When I needed my Elinchrom receivers recently, I found that they where not working. After a couple of hours with unsuccessful charging, I realized that the batteries where dead. Some batteries may loose their storage power and ability to recharge when unused for a long time. I have three receivers and two of them had major power issues.
Unfortunately, the receivers are not designed to have the batteries replaced. I bought these at B&H New York in 2012 and discovered that they only had one year warranty. Having these serviced would cost more or less the same as getting new ones. So, instead of throwing them away, I decided to open them up to see what kind of battery was installed. To my surprise, battery replacement was a breeze. New and cheap batteries are available on ebay. I did buy a couple of 880mAh and 900mAh, both are 3.7 Volt lithium cell. Because the 880mAh arrived first, these are the ones that I installed.
Here´s a tutorial on how to replace the battery. Do it on your own risk and remember that your warranty (if any) will be void.
Woila, the receivers are now as good as new!