i gave up on maintenance free batteries...really regret wasting my money on them...tried few different brands..not just any brands..but reputable brands...all oso hopeless coz all my maintenance free batteries die in about a year of usage....
previously i was running on a wet cell battery and it lasted 4 years with minimal checks and maintenance. n when i say minimal i mean mebbe 2-3 times only in that 4 years. and thats only to make sure the water level is ok and it was...never even top up in that 4 years. when i changed oso it was actually still ok...just gatal wanna use maintenance free so i changed.
worst part is that the maintenance free shows no signs of dying. itll just die. just like that. the indicators on the battery itself is useless.. and when it dies...jump starting is practically impossible no matter wat grade cable u use. everytime oso had to put another battery in to start the car

im sticking to wet cell from now....theyre cheaper. not really much to maintain... and supposedly has better, more stable power delivery compared to maintenance free batteries.
ive had a wet cell for about a year plus now and its still perfect. havent checked on it since the day i bought it.
as for electronics...i have an immobilizer, player, 2 amps pushing 4x6.5" speakers and 1x12" sub. never had any issue with the wet cell battery.