Friday, February 11, 2011

More electrical drivel..

Open heart surgery. A terminal problem
You remember how I said electrics may well give you more grief than storms, well here we are, electrical grief, After my deep discharge of my batteries (I don't like to take them under 12v if I can help It). I checked the following day to see what voltage they were at.... !@>! 12.1volts with no load, and full sunlight. I twiddled with the panels, angling them toward the setting sun.. still no change.

Right.. don the Sherlock hat, and think... (ouch). Since I was getting no charge from either of the two panels the problem must be where they join at the regulator. Elementary my dear Watts-in (sorry..). looking closely I noticed the negative wire was loose, and the heat from the loose connection had burnt and melted the connection strip (see the photo). I can only guess that the deeper than normal discharge had resulted in the full charge being pumped in for the first time in a little while, creating too much heat, either that or I had bumped the wires at some point... or more likely a combination of both. Case solved.

Anyway yesterday I fixed it, after all it does the battery no good to sit half charged for any length of time. I cut away the melted plastic and put it all back together. With enormous satisfaction I noticed the smiley face on the screen saying thank you after I faced the panels back into the sun (I shaded them for safety) and turned the batteries back on.
All fixed, note the smiley face!!

While I was at it I checked all the battery cells with the hydrometer (Being very careful not to get any acid in my eyes,skin or on my clothes). Although all the individual cells (6 cell per 12v battery) are all in the red they all floated at about the same level, and needed just a bit of de-mineralised water to top them up. So maybe there is more life in them than I thought. If  I had one cell that was using lots of extra water, and floated much lower than the others it is really bad news (actually a terminal disease, with no effective cure), and this dodgy cell will keep sucking the lifeblood out of any battery connected to it. This is one thing I like about standard batteries, I'm not sure how easy it is to check the heath of an AGM or other sealed battery?

Buoyed by my success I also installed the 800w inverter. Now I feel very pleased with myself... I think regular maintenance might improve my heath as well as the boats.

By coincidence John has just written a good article on batteries here and it talks alot about equalising the batteries, for those of you that don't know about this it means gently overcharging the battery's to break the sulfates off the lead plates. My solar panel regulator supposedly does this every month, but I need a good sunny day. The only point here is to be careful that you don't blow up sensitive electrical gear, because the voltage can go up to 16 volts or so. Also be very careful of battery gas and water levels. For more info about equalisation see here.

I need to work out how to easily isolate one battery for equalisation while using the other one, Guess it will just be abit of fiddling with wires. One other point, my regulator cuts off the load (ie ALL power like lights and GPS etc at about 11.2v), so I have rigged an emergency bypass switch, this also disables all battery monitoring, like charge in and charge out, but could be good in emergencies.

A note on battery safety, having seen an exploded battery.. not a good look and very dangerous (not to mention the cost!), don't over charge them and be very careful of the hydrogen gas released when charging hard. It goes up (lighter than air), and it goes ventilate well and always use insulated tools, (or at least wrap lots of insulating tape around the handles) to prevent a dead short if you drop it or are otherwise clumsy like me, Oh and don't wear metal Jewellery. Also Battery acid is nasty stuff, wear safety goggles. Oh yeah.. and they are bloody heavy.

The point of all this waffle is that batteries and charging is a big deal, you need to understand your system, and the simpler it is the easier it will be to maintain, fix and understand. This is why I do not have a fridge or freezer, the continued draw would totally overwhelm my system, and I would be forced to run the engine to compensate, and then I would need a smart regulator for my alternator, then extra batteries, then more fuel... well you get the idea.



PS I am working on Storm Tactics part 2, but with my one finger typing it is rather slow going..

1 comment:

  1. I should really add that this was a ridiculously simple fix, it took about ten minutes. On other vessels I have had to rebuild alternators, rewire smart chargers, and trace miles of hidden wires to find a cure. It can take days, So for me I like the fact that solar is very simple. worst case is I end up direct connecting them to the batteries and manually regulate them.