Charging

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Sep 12, 2005
71
Oday 25 Escondido, CA
Can I connect the aligator clips from my solar trickle charger to the bus bar to charge the battery?
 

Taylor

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Feb 9, 2006
113
Warwick Cardinal 46 Seattle, WA
wire size and length of run

By bus bar, are you talking about some sort of power distribution bar? Assuming both positive and negative bus bars are wired back to the battery with larger wire, I don't see why you couldn't attach the clips there (although someone will probably think of a reason).

My concern is that the longer the run from the solar panel to the battery, the more important the wire size is, in order to avoid voltage drop.

This also assumes that the power distribution bus bar is not switched with a battery switch. You probably do not want your solar charge depending on battery switch position.

I wired my solar panel (actually the solar controller in my case) to the output (12v) side of my main 110v battery charger because it was connected back to the battery with large (#3) wire and was not impacted by the position of the battery switch. The larger wires were, of course, protected by big fuses near the batteries.
 
Jun 8, 2004
350
Macgregor 21 Clinton, NJ
several factors

As Taylor says, it could depend on the length of the run and the connection linked to any battery switch. My solar panel is really only a 'refresher' of low amperage, and so I connected it to the battery side of my AC inverter. I'll admit that I've never used the inverter while the panel was hooked up(I use a quick disconnect cable that came with it).
 

Benny

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Sep 27, 2008
1,149
Hunter 320 Tampa, FL
Electricity can flow both ways and like water

it flows downhill. Unless you control the flow of electricity the little trickle solar panel may only help to discharge the battery.
 
Sep 12, 2005
71
Oday 25 Escondido, CA
This is what I am working with. The pic is looking forward; port red 8awg is the panel and starboard red 8awg is battery. There are fuses in the panel (15 amp) and the 16 gauge wires. No battery switch. Distance from the bar to the battery is ~3' and the solar wire is ~6'. I think I have the transmission loss minimized. Should I just connect the aligator clip directly to the battery + wire? What about a ground? Could I hang an anode over the side? There is no internal ground. Thanks gents.

p.s. please look in my profile album 'interior' for the pic. tough transition:)
 
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B

Bill Roosa6491

Grounding and diodes

not sure why you reference a zinc anode but that is not the way to establish a ground for your solar panel.
your buss bars will work fine. + to + and - to -. You might even think of using a wing nut and a circular connector to insure a good connection

a solar panel will charge your battery during the day and then discharge it at night if you don't install a diode in the circuit. They act like one way valves for electricity. just like one way valves they take a little more energy to get the electricity to flow in the right direction. This appears as a drop in voltage at the battery. for small panels this extra power is significant and actually causes the panel to be pretty much useless for charging a battery. Your only alternative is to keep connecting at dawn and disconnecting at dusk. Or install a switch.
many panels already have diodes so check your documentation.
 
Sep 12, 2005
71
Oday 25 Escondido, CA
The panel I plan on using is a trickle charger type, 135 mA. I can't recall if it has a diode built in. I hope so, I don't want a 'useless' panel! The reason I brought up a zinc anode is that I don't want to encourage corrosion by clipping the (-) of the panel to the (-) busbar. I also saw a dock neighbor who uses the anode over the side but he couldn't explain his reason.:)
 

Taylor

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Feb 9, 2006
113
Warwick Cardinal 46 Seattle, WA
Zinc annode over the side

A little off topic, but the purpose of hanging an zinc anode over the side is to save the zincs on your prop and shaft (and elsewhere). Some marinas are thought to be 'hot' with stray currents, and the thinking is that if you tie your bonding system (the green wires that attach all the metal pieces on the boat together) to an additional large anode, that some of the electrolysis will dissolve the big anode, slowing loss on the the smaller and harder to replace anodes on the boat. I don't think it has anything to do with battery ground.
 
B

Bill Roosa6491

Useless or not

The way to tell is measure the battery voltage and then connect the panel. Re-check the battery voltage. If there is an increase at all (>0.1 volts) then the panel is (not much in that case but..) charging the battery.
 
Sep 12, 2005
71
Oday 25 Escondido, CA
A test & the zinc

Taylor, exactly the info I was looking for. I have no zincs associated with my electronics so I feel like I have stray current in the boat. I wanted to connect my boats' current to that of the marinas'. Is that even an issue? The corrosion of my interior electronics due to lack of true earth ground?

Bill, my experiment is in the works. I just hooked up an analog volt meter to measure. I plan on testing sun v. shade as well. it will be submitted for peer review. . .
 

Taylor

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Feb 9, 2006
113
Warwick Cardinal 46 Seattle, WA
More on Zincs

B&B -

This is a complex topic, especially as we wander into the area of unintended consequences and stray current. And I'm by no means a professional in this area, I just read a lot.

Let's start with zincs - the purpose of zincs is to avoid electrolysis from dissolving the underwater metal on your boat. Remember the high school chemistry experiment with the two dissimilar metals in a salt water solution and a wire connecting them together? Current flowed (electrons moved), the less noble metal dissolved and ions of one metal moved over and deposited out on the other metal. They flowed from the anode to the cathode. That's how batteries work, that's how chrome plating works. For a battery it is producing current, in the case of chrome plating they induce a current in order to force the chrome ions to plate something.

(Disclosure - I really enjoyed my high school chemistry class, and not just because I got to burn things).

Well, you don't want to make an anode out of a folding prop, or your through hull fittings - you don't want them to dissolve. So instead you bond them all together and attach them to zinc anodes under water. Then if something is going to dissolve, it's the zinc, which is way down on the least noble end of the electro negativity chart. They are sacrificial anodes, you expect them to be replaced every year or two as they sacrifice themselves to save your prop and through hulls.

The electrolysis will happen faster if the current is not just what you get between zinc and bronze on the electro negativity chart, its is much worse if you have a voltage difference between different underwater metal parts of the boat, which is why they are all bonded together with those big green wires. Basically, if there is a voltage difference, you are sort of zinc plating your brass parts, and when the zinc is gone, you are brass plating your other brass parts, because there is always going to be one metal which is less noble than another (and brass is an alloy that varies from one maker to another)

Ok, so back to your electronics.

I don't believe that marine electronics requires a true earth ground, except for Single Side Band radio, which for sure should have a ground plate of some sort. I think (and I'm not an expert here, check and see what is in Caulder's book) most people do not have a special ground for their marine electronics; they just have plus and minus. Some marine electronics manuals say 'wire straight to the battery' which is just their way of saying 'get me a good low noise source of electricity. It's really a bummer to see a nice electrical panel and a bunch of wires attached to the positive post of the battery for the radio, radar, GPS, radar etc.

About the marina electricity - Boats that have a shore power cable are supposed to run the shore power through an isolation transformer - that gets the 120V AC power into the boat without a physical connection of the boat wiring to the marina wiring. The transformer lets the AC from the marina into a transformer that forms a magnetic field and which causes an electrical field on the other side of the isolation transformer and presto - you have 120v AC inside the boat without a direct electrical path. You do that because you don't want to have a ground leak on the marina put any kind of voltage on the boat that can then leak into the water.

Again - I might be wrong here - this is just what I've read - and AC current is dangerous stuff, especially around water. There have been documented cases of people being killed while swimming near boats plugged into 110V AC with current leaks into the water.

So what's this mean to you?

If you have a real shore power cord, I would hunt around to see if you have an isolation transformer, and if you don't you might consider getting one.

If you are just bringing a 110v extension cord aboard and plugging it into a battery charger, I would check with the battery charger instructions to see if there isolation between the 12v and the 110v.

The one thing I'm not clear on is the 'corrosion on your interior electronics' . That could be a bunch of different things. Boats that have been wired with non-tinned stranded automotive wire can have that wire corrode just by being in a damp salt air environment. I had a #3 cable (and that's a big cable) go completely belly up this summer just from internal corrosion of the copper causing the resistance to increase. Same thing goes for connectors - automotive connectors don't last forever on a boat - the environment is hard on them, and they show this by failing. Yes, I've used them, but I'm not proud of it, and as I find older connections failing (from the previous owner) I'm getting more serious about decent connectors.

And if you have any connectors that are soldered - well even flux in electrical solder seems to be an invitation for corrosion on a boat.

Maine Sail (a regular contributor here) did a great write-up on crimped connectors and made a believer out of me.
 
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