Battery - Revision history

Grrrmachine at 06:48, 27 September 2012

2012-09-27T06:48:11Z

Grrrmachine at 05:32, 18 April 2012

2012-04-18T05:32:11Z

Grrrmachine: New page: Cars have Batteries, everyone knows that, and neither your starting nor charging system will work very will without it. In fact, your whole Electrical system n...

2012-04-16T12:35:29Z

New page: Cars have Batteries, everyone knows that, and neither your starting nor charging system will work very will without it. In fact, your whole Electrical system n...

New page

Cars have Batteries, everyone knows that, and neither your [[Starter|starting]] nor [[Charging|charging]] system will work very will without it. In fact, your whole [[Electrical]] system needs the battery, but not in the way you think...
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=Overview=

The battery in your car is a lot like the defibrillator that emergency medics carry; it's a great big pack of electrical juice, all delivered in one solid punch to get the [[Starter]] moving. And that's pretty much it. It's NOT a long-term power supply like the batteries in your phone or watch. That's why a battery the size of a breezeblock can be drained by leaving your stereo on for more than a few hours.

The secondary job of your battery is to smooth out the current. Your [[Charging|charging]] system will pump out anything from 13.7V to 14.4V, depending on how fast the engine is turning at any one time, and this can change in milliseconds. But delicate stuff like your [[ECU]] or [[Instruments]] don't like dramatic voltage changes - they want a steady stream of electricity coming in, or they'll fry. So the battery absorbs the overcharge, softening the spikes and dips of the voltage into a more digestible 12.6V.

=Sizes=

Batteries are measured in Ah, or Amp-Hours. This doesn't mean how many amps they deliver, but how LONG they can deliver one Amp for. So a 65Ah battery can give 1 Amp for 65 hours, or 65 Amps for one hour.

All E30s came fitted with a '''096''' battery, meaning '''72Ah''' and '''680CCA''' (cold cranking amps). If you're planning on running a lot of extra kit without the engine running, such as heated seats and a massive stereo, you may want to fit a larger capacity battery.

=Dimension=

The physical dimension is also crucial; too tall or wide and the battery won't fit into the car. The E30 uses an '''096''' style battery, meaning its dimensions are: 278 long x 175 wide x 190 high (mm)

=Location=

On almost all E30s the battery is located under the [[Bonnet|bonnet]], up against the bulkhead on the driver's side. However, a second option was to have the battery fitted in the boot, behind the fuel filler flap. This redistributes the 20kg to the rear of the car, making some models feel a bit more balanced. While not standard on any E30, it was a popular option for [[M20]]-engined cars, as well as [[Touring]] and [[Cabriolet]] models due to their heavier design.

=Upgrades=

==Battery In Boot==

Many owners bought the optional extra of having the battery [[Battery#Location|fitted in the boot]], and the kit to do that is very often available from online auctions or the Zone For Sale section. Any E30 can be converted to Battery In Boot simply enough, although it does require removing certain parts of the [[Interior|interior trim]] which are rather fragile and may break.

If you can get your hands on the kit, learn more about [[Battery_In_Boot|fitting battery in boot]].

=Common Problems=

==Battery Drains==

You get in, turn the key and "clunk"; the motor doesn't start. You check further and see your headlights are very dim and your central locking sounds slow and heavy. You've got all the signs of a flat battery.

First thing to do is to get the battery tested. Even if you know you've left your lights on, there's a chance that you've overdrained the battery and killed it, so take it to a professional to have it Load Tested. Specialist battery technicians are better for this, as they're more likely to tell you the truth rather than force you to buy a new battery that you don't need.

Once your battery is good, you need to know why it went bad, and that means finding the Drain. Common drains include internal boot lights or interior lights staying on, and bad radio or alarm installations. But on a 20 year old car, any and all wiring will become suspect, so it's important to go through the car systematically.

@@ Line 12: / Line 12: @@
 Batteries are measured in Ah, or Amp-Hours. This doesn't mean how many amps they deliver, but how LONG they can deliver one Amp for. So a 65Ah battery can give 1 Amp for 65 hours, or 65 Amps for one hour.
-All E30s came fitted with a '''096''' battery, meaning '''72Ah''' and '''680CCA''' (cold cranking amps). If you're planning on running a lot of extra kit without the engine running, such as heated seats and a massive stereo, you may want to fit a larger capacity battery.
+Big-engined E30s came fitted with a '''096''' battery as standard, meaning '''72Ah''' and '''680CCA''' (cold cranking amps). These are a good upgrade for smaller-engined cars, especially if you're planning on running a lot of extra kit without the engine running, such as heated seats and a massive stereo. However, the 4-cylinder wiring loom around the battery tray makes the larger battery a little difficult to drop into place.
 =Dimension=

@@ Line 27: / Line 27: @@
 Many owners bought the optional extra of having the battery [[Battery#Location|fitted in the boot]], and the kit to do that is very often available from online auctions or the Zone For Sale section. Any E30 can be converted to Battery In Boot simply enough, although it does require removing certain parts of the [[Interior|interior trim]] which are rather fragile and may break.
 If you can get your hands on the kit, learn more about [[Battery_In_Boot|fitting battery in boot]].
@@ Line 32: / Line 34: @@
 =Common Problems=
-==Battery Drains==
+==Flat Battery==
 You get in, turn the key and "clunk"; the motor doesn't start. You check further and see your headlights are very dim and your central locking sounds slow and heavy. You've got all the signs of a flat battery.
-First thing to do is to get the battery tested. Even if you know you've left your lights on, there's a chance that you've overdrained the battery and killed it, so take it to a professional to have it Load Tested. Specialist battery technicians are better for this, as they're more likely to tell you the truth rather than force you to buy a new battery that you don't need.
+First thing to do is to get the battery tested. Even if you know you've left your lights on, there's a chance that you've over-drained the battery and killed it, so take it to a professional to have it Load Tested. Specialist battery technicians are better for this, as they're more likely to tell you the truth rather than force you to buy a new battery that you don't need.
-Once your battery is good, you need to know why it went bad, and that means finding the Drain. Common drains include internal boot lights or interior lights staying on, and bad radio or alarm installations. But on a 20 year old car, any and all wiring will become suspect, so it's important to go through the car systematically.
+If these all prove negative, open a window or make sure you have the car keys out of the car, then connect a milliamp meter between the negative pole of the battery and the battery earth lead, and remove fuses until you find where the drain is.