple days ago and the voltage went down a lot quicker than I thought it should. Within half a day after that 11 hour charge. The batteries I took out still showed almost six volts each. With the new batteries I’m getting about the same amount of time before low voltage alarm. So my question is with the inverter left on and the reefer running is 12 to 16 hours after a charge of the Honda normal? I know there’s a lot of variables involved. I have 12.7 coming strait into the back off solar. Granted it’s been unusually cloudy and rainy where I’m at on Maui since I put in the new batteries three days ago. I am open to buying a wind generator I could use some more help and I have searched this forum for info and some is confusing to me and a lot was helpful. I feel like I only get 12 hours of use after 10 hours charging. This might be a little premature but this is the average since I bought the boat two months ago. I motorsailed to Maui from Oahu where I bought her and the alternator seems to top off the batteries great. I am trying to achieve a goal of running the reefer unit and inverter along with a norcold freezer full time with using the Honda Stetson combo once every three days or more. Thanks for reading and helping a younger newer cruiser.

First things first, you need to perform an energy analysis.

You can download a spreadsheet (from google or West Marine site) for this purpose.

You will need to measure (preferred) or check the nameplate, for the Amp draw of each device.

Beware that few loads are continuous.

You will need to calculate the instantaneous Amp draw x the number of hours per day the device runs.

For example a Danfoss (Secop) icebox compressor may draw 5 A at max RPM on a 50% duty cycle, for 2.5A-hr avg. x 24 hours = 60 A-hrs / day.

Your pressure pump may draw 5 A but only for 30 minutes (1/2 hr) per day total, for 2.5 A-hrs / day.

(If you are powering a large 120Vac residential fridge via inverter, off the 12 Vdc house bank, that is going to drain your batteries quite rapidly.)

(Inverters are really best suited for moderate loads, occasionally, for short periods.)

Complete for all loads and total it up. (Most make separate totals for "Anchor" vs "Underway".)

Here are the ratios to consider...

For every 100 A-hr of daily electrical consumption:

1. 300 A-hrs of FLA battery capacity.
2. 20 A of shore power charger.
3. 40 A of alternator.
4. 400 W of solar and/or wind charging.

You can scale these ratios up or down, based on your daily A-hr consumption.

This will pretty much give you complete charging via solar/wind ~ 5 days out of 7, the balance to be made up by running the alternator in the morning.

If your charging sources do not meet your current consumption rate, you can either increase your charging capability, or reduce your energy consumption (or a mix of both).

[Tim francis]

Smac, the inverter is 1500 watt and about 15 feet away from the bank. I’ll turn it off while I’m at work. I don’t believe I’m killing the batteries. The older batteries are still good after this same process since I’ve had the boat two months. I’m getting the 10.5 to 11.6 off the main 4 gauge going into the nav station bus bar. I’ve posted another thread under general sailing asking about my isotherm reefer. The 12.7 volts I got was after the solar controller and it was 14. The flat screen is probly a 36 inch. Something one day I checked before the solar controller. The boat was built in 2000 but is pretty basic. I just ran the Honda about seven hours and same thing. Showing 11.3 with my normal amp use. I’m going to double check the wire gauge leaving my bank going forward to the nav station. I have both battery switches on all right now. It looks like the battery bank switch was meant to be able to something I’m not sure about. Battery one is open with nothing connected. Two works. All works and off works. I have the battery switch in the all position right now and I know in the long run it is bad to have the starting deep cycle battery in line with the bank. When I put the batteries in a few days ago I had 12.low number right at the batteries. I am going to replace one jumper wire going from a positive to negative just in case it’s got a bad connection. Just a hunch that pulling it through a too small hole between the box could have pulled the terminal end off but is covered by heat shrink or a coating cover. I pulled the terminal end off the other connector pulling the wire through. I corrected that by buying a new cable and drilling the whole out bigger. Thanks for the help so far and I’m going to start doing more on the recommendations above. I also know the Stetson is a smart charger and reads the batteries but thought it could or would charge at up to 60 amps if needed.

[Tim francis]

There is an electrical engineer I can pay but of course don’t want to and I’d like to learn more myself. I do feel that I’m close to the point of paying after I’ve learned what I know now so I’d be paying for a lesson I could use. I’m also open to adding a couple more batteries to the bank. If I do that, I need to buy two more batteries soon.

[Sailmonkey]

Your post #7 is all over the place.

I’m confused about several things.

First....stop looking at voltages for the time being. You need to figure out where your current (amps) is going.

Second. You typed that one battery is open ....what?

You need to get a handle on how many amps you’re consuming.
Then figure out your battery true state of charge.

As an example, if your normal draw is 10 amps and you do this for 20 hours you’re @ 50%. Now start the generator and the charger will output 60 amps for a short period, probably drop to 45-50 quickly. From that 45-50 you’re using 10 for normal loads leaving (pessimist) 35 amps charging the battery.

In a perfect world it would take the charger 5.7 hours to replace the consumer power in the batteries. The world is not perfect. You might replace 80% of the power in the batteries in 6 hours. As the batteries become more full they will accept less charge. The last 20% can take as long as the first bit.

[ramblinrod]

Originally Posted by Tim francis

There is an electrical engineer I can pay but of course don’t want to and I’d like to learn more myself. I do feel that I’m close to the point of paying after I’ve learned what I know now so I’d be paying for a lesson I could use. I’m also open to adding a couple more batteries to the bank. If I do that, I need to buy two more batteries soon.

Excellent idea.

While 12 Vdc will not electrocute you, make one little mistake and it can easily burn you, your boat, and set the entire marina ablaze.

Make sure the service provider is a properly qualified marine electrician. (Certified by some marine association and carries commercial liability insurance.)

Not a residential or automotive electrical technician. (This would be like hiring a cosmetic surgeon to perform your quadruple bypass.)

(No disrespect meant to the other trades, a marine electrician has no business working for hire on cars or houses either, unless they carry professional certs in multiple industries which is very rare.)

If you find a good one, it may cost you $150 for the 1 hour service call, and it could very well be the best money you will ever spend on your boat's electrical system, and save you a ton of grief and money in the long run.

[Cheechako]

From "in the field" use I would say that a refrig draws them down very fast and anything like a TV etc for an hour or two adds to that. By charging with a 100 amp alternator twice a day for 1 to 1.5 hours, I could barely keep the battery bank up to minimal ok levels, in the 11-11.5 volt range before recharge. (of course a 100 amp alternator only puts that out for a short time) I usually charged at about 12 hours apart. By morning the batteries would definitely need a charge badly. This was the situation with a few different boats and refrigerator systems.
So if your question is "So my question is with the inverter left on and the reefer running is 12 to 16 hours after a charge of the Honda normal? " with no charging going on, I would say yes.... you are lucky to go that long.
Why are you reluctant to leave the charger going while at work? If the Fridge is the only draw, I would think that would be fine... and what most liveaboards do.

[Tim francis]

Thanks for all the responses. When I said open, I meant nothing going to one side of the battery switch from the bank. I don’t think that is important and I know it’s all over the place because that’s what’s in my head all this stuff all over the place. The engineer is all insured and legal. Does it hurt anything to run the alternator while charging off the battery charger? Once again, I really appreciate the help.

[Cheechako]

Originally Posted by Tim francis

Thanks for all the responses. When I said open, I meant nothing going to one side of the battery switch from the bank. I don’t think that is important and I know it’s all over the place because that’s what’s in my head all this stuff all over the place. The engineer is all insured and legal. Does it hurt anything to run the alternator while charging off the battery charger? Once again, I really appreciate the help.

Your alternator may not kick on with the charger running. It's regulator senses voltage to kick on.
BTW, are any of your batteries hot when you touch them? A battery with an internal short will be hotter than the others while charging or right after, and draw the system down fast. Not uncommon, I've had it happen on boats twice. And both times the batteries were less than a year old.

[Tim francis]

Leanord, nothing is hot on the bank. Thanks for the info on the alternator and charger question. As I’m getting all my amp hour usage numbers and from what I just learned from y’all, I’m starting to understand that everything is working right. I was probably more hopeful that I’d get more time between charges. I don’t know what amp the alternator is. I asked my mechanic. The electrician may be able to tell me soon. I just know the alternator does charge. I think I’ll add two more batteries. Im still a few years away from my first crossing to s pacific but would like to start as early as possible figuring out what to expect as far as running the freezer and reefer unit. As of right now, it looks like I’ll need to run my Honda every morning when I leave for work .9 gallons a day. Where I’m moored in Maalaea, it is normally windy everyday being between west Maui mountains and Haleakala. I’ll look into a wind gen after talking to the engineer. Thanks again for the invaluable advice and help.

[Davy J]

This response is worth exactly what you paid for it.............

I read through the thread and couldn't find a mention of how old the batteries are? How old are they?

Battery voltage is only one measure of a battery. A "load test" is a completely different thing. New batteries will be around 12.7 volts. As the batteries are charging, voltage will show 13-14.4 volts. Old, tired batteries may be 12.7 volts at rest, but under load, as running an inverter, voltage may drop down to an unacceptable level. Indicating it's probably time to replace them.