Originally Posted by mikerkba
I often read that using a generic battery charger to keep your battery level up during an extended ground avionics run puts your sensitive electronics at risk. But, I have never heard of a report of such an outcome.
Has anyone had this happen? And, if so, was your battery in the circuit during the charger operation or was the charger the sole source of power? I have the impression that having the battery in the ground power loop (meaning a charger to the battery while the battery is in the normal circuitry and the avionics master on) buffers even the ragged-est of battery charger output and protects electronics.
Having a battery in parallel with a noisy charger will only mitigate DC voltage fluctuations (if not too severe). It will do little to filter out the AC hash and various harmonics that will be floating on top of the DC voltage. Read you manuals, some have specific cautions about running with a battery charger connected.
Sure - some chargers are better than others but why flight it? For about the same price (or cheaper) a $99 30 amp regulated DC power supply will run the panel forever and keep your battery(s) topped off, just like when you are running the engine with the alternator on line. Get a power supply with adjustable output voltage so your can match to whatever battery you have.
Note, no matter how you put juice back in your battery(s) I strongly recommend never leaving any charger or power supply connected unattended, and never for days/weeks/months on end.