I have these devices.

  • Sealed type car battery (35Ah)
  • 1000W Power Inverter (Modified Sine Wave, Model:Suder)
  • 2 Solar Panels (37V, 8.2Ampiers, 310W each)
  • Solar Charge controller(30A)

My Grinder is 230V, 620W device.

I use solar panels to charge my battery.

I did this:

  1. Fully charged my battery using solar panels. Solar charge controller showed that battery is full in LCD display.
  2. I connected my inverter to battery while charging with solar panels.
  3. Plugged my grinder to inverter.
  4. Turned on inverter power button. Inverter is working normally.
  5. Turned on my grinder, Then grinder blade is slowly turned around and stoped. and also in my inverter, a red bulb named fault is lit. But battery level is still full.

What is the reason for that? I am bit confused because as i calculated, my grinder need only 2.69Ampiers. But battery already have 35Ah fully filled. And also grinder need only 620W and my Inverter outputs 1000W.

And also my inverter is works with CFL Bulbs, Cieling fans etc. without any problem. And also my grinder works normally with Normal government electricity line.

Can anyone tell me whats the wrong I got?

  • 3
    \$\begingroup\$ "I am bit confused because as i calculated, my grinder need only 2.69Ampiers. But battery already have 35Ah fully filled." This is doubly mistaken. First 2.69 amps at 230v requires drawing more than 51.5 amps at 12v when inverter losses are taking into account. Second 35AH is the capacity of the battery, not the power delivery rate it can support. Within a given type of construction a higher capacity battery will often be capable of more power, but it's not an absolute. 35 AH would be small for a car battery. Your load is probably less than starting a car, but that's supposed to be brief. \$\endgroup\$ May 28, 2017 at 15:40

2 Answers 2

  1. You would need sine wave output (for induction motor)
  2. Having an inverter with 1000W sticker doesn't mean it's truly 1000W
  3. An induction motor needs 4x, 5x starting current, so even 1000W is too small, you would need 3000W inverter (if the grinder has induction motor) .
  • 2
    \$\begingroup\$ Startup surges are not limited to induction motors. They occur with pretty much any type of motor. \$\endgroup\$
    – Dave Tweed
    May 28, 2017 at 14:05
  • 1
    \$\begingroup\$ And as with most power tools, only fixed ("bench" or "pedestal") grinders will use an induction motor. Handheld ones of the sort most often used portably are universal motors. That possibly adds commutation grunge annoying the inverter management circuitry as a cause. \$\endgroup\$ May 28, 2017 at 15:32
  1. Try to operate it first without load.

  2. Measure the DC battery voltage when you operate your machine, if the voltage low then 11.5Volts when you operate the machine it's mean your battery is not full charged or the battery has not enough current for starting.


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