Mostly good advice on here (excluding the anti emowers). Get on the WWW for Lowes or Kobalt Operators Manual for the specific part numbered mower. Read the book; don't skip to the back for the surprise ending. In the manual pay attention to the dos and donts as to batteries, safety interlocks, loss of power and or foreign object strikes. A severely bent blade can cause an impossible start load for a battery; battery internals shut down, or blow fuses. Battery checks can easily be performed with the charger. Mowers with two batteries usuallly have a higher operating voltage if paralled, or a demand for higher current if configured in series. The best way to test the batteries is with a standalone charger; specific to the battery. A charger plugged into the mower can verify battery fail due to internal failures, but has to have special circuitry for multiple battery configuration and that circuitry can fail if you have a combination of events clouding the issues. Issues include but not limited to:; such as reading the manual, driving while under the influence of tall trees blocking the view of the forest, tall grass, short grass, grass offering safe harbor for the dogs screw anchor!....the list goes on. If the mower lurched when you hit the stake it is possible the start stop safety interlocked control took a hard lick. It is fixable; it may not be practical unless you wish to further your education. Parts are probably not available. Warranty is highly disirable in these mowers and paying attention to normal wear and tear will help prevent bent or broken belts and blades, broken or faulty interlocks and especially electrical components. Motors have an internal temp sensing device and will disconnect the battery to prevent further damage to the motor. Safety interlocks are external to the motor; are mechanically interlocked to open a switch, or mechanically brake a rotating blade. Hope this doesn't discourage you.....anything is simple once you understand it.