Which battery charger? What to do with batteries?

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timlabute

Which battery charger? What to do with batteries?

Post by timlabute »

Hey all! Tim here. Question about battery charging...

I have two large deep cycles, not sure what the numbers are but I can look after work. I plan to run the following:
Stereo (simple automotive CD/radio with two speakers)
VHF
LED NAV, mast, stern lights
LED cabin lights (lots)
Two DC cigarette lighter style receptacles
Two USB ports (power only, to charge cell phones, etc)
Potentially a depth finder and auto bilge

Question 1 - How do I wire my two batteries? I had planned to just wire them together (12v, not 24). I do not see the point in a switch (1, 2, or both) as they are just house bank and I do not have electric start...

Question 2 - What kind of charger do I need? Will this work?
http://www.canadiantire.ca/AST/browse/4 ... ?locale=en

Thanks all! Fair winds!
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Windwalker
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Battery Chargers

Post by Windwalker »

DO NOT USE AN AUTOMOTIVE BATTERY CHARGER WITH DEEP CYCLE BATTERIES! (Did I say that loud enough?)

Assuming both batteries are twelve volt blocks, you wire positive to positive and negative to negative, then to the fuse/breaker panel and then to the equipment. You can tell if there are twelve volt by counting the fill ports (assuming they are not sealed VRLA type), six fill ports means 12V (3 means 6 volts).

I use a ProMariner ProSport battery charger, http://www.pmariner.com/productFeature. ... tNum=42006. Wire the battery charger to the fuse/breaker panel with 1.5X breaker/fuse size times the charging current. (In my case I have a 6 amp charger and use a 10A breaker, 9 amps to 12 amps is satisfactory) This will protect the batteries if there is a fault in the charger. Each of your accessories should have their own fuse/breaker, so with your list that means a 10 to 12 position panel. Cigarette style jacks are 10 amps each, the rest depends on the equipment. The rating should be on the equipment somewhere. Use fuse/breakers that are sized as above, i.e. if it draws 10 amps use a 15 amp fuse/breaker.

The wire used to connect the batteries together and to the fuse/breaker panel depends on the maximum current draw expected from ALL of your electrical accessories. 10 AWG is good for 30 amps, more or less, depending in if the wire is in free air or in a conduit. Use ONLY good quality tinned (silver colored) stranded marine grade wire. Do not use non-tinned (copper colored) or solid household grade wire (What my boat was wired with when I got her).

What boat you have depends on where you place the batteries. I placed three 150 amp-hour VRLA telecommunications batteries under the cockpit of my C26 with one additional starter battery in the port outside locker, all wired together.

Are you planning to wire your boat with AC as well?
Dave

1976 Mutineer
timlabute

Post by timlabute »

Good morning Dave

Thank so much for writing that all out for me. I really appreciate it.

Both batteries are 12v. So it is ideal in my situation to wire them together? That was a concern that I had as I never see anyone doing that. But, this is likely because everyone else has electric start while I do not. I figure use both batteries to get more life out of my electronics.

I currently have a 6 gang marine switch panel with blade fuses. All the current fuses are 15amp but I can swap in a lower fuse if needed.

This leads me to a fused connection for the charger. As I do not have an extra switch on my panel, I assume I could add a fuse in the wiring between the charger and the battery. The link you sent shows a charger that appears to already have this fuse in its wiring... so if I buy that one I should be good?

I will also look in to more wire. I have already purchased 60ft of tinned marine 12awg wire to run power to most of my accessories but have yet to purchase my battery wire yet.

Thanks again! Your advise is very well appreciated.
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Windwalker
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Post by Windwalker »

Doh!, I took the fuse out since I mounted the charger out of the way and did not want to crawl around to replace it if needed. I prefer to have ALL my fusing readily accessible. You can of course use the fuse supplied.

12awg should be fine for your application and for 15A. I used 1awg to tie my batteries together but then I'm in the industry and have tools to deal with the larger wire gauges. Use the largest largest wire you can handle, i.e. have the tools for. Use compression lugs, not the bolt-on wire battery lugs. Invest in a high quality lug compression tool for the correct gauges of wire you are using. Compression lugs if install correctly are an extremely reliable connection, if done incorrectly are extremely unreliable. There are battery lugs that have an integral bolt or if your lucky your batteries have a bolt on connection.

A word of warning, batteries can produce thousands of amps if shorted. I have seen steel tools vaporize when shorting very large batteries. Wires can act as fuse links or even worse, heating elements, i.e. fire starters. Do not hide the wires from the batteries to the fuse panel. Restrain them but keep them where they can be inspected.
Dave

1976 Mutineer
timlabute

Post by timlabute »

Excellent advice! Thank you! I had planned for 4 AWG for the batteries but have not done the shopping yet. As my power needs for the first season will be minimal, I may only go with the one battery. Undecided.

The batteries are very large and both have the top post and an additional screw on bolt connection for each post. I really like that feature and think it will save me some time.

I will post a new thread when the weather gets warmer and I get my electronics laid out on the garage floor too see what I need to buy for wiring. It is just skimming -3 F here right now, so boat work has stopped all together.
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Post by CaptainScott »

Sounds like you are getting great advice and the world is very cold in your neck of the woods! LOL!

Pictures and updates are always welcome! You see, the next guy that comes along will need the help too!

Scott
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Post by mcrandall »

A switch (1, 2, 1+2, Off) or (On/Off) is a good idea as a means to shut down your power source from the rest of your boat quickly in case of an emergency.

Also, ABYC requires fuse or breaker protection near (7-inches) the batteries. The intent of this requirement is to protect you and your boat from electrical shorts throughout your system. Note that your breaker/fuse panel will take care of the smaller wiring going out to your devices, but the main fuse right near your battery will protect that main line going to your distribution panel.

Be mindful of the temperature rating on the wire you use as it drives the ampacity that wire can handle safely. Typically, all same guage wire will heat similarly as the current increases in them. The difference between wires with different temp ratings (assuming same guage and material) is NOT with the conductive material, but rather, how well the insulation on that conductor can withstand that heat. More heat tollerant = higher temp rating = more allowable current.

Last thought for now: Have heard from several boatowners that the autobilges are annoying, especially if you sleep aboard. They run every 3-minutes or so to sense if water is present. If they sense water resistance, they pump until it's gone. Else, they fire up for a few seconds EVERY 3-minutes. Especially on a small boat like ours--hair puller! Second, though small, it IS a drain 24/7 on your battery. (If you're only planning on using it while you are away and charger happily keeping a charge from your dockage--please disregard.) :wink:

Cheers!
Mark
http://s1213.photobucket.com/albums/cc4 ... ew%20C-22/
1975 C-22 currently named Stardust (soon to be "Angela Marie")
timlabute

Post by timlabute »

Thanks! I will be very careful which wire I buy and make sure that it is fused. I have a car audio fuse for 4 AWG that may work. Thoughts on that? It is the inline barrel type. I could put it in line within 7 inches of the battery on the main lead...

I didn't think about the bilge like that. I suppose it would be very annoying. Perhaps I will run a switch to the bilge so shut it off if I am sleeping on the boat. My concern is, I live a 30 minute drive from the Marina so if there is a big rain storm, I would like to know that the bilge is turned on.
timlabute

Post by timlabute »

Hey all. A quick map of my electrical plans. I used Orange for the hot wires in this diagram, but they will actually be Yellow.

I have fused the battery charger, the main hot wire between the battery and switch panel, and the switch panel has fuses for every switch.

This is a diagram without any reference to AC power. I am aware that AC must be grounded to DC but that is not referenced here.

Main leads are 4 AWG and the rest are 12 AWG.

Thoughts?

Image
timlabute

Post by timlabute »

Or is negative supposed to be yellow? Apparently I have some research to do
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Post by Windwalker »

I am not aware that DC MUST be grounded to AC, maybe those of you who have read the ABYC spec can comment.

I would worry about a bilge pump that runs as often as once every three minutes. Without it it should be on the bottom! I have only noticed the automatic bilge pump going off once in the years I have had the boat. I would think they have a defective pump.
Dave

1976 Mutineer
timlabute

Post by timlabute »

I think there are two different types of bilge pumps in question here.
Typa A) Bilge pump with a float
Type B) All in one automatic bilge unit
The type A would only come on when the float turns it on, while type B is basically an all in one unit that is set in the bilge without a float or any sort of sensor. A local hardware store here sells these. Best I can tell, it has to turn on every once and a while to sense load. If it senses load it knows it is under water and stays on until the load is gone. If it does not sense load, it shuts back off.
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Post by mcrandall »

Yellow is DC return. Black is suitable as well, but the industry is trying to migrate to a yellow DC return. Some duplex boat wire is made with red and yellow inner insulation.

Tim is correct on the bilge pumps. Dave, the automatic ones get away from using a float switch by regularly testing the water, so to speak. They activate every 3-min or so and if they don't sense a water load, they shut off until the next cycle, 3-min later. If there IS water, the load is sensed and the pump runs until the load goes away. The pump then goes back into sense mode, briefly firing up every 3-minutes. Drives you nuts!

AC ground. Yes, the DC and AC grounds bond at the boat ground, typically the engine block of an inboard-type engine. Our little boats obviously don't have such an engine, so I would have a ground buss that ties the dc grounds together, provides for a bond for your ac ground, and finally ties to a boat ground (keel, perhaps..external grounding plate..fittings...etc)

That said, if you are only running a charger on your boat, or just an extension cord from the dock...your call.
Mark
http://s1213.photobucket.com/albums/cc4 ... ew%20C-22/
1975 C-22 currently named Stardust (soon to be "Angela Marie")
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Post by mcrandall »

Here's the back of a panel I'm currently installing:

Image

Not on MY boat!!! This is going on one MUCH bigger and whose owner has deep pockets. $4000.00+ for the panel alone.
Mark
http://s1213.photobucket.com/albums/cc4 ... ew%20C-22/
1975 C-22 currently named Stardust (soon to be "Angela Marie")
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Post by Windwalker »

Dave

1976 Mutineer
timlabute

Post by timlabute »

Good read. I didn't think of that... if we have no metal in the water, we do not run the risk of damaging other boats, do we?

As my through hull is getting plugged, and no electrical will be anywhere near it, I should not have to worry about putting stay electricity in to my marina. Nor shall I worry about getting anyone else's stray electricity.

I did some research on your bilge and am going to go the same way. The electronic "float" looks very nice!
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Post by mcrandall »

I agree on the electrical switch vice mechanical for your bilge. That idea satisfies my EET training/experience as well!

On the AC-DC bonding issue, galvanic isolation is be considered, naturally. However, I believe the intent of bonding the two grounds are as follows: If you lose that AC "safety" ground and stray AC currents are passed through any of your devices connected to it (DC ground connected devices), you now have the potential to send stray AC currents through your DC ground to the nearest (least resistant) point of AC return-maybe as far away as where the shore power earth terminal is located. Folks hopping off their boats for swim have been hit with very rude awakenings (read: electrocution drownings.)
Mark
http://s1213.photobucket.com/albums/cc4 ... ew%20C-22/
1975 C-22 currently named Stardust (soon to be "Angela Marie")
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