weird start up, dead battery?

so this just started a couple days ago never had it happen to my 89 xj before. After work I went to my car and tried to start it it clicked and cranked I saw that the battery level was low its started up after about 10 seconds. Ran fine I turned the car off thenstarted it back up no problem it was fine. Next day turned the key saw the battery voltage on the meter was fine cranked it started to crank fast the slow and slow and slower then started up. Not sure what this be !?!? Any idead would be appropriate thank you

How do your battery connections look?
What is the resting voltage of the battery?
Did you leave the lights on while at work?

the terminals look okay I cleaned the negative cables to the block and wire brushed the terminals it was cranking fast. But this morning when i checked the meter it was a little over the 9 like always buy cranked fast then slowed down like the battery was dead (slow motion) then started up.

As for the resting voltage do you mean when the car is off or on? When off its above the 9 well today it was last night when going home from work it was almost dead but still started .

I'm not sure if it could be the new cps I installed or my hid lights

Thanks for the reply

HID lights wont have anything to do with it, unless you leave them on.

Sounds like a low battery. WITH A MULTIMETER, check voltage non-running, then start it up and check to make sure you have 13+ VDC with the alternator spinning.

UPDATE UPDATE

Okay so on my way to getting my hella lights I noticed two dim light ! Well look at that both my dome lights were on since 3 days ago geeze I just didn't notice them because they are so dim it popped in my head when I gave my friends gf a ride and she went all ape Shit on me and was oressing the lights but her dumbasd didn't turn them off ! ugh thanks a lot guys for your support and help I was almost on my way to buying a yellow red top witchever I could afford haha. think I still should haha

The sears platinum is suppossedly a better battery, with a better warranty
Red tops just aren't what they used to be

Awsome ill look that up , first time actually looking to upgrade to an good battery instead of that wallmart junk