I purchased a 120AH deep cycle leisure battery a year or two ago for a solar power project I wanted to do in the garden to power exterior LED lights. I still have plans to do this where I have a small solar panel charging the deep cycle battery via a solar charge control unit. I just haven't had the chance to do this and the battery has been sitting indoors in a cupboard. I can't remember exactly how the battery looked when I purchased it but when I look at it from the side view it looks a bit puffed up on the sides. Not the long side but the two short sides. It's not 100% flat and i'm not sure if it was like this from the beginning or not. Is there a problem with the battery? Should I get rid of it? I would post a pic but it's impossible to picture how it looks. it looks normal in the pics

 

I would put a charger on it with my clamp meter attached and see if it will take a charge. It's life will certainly have been reduced but it might still be useable. Don't leave it unattended especially if it's taking a big current it may get hot if the bulges are some sort of damage or a shorted cell, it's funny how it's both ends though

 

Before you put a charger on it, has this battery been outside and has it by any chance frozen? If it has, get rid of the battery as you may have shorted plates and putting a charger on it may result in an experience you won't soon forget. The other side of that may be that the plates are very sulphated and have swollen inside the case. In either case, if it has sat around for a couple of years or more and never been charged properly, it is probably scrap.

 

Before you put a charger on it, has this battery been outside and has it by any chance frozen? If it has, get rid of the battery as you may have shorted plates and putting a charger on it may result in an experience you won't soon forget. The other side of that may be that the plates are very sulphated and have swollen inside the case. In either case, if it has sat around for a couple of years or more and never been charged properly, it is probably scrap.

No it's always been indoors and I haven't actually put any load on it. So it's been fully charged since new and haven't used it. So have a battery sit around fully charged without draining it or charging it is not a good idea?

I'm just wondering when I get round to actually doing my mini solar project, what will be the solution for the battery? As it will need to be outdoors housed inside a storage box and when I do that, it will definitely be exposed to cold and hot temperatures

 

Keeping the battery fully charged is the best insurance that it will have a long and healthy life. You didnt mention that it was fully charged in your earlier post. The next step would be to take it somewhere and have it professionally tested. My preference would be a good load test and then a 3 minute charge test to check for sulfation. If it passes those two tests you should be good to put it inside, outside, hot, cold or whatever as long as you keep it charged.