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 2 of 4
FirstFirst 1 2 3 4 LastLast
Results 11 to 20 of 31

Thread: New inverter batteries or portable generator?

  1. #11
    Senior Member
    Join Date
    Jul 2012
    Location
    Wheeling, WV
    Posts
    356
    Quote Originally Posted by GoVols View Post
    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?


    I bought 8 - 6 volt batteries from Sam's. I believe they ran about $85. I wired them in parallel and series. You basically make a 12 volt battery with a pair of 6 volts and then you tie all the pairs together. You have to buy an even number. Endurance has great info in the post above.

    With my 8 bank of batteries I was able to run 2 mini refrigerators and 2 industrial fans for about 3 full days.

  2. #12
    Senior Member Stmbtwle's Avatar
    Join Date
    Apr 2003
    Location
    Ruskin, Florida
    Posts
    2,477
    Some years ago I attempted to charge my batteries by plugging my Honda into the shore outlet. It went fine for a while as the charger was in "bulk" mode. However as the batteries started coming up to full charge the charger went to switching on and off (normal for that charger). The sound of the little generator going from full power to no-load and back again (and again, and again) was maddening. That's when I went to Solar.
    She's a tired old barge but she's paid for!

  3. #13
    Senior Member Endurance's Avatar
    Join Date
    Nov 2005
    Location
    Lake Powell, Utah
    Posts
    270
    Quote Originally Posted by GoVols View Post
    What voltage should I look into?
    The short answer is that you will probably find 6v batteries to be best for your situation. If you're interested in the reasons why, read on.

    The way you measure the storage capacity of a battery or bank of batteries is in Amp hours (usually abbreviated Ah). To get Ah, you just multiply the Amp draw on your battery bank by the number of hours you're pulling from your battery bank. Let's say that you are drawing 30 Amps from your battery over a 10 hour night. That would be 30 Amps x 10 hours = 300 Ah.

    In addition to the number of Ah a battery has, it matters at what voltage you get your Ah. Two batteries might have the same Ah, but if one of them gives its Ah at twice the voltage, it is storing twice the energy because of the higher voltage.

    The way you get different Ah and volts out of a battery bank is by making parallel and series connections. A parallel connection looks like this:

    You will notice that the positive terminals are hooked together and the negative terminals are hooked together. When you make a parallel connection, you add the Ah of the batteries you are combining but the voltage stays the same. If the two batteries in the picture are 100Ah 12v batteries, the parallel connection will give you 200 Ah at 12v. You can make many parallel connections to increase the Ah capacity of a battery bank by combining a lot of batteries.

    A series connection looks like this:

    Here, the positive terminal on one battery is hooked to the negative terminal on the battery next to it and the cables going to the load attach to the two terminals that are left over. When you make a series connection, you add the voltages of the batteries you are combining but the Ah stays the same. If the two batteries in the picture are 200 Ah 6v batteries, the series connection will give you 200 Ah at 12v. You can make a lot of series connections to get higher and higher voltages.

    Usually, battery banks have both parallel and series connections. That looks like this:

    Just as you would expect, you have a couple of series connections and a couple of parallel connections. If the batteries in the picture are 200Ah 6v batteries, the series/parallel wiring shown would give you 400Ah at 12v. You might also describe this bank as two parallel strings of two batteries. The more series connections you make, the higher the voltage; the more parallel connections you make, the higher the Ah.

    Parallel connections and series connections are not equal in how they affect battery life. For good battery life, series connections are good; parallel connections are bad. The reason is that series connections force the current to flow through multiple batteries, which keeps them in balance. With parallel connections, the electricity follows the path of least resistance. That makes some of the batteries do more of their share of the work while others do less. The batteries that have the positive and negative leads attached to them work the hardest and the ones that just have jumper wires attached to them work the least. That's why it's best to connect the cables going to your loads to opposite ends of your battery bank so you spread the work out among the batteries as much as you can.

    Given this background, let's say we are making an 800 Ah battery bank and that the bank is going to operate at 12 volts. You could do that with 12 volt batteries, 6 volt batteries, or 2 volt batteries.

    If you had 100 Ah 12 v batteries (a pretty typical size for group 27 batteries), you would buy eight of them and wire them all in parallel. That would give you 800 Ah because 100Ah x 8 is 800Ah.

    If you had 200 Ah 6v batteries (a pretty typical size for golf cart batteries) you would buy eight of them and make four strings of two batteries each. Each set of two in series would make 200Ah at 12v because 6v x 2 is 12v. You would have four sets of these. That would give you 800 Ah because 200 Ah x 4 is 800 Ah.

    If you had 800 Ah 2v batteries (there is no typical for 2v batteries) you would buy six of them and hook them all in series. That would give you 800 Ah at 12v because 2v x 6 is 12v.

    Since series connections are good and parallel connections are bad, the battery bank with 2v batteries is the best and will last the longest. The bank with 6v batteries is second best and will last the second longest. The one with 12v batteries is a poor design and will have the shortest life of the three. If for some reason you get a good deal on 12v batteries or otherwise need a bunch of parallel connections, there is one way to make those connections with a bus bar system and a lot of fuses. But that is a discussion for another day.

    Armed with this knowledge, you would then go out battery shopping. Thanks to the solar industry, 2v batteries are getting more common and cheaper. But you will probably still find them harder to find compared to 12v and 6v batteries and still pretty expensive. Since you will probably pay about the same for eight group 27 12v batteries as you would for eight 6v golf cart batteries, you will wisely steer clear of the 12 v batteries and buy the 6v ones. I hope the day comes when 2v batteries get cost effective. But until that day comes, I am confident that you will find 6v batteries to be your best bet.

  4. #14
    Senior Member
    Join Date
    Jul 2012
    Posts
    113
    Never really thought of solar panels for my boat...now I am asking myself why? I have an aluminum flat cover over the back. It gets sunlight from mid day to dark in the summer. Inverter sounding more like the way to go!

  5. #15
    Endurance,
    Great post. Thanks.

  6. #16
    Super Moderator OLD HOUSEBOATER's Avatar
    Join Date
    Oct 2002
    Location
    Tavares Florida
    Posts
    1,909
    There are 2 major types of batteries. The typical battery we think of most is a starting battery. These are made to give high amounts of current for a short amount of time. The second type is the Deep Cycle battery. They are designed to store large amounts of energy and disperse it over long periods of time. Construction of these batteries is robust, The plates are thicker and they last a long time in their intended service. They are used in Golf Carts, industrial machinery, bulk storage in solar power installations etc. They are ideal for your boat house bank. Life, if properly maintained can be 5 years of more. The "flooded" type. 100 AH 12 volt typically weighs 60 pounds 150 AH weighs 80. A 3rd type currently popular is the MDC - Marine Deep Cycle. These are popular as a starting and house battery bank service in many boats. These are a "price point" product that gives adequate service in many installations but are not the optimum for bulk storage. Typical life is 3 years.

    If you have the space and don't mind the maintenance of flooded batteries the Golf Cart Deep Cycle batteries are the best for bulk storage. The Trojan T1275 is a 150AH 12 volt battery in a size 31 case and weighs 80 pounds. East Penn DEKA has equal models. Series parallel 6 volt units are also a good setup just a little more involved wiring wise. The QUALITY flooded batteries from Trojan And East Penn give the most bang for the buck over time. They do require maintenance but will normally give 5+ years of service. Flooded batteries are the most rugged and tolerant batteries you can buy and will stand the most abuse. In most cases the best "Bang for the Buck" overall.

    If you want less maintenance AGM and GEL's are sealed so there is no water make up. HOWEVER connections have to be inspected periodically and the proper charger and charging protocols are MANDATORY. A proper system using these batteries will, in most cases, last longer than your ownership of the boat. First cost is the downer. Most existing chargers don't have a charging algorithm for GEL's or AGM's and will have to be changed out in addition to the high cost of the batteries. Many of these batteries have failed prematurely because of the wrong charger or settings. (charge cycles are milder. Flooded batteries need to gas a little bit to stir the fluid and prevent stratification. In AGM and GEL high charging rates dry them out and shorten the life)
    Last edited by OLD HOUSEBOATER; 04-29-2015 at 09:05 PM.
    The fries are cold so we gave you extra.

  7. #17
    Senior Member easttnboater's Avatar
    Join Date
    Nov 2002
    Location
    GA
    Posts
    653
    I bought mine at Sam's - they were in the $85 dollar range.

  8. #18
    Senior Member Endurance's Avatar
    Join Date
    Nov 2005
    Location
    Lake Powell, Utah
    Posts
    270
    Taking all you've said about your boat, here is a suggestion for what it's worth. If an eight battery bank is sufficient for your needs, you could go to Sam's and buy eight of the golf cart batteries like East TN bought. You would wire them exactly like the photo in my first post. Yes, you have to put distilled water in them once in a while but you strike me as someone who stays on top of things like that. Next, buy a Bogart Trimetric meter. As the name suggests, it is metering three things. One is state of charge in a percentage, second is how many amps you're putting into your bank when you're charging or taking out when you're discharging, and the third is the instant voltage readout you've been looking for. Next purchase is a solar charge controller like a Morningstar Tri-Star MPPT 45 and about 700 to 800 watts of solar panels. These are higher voltage panels that you would usually buy for less than $1 per watt. The higher voltage is good because the MPPT controller converts that down to the 12 volts (nominal) that your batteries need. From the picture in your avatar, it looks like you have plenty of space on your shade top for something like three 250 watt panels.

    The best part of this is how the different parts of this charging system would integrate. You would get up each morning and check your Trimetric meter to see how much power you used in the night. Let's say that you find yourself at 50%. You then fire up your Westerbeke generator. Yes, it uses a fair amount of gas and makes a some noise, but that's not that big a concern because it's breakfast time and you wanted to run your coffeemaker and electric griddle anyway. Besides, you're only going to run it an hour or two and because your batteries are at their low point of the day, they can take some good bulk charging. I don't mind putting gas in and listening to a generator if I'm getting a good bulk charge out of it. About the time your charger switches to acceptance charging, you turn off your generator and enjoy the quiet. The solar controller and panels I mentioned are capable of providing a 45 Amp charge, but if it is a little overcast and you are only getting 20 Amps, that's fine because the solar system literally has the rest of the day to take your batteries through acceptance and float charging. Your generator is doing what it does best -- big time charging done quickly when your batteries can take a lot of Amps. Your solar panels are doing what they do best -- slow sustained charging at a time when your batteries want slower sustained charging.

    At some point in the afternoon, you check your Trimetric meter and see that you're at full charge or near to it. Maybe you run your generator a bit at dinner time but that would be just to run a stove since your batteries are sitting well between 95% and 100% charge. You then go to bed and enjoy the quiet of the night and the good feeling that comes from knowing you will still have your electrical system working and reasonably charged in the morning when you awake.

    Here is a cost breakdown (I rounded odd numbers upward):

    Eight Sam's Club batteries: $700
    Bogart Trimetric Meter: $150
    Morningstar TS-MPPT-45 Solar Charge Controller: $400
    Three 250 Watt Solar Panels: $750

    Total Cost is $2,000. By an odd coincidence, that's what a Honda eu3000is generator costs. You would have some wire and maybe a few breakers to buy, but you would have to buy some of that kind of equipment anyway if you safely wired the portable generator. I think you'll be more happy with the solar panels with new golf cart batteries than you would with a portable generator and your old batteries. There are getting to be some good solar suppliers out there. My favorite is Northern Arizona Wind and Sun.

    Again, just a suggestion. There are several ways to improve things for this season and this is just one of them.
    Last edited by Endurance; 04-30-2015 at 04:11 PM.

  9. #19
    Senior Member GoVols's Avatar
    Join Date
    Aug 2011
    Location
    Nashville, TN
    Posts
    472
    Wow! That's a lot of info to digest! Getting the solar power from the panels down to the batteries would require some wires to be run between the 2 and I have no idea how to tastefully get that done. This is a LOT of stuff to think over.

    Isn't degassing on the golf cart batteries a concern? They sit under my master bed in a compartment that has a Coke-can-sized vent hole in the floor. I seem to remember the gasses from the unsealed batteries being a concern when I was buying batteries the last time. I was told to go with AGMs for this reason. Unfortunately, my pontoon houseboat has no other storage location available for the batteries. I have other items stored under the bed as well, so there's plenty of room for even more batteries, but I need the storage at this time.

    A dock friend of mine owns a battery distribution company, so I'll talk to him the next chance I get and get some pricing for the different battery types.

    Thanks for your help and advice guys! I love this site!!
    Formerly owned a 16X69' Sailabration

    Bet On Another Thousand

  10. #20
    Senior Member Endurance's Avatar
    Join Date
    Nov 2005
    Location
    Lake Powell, Utah
    Posts
    270
    If your batteries are inside your cabin, AGMs are a must. Flooded lead acid batteries inside would be about as unsafe as a generator wired into an outlet with two male plugs. AGMs will cost more. On the bright side, you won't ever have to check water in the AGMs.

    Thankfully, golf cart sized batteries (usually GC2s) come in AGM as well as flooded lead acid. If you're working with a battery distributor anyway, you might want to price L-16 size batteries as well as GC2 size. One L-16 will about equal two GC2s. If the total dollar cost is even close and you have room for the L-16 size, I would go with the L-16s because that would cut your number of jump wires in half. That is easier to wire and will result in better battery bank balance compared to twice the number of GC2 size.

    Speaking of jump wires, did you mean it when you said that your jump wires are 4 gauge? Unless you have an inverter around 500 watts or have a bus bar system, that's too small. To keep batteries healthy, jump wires need to be the same size as the main cables that feed your inverter. Even a 1000 watt inverter five feet away from the batteries would need 2 gauge. If your inverter is larger or farther away than that, you would need to go bigger like 0, 00, or even 0000. I am wondering if you meant that you have 0000 jumpers. Most people pronounce 0000 as "four aught," which would be pretty easy to confuse with 4 gauge.
    Last edited by Endurance; 04-30-2015 at 04:49 PM.

+ 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