How to check and maintain your Beetle's battery

Why you might need to do this

Your car battery will need an occasional charge, and can lose fluid to evaporation which will need to be topped up or the battery will become useless. If your Beetle won't start, charging the battery is one of the first things to try - it's an easy fix that will hopefully work.

You will need:

What's going to happen:

We're going to find the battery, check it's fluid levels and recharge it.

Finding your battery

If you have a 1970s Beetle or Karmann Ghia, you'll probably find the battery in the engine bay. If it's older (like my '68) you'll need to look underneath the rear seat. To pull the rear seat up, hold it just under the bottom at the front of one end and pull it towards you and up. You might need to jiggle it about a bit as it can get firmly stuck down, especially if you often carry passengers in the back.

Back seat down Back seat lifted up

Once one end is up, you should be able to manhandle the seat out of the car. You can probably get the battery out with the seat jammed above it, but it's a lot easier if it's completely out of the way.


Taking the power off

The wires from the car are held on to the battery contacts using bolts - mine has small circular clamps, your may have these or some vertical tabs, depending on the type of battery that has been fitted over the years. Unbolt the positive side first - it's labelled with a '+' sign.

Unscrewing the cable from the contact Cable off of the contact

Unbolting the battery

The battery should be secured to the bottom of the car by a tab of metal, stopping it sliding around when you corner. You'll need to unscrew the bolt either enough to get the tab away from the battery, or to get it completely off.

Remember which way around the battery is, as it means you'll get the connectors around the right way when you put the battery back in the car.

The battery is quite heavy (it has a load of metal plates and liquid in it), when you pick it up, be careful as you don't want to drop it and risk spilling the acidic liquid inside on your carpets, or over you. The top usually overlaps the sides slightly, so you can grip on to that when you pick it up. Don't touch the terminals while you're holding it as you want to avoid any chance of a shock, however minor.

Car battery from above Unbolting battery from car

Checking the fluid and charging

Inside the battery are metal plates covered by an electrolyte fluid. As time goes by the fluid evaporates and needs topping up. You top it up with distilled water, normal water can have minerals in which can cause short circuits within the battery by connecting the metal plates together, which will ruin the battery.

To see if the fluid needs topping up, remove the stopper (or one of the many, as in my battery's case) and look down inside it. The liquid is acidic, so try not to get any on your skin and if you do, immediately go and wash it off with lots of water.

I've used some needle-nosed pliers to remove the stopper, but a broad, flat-headed screwdriver would have done the job quite well. Basically, anything that will fit in to the top of the stopper and let you turn it.

Removing stopper from the car battery Battery with stopper removed

Below we can see down inside the battery now the stopper is out (click on the image for a larger version.) There is a lump of plastic visible poking out of the liquid - this is an indicator and should be covered up, so my battery needs topping up. I do this by squirting distilled water down through the hole until the indicator is just covered up. Don't fill the battery up completely as the liquid expands when it's hot and could squirt out and damage the inside of your car - it's only slightly acidic, but you don't want it flowing about on your floorpan.

Looking inside the battery at fluid level Charging the car battery

When the battery is topped up, screw the stopper back in to it's place. You're now ready to charge the battery. If you don't have a charger and were just checking the battery, you can put it back in the car and it should work. If you had to top it up with distilled water, it will need charging to work properly.

When the battery is charging, it is causing a chemical reaction inside the battery. It's very unlikely, but it means some fluid could spit or drip out of the battery. I usually put a newspaper or something disposible under the battery when it's charging, just in case something spits out I don't want it to mark the floor. It's also best if you charge the battery in a well ventilated place, as the gas escaping during the charging is slightly acidic and you don't want it building up.

The battery charger will have two clamps, one for the positive connection on the battery, one for the negative. Generally the positive will be coloured red and the negative black. Clamp on the positive one first, then the negative, then plug the charger in. Some chargers have a light on them to show when the charging is finished, mine doesn't as it's very cheap, so I just put the battery on charge overnight.

When it's charged, put the battery back in the car, clamp it down, then attach the cables to the connections - first one to the the negative '-', then the positive '+'. Make sure you're connecting the right cable to the right connection, it can damage your electrics if you don't, or at least the car won't work properly.

Which cable is which?

If you've forgotten which way around the battery was in the car and the cables aren't colour coded or labelled, then there's a simple way to find out which is which: The positive cable has two leads coming off it, whereas the negative cable just has one. If you look at the pictures above where I'm disconnecting the connections, you can see the positive one has two cables bound together by some tape just before they clamp on to the battery. Connect the lead with two cables to the positive '+' connection and you'll be fine.

Once the battery is in, try starting the car before you put the rear seat back in, just in case something has gone wrong and you need to dig it out or check the connections.


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