Equallogic PS4210 Battery Replacement Frequency

Hello Everyone, 

I made an account to ask this question as I cannot find any information about it online. I have inherited several Equallogic PS4210's that are in production. I have 6 of them with 2 controllers each for a total of 12 batteries in production. I am no stranger to the older Dell Equallogics needing battery replacements, the procedures for doing so, and the caching modes tied in with everything. 

 

My question is about battery replacement frequency. I have been purchasing batteries for the last 2 months from serversupply. I originally went with a couple Refurbished batteries through them and didn't have much luck. Batteries reported end of life on install, even after allowing 72 hours to charge. Next step was to order "NEW" batteries, double the price but hopefully more reliable. I ordered 8 batteries in total. Replaced 2 in one SAN, 2 in another, and kept some on hand. 

 

One of the batteries had the same issue, end of life on install. "OK, bad batteries are bound to happen". Since replacing the 4 batteries about 3 weeks ago....all have failed.... I ended up overnighting some for emergency again but I am concerned about this trend. 

 

Going through the list in my head (Could be...)

1. Bad controllers? (replaced one of mine with a spare controller just to see but I doubt it considering all 4 failed.)

2. Bad Chassis power, causing shorts? (Wouldn't think so because I am seeing the failures on 4 controllers across 2 SANs.)

3. Bad batch of batteries? (Possible)

4. Need to order from another vendor because the standard for whoever is making these obviously isn't even close to OEM. (Possible. Normally ServerSupply is a pretty trusted source for me though.)

5. Older Firmware bug not allowing the new batteries to register properly or killing them early? (Possible. I admit I am not on 10.0.3 for all the SANs due to not having a current contract and haven't found a reliable method for updating the controllers)

6. Dirty 120v power causing failures (Wouldn't think so, we are hosted in triple redundant racks connected to 3 enterprise grade UPS's the size of a small train in a datacenter. backed up by 2 power companies and 2 generators outside. Considering all the other equipment in the server room, I would imagine we would be seeing many more problems if this was our issue.)

This is was is going through my head. I would love to hear the thoughts of everyone else and maybe someone has seen these issues before or has some better insight than me.

Thank you for your time!