Problem with battery on 306

have the altenator checked. BTW i got a new battery for £31 from an independent pug dealer 4 yr gaurantee motoquip brand last week for my 306 DT

1998.

I had the very same problem with the battery on my 98(R) 306 XS 1.9d I had the battery checked by three places, one was a small backstreet garage which I trust religiously with my serviceing etc, Charlie Browns autocentres and Kwikfit. All 3 said the battery was in good health and wasn't the problem and that maybe the boot light wwas staying on or the alternator was duff. The last place .. Kwikfit.. said that the 300ah battery wasn't really big enough for the engine and that a bigger one may help anyway. I bit the bullet and bought a new 600ah battery for £73. Problem went away from that minute and the car starts a dream every time now. It even starts the car from cold without preheating (did this by mistake one morning and it surprised me by bursting into life on the second revolution)

funny you should mention the 300ah battery problem. my 306dt had one on too. went for a replacement as the battery was loosing charge overnight and was told it was the wrong size. 600ah is recommended. cost me £31 from independent pug dealer for one with a 4yr gaurantee.

Simon

I seriously doubt you have a 600Ah battery as the normal car battery size is about 60Ah. If you mean 600CCA, that's a whole different matter :)

600ah is what is written on the top of the battery, what it means I have no idea but the old one has 300ah written on that too. Make of it what you will... I am just writing down what I see and was told.

Weird. What it probably means is that the battery can deliver 600A of energy for a short time when it's cold. Not that it can store 600Ah of energy, such a battery would be _huge_ and weigh several hundred kilos :)

Still weird they put it that way.

"Jens Kr. Kirkebø" schreef in bericht news: snipped-for-privacy@4ax.com...

Still weird a battery of 600ah? that would be a very big battery. The Battery in my 306 1.9D Break from 2001, has a 60ah battery That means the battery can deliver 1 hour a current of 60 ampere. (ah= ampere hour), or 30 minutes 120 ampere, 15 min. 240 ah, etc. That means a few thousand amere for a few seconds to start the engine. Lets say 4000 ampere for a few second multiplied by the voltage of the battery: 4000A * 12V = 48000 watt = 48 Kw, should be more than enough to start the engine. The 600ah is sure somekind of advertisement bla bla.

I think the original poster probably got mixed up - the battery would have a capacity of 40-70Ah. Most batteries also have a 'cold-cranking capacity' (cca) printed on them, which is the current they can deliver to start the engine without the voltage dropping below (IIRC) ~8v. For most batteries the cca is around 350-400A, but for heavy duty baterries it is typically about 500-700A. As a side note, a battery with a cca of

600A will have an internal resistance of approx 7 milliohms, so even if shorted out it could only deliver 1800A, and the maximum power it can deliver is 5.4kW.

Hello,

Here, it's commonly called "short-circuit current", I don't know if it makes sense in english, though. I always considered that as an information, say, unusual for car batteries.

And 2milliohms if you take true short circuit (12/600).

Regards, G.T snipped-for-privacy@worldonline.fr

205 Diesel & turbo-Diesel :

Bonjour,

That does make sense, although I think that is something slightly different...

...the cold-cranking amperage is the current the battery can deliver without the output voltage dropping below a specified level (IIRC it's 8v, and at a low temperature: -20C rings a bell), so it is quite a bit less than the short-circuit current.

Internal resistance = [batt volt(~12v) - terminal voltage(~8v)]/CCA(600A) =~4/600=6.667 milliohms

Andy

Hello Andy,

Right, and I just noticed that 8V on a 12V batt was representing 75% of its nominal voltage, which looks like an "electrics evident value" (like

0%-25-50-75-100-125% load when testing a generator or a motor).

Which is a derivated formula from the generators' circulation currents, given by I=(E-E')/(r+r'). I'm not totally lost here, as I took a B-Tech 1st in electrotechnics before going on with electronics (A-level +2 years) and now being @ idle :-(

Regards, G.T snipped-for-privacy@worldonline.fr

205 Diesel & turbo-Diesel :

Well, maybe in the metric system, but in good old imperial measurements that would be 66.666...% :-) I'm probably wrong about the absolute voltage anyway - I'm relying on a dim memory of something I read in a garage manual several years ago whilst waiting for some tyres to be fitted!

You have B-Techs over there too then? I wonder if they are the same as ours? I don't have any formal electronics education - I've just sort of grown up with it (father is electronics engineer). I teach physics now and it's amazing how many degree level students don't even know ohm's law!

On an unrelated topic (too lazy to start a new thread :) do you have any annual inspection of cars in france, similar to our MoT?

All the best, Andy

Hi Andy,

Or 20/300 :-) And I said something wrong : a true short circuit (i.e with U=0V, and I ~infinite) would brake the motor, so the peak amperage given by my relation above can't be seen on a real situation, not with starter running (moreover the inductor's own resistance acts as a current limiter, of course).

Of course, but that's an equivalent diploma which is took within 2 years after what should be UK's 4th form.

I guess they're similar. We learn how to wire systems, base schematics (for both home & industrial electrics), technology (principles of electric distribution network, transformator, ...) and tests (generator ; DC - AC -

3~ motor ; phase compensation and so on).

Well, electronics are made of physics, logic, intelligence and luck. you just took a part of it :-)

So as you're a physics teacher, you aren't lost when talking about electric power, are you ? Of course, some students may not know the ohm's law, still it's easy, it's U=R.I ; but perhaps some of them could say that U²=P.R as P=U.I :-)

Of course, after 4 years for a brand new car (i.e for cars built in 2003, first control is due to 2007), every two years for older cars. And we also have a specific emission test for Diesel engines, which seems not too different to yours.

Regards, G.T snipped-for-privacy@worldonline.fr

205 Diesel & turbo-Diesel :

Hey G.T

I'd estimate it to be about 3 furlongs per bushel :)

The U.K 'Btec' is supposedly equivalent to an 'A-level', but more concentrated on applications, (the A-level being more theoretical).

Heh, or I could say that electronics is a small subdivision of a section of electromagnetics :)

I teach physics and electronics and my research involves a lot of electronics, so I'm o.k.

Interesting. On a recent visit to Albert, it seemed that there were more older cars still on the roads in france than in the u.k., so I wondered whether there was a test. My 205 GRDT has just failed it's MoT :-( I see a weekend of lying under the car, getting rust and brake fluid in my eyes. Sounds like fun...

Ours is just a smoke test, IIRC, but modern petrol engines have to meet quite strict emission tests.

All the best,

Andy

Hello, Andy,

Huh, it's far over my english level... Don't you know (I already wrote that at least 1000 times here before) that my english isn't as good as I'd like ? Ok, I agree I also wish my german was as good as my english :-) I suppose it was a joke about some old measurement system ? And 66.6% just are 2/3, not 20/300 - Doh !

I thought the BTec Nat was the equivalent of A-Level. Unfortunately I had an equivalents table between british & french educational systems, I certainly threw away, as I can't find it in my archives. Where could I find this kind of documents ?

I definitively prefer my explaination :-)

Nice to read.

Of course there's one (EEC ruleZ). The average age of french running cars should be about 7yo, but a lot of them are far beyond : my 205D is a '93, my brother's DTurbo is a '91 and my mum's 405 SRi is a '88. They certainly rust less in France, as I know some 911s exported to UK had special anti-rust treatments.

Take it like an afterschool work, rust is just iron oxyde, Fe3 O2, IIRC :-)

Smoke test is the word I was looking for, as emission tests are for petrol engines - strict here too, as now most petrol cars are catalyzed (of course, car's results are compared to its official data - my mum's 405 can't be as "clean" as a cat'd 405).

Regards, G.T snipped-for-privacy@worldonline.fr

205 Diesel & turbo-Diesel :

I had the same problem with the boot light draining the battery and I took the bulb out. I still had significant battery drain which resulted in a flat battery after 48 hours standing. I did a load test using an ammeter between the battery earth terminal and the main earth connection which showed a drain of about 0.4 amps with nothing switched on except for the clock and alarm etc. To find the offending circuit I removed each fuse in turn until the current went down to nearly zero. In my case it wss fuse No.

14 that was causing the problem. This does the central locking, factory fitted alarm and the radio circuits. I now need to find out what is wrong with the circuit causing the battery drain but for now I just remove the fuse when it is standing for any length of time. Life without central locking is a real pain!

Hope this helps

Richard

(My car is a 1998 306 Gti-6 (Mk 2)

probably the alarm. always going wrong. can u unplug it? it's under the left wing.