New battery
- Thread starter zcacogp
- Start date
pauljmcnulty
Active member
Sadly, there's been far worse! [
]Steve, Speed of cranking when starting is a much-debated issue on here. Broadly, a new starter helps as does cleaning up the connections from the battery to the starter and from the block to the bodywork (both ends), as well as the earth strap from the battery to the bodywork. (Take 'em off and rub 'em with a bit of sandpaper to make 'em shiny and nice.) I'd suggest this is a good place for you to start if you are (or the car is!) struggling. The reason I changed my battery was because it was struggling if the car was left for a week or so without being driven (and I am hardly driving it these days, and winter is hard on car batteries.) I was pleasantly surprised by the fact that it cranks more quickly when starting, as a result of the new battery. The new battery is a 65AH one, but that won't give an idea of how many amps it delivers when cranking. 'Cold cranking amps' is the relevant figure for this, and I don't know what that is on the new battery. Oli.
Sc0tty, If yours has a new battery (and if it is that high an AH then it should be able to deliver a reasonable current - are you SURE it's that high a capacity?) and a new starter then I'd be suspecting the connections. Take 'em off as described above and clean them up. (I know your aversion to DIY on cars but it's an easy and quick job, the hardest part of which is jacking the car up to get to the terminal on the bottom of the starter.) That should help a lot. If it doesn't then it's probably worth measuring the resistance of the main cables - particularly the big one that goes from the battery to the front of the car, just to make sure there aren't any oddities in that. Changing the leads and cap won't make any difference to the cranking speed. Time how long it takes to turnover? Better would be to video the starting process. If I have time then yes, I will. But it won't be for a while ... Oli.
as i understood it,944s are slow starters, mine always starts on the first crank although sounding quite slow before she bites, but never let me down and i just thought it was an accepted "quirk" in the cars overall character, either that or i am gonna neeed a new starter in the future, regards all jason p
Chaps, Let's not confuse two parameters here. The Amp-Hour rating is a measure of the capacity of a battery. An X Amp-Hour battery will (theoretically) produce X amps for an hour, or 1 amp for X hours, or anything between the two. The amount of oomph a battery will supply to a starter motor to turn the engine over is the current (rated in number of amps) that it can provide continuously - 20 amps, 35 amps, or whatever. This is (occasionally) given as a battery rating parameter called the 'Cold Cranking Amps', which is the amount of current (in amps) that it will provide for a given number of seconds at a given temperature. However these ratings are different, and are not to be confused. There may be a link between them, but it's not a formal one. (Broadly a bigger battery will probably have a bigger Amp-Hour rating and will probably provide a bigger amperage at low temperatures, but it's all a bit hand-wavy.) Oli.
Wigeon Incognito
New member
That's a difficult one, mine has 'moods' but does seem to be a quick starter when compared to other S2s I've experienced. It cranks fast and generally starts on the first turn although if it's having an off day it can take two turns. Timewise I'd guess 1-2 seconds depending on the wind direction, sun, relative humidity, time of the month, or whatever else it might be that affects it. It's on new everything though now as far as I know and very clean earth terminals so that all has to help.
944 man
Active member
The cables, earths and connections all deteriorate. Whats the amperage at the starter moor itself? I'll wager that its less than the 13.8v that youd hope for... 944s will always require a couple of cranks at a very minimum (or at least they should), because the fuel pump shouldnt turn on until the engine is turning over.
Scott, Telecoms engineer - you'll be used to electrickery and whatnot - it'll be easy for you! Amps is a measure of current flow. Like the amount of water flowing in a pipe. VERY like the amount of water flowing in a pipe actually. Think of more amps as being akin to more water there is flowing in a pipe. (Amps flow through wires and water flows through pipes, and you can think of those in the same way too.) With me so far? Think of the battery as being like a big water tank, in the loft in the roof of your house. It is a store of water. A bigger tank holds more water, a smaller tank holds less water. A bigger amp-hour battery is like a bigger water tank. A smaller amp-hour battery is like a smaller water tank. They both do the same job (allow water to flow down pipes), but one will do it for longer than the other one before it runs out of water. Still with me? Think about those two water tanks - a big one and a small one. You know that the big one has more water in it and will allow a given rate of flow to keep going for longer (it has to - there is more water in it). BUT the rate at which the water flows out may be smaller - perhaps it is flowing out through a half-closed tap, or a small pipe. The small tank may flow quicker - it may have a really, really big pipe connected to the bottom of it, and thus the rate of flow could be huge. (It's a small tank, so it can't keep this huge rate of flow up for very long at all, but that's a side issue.) The rate of flow is not the same as the size of the tank. A bigger tank will have more in it than a smaller tank, but the rate at which the water can flow out is independent of the size of the tank. The battery works in the same way. A bigger battery has a larger amp-hour rating, but may not be able to deliver as many amps at any one time as the smaller battery. And when you are starting your car, you need a nice big juicy current, as big current = more twist at your starter motor = faster cranking. So if your S2 (much better than a turbo BTW [] ) isn't cranking very quickly, the question isn't "What amp-hour rating is my battery?", it's "What amperage can my battery deliver?" Amperage, like water flow in pipes, can be hindered by resistance in the wires (or blockages in the pipes - again they work in the same way). Resistances in wires can be caused by wires getting old and grotty, or by poor connections where wires join other metal things - where they connect to the starter motor or to the bodywork. Literally, such problems resist current flow. So, make sure the connections are better (clean them up), and the resistance will go away and the current flow will be better. More current flow = more twist at your starter motor = faster cranking. Did that help? Oli.
] ) isn't cranking very quickly, the question isn't "What amp-hour rating is my battery?", it's "What amperage can my battery deliver?" Amperage, like water flow in pipes, can be hindered by resistance in the wires (or blockages in the pipes - again they work in the same way). Resistances in wires can be caused by wires getting old and grotty, or by poor connections where wires join other metal things - where they connect to the starter motor or to the bodywork. Literally, such problems resist current flow. So, make sure the connections are better (clean them up), and the resistance will go away and the current flow will be better. More current flow = more twist at your starter motor = faster cranking. Did that help? Oli.
appletonn
New member
Oli, brilliant analogy and superbly clarifies a potentially confusing issue![ORIGINAL: zcacogp Scott, Telecoms engineer - you'll be used to electrickery and whatnot - it'll be easy for you! Amps is a measure of current flow. Like the amount of water flowing in a pipe. VERY like the amount of water flowing in a pipe actually. Think of more amps as being akin to more water there is flowing in a pipe. (Amps flow through wires and water flows through pipes, and you can think of those in the same way too.) With me so far? Think of the battery as being like a big water tank, in the loft in the roof of your house. It is a store of water. A bigger tank holds more water, a smaller tank holds less water. A bigger amp-hour battery is like a bigger water tank. A smaller amp-hour battery is like a smaller water tank. They both do the same job (allow water to flow down pipes), but one will do it for longer than the other one before it runs out of water. Still with me? Think about those two water tanks - a big one and a small one. You know that the big one has more water in it and will allow a given rate of flow to keep going for longer (it has to - there is more water in it). BUT the rate at which the water flows out may be smaller - perhaps it is flowing out through a half-closed tap, or a small pipe. The small tank may flow quicker - it may have a really, really big pipe connected to the bottom of it, and thus the rate of flow could be huge. (It's a small tank, so it can't keep this huge rate of flow up for very long at all, but that's a side issue.) The rate of flow is not the same as the size of the tank. A bigger tank will have more in it than a smaller tank, but the rate at which the water can flow out is independent of the size of the tank. The battery works in the same way. A bigger battery has a larger amp-hour rating, but may not be able to deliver as many amps at any one time as the smaller battery. And when you are starting your car, you need a nice big juicy current, as big current = more twist at your starter motor = faster cranking. So if your S2 (much better than a turbo BTW [
] I think you could have found your vocation - 'Electricity for dummies' etc[] Not patronising in any way whatsover, trust me.[8|][]
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