houseboat magazine
Your Ultimate Online Houseboating Resource
Welcome to Houseboat Magazine
Contact UsAdvertise

AFTERMARKET MANUFACTURERS BROKERS FORUMS
Administered by The Pirate
+ Reply to Thread
Page 1 of 4
1 2 3 ... LastLast
Results 1 to 10 of 31

Thread: New inverter batteries or portable generator?

  1. #1
    Senior Member GoVols's Avatar
    Join Date
    Aug 2011
    Location
    Nashville, TN
    Posts
    472

    New inverter batteries or portable generator?

    In the Spring of 2012, I forked over $1k for 8 new AGM batteries. I conserve juice as much as possible at night, but the dumb things go from full charge at bed time (~10PM) to dead by around 6:30AM. Now the batteries seem to be doing worse and I'm wondering what I should do this year. Most of the folks on my dock remedy this problem instead by installing a portable generator / inverter, like a Honda 3K watt. Instead of 1.25 gallons of gas per hour with my 12.5KW Westerbeke, the Honda can run for 4 hours on a single gallon! I only aim to keep my 110V going and know that I won't be able to run the AC / Stove / etc b/c they're 220.

    Let's all assume I'm not completely ignorant about the emissions hazards of the portable generator. It will be placed on my swim platform on the back of my pontoon houseboat with lots of air movement around it. In fact, all my neighbors have large fans blowing the emissions further off boat as well.

    How could I go about hooking this thing up to my electrical system, if I should decide to get one? The guy across from me tells me I just get a male-to-male plug and simply plug the portable generator into an outlet on the back porch. Another option would be to hard wire into the control panel, but this would be much more difficult.

    How would either of these methods affect my house Xantrex inverter, which automatically begins charging the batteries once it senses current?

    Thanks for the feedback.
    Formerly owned a 16X69' Sailabration

    Bet On Another Thousand

  2. #2
    Senior Member
    Join Date
    Jul 2012
    Posts
    113
    Will be keeping up with this. I have the same question(s). thinking of going with a combo but like you going to shed the big generator for sure. Nothing but trouble out of those and the little Honda just runs and runs. Thinking of keeping the inverter/batteries because of the noise of a generator.

  3. #3
    Senior Member
    Join Date
    Jul 2012
    Location
    Wheeling, WV
    Posts
    356
    What type of amp hours did you have? Are they 6 or 12 volts? I had a much smaller boat with less household appliances but my battery bank of 8 6 volts was able to handle 3-4 full days of fairly heavy drawdown.

  4. #4
    Senior Member easttnboater's Avatar
    Join Date
    Nov 2002
    Location
    GA
    Posts
    653
    This is all based on my experience - your mileage may vary.

    First - AGM batteries want to be discharged, then FULLY charged. If you were discharging them and not fully charging them before the next discharge, then you will not get a decent life out of them. If you want to stay with your inverter, then I suggest 6 volt golf cart batteries. Yes, they are lead acid and you have to check the water level 3-4 times a year, but they will take a beating and keep on working. I have 12 6 volt golf cart batteries wired in pairs to make 12 volt batteries, then all the 12 volt batteries are wired as one big bank. Like JTAlberts, I can power my normal 12 volt and 120 volt loads for several days.

    Second - if you want to go the Honda route, then I would not back feed it through a plug like your dock neighbor told you. I would get the correct adapter and plug it into your shore power receptacles. If you are worried about your Xantrex inverter/charger, then simply turn it off at its control panel.

    That being said, I do not understand people having trouble with their generators. I have a 15 kva Westerbeke with 1600 hours. Give it decent gas, change the gas filter, oil filters, oil, and impellers and most importantly run it like it was meant to be run and it will be good for thousands of hours of service. I can buy a lot of gas for what you are going to pay for your Honda generator.

  5. #5
    Senior Member GoVols's Avatar
    Join Date
    Aug 2011
    Location
    Nashville, TN
    Posts
    472
    I could buy a Ryobi 2,200 from a friend for only $400, but I don't suspect it would be enough to power all my 110 stuff. I could get a brand new Yamaha 3200 for $1,700, but that's more than I want to spend on all this. Am thinking of just biting the bullet and buying 8 new batteries and running the gennie more. My Westerbeke only has 350 hours on it anyway. I run it regularly during the season, but I just don't let it run all day / night long.
    Formerly owned a 16X69' Sailabration

    Bet On Another Thousand

  6. #6
    Senior Member easttnboater's Avatar
    Join Date
    Nov 2002
    Location
    GA
    Posts
    653
    If you do batteries, go to 6 volt golf cart batteries. I got mine at Sams. They take a ton of abuse and keep working. If you are concerned about how to wire them, look at some of the solar power sites. You will get more information than you can absorb. AGMs are neat technology, but are finicky. Discharging without fully recharging kills them.

  7. #7
    Senior Member Endurance's Avatar
    Join Date
    Nov 2005
    Location
    Lake Powell, Utah
    Posts
    270
    It sounds like your power difficulty is during the night. A generator may not do much good then. I have a Honda EU3000is on my boat. At 49 to 58 dB(A), it is the quietest generator Honda makes and there's no way I would even consider running it all night. A lake is a pretty quiet place where sound travels far and even a quiet generator would be more noise than I would want to inflict on myself and my crew. I would also never want to be "that guy" at the lake. Maybe your lake is different than mine, but at my lake a common joke is that running your generator or loud music at night tends to cause vibrations that will make your drain plugs fall out in the middle of the night.

    If you are like most boat owners and want to rely on batteries at night, here are some things that will help you get a better lifespan out of them. Buying batteries is just buying a given number of "cycles." A cycle is just going from full charge to discharge and back to full charge. How many cycles you get is a function of how deeply you discharge your battery bank with each cycle. Here is a chart from one AGM manufacturer:



    This chart would predict that if you're taking your batteries to dead each cycle, you'll get about about 500 cycles. If you can discharge 30% and leave 70% in your batteries each cycle, you would get over 2000 cycles, which quadruples the life of your batteries. You might want to up the size of your battery bank so that your discharge cycles aren't so deep.

    If you're like me on my first set of batteries, your answer to how much charge percentage you're leaving in your batteries each cycle is, "What? How would I know that?"

    After I killed my first $1,000 set of batteries, I began to see what a bargain it was to spend a hundred or even $300 on a good battery meter. I bought a Blue Sea Systems VSM, but a lot of people swear by a Bogart Trimetric. Meters like this mount permanently on your wall or on an instrument panel. Either one will give you an instant readout of percentage of charge left in your battery bank. It is good to check each morning to see how much you pulled out of your batteries over the night. It is also good to know you are at 100% before you start the night's discharge. As East TN said, that is important.

    Battery balance is another key to a long life. If you have eight 12v batteries, it would be all but impossible to keep them in balance because you have so many parallel connections. Even if you have eight 6v batteries, you want to make sure you pull power from two corners of your battery bank rather than from the same end. Here is what wiring would look like for eight 6v batteries wired to work as a 12v battery bank:



    You will notice the positive lead in the upper left corner of the picture and the negative lead in the lower right corner of the picture. If you already have golf cart batteries and want to up the size of your bank, you could do that by buying something like L-16 batteries. Six L-16 batteries have about the same storage capacity as twelve golf cart batteries. That's what I did on my boat:



    Just like the eight battery bank, the leads come off the corners of the bank. My inverter runs a 120v residential side by side fridge all night. I usually have about 80% charge left when the sun comes up in the morning and my solar panels can start making power.

    One final thing you might consider is adding solar panels instead of another generator. Generators do a great job of dumping a lot of amps into a battery bank when the battery bank is low and can take a lot of amps. On a three-stage charger, that's called "bulk charging." But as a battery bank fills, it moves to "acceptance charging" and "float charging." During acceptance and float charging, a generator is still using fuel and making noise like it's doing a lot of good, but it's not because the batteries can take little more than a trickle as they near full charge. At the risk of making a bad pun, that's where solar panels shine.
    Last edited by Endurance; 04-28-2015 at 12:31 PM.

  8. #8
    Member
    Join Date
    Jul 2012
    Location
    Pacific Northwest
    Posts
    97
    All good advice. I also might add, did you make sure the charger you are using is designed for AGM batteries? AGMs as someone said are finicky especially about how they are charged. They are temperature and voltage sensitive. Too low a voltage and they will never fully charge, too high a voltage and it will slowly destroy your batteries. If the battery gets too hot it will also boil off the gel and wreck them.

    A portable generator on yur boat is a bad idea. Unfortunately it has become popular and is a disaster waiting to happen. Especially if you do as your friend advised and backfeed into the system. That's an electrocution waiting for a victim. If you are going to do it, do it right. There are valid reasons why on board generators are required to meet US Coast Guard rules for fuel and electrical standards. Those portables do not meet those rules. See http://newboatbuilders.com/docs/portable.pdf Portables? Pro and Con.

    If you are having problems now with batteries overnight, running AC appliances off an inverter will just make it worse. AC equipment draws far more Amps than DC. Running you AC fridge off your batteries can kill your batteries in a few hours.

    PS if you do go the Portable route, as easttnbbboater said get a shore tie connection, and plug it into the shore power plug. Then it will be properly grounded, there will be no back feed and your inverter will automatically sense current and charge your batteries.
    Last edited by Ike; 04-28-2015 at 04:07 PM.

  9. #9
    Super Moderator OLD HOUSEBOATER's Avatar
    Join Date
    Oct 2002
    Location
    Tavares Florida
    Posts
    1,909
    No matter what you decide DO NOT back feed thru an outlet. This is beyond dangerous. If something bad happened you could be sued with no recourse.
    The fries are cold so we gave you extra.

  10. #10
    Senior Member GoVols's Avatar
    Join Date
    Aug 2011
    Location
    Nashville, TN
    Posts
    472
    I have a Xantrex Inverter with multistage charger and it allows for several types of batteries, including AGMs. My biggest complaint is that it does not have an instant voltage meter. It has an auto cutoff feature that shuts down the inverter at X amount of charge. Can't remember off the top of my head, but several people told me that it's set properly. Maybe I'll ask my battery guy about the golf cart batteries this time. I can say that when out on the water, I might not have charged them fully when the inverter shut down. I typically did, but I would shut the generator back off once it went from BULK charge, to medium (can't remember what it's called) charge, and then finally FLOAT charge (it's full). I'd shut it down at the medium charge point b/c it can take a while for the batteries to go from ~90% to 100%.

    When I bought these 8 - AGMs in 2012, I spent $1K and had custom 4 gauge connectors built. That would put me at $125 a battery. What could I expect to spend for the golf cart batteries? What voltage should I look into?
    Last edited by GoVols; 04-29-2015 at 08:10 AM.
    Formerly owned a 16X69' Sailabration

    Bet On Another Thousand

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts