battery charger/ inverter ???s

mattttt25

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Sep 29, 2002
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i'm thinking of expanding my electrical system on my 24' grady. currently have 2 battery system with switch. since it's a grady walk, i have plenty of lights, pumps, and a ton of electronics (radio, vhf, cb, loran, gps, ff). no problems to date, but i want to increase my usage while docked at marinas.<br /><br />i don't think a full blown shore power set-up is necessary. i was thinking of starting with a 2 bank installed charger. i could then easily run a cord to the marina power (already have a 30 amp twist connector) and charge my batteries.<br /><br />would then go with an installed inverter. i know i need to check the numbers with what i want to run. don't need much, but would like to run a cell phone charger, maybe a laptop charger, etc. but could expand this requirement.<br /><br />question is how it all works together. if i'm docked and my charger is plugged in and actively charging my batteries, can i then use the inverter at the same time and draw from those batteries? will the charger keep up? will the charger simply send electrons straight to the inverter and not charge my batteries (this would be ok with me). i just get fuzzy when it comes down to how it all works.<br /><br />if there is a better setup, i'd be interested in hearing about that as well.<br /><br />thanks-<br /><br />edit- ok, just realized this question would sound really stupid. hey matt, why don't you just run an extension cord from the shore to the boat and power your 120v items from there? eliminate the need for the charger and inverter all together?<br /><br />well, that makes sense. but having the charger is a good idea anyway, and the inverter gives me flexibility when away from the dock.<br /><br />so my questions above still remain, to help me understand how it all works. but i'd also like to add this scenario- docked, plugged into the shore with charger, and now using 12 volt items on the boat. how does that all work? charger simply power those items and the batteries remain in their current condition?
 

RubberFrog

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Apr 9, 2005
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Re: battery charger/ inverter ???s

I wouldn't try to charge the batteries while you're using the inverter. Inverters are very inefficient and suck down a lot of extra "juice." I think this may cause the charger to pump too many amps into the battery trying to keep up. Sizzle. I would do the two things seperate. use the inverter while you're awake and fooling around. Charge the batteries after you go to bed. Obviously, don't wire the inverter to your starting battery- keep it isolated.
 

briannh1234

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May 19, 2003
Messages
233
Re: battery charger/ inverter ???s

Most battery chargers are not made for continuous duty at high amp output. However they do make inverters/charger combo units that know to switch your 110 stuff to shore power and charge your batteries when you plug in. Pretty expensive but would fit what you want nicely.
 

18rabbit

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Nov 14, 2003
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Re: battery charger/ inverter ???s

Mat, you’ve been around here long enough to know that running a 120vac extension cord onto a boat is worse than a bad idea. You’re a very capable person that likes things done the right way, so…do it the right way and add shore power. It won’t be difficult for you to do.<br /><br />Some inverter/chargers have a power manage scheme that allows you to divide incoming shore power. They relegate a certain percentage to the boat’s house system and the rest to charging batteries. That’s probably what Briannh1234 was referring to. Your house system can be as simple as a single GFCI duplex receptacle.
 

Boatist

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Apr 22, 2002
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4,552
Re: battery charger/ inverter ???s

Why not just get a 12 volt cell phone charger and install some 12 accessory outlets. <br />also a 12 volt adapter for your laptop.<br /><br />If your boat is docked then a onboard charger makes since. <br />Get one that fits your needs. If you have 2 battery banks then get a two bank charger. <br />Also if you run TV's, Radios, Lights while docked then get a charger <br />with enough amps to run you gear plus charge your battery.<br /><br />The on board charger I have seen are all smart chargers and will not <br />over charge your batteries or hurt any 12 volt electronic gear.<br /><br />For me I do not like inverters. <br />They are ineffecient take lots of room some are noisy and <br />I do not like 120 volts running around the boat when I am out on a wet day.
 

mattttt25

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Sep 29, 2002
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Re: battery charger/ inverter ???s

i know the extension cord is a bad idea. but then again, how do you power your charger?<br /><br />thanks for the ideas, fellas. will spend some time thinking it through this weekend as i fish for the ellusive striper. also need to start looking at products that are out there.<br /><br />i'll have more questions, so stay close. thanks-
 

amirm

Petty Officer 2nd Class
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May 7, 2005
Messages
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Re: battery charger/ inverter ???s

Here is what I would do:<br /><br />1. Get a 12 volt charger for your cell phone. No sense is running this off of 120 when these are so cheap. I leave one on the boat permanently. Cost: $20 or less.<br /><br />2. Get a 175 watt inverter that plugs into the cigarette adapter. My favorite is the unit from Xantrex. It will power just about any laptop, and is super efficient. I have one of these in our cars too for laptop use there. Cost: $39 and sometimes less when Westmarine has a sale: http://www.westmarine.com/webapp/wc...sNum=1&subdeptNum=&storeNum=&productId=126732 <br /><br />BTW, RadioShack sells the above under their name if you are not close to west marine.<br /><br />So for $60 or less, and zero installation cost, you have a super convenient system for the uses you list. <br /><br />An on-board inverter is useful if you are going to run outlets everywhere and plug-in various things into it such as TVs, Microwave, etc. For what you want to do, the above is more than ideal, will cost nothing to maintain and take no space.<br /><br />Amir
 

mattttt25

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Sep 29, 2002
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Re: battery charger/ inverter ???s

ok, think i decided what to do. saw one of these at boaters world the other day and immediately thought it would suit my needs. charge my batteries, let me use dc power at the dock, and be done with it.<br /><br /> http://www.marinco2.com/nw_SportmanPowerCenter.asp <br /><br />what ya think? was going to go with the 20amp (10/10) version.
 

18rabbit

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Nov 14, 2003
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3,202
Re: battery charger/ inverter ???s

Personally, I’d bite the bullet and opt for the 30-amp/2-output model if you were planning to use DC on the boat while the bats are charging.<br /><br />The safety issue has to do with appropriate protection; breaker near shore power, and GFCI near the outlet. With that charger you won’t have any outlets, so GFCI of outlets won’t be a problem.<br /><br />I would be more comfortable with a single cable between the charger and an outlet with circuit breaker at the dock. Unless Guest put a 30-ft power cord on those chargers it isn’t going to happen. Where the extension cord outlet meets the charger’s power cord is a vulnerable connection. If that connection drops into the water, there is no circuit protection available to you.<br /><br />[shore power plug]-----------------------------------------[outlet]: =[pwr plug]------[chrgr]<br /><br />It would be real easy to make a breaker/extension cord combo. Stick a 5-amp (120vac), double pole circuit breaker in a NEMA 4x box with waterproof seals where the extension cord enters/exits the box. The NEMA 4x box (usually fiberglass) will resist water, has a rubber seal, stainless steel fasteners. Since the breaker will be entirely inside the air-tight box, should it fall off the dock it will float and water can’t get in. The only problem I see is if you trip the breaker you will need a screwdriver to open the box to reset it.<br /><br />[shore power plug]---<box w/brkr>---------------------[gfci outlets]: =[pwr plug]------[chrgr]<br /><br />If you do the above using an extension cord with GFIC plugs at one end, and put the breaker/box about 3 feet from the shore plug end, you are good to go and you will have ac available on your boat as well.<br /><br />Or you could cut the household plug off the charger and splice on a longer cord with a 30-amp shore power head. I think you would be ok if you used waterproof adhesive lined shrink tubing to seal the splice.<br /><br />[shore power plug]--------------------------------------------------<splice>-------------[chrgr]
 

Ralph 123

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Jun 24, 2003
Messages
3,983
Re: battery charger/ inverter ???s

If it were me, unless I wanted to use AC stuff underway, I'd forget the inverter (except maybe one like Rabbit mentioned) and put in a decent shore power system.<br /><br />I'd get (and did) a distribution panel like this:<br />
18177.jpg
<br /><br /> http://www.bluesea.com/dept.asp?d_id=7989&l1=7460&l2=7989 <br /><br />Add a decent 2-bank 3 stage charger and wire it into one of the circuits and put a GFI duplex on another to run AC stuff when docked.<br /><br />All together $200 or so for panel, Maybe $100 or so for a good 30A shore power inlet ( like these: http://www.marinco2.com/pdf_files/Marinco-AFI-Nicro/30_amp_products.pdf , another $100 for good quality marine AC 10 & 12 gauge wire, and the GFI outlet. Maybe $200 or so for a 20A, 2-bank charger (like these http://www.marinco2.com/pdf_files/Guest/battery_chargers.pdf . <br /><br />If you're patient like me, and good with eBay, you can do it for pennies on the dollar... I did all these things for maybe $300
 
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