尊敬的 UPBattery 尊贵客户，

Today we’re going to share what kind reasons may cause the AGM Battery or sealed lead acid batteries to swell.
Firstly, Batteries overcharging ( batteries charging voltage are too high)

Secondly, .batteries powered off,  charging current of the batteries is too high

So for the AGM batteries or the Sealeadl lead acid batteries usually suggest customers use a good charger ( a good charger controller, a good inverter) to make sure their batteries are charging properly and it’s very important. 
Thirdly, Positive and negative were connected reversely, then load short circuit would cause the batteries to swell as well. 

That’s all reasons may cause swelling. Hope the above tips may be helpful for you to avoid this kind of problem during daily use.

UPBattery Sales Team