This workhorse SLA 12 VDC 8AH battery fits all versions of the M4 backpack. Easy to charge using the built in system in the M4 backpack sprayer or available external battery chargers. See picture showing maximum bend angle for J2 terminals to engage battery compartment spring plates (15-30 degrees).
If you already own name brand lithium ion 20 volt power tool batteries (ie, DeWalt, Milwaukee, Makita, Ridgid, Black and Decker, etc) and would like to convert you M4 sprayer to use them instead of replacing the brick style battery, use the link below for the battery conversion kit (requires installation):
If you have a digital voltmeter, refer to the Battery Condition Based on Voltage Table below:
DC Volts Condition
12.85-14 (Good - charged)
12.3-12.8 (Depleted/damaged/bad- try charging for 8 hours maximum)
Batteries are misdiagnosed 50% of the time. To determine if your battery is good, please watch the video at the top of this page. If you do not own or use a voltmeter, use following information to determine battery condition:
Battery is most likely good if it has gone through a successful charge cycle using the original automatic charger provided from the factory. A successful charge cycle occurs when the LED on the corner of the 12 volt 1 amp charger brick turns green, then red, then green. The LED turns green when plugged into the wall ( meaning the charger is good, ready to charge), turns red when plugged into the M4 base charge receptacle (meaning the charger has successfully connected to the battery and is delivering 1 amp), then turns green after 8 hours or less ( meaning the battery is now fully charged and ready to use).
Battery is most likely bad if during the charge cycle the red light begins flashing ( make sure both switches are turned off during charging). False negative warning: A flashing red light also can occur when either of the M4 switches are turned on and the charger is plugged in, and there is no connection/power available from the battery.
Battery is probably in poor condition if during the charge cycle the light never turns green after it has turned red. This indicates voltage is more than 12.3 but less than 12.85.
Battery is probably bad if during the charge cycle the light never turns red ( stays green). False negative warning: LED staying green can also occur when there is no connection or a weak connection from the charge panel to the battery.
Refer to the diagnostic section from the video pull down menu (top of main page) or text Lance at 707 478 2162 if you still need help.