You may remember back when I posted about
our solar panels I said something along the lines of “How hard can it be?”, well it turns out it's
a little more complicated than I had first presumed. Because I had wired all
eight panels in series it resulted in the voltage being pushed above the
maximum voltage that the charge controller can handle. This means that the
controller doesn't pass on all those lovely solar-generated electrons into our
batteries which means that our batteries haven't been charging which is not
ideal given we need the power in the batteries for propulsion, any power tools
we use for the refit, and (more importantly) I can't listen to the radio.
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| Isolator switch mounted into ply (rear view). |
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Additionally, we have no way of isolating the panels which means I
risk an electric shock any time I do maintenance work on the electronics, now
and in the future. So far I haven't had a shock but it seems silly to tempt
fate. Therefore it seemed prudent to re-wire the panels, and whilst doing so,
add in some isolator switches. This should allow us to charge the batteries
properly, and do maintenance work safely in the future.
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| Front view of switch. |
Having purchased some isolator switches, crimp ring connectors, cable, and a crimping tool I set off for the boat. My first task was to make
some wooden mounts for the switches to screw into. I used a
ply off cut and cut it into 2 strips to fit to the underside of the panels, then, after marking up where the switches
would be mounted, I drilled a hole using a spade bit and then used the jigsaw
to cut out a a hole big enough to slot the switches into. Once that was
completed it was just a simple task of bolting the switches to the ply, and
mounting them under the solar panels.
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| Getting wired. |
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With the switches ready to go, I set about tackling the wiring. As
the sun was sinking in the sky and we were shaded by trees I rather foolishly
assumed it'd be ok to just go poking around with a screwdriver. I quickly realised my mistake when the current decided to pass through my arm,
into the steel roof, and to earth via the hull which (being a boat) is sitting in more than a little water. Remember what I
said about tempting fate? I think I just proved my point.
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| More wiring. Negative block on the right, awaiting the final connection. |
I haven't had an electric shock before, and I don't intend to have
another one. It's not exactly a pleasant experience, especially when you're on
the roof of a boat with no one else around. Fortunately it was only a small
shock and I survived to tell the tale. With my lesson learned I covered as many
of the panels as I could and very cautiously, keeping myself out of direct
contact with the boat, took apart the wiring. The ring connectors I had weren't large enough to fit
over the poles on the isolator switches, so I chopped them in half to
create some fork connectors (ish) that would allow me to connect the
cables to the switch.
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| One switch, ready to go. |
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Reconfiguring the panels was pretty straightforward. I added a bolt
to one of the pieces of ply to act as a negative block and countersunk it far
enough into the wood so that you can't touch it accidentally and shock
yourself. Each set of 4 panels is now wired in series, with the wires re-joining
before they re-enter the boat so I only have to deal with two wires on the
inside which makes life much s
impler.
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| Totally switched on. |
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All in all it was a pretty successful evening. Only one shock, and
hopefully the changes I've made will mean there will be no more! Plus when the
sun comes up tomorrow we should start to get some juice into the batteries so I
can listen to the radio! Oh, and use power tools and actually move the boat.
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| New configuration of solar panels with isolator on each set of four. |
