corolla 2002 TS radio wires and quick battery drain

[gen0]

Hello everyone, just replaced my stock stereo with a new pioneer mvh390bt and the Battery gets drained down to not being able to start the engine in about 30 minutes of listening to music with engine off. With stock stereo it would last for 2h+ at least. When connecting the new unit, I used an adapter, that would only take the two right plugs seen in the image below. What is the function of that wide plug and could it be the reason for quick drain if I left it unplugged?

https://www.dropbox.com/s/djk6n141bbaplx4/20170824_163731.jpg?dl=0

[oldcodger]

Hi,

Not sure about the wiring connectors, have not replaced mine yet, though have fitted pioneer Speakers

Things like the mpg reading , steering wheel audio controls  will also come in on the connector to the original head unit.

Assume you are not using a separate power amp or sub woofer  ?

If Not, then the Pioneer uses a maximum of 10A according to its manual; taking 10A means playing it at full volume all  the time  ... ?

Even with that load your Battery,  I would think it  should be able to run it for 2-3 hours without any problem.

To me it suggests your Battery if low, due for renewal, and /or the alternator is not giving out the correct charge.

How old is your Battery and what Amp rating is it ?

Have you done a charging test with a voltmeter  to prove the alternators working ok ?

If you intend to do lots of playing without the engine running, then you need to fit a high amp battery when getting a new one, though that limited by the space it can fit in.

[gen0]

alternator is fine, so I just swapped the Battery. Will see how that goes.