The new battery voltage measured 3.20v and the removed battery measured 2.53v. The battery will deliver 3+ volts until it reaches a minimum voltage of about 2.50v and then it triggers the 'Memory Battery Low' message.
They presently sell online for $13.75 including shipping. First of all you will need a CR 14250SE-FT, a 3 volt lithium memory battery with 3 solder pins.
If you are up to the task and have the proper equipment and experience, then there are really no surprises. The battery location on the GNS 530 circuit board looks the same as the 430. It will be a very expensive mistake if you damage the circuit board. I worked in the electronics industry and have a lot of experience replacing circuit board components, and would not recommend this battery replacement to anyone not knowledgeable with ESD precautions and the proper use of a soldering iron, solder sucker, and solder wick. I read a few posts online about replacing the battery at home rather than sending the unit to Garmin along with hundreds or usually thousands of $$$, and I read that if you choose to not upgrade to WAAS, Garmin will remove your serial number tag. About a month ago a 'Memory Battery Low' message was displayed on my Garmin 430.
