3/V150H Mempac Varta Programmer Battery

If you're 3/v150h programmer backup battery has seen better days, and is not holding a charge anymore (Example: programmer resetting if there's a powercut), it's time to replace it with a brand new one. They have proved tricky to source at some times but can now be found for sale in many outlets online. A quick search for the model in Google using the term - Mempac 3/V150H Varta - 3.6v (Pictured below) and you will be met with many choices.

There are quite a few different types available in regards to whether they have polarised pins (tags) or not. Some have no pins (tags) and others have either 2, 3 or 4 pins. Some have pins and wires for connection to the internal PCB (circuit board).

One of the most common is the 2 pin, no wire version, and this is the type you will most probably need if replacing the battery in an older model programmer. However, as there are so many different makes and models, that is not always the case. So it's always wise to check beforehand by taking a look inside at the battery that is already present within the unit (the faulty / dead one).

While many models will require a no pin replacement, all is not lost if you do end up buying a battery that has pins (tags), and your model needs a battery with none. For this scenario, all you have to do if, for example, you have bought the well-know green 2 pin Varta Mempac Ni-MH 3/V150H (150mAh) - 3.6v (Find it for sale here), is to snap / bend off the two pins.

Then just pop the battery into the programmer and it should work fine. As I'm sure you're aware, these batteries have a long life and shouldn't need to be replaced for quite a few years, so its money well spent to keep all your timer / heating settings intact. This battery works with many different makes and models of thermostats, including older Potterton's and Honeywell models (Including the earlier model ST699 - Year 2000 and older).