Get An Extra Charge For No Extra Charge
The Age
Saturday June 21, 2003
You can lose big money on any battery you are not charging every few days. When did you last charge up your old MG, the Harley you haven't ridden since it started raining, the caravan or the camper? And what about the boat?
Snow time is battery time. That bright, white footage on the TV weather story is a wake-up call to do something about your recreational vehicle's battery, which is quietly dying outside on the driveway.
You can lose big money on any battery you are not charging every few days. When did you last charge up your old MG, the Harley you haven't ridden since it started raining, the caravan or the camper? And what about the boat?
Those unused batteries are losing charge - and sulphating.
The textbook says: ``Sulphation occurs when a battery is stored over a long period of time in a low state of charge. The crystalline structure of the discharged active material, lead sulphate, is gradually transformed into a substance that resists recharge, causing permanent deterioration."
You'll say: ``I charged it up after the winter. But it won't hold the charge. I got stranded out there. Had to buy a new one." Why can't you just pump batteries up again? Isn't that what they are designed for? The answer is yes, but from a charge level of about 75 per cent, not near zero. And daily, not quarterly.
Batteries discharge for two reasons. A vehicle can have ``key off" current draw. Maybe it's an immobiliser, or an alarm, radio memory, or a clock.
Sulphation may take only a few weeks. One trusted auto electrician we spoke to said significant levels can occur in some cars in 10 days. Sulphation insulates the battery plates, which accept less charge. Crank slower. So they are cranked longer. And this is the start of a downward spiral.
An old remedy was disconnection. But isolated batteries eventually self-discharge. And anyway this may no longer be a feasible option. Most vehicles these days have an on-board computer that needs to be powered to retain data for the car, at least radio PIN coding. And often much, much more.
The car maker has no option but to expect you to drive regularly. You are unlikely to see disconnection recommended in the handbook of a modern vehicle when this involves loss of electronic settings and the dangerous possibility of an owner waving live terminals around when hydrogen gas may be venting off the battery plates.
Disconnection these days is for mechanics and technicians who use a second power supply clipped onto the terminals to keep the wiring loom powered up.
So what is the answer to all this winter doom and gloom? There are two, and they are set-and-forget brilliant. One requires access to direct sunlight, not necessarily cloudless sunshine, for about four hours a day. Two hours might just get you by. The other requires access to a 240v socket on the garage wall. You can leave both types connected and come back in the spring to a battery that is as excited about getting out there again as you are.
The first answer is a solar panel, probably sitting on your dashboard or rear parcel shelf. It can usually be plugged into the cigarette lighter socket, or be wired directly to the battery. Whatever stays connected with the ignition switched off.
If your windscreen is UV protected, try the parcel shelf, or the roof. The Projecta 1.5-watt panel retails for around the $50 mark. To overcome a particular problem two years ago, I found a 5-watt Uni-Solar, which one retailer quoted this week at $190. The flexible panel is powerful and easy to handle. This was for a diesel which was not driven daily and had short drives when it was used, which prevented full recharge. And it had a highish loss of .05 amps just standing there.
Many of you know that diesels take a big current draw to get the bank of glow plugs hot, and add to the load with a huge cranking current to overcome a compression ratio of about double the normal petrol engine's 10:1 figure. The battery must be in prime condition.
A bit of experimentation was required. The winter sun can be more elusive than you think. The neighbour to the north has a high gum tree with a shadow that runs right across the street. But there were enough hours of full sunlight coming through the rear window to keep the battery slightly above 12 volts at all times. A $20 voltmeter left in the car showed good results when checked daily.
In normal cases, a solar panel, well placed, constantly tops up the battery, preventing discharge and thus the formation of lead sulphate on the plates, long-term. But find yourself a parking spot this weekend, at winter solstice, before you invest in solar.
The second option is the innovative 240v on-board automatic battery charger. It replaces your old hit-and-miss method with a manual charger, which requires you to remember to switch it off before overcharging, and to disconnect it.
Between charges, sulphation will occur, and contrary to common belief, the charger will not burn the sulphation off, even at a high charge rate. High rates can also damage a deteriorating battery, generate gas, and are usually not recommended.
I recently bought a Projecta on-board charger for a relative's infrequently-driven six cylinder wagon. It works perfectly. The Projecta AC250 can be found at auto shops for around $70. It can be mounted next to the battery or screwed to the vehicle's firewall. All mounting hardware is supplied with the unit.
Projecta says: ``The AC250 can be left connected indefinitely without the risk of over charging. Batteries that are stored and maintained in this way will have a much longer life than those that are allowed to flatten and sulphate."
The great thing about the on-board charger is that once someone handy has fitted it, a non-technical car owner simply plugs it into an extension cord and into a 240v wall socket, turns on the switch and walks away.
Whatever method you choose, it will pay for itself in a vehicle standing unused for one, or certainly two, winters. People in the know fit one of the above to their daily driver to lengthen battery life, and to keep it topped up when they are away on holidays.
© 2003 The Age
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