DIY power supply for J720 or MP900c

Be careful using an under-amped charger. The device will likely attempt to pull more current from the charger than it can provide, forcing the charger to run over-specification. This can cause it to run hot or possibly be a fire risk. It can also lead to under-volting as the battery can't charge properly, causing device instability.

Good advice , to be cautious in that way. Well, I recommend at least a 2 watt charger, the inverter seems to have some protection...it won't charge...charge light goes out say if battery is really drained and then you turn on the MP900c. If you turn the MP900c off, charge light comes on. Once it's partially charged seems ok. I measured the current and voltage with a usb measuring device...nothing alarming...less than 5 volts, less than 2 amps draw. Inverter should be encased...will see what works. Wouldn't recommend those 0.5 amp chargers. 2 Amp works well for Date/Time clock continuous display...barely warm (if even that). My 2 cents worth...

For comparison, my laptop charger would fry an egg at times when gaming using the Nvidia GPU...heavy draw...

Funny you mentioned this after charging your J720 with a 6.5 volt charger...

Edited by joval 2019-06-28 8:04 AM

Yes, but my 6.5v charger had the correct current output for the 720, so it wasn't going to overload the charger or pose a fire risk; just fail to charge the battery.