10/02, 17/02 and 19/02, car starts and drives fine, albeit passenger (left-hand) electric window is dead
21/02 - car unlocks from fob but power is immediately lost afterwards. No power when turning ignition.
22/02 - attempt to jumpstart using working battery from a different car, still no power.
I'm leaning towards it being an electrical or computer fault of some sort, has anyone had something like this happen before? Changing fuses alone would leave me nervous about leaving the car away from home in case there's an underlying fault that's causing them to blow.
Passenger window is likely to be accidental pressing of disable switch on r/h side of dash.
Power likely to be a poor earth. Get wd40 or similar & loosen earth connections & spray them.
Corrosion on battery posts?
Battery and terminals were changed last year.
What voltage does the battery show?
About 1.6V.
The transport plugs were removed from the battery when new.
Quote from: Paianni on February 23, 2026, 18:04About 1.6V.
The transport plugs were removed from the battery when new.
Typo? 12.6 ?
Quote from: Gaz mr-s on February 23, 2026, 18:08Typo? 12.6 ?
Nope, it was definitely around 1.6V.
Quote from: Paianni on February 23, 2026, 18:28Nope, it was definitely around 1.6V.
That battery is deep discharged and useless. Something left switched on?? The car probably won't start with that battery in place.
I don't know what warranty you had when you bought it, but one year is usually the maximum.
Quote from: Carolyn on February 23, 2026, 18:56That battery is deep discharged and useless. Something left switched on?? The car probably won't start with that battery in place.
I don't know what warranty you had when you bought it, but one year is usually the maximimum.
+1.
New battery (YBX5053) is on the way. Poor/no charging from bad terminals must have triggered sulfation last summer and it finally collapsed just now.
I had a similar problem recently where the battery would discharge over a short period of time (1 or 2 days if unused), even after installing a new battery.
I traced the problem to the car alarm. The Horn body holds 3 rechargeable batteries that no longer hold a charge and was constantly drawing power from the battery. Having removed the alarm batteries I no longer have problems with the main car battery.
Worth checking out ;)
As a side note, that would explain why the sounder is comparatively heavy for its size.
Yuasa battery on my 2 for more than the 5 year warranty that came with it.
Always disconnected when not using the car ( too often) and kept in a good state of charge.
Hopefully still going strong for the new owner.
@utterclarity Similarly a Yuasa on my diesel daily. Regularly used, but for more short trips than long these days. Charged when needed. I check it when a cold spell is forecast or unused for a while.
I suggest a battery is not unlike tyres, look after them by checking regularly and they last longer.
We regularity get 7 to 10 years out of a 12v battery in a couple vehicles that don't get driven a lot. The secret is we have battery maintenance chargers hooked up whenever that are sitting for more than a week. We use a small 750 mA Battery Tender charger on the MR2, but there are many good brands like NOCO.
Quote from: moredun on February 24, 2026, 05:56I had a similar problem recently where the battery would discharge over a short period of time (1 or 2 days if unused), even after installing a new battery.
I traced the problem to the car alarm. The Horn body holds 3 rechargeable batteries that no longer hold a charge and was constantly drawing power from the battery. Having removed the alarm batteries I no longer have problems with the main car battery.
Worth checking out ;)
Apologies if I'm hijacking this thread but this is interesting.
I take it you're referring to your MR2? Mine also has an alarm that drains the battery. Can you explain what you did in more detail please?