Problem with battery on 306

I've got a problem with my battery on my 306 D-Turbo

When I say problem I mean it keeps going flat and I have to use a booster
starter pack to get the car going.

I last used the car last night and It's been parked on the drive all day,
come 7pm I tried to start it and it give a few turns then died, so I used
the booster pack starter to get it going, I decided to drive to my local
halfords (5 miles away) and have them price me up a new battery, which was
£63 for a decent one, but the kind sales chap offered to test my car battery
just to make sure before I shell out the cash.

He did 3 tests and all showed that the battery was in good health and
holding its charge on all 3 dummy load tests, the guy from halfords said
it`s not the battery but something else draining it like a boot light or
something, now I had a problem with the boot light back in June where is was
draining my battery by staying on when closed so I took the bulb out as it
kept draining all the power from my battery.

Now am I correct in saying that If there is a fault with my boot light would
it drain any power from the battery even with the bulb taken out?? I
wouldn't of thought so but I've just got back from doing a bit of shopping
(must of stopped and started at least 3 times in 2 hours) and the battery is
fine, it seems to be draining over night.
I have an alarm fitted but it`s not that, and no door switches are shorting
so If it`s not the boot light problem then I don't know what it could be.

Anyone any suggestions please.

Thanks

Peter

 

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.

 

<snipped>

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.

 

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.

 

600ah is what is written on the top of the battery, what it means I

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).

 

Hello,
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 :-(

 

...the cold-cranking amperage is the current the battery can deliver

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).

and
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.

 

Hi Andy,
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).

 

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.