E-News Issue #19
In the last newsletter I mentioned that various appliance stores were selling 12V Orion televisions. Someone has confirmed to me that it draws a very respectable 3.2A and they also confirmed that it worked very well.
Peter wrote some time ago to mention that his Hoover Electra runs well on the Selectronic SA21 inverter. Being a front loader, it is water efficient and has an excellent spin cycle which really dries the washing. He has noticed that when it switches cycles, it causes a 'crack' on his computer speakers. So, as a precaution, he shuts his computer off while the washing is being done.
A few things - the 10W tubes are unavailable for one month. The 16W-2D inverter (INV-136 and 236) now are designed to run both the 10 and 16W tubes. The cheaper 2D light (LYF-032) is now back in stock. These have a Chinese tube which are inferior to the Thorn brand. We warn people that this tube may not last as long.
Plasmatronic PL40 Regulator
These will slowly be trickling off the production line later this week.
How Green is Browne? (Economist, April 99)
Sir John Browne, the boss of BP, wants to be loved - and he may even deserve to be - the deal just signed by Sir John Browne, chief executive of BP Amoco, could revolutionise the energy business. No, not the $27 billion takeover of America's Atlantic Richfield (Arco) which was unveiled last month and has been hogging the headlines. But the decision on April 6th to spend $45m to win control of Solarex. This will make BP the world's biggest solar-energy company.
Despite its trifling size, the deal raises interesting questions about the thinking of its mastermind. Sir John runs the world's second-biggest oil company. He has helped turn BP into one of the world's highest-rated, least sentimental majors. He shocked the industry with his acquisition last August of America's Amoco, setting off a round of mergers that included the marriage of Exxon and Mobil last December. By gobbling up Arco, he has once again caught his rivals off-guard. "He clearly has the first-mover advantage,"says Robin West, an American industry expert, "and the industry is dancing to his tune."
Yet the man who has made a name for himself as a ruthless cost-cutter and daring deal maker now seems to be behaving like a quixotic dreamer. Solarex is not the only example. Sir John is pushing ahead with other environmentally friendly schemes. This week, for example, BP kicked off a programme to bring power to 200 petrol stations using solar panels. Earlier, Sir John also came clean on global warming. Since environmentalists first began to raise the alarm about greenhouse gases, oil companies have tended to react by circling their wagons. Most have resorted to rubbishing any alarming scientific evidence. In the run-up to the UN's Kyoto summit in 1997, at which rich countries agreed to binding cuts in emissions, the industry spent a fortune pressing its line that the issue is nonsense. That was when Sir John broke ranks and declared his support for the aims of the Kyoto process. Since then, he has even committed his firm to reducing its own emissions of greenhouse gases well in advance of any legal requirements.
With the help of the Environmental Defence Fund, a green group, BP has launched an internal market for emissions-trading among its divisions around the world.
Sir John thinks that demand for clean energy - from natural gas, renewables and new technologies - will grow faster than the demand for oil in coming years.
His acquisitions of Amoco and Arco have boosted BP's reserves of cleaner-burning gas (see chart). Arco's boss, unusually for an American oil man, agrees, declaring these to be "the last days of the age of oil."
Sir John may yet prove a visionary. But some still suspect him of mere window-dressing. After all, grand talk aside, few firms - especially oil companies - have ever succeeded in promoting clean alternatives to oil. Does Sir John really expect to be taken seriously for his greenery, let alone make money from it? Many oil bosses and environmentalists remain sceptical. They suspect he is either a naive turncoat or a sophisticated fraud.
Yet it is just possible that Sir John saw the stand-off over global warming as a brilliant business opportunity waiting to be seized. Since the tide was always likely to turn against the oil companies, goes the argument, BP should take the moral high ground with some early burnishing of its environmental credentials. After all, that is how things have played out: the past year has seen BP applauded as a farsighted, ecologically sound firm. Its emissions-trading scheme is being watched on both sides of the Atlantic and in Japan. Even some rivals, such as Royal Dutch / Shell, are now following BP's lead.
So was this a clever effort to seize yet another "first-mover advantage" over his rivals? The unflappable Sir John falls silent. On the contrary, he says, BP's top management was concerned that there might be a "first-mover disadvantage". Oil companies have such a poor public image that the first to profess concern for global warming might quickly suffer a backlash from a cynical public. And fellow oilmen might have ostracised BP, even to the point of damaging its future business ventures.
Who dares wins. Why then did Sir John set out on the green path? One reason, he explains, was the science: both his researchers and he himself grew troubled by the mounting, though still inconclusive, evidence of global warming. He says he was concerned too about the implications: "We simply cannot survive for long if we remain so out of tune with our consumers' perceptions, and the next generation's attitudes." Another factor was a conviction that oil companies "must engage in the debate, and not be shut out as the bad guys. I want us to be . . . " Here he again pauses, and continues softly, "I want us to be - dare I say it - progressive."
Sir John's greenery belongs. It is part of his general eagerness to modernise a business that has long thought it was above change. He has imposed a discipline on costs that were inflated by folk memories of the great petrodollar era. In the same way, he is demanding that an industry on the defensive should come out fighting, declaring that it is ready to be held responsible for the environment. The history of oil is full of tough, cocksure men who are certain they have the future right and damn the rest.
Sir John, in contrast, seems aware of the risk of hubris and is ready to learn from anyone who talks sense. With his greenery, Sir John may be doing nothing less than preparing BP for the unthinkable: life after oil. If he is right, it will be his rivals who turn green - with envy.
Amps and Amphours - automotive and deep cycle batteries
The difference between amps (Amperes) and amp-hours (Ampere-hours) - by Peter Pedals.
Every once in a while someone will walk into the solar shop and ask for the price of a 250 amp-hour battery and be given the price of $350 (tax exempt). The customer will then invariably storm out of the shop muttering that she/he can buy a 250 amp battery from the nearest automotive shop for $70 including tax. It is then a very difficult task to appease the customer and point out that he/she is not comparing apples with apples when she/he compares a 250 amp-hour battery with a 250 amp battery. I hope the following clarifies this difference:
Amps: Electrical current is measured in amps just like water flow is measured in litres per second. But you can't measure a quantity of electrons with a container in the same way as you can measure water. Electrons flowing through a piece of copper wire cannot be observed by the human eye in the way that you can observe the water flowing out of the tap or you can see the boat being swept along by the current. Nor can you put a measuring stick next to a line of electrons and say that they are moving at x metres per second. When a surplus of electrons are stationary within a material (ie not moving from one atom or molecule to the next) they can be measured by the degree of static charge or coulombs that is present.
When electrons move in a given direction we need to have some way of measuring this rate of flow. An electrical device called an amp-metre or ammeter is what is used to measure this electrical current. An amp is a unit of measure equal to 1 Coulomb (6.25 x 1018 or 6,250,000,000,000,000,000 electrons) passing a given point in one second. Notice that time (ie one second) is already incorporated into the definition for amps and so to talk about amps per hour is the same as saying coulombs per second per hour. If you were to talk about 9.8 metres per second per second (9.8 m/sec2) you would talking about a rate of acceleration equal to a free falling body above the earth. In the same way amps per hour would either be an acceleration in electron flow or else it's a total nonsense. I would vouch for the latter and would suggest that if an electric current flow is what is referred to then a second unit of time should be left out and recognise that the definition for amps already includes time.
If an automotive battery was rated at 250 cranking amps it would mean that the battery is able to turn over a starting motor that consumes 250 amps, but it may not be able to do this for more than a few minutes before it starts to get tired and starts having difficulty with keeping it up any longer. When you pause with attempting to start the car, the battery recovers a little and you can turn the starter motor again for a shorter duration etc until it totally gives up the ghost or the battery is recharged. The fact that the battery will turn the starter motor at all is due to its cranking amps, but for how long it can maintain it is more to do with storage capacity or amp-hours.
Amp-hours: Amp-hours is a very different animal to amps per hour. Amp-hours is the accumulated effect of current flowing over a measured time span. If you were to have a light bulb for example that consumes 2 amps when it is turned on, it will consume 1 amp-hour in half an hour, 2 amp-hours in one hour, 4 amp-hours in two hours etc. If a battery is rated at 250 amp-hours, in simple terms it can run a 2 amp light bulb for 125 hours or a 5 amp TV set for 50 hours etc. You must be careful here that the rated amps being consumed by the light or the appliance is measured at the same voltage as the battery and not at 230 volts. Whereas watts is a measure of power which is not voltage specific, amps need to be defined at a specific voltage (electrical pressure) in order to get the full picture of power consumption. Likewise an amount of amp-hours needs to say at what voltage this occurs (e.g. at 12 volts) for it to become totally meaningful. If a larger battery was fitted in the vehicle that had sufficient cranking amps to turn over the starter motor but had more amp-hour capacity, it could continue turning over the starter motor for longer before showing signs of exhaustion.
Automotive Battery Design: Automotive batteries have many thin plates to expose a maximum surface area of the reactive lead to the electrolyte (sulphuric acid) in order to maximise the rate of reaction between the two and hence deliver a very high current (amps). The amount of current that a battery can deliver is referred to as cranking amps. Over the years the automotive industry has managed to fit smaller and smaller batteries in vehicles by managing to have the same amount of plate surface area in a smaller battery. This is why you hear reference to a battery having seven plates or whatever. The number of plates in a battery has nothing to do with how long it can deliver a given current. Because an automotive battery does little else than behave as a voltage regulator whilst the engine is running, one of the few times that the battery is really required is when the engine is being started. Starting a car engine is hard work for a small battery and so it is very important that the battery can deliver sufficient current for the task at hand. If a larger battery was used in the same car, it would either be able to keep the starter motor turning over for longer or you would quite likely notice that the battery would last longer before it needs to be replaced because it wouldn't be worked as hard.
Deep Cycle Battery Design: Deep Cycle batteries have fewer and thicker, more porous plates than automotive batteries that can maintain the reaction between the reactive lead and the sulphuric acid to deliver a given current for a longer duration than a similar size automotive battery but then not be able to deliver the high current. It is the total amount of reactive porous lead within each cell of the battery that determines the amount of storage in the battery.
In years gone by automotive batteries generally supplied the information with the battery giving you both the storage capacity of the battery in amp-hours and the cranking capacity of the battery in amps. These days they generally only tell you the cranking capacity of automotive batteries and not the storage or amp-hour capacity. With Deep Cycle batteries used in home power systems, on the other hand, they usually tell you the storage or amp-hour capacity but will omit any reference to cranking amps.
I hope that the discussion about Automotive and Deep Cycle batteries clears up the confusion between amps and amp-hours and gives some insight into battery construction and the differences in battery design.
Cheers from Dave and all the RPC crew.
Dave Lambert (Director)
- Issue #92 - 06/12/2005
- Issue #91 - 15/11/2005
- Issue #90 - 20/10/2005
- Issue #89 - 29/09/2005
- Issue #88 - 01/09/2005
- Issue #87 - 29/07/2005
- Issue #86 - 04/07/2005
- Issue #85 - 03/06/2005
- Issue #84 - 05/05/2005
- Issue #83 - 01/04/2005
- Issue #82 - 03/03/2005
- Issue #81 - 23/02/2005
- Issue #80 - 02/02/2005
- Issue #79 - 05/01/2005