This year I am upgrading my battery powered lawn equipment to lithium batteries. I will try to document the upgrades as much as I can. This first post will have all the information. I'm starting with my Ariens AMP riding mower. Ariens has discontinued this and no longer makes an electric riding mower. Read my review of it here. http://www.cleanmpg.com/forums/showthread.php?t=31097 To start off I'm replacing the 20 SLA batteries in a 4S5P configuration for a total of 48v 75Ah with 16 CALB CAM80FI LiFePO4 80Ah cells. The batteries were ordered from http://evtv.me for a total of $2,215.12. The reason I picked these cells was because of their height and capacity. A bit pricy but they should outlast the mower and will pay for themselves in about 10-12 years given that lead batteries will last about 4 years and their cost. With these lithium batteries I expect to be able to cut my whole yard every year on one charge. With the lead batteries every year seen about a 25% reduction of run time. Since I have a robot lawnmower that cuts 90% of my yard I dont have to worry about loss of run time but if something happens to my Lawnbott I can still use my riding mower to cut my whole yard if needed. I also plan on using a 5000W pure sine wave inverter with these batteries as a temporary backup source for power when the electric goes out. To go along with this battery upgrade I will be installing a proper volt meter and amp hour counter so I can tell how much juice I have in the batteries and how much the mower is using. The included fuel gauge and amp meter on the mower is just crap and you cant even see the fuel gauge in direct sunlight. Plus the fuel gauge does not really tell you anything and has never been helpful. I'm currently in the process of bottom balancing the lithium cells. I will update with more information and pictures as I go. I hope to have the mower ready before the grass gets too high. Black & Decker 36v Cordless Push Mower The original SLA batteries were 10Ah. I ordered 10Ah LiFePO4 batteries from http://www.batteryspace.com Price was $291.00 not including battery holders and connection plates which were $12.76 and $14.52. The total was less with a 5% discount. I could have ordered the 15Ah batteries but after measuring it would have been a tight fit. Plus 10Ah was getting me plenty of cut time anyway and they was cheaper. I could have even gone with 20Ah cells but that would have required a battery box modification. These will be a drop in replacement of the SLA batteries. Black & Decker 36v Cordless Trimmer The original Ni-Cad batteries were 2400mAh. I ordered 3300mAh LiFePO4 batteries from http://www.batteryspace.com Price was $90.24 with solder tabs. I ordered these with the push mower batteries and received a 5% discount on the total. I could have gone with 5000mAh cells but after measuring I don't think I could fit them into the Ni-Cad battery box without heavy modification. I estimate I should at least have 25-30 minutes of cut time with these batteries which should be plenty for me. On a good day the original batteries would let me get about 90% done so I think these lithium batteries should be OK. Worse case I can always buy larger batteries next year and make a fanny pack out of them for longer run time.