I have a similar situation but my lift is 36 volts. I bought 3 of the AGM 4D batteries from batteries plus and hooked them together with heavy duty top post terminals. I can operate for a couple of hours with no noticeable decrease. I added cement blocks to make up for the loss of counterweight since the old battery pack was 1800 lbs. I now have about 800lbs. I am mindful of this and am careful. However it is very stable and I use it for 2000. loads and less most of the time. I bought a maring 36 volt charger for 199. and it keeps it charged and ready to go. I have been very happy with this fix and it works for my shop very well