Battery Drain - Coincidence?

e.a.greenwell Newbie
Hi all,

A month ago I bought a Lexus RX 400H, which is a hybrid model. The car is fairly old, a 2006, but it has low miles and has been maintained really well. The title is clean. No damage or any past accidents.

The only issue with the car after we bought it, it was the factory door speakers, which sounded terrible. We replaced the front door and back door speakers with Kicker 46CSC6934 6 x 9’s in the front door and 46CSC674 6 1/2‘s in the back door.

When we bought the speakers, the retailer only had two Toyota/Lexus wiring harnesses, which we used for the front speakers. Install fit, no mods. For the back speakers, we installed the 6.5 Kickers by cutting the wires and re-wiring and crimping them/using wire nuts since we didn’t have a harnesses. We also taped them after crimp nuts or screw nuts. We completed the install about a week or so ago.

This morning, the car started to warm up, ran a while and died. We took it to a dealer who said the battery is dying. To be clear, he didn’t mean the hybrid battery. He meant the traditional 12 V battery under the hood that helps with starting.

Is it possible that when we rewired the back speakers (or front with harnesses) we created some kind of slow drain? Could the speakers be drawing too much power and/or drawing while the car is off? Is it more likely that this is a coincidence?

Any perspective is much appreciated.


Team Lethal Pressure
5,000+ posts
10+ year member
Central FL
Nah. Just a coincidence.
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hispls Veteran
5,000+ posts
10+ year member
Central Maine
Is it possible that when we rewired the back speakers (or front with harnesses) we created some kind of slow drain?
No. Your factory head unit, if functioning correctly, will consume only a very tiny amount of power (to keep your radio presets and clock settings) when it is powered off.

I've had to replace batteries on used cars more often than not very shortly after buying them.

That said, it may well be worth having the alternator load tested. Dead or dying battery can put undue stress on your charging system and a malfunctioning alternator won't do your new battery any favors when you replace that.
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