Bosch Car Battery

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This is a guide to the BOSCH silver series of batteries and gives some battery information which applies to any brand of car battery too.

BOSCH sell a series ("Silver Series") of batteries with numbers like 3001, 4001, 5001 -  you get the picture.

The first part of the number (3, 4, 5, 6) is how many years that battery is guaranteed for. The commonest ones seen are the 4xxx series, which BOSCH guarantees for .. 4 years.

Now although I'd seen people saying this number refers to the length of the guarantee, I'd not seen anything on BOSCH's own web sites about this, despite searching several times, nor does anything on the batteries themselves tell you this. So  I contacted BOSCH myself and they have told me directly that this is the case. They even produce two 6 year guaranteed batteries in their range !

The other numbers after the first one relate to the specific model of battery and  have no meaning beyond that - they don't relate to the battery amperage for example.


Battery amperage is quoted in 2 ways in a battery specification. Lets take a look at a typical one:

12v  CCA440 Ah44   -  Now I know that looks like gobbledygook at first glance, but it tells you a lot.

The first bit, 12v should be fairly obvious, but in case it's not, it means 12 volts. For cars you will rarely see anything else. But be aware a lot of lorries and large vehicles (and some boats) can be 24volt.

CCA  - (sometimes also shown as EN - just to confuse you further)

The next bit, CCA, stands for Cold Cranking Amps .  This is the figure that is important on a cold winters morning and refers to the big flow of power needed to turn over your engine.

So in this case, that's 440 amps immediately available when the battery is fully charged. This particular example fits Corsas and Astras and other  mid range cars. Remember it's about the size of the engine rather than how big the car is. So  up to 440 amps are available to start the engine.


Ah44  This means that the battery when fully charged can supply 44 Amps per hour - or 1 Amp for 44 hours.  When you are running the engine, the battery is being charged, so in fact this does not mean it would run out in an hour if you were drawing 44 amps from it with your radio, lights and air conditioning on for example.

As a rule of thumb, the more "services" a car has, the larger this figure needs to be. So by the time you are running something like a Lexus GS300 you'd be needing a battery with something like 77 Ah.

Nowadays however, you don't need to consider these figures too much unless you have added something which drains a lot more power than the car was originally designed for. Battery manufacturers prepare tables which give each model of car and show which of their batteries is best suited to it, so all the hard work is done. Adding something like a new Sat nav for example won't require you to upgrade the battery as there is always spare capacity in a specified battery.  Adding something like a winch or running a caravan fridge and lights is another matter and something we'll go into in another article.


Another thing which is taken care of by using a battery manufacturer's tables (or asking a seller which battery is best for your car - most reputable sellers will have the tables to hand) is the battery layout.

So while your car battery may have the Positive terminal (marked + and often red) on the left, it may be on the right on another battery. Some Fords also have different shaped terminals too, so this is another reason why it's best to specify your actual vehicle to a seller unless your absolutely certain from a picture, that the layout is the same on your car or the battery is advertised as fitting your exact model. It costs a lot to post a battery, so that's worth checking with the seller if you are at all unsure.

Batteries come in all different sizes too -  to quite a surprising degree, and as manufacturers move towards car-specific batteries (i.e a battery that will only be designed for one model of car) this will become more important due to the size and shape of the battery box in the engine compartment.

The larger battery manufacturers publish their battery sizes and again, if you or the seller are using the manufacturers tables, this issue is already taken care of. If you are buying the battery for a non standard application such as a caravan or boat, it's worth finding out first how big the battery is to make sure it will fit however.



Basically, car batteries come in 3 ranges.

First you have the own brands. By that I do not mean a shops own brand, but rather I mean the basic (usually a lack body, but sometimes white or translucent) old fashioned lead-acid battery. There are lots of small makers of these who buy in the body, top it up with acid and put their own sticker on the front. Whilst all sorts of claims are made for these, they are in reality, no different  in design from lead-acid batteries made 60 years ago, & as they age, may need topping up with distilled water. You are likely to get a 1 or 2 year guarantee with these. Some claim 3, but the battery does tend to be on it's last legs by then. If you are not keeping the car that long, or price is all that matters, then they will do the job.

Next you have the mid-range.  These will give you a 3 year guarantee and may boast "calcium" and "high power" and so on. These are shops-own brands and the standard range offerings from  Exide and the likes.

They are also marketed by car manufacturers as their own brand (often as a massively inflated price for what you are getting - no matter what the main dealer tells you - you do not need to fit their brand of battery to your car -  people believing that sort of thing is the reason the dealership manager is driving a Porsche and you are not). 

A lot  of these are marketed as maintenance free. Personally I have found myself topping up some of them  toward the end of their lives when heavily used or used on battery chargers a lot. You could even take the view that if they were maintained, you might get a little longer life out of them. Increasingly though, they are sealed so you can't.

You will usually get a 3 year guarantee with these, sometimes 4. They tend to be second generation battery technology and will "drop off" (i.e start to lose how much power they can hold) very rapidly when they reach their guaranteed life. In reality they will begin losing capacity before then and it will reach a critical level (i.e you'll need a new one) shortly after the guarantee period. In fact, it's quite amazing how soon after most of them go! Sometimes you will get lucky and one will last another year or so. Again, if budget is the main concern, these are absolutely fine - but do be careful how much you pay as there really is not much difference across them in performance.

Premium Range.

This is where our BOSCH Silver series come in. In this range you find batteries such as BOSCH and the top end of the Exide range . They will feature 4 and more years guarantee and make use of higher quality materials and design such as glass fibre matting inside, special grid patterns for maximum internal surface area, leak  proofing and so on. They will be truly  maintenance free and may outlive their guarantee period by a significant amount.  They will feature extras such as charge indicators (found on mid range too) , shaped handles, terminal covers when new and so on.

Some, such as the BOSCH 6000 series, will even be gel-based and leak proof in any position. So ideal for less usual uses such as in boats (here sea water and battery acid have the unfortunate effect of creating chlorine gas if mixed together) and off-road and other uses, or where the mounting position is not conventional or is even inside the passenger compartment.

The top end batteries do cost more, but surprisingly, when you divide the price by how many years they will last, quite a few are actually cheaper per year than the bottom end batteries. Not everyone has the money available to take advantage of this of course, but if you have, you can actually reduce your annual car costs in this way. 

So  to sum up:  

 1.  unless you are going to use a car battery for a non standard purpose, or you have a heavily modified vehicle, use  a reputable seller's advice or the battery manufacturer's tables when  selecting the battery for your year, engine size and model.

2. Don't be taken in by "super", "extra power"   etc. or car manufacturers names on the label - look at the actual figures, including the guarantee period.

3. Bearing no.2 in mind, if you are keeping the car, buy the best battery you can afford. It's actually cheaper in the long run, and far batter than finding out one freezing winter's morning in a couple of years time that your car will not start!






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