Sparks will fly!
Still in George Town
We have been attached to a mooring in Hole 1 at Stocking Island for the past eight days, the anchor enjoying a mid-term rest on the stem head roller. The weather from a wind prospective has been the longest time we have endured such conditions since we were imprisoned off Cape Sounion in Greece many many years ago. That was nine days of sheer misery on a much smaller boat without actually knowing when it would stop blowing. We almost ran out of food in the process. Nowadays things are different and we can time almost to the minute when the wind will start or stop and how strong it will blow. But of course you still have to weather the event. Anyway that’s all beside the point. The reason we took a mooring was that we’d been suffering charging issues from the engine alternators which feed through a very clever zero loss split charge diode system. All very hocus pocus black art stuff which we barely understand ourselves but since we fitted the various components over a few years it’s always performed extremely well and that’s all you can ask.
Unfortunately over the past few weeks things haven’t worked exactly as they should. Without going into tedious amounts of detail (although he probably will !!! Ed.) warning lights at the engine control panel indicating over voltages on the start battery circuit started to blink. Because of that clever diode thingy it wouldn’t let any charge get to our house batteries that run the fridges, lights, water pumps etc. The solar energy continued to work fine through all this so we did have power into the house batteries. But when motoring for the amount of time we’ve been doing recently it’s unacceptable for such warnings to be ignored. So having reached the relative security of George Town we needed to sort this issue out. With gale force winds forecast over a period of some days we rented the mooring from ‘Little Toot’ for as long as we needed its security. Firmly secured we could set about investigating what the problem was and if we needed to ship any parts into George Town before heading off again. As the over voltage was being experienced on the engine start battery it seemed logical to switch that out with a brand new battery we are carrying to see if it was the offending item.
Our battery box in the cockpit is not an area to go poking around in. Just gazing into the mass of batteries and heavy duty leads is enough to think of other things I could be doing onboard.
There’s a massive amount of available power on tap should the wrong lead or a spanner fall in the wrong place. Memories from the past come back of when I accidently bridged the terminals on my old Ford Anglia starter battery with a spanner whilst removing it from the car resulting in a small area of the skin of my index finger melting with the heat. Unfortunately the engine start battery we have onboard is tucked partly under the cockpit floor surrounded by our five battery house bank. All linked into the whole system with some mighty thick red and black leads – none particularly flexible. There are evil spirits living in battery boxes. Rather like those in Pandora’s Box, ready to emerge. Nasty things happen to those unfortunate enough to tangle with those battery demons. When you remove leads and pull a battery out those demons somehow take control of those loose leads and manoeuver them back towards where they had been previously secured. Now there is no where for them to rest so they choose the next available place to land which is on a different terminal altogether. That is, a big black negative cable would naturally land on a big fat positive terminal...........................
(Hang in there – Ed)
Before lifting the battery that was the possible cause of our overcharging woes clear the replacement battery was stood on wooden slats atop the house bank. There the start battery cables would reach its terminals and the engines were started. Bingo! All was working normally again. It was the battery after all and as we were carrying a spare in the cockpit locker it just remained for the ‘dead’ battery to be removed and for the replacement to be installed. The slats were left in position covering the positive terminals of the adjoining house bank. The old start battery was lifted out at an angle to clear the cockpit floor........................................
(Wait for it! – Ed)
With the forty pound battery almost out of it’s hole the slats covering the positive terminals became dislodged. With both hands still occupied hauling the battery away from the locker those spirits mobilised all their available forces to ensure that the negative cable of the start battery shifted from it’s safe position parked to one side of the locker straight onto the positive terminal of No.2 house battery. There was an initial flash as the cable bounced off the terminal. Horror of horrors it then as if by magic firmly settled itself at the same point on the terminal a split second later. This time it was there to stay. In a scene reminiscent of the creation of Frankenstein’s Monster there were massive sparks along with pieces of molten metal being flung all over the house bank. The old starter battery had now been hastily parked. Automatic reactions kicked in to pull what was left of the circular lug terminal of the negative with its attendant cable off of the positive terminal before the bank could explode. Something the boffins mention in their manuals and on the internet. (Air is blue – Ed)
They used to be exactly the same each end ! Number 2 battery terminal - a molten mess
Replacement starter battery finally in place at last – with a spare replacement cable fitted
Calculating the potential damage resulting from what had just transpired began in my mind almost immediately. After all, these batteries are meant to spend their days gently providing small amounts of current to the fridges, lights, instrumentation, computers and our good old television. They are not suitable for arc welding or metal melting on the scale of what had just been witnessed. It was safe to assume that whatever charging woes we had been experiencing to date would now be inconsequential given that we probably didn’t have a battery bank to charge anymore. We could be in some serious trouble.
Where to start first? Well, was anything electrical still actually functioning onboard? Yes, the day fridge was. That was strange as the first thing I would have expected would be for the main 100 amp fuse to blow. Well, it didn’t. Were the solar panels still imputing? Yes they were. The protecting fuse was still intact between the solar input and the house bank. So what next. Check the batteries themselves. Well, number 2 looked like it had been in a fight with something hot. In fact it’s own positive leads were welded to the terminal so if this battery was going to be removed anytime soon it’s leads would have to be cut free. Next the specific gravities were taken on the 30 individual cells that make up the battery bank. All were in the red sector indicating a poor charge. So that was that. The house bank looked to be on it’s way out. Not a disaster except to the bank account perhaps.
So we have remained on this mooring for eight days now. With winds to forty five knots blowing over the bow. Getting ashore to buy even an onion has been impossible unless we took the water taxi. We were OK for onions anyway and strangely enough the batteries have shown a tendency to recuperate over the past few days as well. The critical factor was what would happen when that day’s solar input had ceased with the setting sun. Would the voltage capitulate in the night hours with both fridges demanding their share of amps? We immediately reduced the setting on the big fridge to a more sensible temperature (we have no fish to go off yet) and ran the engine at 10 pm that first night to give the batteries some overnight assistance. All was well the next morning. That is things were no worse than before the big flash. The capacity of the bank isn’t what it was at new but they are relatively cheap batteries and last at best three seasons anyway.
We not so much dodged a bullet as a missile which is what the batteries would have become had the lead stayed in place on that terminal. Now all we need is to find a local priest who can exorcise those demons from that battery box before they can do any more damage. Of course I should have removed the link negative cable from the house to the start battery and shut all systems down – especially the solar. (Silly Boy!) But you think you have the situation under control and all the angles covered. But I didn’t of course.
Meanwhile when we’re not staring down into battery boxes we managed to get ashore for a look back to where we’ve spent the last week or so.
There we are – dead centre, just offshore