ODBEleven reported that both keys were getting problematic on the error check. B147918 - Remote key 1 Voltage too low static B147A18 - Remote key 2 Voltage too low static I didn't get a screen warning thou. Had the car since November 2016, built in September so judged the time was right. It has Kessy which taxes the battery more. It had been playing up. The manual doesn't say which battery to use. Seat parts online say CR2025. Checked my spares, had CR2025 with no date on the packet, it was dead. CR2032 with two years to go. Wondered what the difference was. There are some YouTube videos. The first is good showing the action to open it up. A CR2025 battery fitted: The second video shows a CR2032 in it but slightly different remote to mine: The Briskoda thread covers upgrading to a CR2032 from a CR2025: https://www.briskoda.net/forums/topic/382112-change-key-battery/ They have 50 percent more capacity. The 7 number different is the thickness for more battery. Voltage is the same. Taking apart the unit the first video is the one to use with the screwdriver to leaver off the case. A bradel can be used to ping the battery out of the slot. The back of the case lid does say CR2025 on it. Briskoda page says the case holds the battery in with a CR2032 - true. The Orville tip on that thread followed by others. I didn't press the battery down hard to get it below the the holding pin but used the case holding mothod. Note the waterproof seal might not come down all the way before I get told this . Was the summer months when it started to play up so not a voltage drop introduced by winter months. So fitting the more heavy duty battery in is a hack and obvious question is whether it might pop the case - We'll see. It does work thou. One warning is swap the battery in and out quick since they are suppose to loose the settings. The original was a Panasonic, replaced it with a Panasonic again, Duracells may be better.