|Location||Wilmington, North Carolina US map|
|Vehicle||2009 Sears Sears Craftsman #18A-188-799 247.37048.0 |
Sear 19" 48Volt mower that came with 4 lead acid batteries rated at 8.5Ah. These have been replaced by 4 EarthX Lithium Iron Phosphate batteries rated at 18Ah.
|Motor|| 724_04025 Permanent Magnet DC|
Motor: Johnson Electric
550Wo@48VDC/15A (Calculated amps 11.46amps @48VDC)
Master fuse: 40amp/58Volts
Blade: direct drive off motor
|Batteries||4 EarthX ETX18B, 53.40 Volt, Lithium Iron Phosphate|
These batteries are assembled and sold by EarthX. These batteries run mower for 36 minutes(until 39Volts). Tried EarthX ETX12A batteries 1st. They ran for 32 minutes until 39volts. Stock batteries ran mower for 30 minutes. Stock batteries weighed 24lbs 4oz. ETX18B batteries weigh 7lbs 3/4oz. ETX 18B batteries fit in stock battery tray with removed center divider.
|System Voltage||48 Volts|
Made by SL Power Electronics
Input: 120V AC 1.0 amp. 50-60Hz
Output: 57.6V @ 1.0amp charge
Output: 54.5Volt float charge
Charges EarthX batteries OK
|Range||36 minutes of run time until 39volts.|
17lbs lighter than stock.
|Conversion Time||2 hour including cleaning of mower.|
|Conversion Cost||Discount from EarthX for buying 4 batteries at one time.|
|This change in batteries works. Went from 30minutes of run time with new lead acid batteries to 36 minutes of run time with new Lithium Iron Phosphate batteries from EarthX.|
Lost 17lbs in the changeover. Had to trim center divider of battery box to allow comfortable fit of new batteries. The blade speed stays the same for 29 minutes with the EarthX batteries. Had to make 2 new ends at battery connectors to match up to stock spade lugs. EarthX supplied 6 lugs and 3 jumper wires for middle conections.
Stock Sears Craftsman Charger charges EarthX batteries. EarthX has internal circuitry to equalize Lithium battery cells when using a stock lead acid charger.
Update: I have found that the increased blade speed, for a longer time, causes the blade to wear out quicker. The mower also sounds like a gas mower for the first 29 minutes.
Update 2: Although the Earth X batteries have internal equalization circuitry for the cells in one battery, it appears that the battery voltages have drifted so that they are not equal when the machince is fully charged. It appears that I may need to charge the individual batteries seperately every 10 or so~ charges to equalize the batteries. The two batteries closest to the negative cable have drifted down in voltage over the past year.