Friday, July 06, 2012

Solar Charger for ‘Sandpiper’ – Part 2

A close examination of the wire between the solar panel and the crocodile clips revealed that it was damaged. Yesterday I didn’t notice two places where the protective coating had been breached. The copper wire had become so hot that the filaments fused together. Consequently, the wire was weakened, and I would not like to trust it for long-term use.

Having explained the situation to the Ebay seller, he said he would send me a replacement panel. Meanwhile I have made a mahogany frame for attaching the new panel to ‘Sandpiper’s’ sliding hatch.

When away cruising I shall be more self-sufficient by having an independent means of topping up the battery. I am hoping the 10 watt panel will be adequate for the task. Obviously I must take care not to overuse the Autohelm.


Steve Carey said...

I guess that your battery has recovered from ½ Volt drop due to a near short. It should be OK and has probably already recovered. I once used a 2,000G/pH bilge pump to drain a swimming pool. Close on 100A/H from a 50 Amp battery. It lasted 30 mins before going flat and got quite warm!

Are you permanently mounting your unit on the hatch? Or does it just drop-in when you are on the boat? If you are nearly always bring Sandpiper back home, you can charge your battery fully between trips.

I've got a Nasa 10 Watt semi-flexible unit. It's a bit bigger than A4 size. Not sure whether to fit it on the aft cockpit hatch (mine is plywood) or bend it to the shape of the main hatch which seems to be a lot smaller than yours.

Sandpiper is becoming well equipped!


solozeiler said...

I bought almost the same solar panel on the internet. It was delivered yesterday.
The manual suggests to provide enough ventilation underneath the panel to keep it cool. When the soloar panel gets hot without ventilation, it will drop to almost 60% of its total loading capacity.
I want to place the panel the same way as you do: on the sliding hatch, but have to find out a way to keep it removable so that I can take it away after sailing to prevent theft...

William Serjeant said...

Hi, Leisure 17 zeiler,

You could make a frame similar to mine, into which the panel will fit while you are on the boat. The connector passes through a small hole in the hatch. You could make a stopper to prevent rain water entering the hole when the panel is not in place.
If you want better ventilation you could make vents through or under the wooden frame.


William Serjeant said...


Knowing of your background, you have far more knowledge about things electrical than me. I wouldn't mind betting that you could calculate how long my Autohelm 800 would function when the power source is a 12 volt 100A/H battery fully charged.
I could only take a guess, and hope for the best! Fortunately, I do not rely on any of the electronics. I can work the boat without them.

Steve Carey said...

. . . . Actually, I could! LOL. BUT, the full "ON" current of the motor might be 1.5 Amps and standby current of only 0.05A. If you boat naturally stays on course, then only the lowest current is drawn by your Autohelm. If you're battling a storm (heaven forbid in a WWP!) then it will be working overtime. I've never seen any form of Tiller Pilot in use but conjure up the idea that it's continually pushing and pulling the tiller?

Your 100A/H battery is massive for a small boat. Might have to re-think my 34 Amp one! I know you've done this many times before, so there's no one better than "Managing" things, especially batteries, Internet connection, Notebook computer, GPS's, phone, Nav Lights etc etc. You're a miracle man!

I'm not sure that a 10 Watt Solar panel is big enough (for me either). Most of my "stuff" is of very low consumption. Even my intended Nav lights are LED. The cabin light is LED. The only "Heavyweight" in my boat will be VHF DSC Radio!

Does your Honda OB by any chance have a charging output?