Frequently Asked Questions

1. All about watch batteries
2. How to change a watch battery in your watch
3. How to change a watch strap on your watch
4. How to adjust the metal bracelet on your Casio watch
5. Table listing those applications for which Watch Battery customers use their batteries. Is your application listed here?
6. Battery Chargers. Which to choose
7. WEEE Regulations

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All About Watch Batteries

We thought that you may find it useful for us to give you an insight into the interesting world of watch batteries. (We know it's not that interesting, but it may help you order the correct battery!).

Battery Chemistry:

With respect to watch batteries there are 3 main types of chemistry, Silver Oxide, Alkaline or Lithium. The Lithium button cells will be 3 Volt cells (apart from the Renata 751 which is a 2V lithium battery) and the Silver Oxide and Alkaline button cells will be 1.5 Volt. Therefore, the voltage of your application will dictate whether you will need a Lithium battery or not. The Lithium cells tend to be the larger button cell batteries and their references tend to be prefixed with either CR or BR. For example, a CR2032 is a Lithium battery.

Silver Oxide or Alkaline

Since Silver Oxide and Alkaline watch batteries give the same voltage (1.5 Volts) then which battery do you choose?

Well, firstly Silver Oxide watch batteries tend to be more expensive than an Alkaline cell of the same size. So can you just use the Alkaline watch battery of the correct size? Well, this depends on your application and if the Alkaline version is available. There is a much wider choice of Silver Oxide watch battery sizes. In fact Rayovac make only two Alkaline button cell sizes but approximately 30 different Silver Oxide watch battery sizes. Where Silver Oxide cells score over their Alkaline counterpart is in their ability to maintain a more stable voltage. This characteristic makes them better for clocks and watches and absolutely essential for metering equipment (like light meters in cameras for example) where a stable voltage is required. An Alkaline cell though is good for high current devices where a stable voltage is not required, for example, in electronic toys and calculators. Many of those children's noisy books use LR44s (Alkaline), but can run equally as well using the Silver Oxide equivalent (Rayovac 357). Many electronic toys use LR44s or LR41s and there is no problem using a Silver Oxide watch battery of the equivalent size. Rayovac do not make a LR41 so we have no problem in suggesting to owners of the Thunderbird Soundtech toys (which use 3 x LR41) that they can use the Silver Oxide equivalent (Rayovac 392) instead. Since some of our customers have been charged £4.00 for each LR41 by High Street jewellers, they have no problem in paying us for the more expensive Silver Oxide watch battery at a mere £1.25 each!

So to summarise, if your application calls for a stable voltage under load (watches, clocks, metering equipment etc.) use a Silver Oxide watch battery. If not, and you can get the Alkaline equivalent then use that. And remember, you can always use a Silver Oxide watch battery to replace an Alkaline watch battery.

Battery Sizes:

Now this is interesting (honest). The Lithium button cell battery sizes are easy to determine from their reference numbers. The first two digits refer to the diameter of the battery in mm and the second two digits give the height or thickness of the battery in tenths of mm. So, for example, a CR2032 is a Lithium button cell that is 20mm in diameter and 3.2mm thick. A CR2430 is a Lithium button cell that is 24mm in diameter and 3.0mm thick. There, told you that this was interesting!

Now having had this lesson, you will begin to see that other watch batteries also have a reference number which give a similar clue to their size. Take for example a Vinnic L1154. Now you would be excused for thinking that this was 11mm in diameter and 5.4mm thick. Close. But in this case the first two digits refer to the range of the diameter and the second two again, as for the Lithium button cells, refers to the thickness in tenths of mms. The diameter in this case is in the 11mm range. A quick check in our reference table will show that all watch battery diameters in the 11mm range are 11.6 mm in diameter. Therefore, a L1154 is an Alkaline button cell 11.6mm in diameter and 5.4mm thick.

Other manufacturers use a similar reference numbering system for their watch batteries, and as a general rule wherever you see a three or four digit reference number for a watch battery it is likely to follow the rule described above. For example, a Sony SR626SW is a Silver oxide watch battery which has a diameter in the 6mm range and is 2.6mm thick. All watch batteries in the 6mm range have a diameter of 6.8mm. So a SR626SW is 6.8mm in diameter and 2.6mm thick giving a Rayovac equivalent battery, from the reference table, as a 377.

Other manufacturers, like Rayovac, number their batteries without giving a clue as to the size of the watch battery, so to refer from these to other manufacturers' batteries you really need to use a cross reference table like ours.

Battery Prefixes:

What do the letters at the beginning of the reference number mean?

So what about these prefixes? This is just down to experience I suppose so here's a short list. Manufacturers who use SR to denote a Silver Oxide watch battery will tend to use LR to denote Alkaline. Those which use SG to denote Silver Oxide will tend to use AG to denote Alkaline.

Battery Prefixes:
• BR/CR = Lithium
• L = Alkaline
• SR = Silver Oxide
• LR = Alkaline
• SG = Silver Oxide
• AG = Alkaline

Battery Suffixes:

The letters at the end of the reference number are different, one is W the other SW. Which one do you choose?

In the Silver Oxide range of batteries you will often see a different suffix to the same battery reference. For example you can get a SR1130W and a SR1130SW. The ¨SW¨ refers to use in low drain devices whereas the ¨W¨ refers to high drain devices. So what's the difference? Well you would tend to only use a ¨SW¨ battery in a watch without a backlight. Your standard analogue quartz watch would be fine with a low drain watch battery, whereas a watch which used a backlight would really need a high drain ¨W¨ watch battery. Having said that, you could quite happily run a low drain watch using a high drain watch battery. ¨SW¨ batteries will tend to have a slightly longer life when used in low drain devices than their ¨W¨ equivalent. If in doubt use the high drain "W" type since there is likely to be little or no difference in price.

Battery Capacity and Shelf Life:

Just a few words on battery capacity. This tends to be given by the manufacturers in mAh (milli Amp hours) and this figure gives us an idea how much current can be supplied by the battery and for how long. For example, a battery which had a capacity given as 40mAh will be able to supply 40 milliamps for an hour or 20 milliamps for two hours. We can provide this information if you like, but you don't need to know this if you are replacing a watch battery in household gizmos. Really it's for the electronic buffs who need to know which battery to use in a newly designed circuit.

The shelf life of watch batteries is determined by storage temperature and their chemistry. Typically, at 21 degrees Celcius a Silver Oxide battery will lose less than 10% a year, an Alkaline button cell about the same and Lithium button cells less than 2% a year. This loss decreases as the storage temperature decreases.

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How to replace a watch battery in a watch

Do I need a special tool to remove the watch back?

First you need to determine if the watch is a snap back type or a screw back. If the watch back has a series of equally spaced slots (usually about 6) around it's perimeter, then it is a screw back and you will need a special tool in most cases. You can sometimes remove a screw back using a pair of snipe nose pliers in two of the slots, but unless the watch can be mounted safely in a small vice then this is quite difficult. We can sell a tool for this purpose, but they are 6.50 each and so you need to weigh up how many times you will be removing the watch's back to know if it's worth buying one. The back from snap back watches can be removed with a blunt penknife. If you look carefully around the edge of the watch casing you should see a small indent in the cover. This is where you start with the blunt pen knife, working your way around the edge twisting the knife gently as you go. Eventually the back will snap out of the watch casing.

Do I need to replace the rubber seal?

Well, you should really, but we bet most high street jewellers who change a battery for you won't do this. It depends if you want the watch to be waterproof or water resistant again and if you are going to use it in conditions where it will be exposed to water or dampness. If this is the case then you need to take the watch to a jewellers, make them aware of your requirements and then it is likely that they will send it off to the manufacturer to have the battery changed and the watch pressure tested. If however, your watch is not exposed to these conditions then it is likely that changing the battery yourself will leave you in no worse a position than had you taken the watch to a high street jewellers and got them to change the battery for you. They will often say, after changing the battery, that they cannot guarantee that the watch is now waterproof but still charge you around £6 or more.

My watch is waterproof, how can this be guaranteed after changing the battery?

The bottom line is that the watch is likely to have to be sent away unless you can find a jeweller or watch repairer carrying the special piece of equipment required to verify that the watch is still waterproof after the battery change. The test equipment required to do this only costs a couple of hundred pounds and we are surprised that most high street jewellers don't have it. It consists of a small tank which is half filled with water. The watch is suspended in the air space above the water and the tank is sealed. The tank is then pressurised with a hand pump to the required test pressure. Once at this pressure, the watch is lowered into the water and then the pressure released from the tank. If bubbles are seen coming OUT of the watch then clearly it is not water tight (well, not air tight actually). The seal will have to be changed again, the back retightened and the test repeated. This is what is likely to happen when the watch is "sent back to the manufacturer" when you take it to the jewellers and ask that the battery be changed, but you want it to be waterproof again.

I have the back off the watch, but it seems that I need to remove a screw in order to get the old battery out.

Be careful here. This may or may not be the case. In some watches it is merely a case of loosening a screw which will allow a clip to be moved to the side enough to allow the battery to be levered out. Once the screw is removed they are rather difficult to get back in, although not impossible. Just don't go trying it when you have had a glass or two of wine that's all. So, check that you really do have to remove a screw in order to remove the battery. In most cases it is a merely a question or loosening a screw and on some even there is no screw at all, just a clip which when prised back slightly will allow the old battery to pop out.

I have a snap back case and I am having trouble getting the back on.

Some case backs are tight. When placing the case back be sure that the indent on the cover lines with the winder. Most cases have a small indent to allow for the winder shaft. The best way to put the cover back on is to place the watch face down on a flat protected surface - a mouse mat is ideal. Then with the case lined up with the back, push down with both thumbs, applying even pressure to the case edge, making sure that one side doesn't get pushed further in than the other. With the cover being pushed evenly around its edge, it should snap back into place. If this still fails to get the cover back, then a jeweller would use a case press. Basically this is a vice which comes with dies which fit over the back and one around the watch glass which means that the glass doesn't get broken when the vice is tightened. If you have a vice at home you may be able to improvise something which would give you the same thing.

I have replaced the battery but the watch isn't working.

The obvious one first. Is the winder (crown) pushed fully home? If so, has the watch been left standing with an old battery inside it for a long period of time? If this is the case it is likely that the watch is at fault. New battery failure is very rare, and if the watch has been left idle for a long period then it may never work again. Sometimes placing the watch in a warm place will "loosen" things up sufficiently to get the mechanism working again. We have fitted several new batteries to watches which have started for a while then stopped. Leaving them in a warm airing cupboard over night, believe it or not, actually got them going again. It is always best to replace a battery in a watch as soon as the watch stops working.

I have replaced the battery in a LCD watch, but the display is all funny.

If this happens then most of these watches can be reset. If you remove the back again, you should see some indication of a reset hole on the watch's movement. This is a hole into which you place one leg of a pair of metal tweezers and the other leg touches the main movement housing. This should reset the display.

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How to replace a watch strap on your watch

Replacing a watch strap on most watch types

Nearly all watch straps are held to the watch with spring loaded bars called, funnily enough, spring bars. These are the bars that spring into tiny holes in the watch case securing the strap to the watch's body. To remove the strap you will need to compress one end of the spring bar so that it can be freed from the hole in the watch case in which it usually sits. You can buy a special spring bar tool to do this (available of course from us at a very competitive price) which has a special shaped forked end or you can improvise by using a small screw driver to compress the bar enough to free it. Once one end of the spring bar is free the other should just come out freeing the strap. Before you completely remove both parts of the strap, remember which of the two pieces goes on which side of the watch. Usually, with the watch upright in front of you, the part of the strap with the buckle goes at the top. Repeat the same procedure for the other side of the watch. It may be a good idea to clean the gunge you are likely to find around the watch at this point, prior to fitting the new strap. Fitting the new strap is merely a reverse of the procedure above and is in fact easier than removing the strap. Making sure the correct part of the strap is going on the right end of the watch (and is the right way up!), locate one end of the spring bar into one of the small holes in the watch case. Then, using a finger nail, small screw driver (or one of our reasonably priced spring bar tools), compress the other end of the spring bar and slide it between the shoulders of the watch and move it until it locates in the other hole in the watch case. Repeat this with the other part of the watch strap.

Replacing a Swatch watch strap on Swatch watches

If, having read the above procedure, you are looking perplexed, then it is probably because you have a Swatch watch which needs a replacement Swatch watch strap. Swatch watches do not use spring bars and their notched Swatch watch straps are held in place with a metal pin. In most cases this pin can be carefully driven out from one side to free the strap so that it can be replaced (with one of our reasonably priced quality replacement Swatch type watch straps of course). Be very careful if your Swatch watch is plastic and old. Sometimes the plastic becomes very brittle and while driving out the metal pin it is possible to snap the watch case. Use a drift (a small metal pin or nail will do, or if you have one of our reasonably priced spring bar tools there is a drift on the other end of this tool) which is smaller than the pin you are removing and ensure the other side of the watch is supported as you drive it out. We clearly don't recommend the use of large hammers from a lorry mechanic's tool kit to carry this out, but the pin may need some gentle persuasion. A gentle tap with a small pair of pliers on the drift may be enough to get the end protruding so that enough of the pin can be seen to remove it with a pair of pliers. To fit the new strap just follow the reversal of the removal procedure.

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How to adjust the the metal bracelet on your Casio watch

Instructions on how to adjust the metal bracelet of your new Casio G-shock or WaveCeptor watch.

The Casio bracelet is held together with removable pins secured by a central metal ferrule. Arrows on the underside of each link show which links can be removed. If more than one link is to be removed then it is advisable to remove a link from each side of the bracelet so that the clasp remains central on the underside of the wrist when the watch is worn.

Tools required:

• A thin pointy object - like a bradawl. Our Spring Bar removal tool is ideal.
• Long nose pliers
• A vice and material to cushion the bracelet.
• A small craft hammer.

Preparations:

Make sure you work area is clear and place a sheet or other covering on the floor to catch any small bits that may 'ping' off as you work on the bracelet. Using a small vice to hold the bracelet when working is helpful. Identify how many links you need to take out. Put the watch on your wrist and work out how many links need to come out. Usually 2 or 4 links will have to be removed.

Step 1 - Separating the clasp

Remove the spring bar from the clasp so that you have the bracelet separated. If you hold the clasp in your left hand it is the spring bar on the left side of the clasp. You can use the bradawl to push and compress the spring bar so that it can be slid out of its retaining hole and this will release the two parts of the clasp. You will notice two holes for this spring bar on the clasp giving you the opportunity to make a small adjustment to the bracelet length should you need it. Be careful that the spring bar does not ping across the room, as it is the only one you have and losing it will be an inconvenience.

Step 2 - Removing a link

Identify the link that needs to be removed and using a bradawl push the pin securing that link. Follow the direction of the arrows imprinted on the underside of the link. The pin should be pushed about 2 or 3 mm and then pulled from the other side using the pliers. When the pin is pulled out completely it releases a small metal ferrule that sits in the central part of the joining link. This ferrule will fall out on to your worktop or the sheet that you carefully placed on the floor! You will need the ferrule later so don't lose it. Repeat the process on the other side of the link so that you now have removed one entire link and have two pins and two ferrules sitting safely to one side. Now you have a bit more confidence the next link will be easier. The second link should be taken from the other side of the bracelet. Repeat this process if more links need to be removed.

Step 3 - Connecting the bracelet together

The small ferrule needs to be put back into the central part of the link that you are joining back together. This time working in the opposite direction to the arrow on the link, push the pin back through the link to engage the ferrule. If necessary you can carefully tap the pin back into place with the hammer.

Step 4 - Reconnecting the Clasp

Reconnecting the clasp is a simple reversal of the disconnecting process. Try on the watch and it is a little loose or a little tight you can adjust the clasp by inserting the spring bar into the alternative set of holes. After the adjustment you will have spare links, pins and ferrules. These will be useful if you have bent a pin or lost a ferrule during the adjustment process.

Job done!

If you need further advice just contact us using our contact form

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Help Regarding Battery Chargers

There are two main types of battery charger...

A timed battery charger and an intelligent battery charger. A timed battery charger will tend to charge rechargeable batteries for a fixed length of time, after which the battery charger may switch to trickle charge or simply switch off. These battery chargers are fine for batteries of a certain capacity. Say your battery charger takes 5 hours to fully charge 1700mAh AA batteries. Perhaps these batteries came with the battery charger. All will be fine and your batteries will reach their full charge. However, if you put higher capacity batteries in the same battery charger, it will charge for 5 hours at the same rate and your higher capacity batteries will only ever be partially charged (to about 1700mAh).

Ok, so how about I charge the higher capacity rechargeable batteries again before use, using the same battery charger?

You could do this of course as this will give the batteries a double dose. But how would you feel if, on a drinking binge, your capacity was say, 8 glasses of wine, and you were forced to take two lots of 5? You get the gist? The charger will spend another 5 hours charging the batteries, but of course you risk damaging the batteries by overcharging them. This will shorten their life. Quite an apt analogy perhaps? We get many customers who purchase the new high capacity Uniross 2500mAh NiMH AA batteries and find that the performance of these batteries is not much better than the 1700mAh batteries they were replacing. In most cases this is because the battery charger being used is a timed battery charger. The best solution is to use an intelligent battery charger.

What is an intelligent battery charger?

An intelligent battery charger is just that, cleverer than a timed battery charger. It is often microprocessor controlled and charges the rechargeable batteries until their full capacity is reached. Once they are fully charged, the battery charger stops charging and goes into trickle mode, preventing your batteries from being "cooked" thus prolonging their life.

Can I charge NiMH rechargeable batteries in my existing NiCd battery charger?

Sorry, no. Well you can, but the battery life will be severely affected by this treatment. Some battery chargers allow the charging of both NiCd batteries and NiMH batteries. Some battery chargers auto sense the battery type (like the Fameart UC05 Universal charger) and some require a switch to be used to select the battery type.

The Camlink Zeta and Z1 chargers are brilliant for charging batteries for digital cameras because they charge so fast..

Another option, slower, but an excellent, versatile charger is the Fameart UC05 Universal microprocessor controlled intelligent charger, which can charge both NiCd and NiMH batteries in all the popular sizes (C, D, AA, AAA and PP3).

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And finally we thought it a good idea that if people who have ordered from us told us what their watch battery was going to be used for we could list it here in the table below. If your gizmo is listed here, order the battery suggested.

You can use Control-F to do a search for what you want on this page

WEEE Regulations

WEEE Regulations - Disposal of Electrical and Electronic Goods

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