When the battery gets low

Hello

A couple of days ago I was parked in a field, and I had to charge something via USB. So I turned the ignition to ON, and left it like that.

I believe it turns off automatically after 15 minutes, so I restarted it at about 10 minutes, and left it on for less than another 15.

I turned it off and about an hour later when I came back: there was no power. Like - nothing, as if there was no battery connected.

I'm used to older cars which will at least glow some dim lights, and you can tell immediately that the battery is discharged.

So there must be some electronics that shut off power to the truck when the battery drops to a certain voltage. Does anyone know how that's implemented? I'd like to understand.

Thanks in advance.

p.s. It's nearly 4 years old now, which I guess is an average lifespan of a lead-acid battery. I'm going on a trip to Alaska in the summer, so I'm tempted to replace the battery in april even if it doesn't die on me again until then. Probably put in an AGM. Does that make sense or am I worrying too much about it?

 

Yeah, at 4 years I'd definitely replace it before your trip.

Have you checked the water levels? (I'm terrible about remembering to do maintenance on FLA batteries.)

 

Replace the battery, you did great getting 4 years from the factory unit.

Batteries work in Tundras until they dont. At best, you might get a couple slow starts as a warning but usually they just fail without warning.

Just replace it, cheap and easy and you wont have to worry about it again for another 3-4 years.

 

You will need a diode or top it off with a charger periodically if you go AGM.

 

I’ll echo everyone else.

Go have it load tested so you can know for sure.

 

You are fortunate to get 4 years out of an OEM Toyota battery. I would just replace it. My Tacomas gave me a slow start warning but Tundra battery had a bad cell at <2 years and dead dead. I replaced it with Auto Zone's best flooded cell battery 5 years ago in May and still strong. I put an AGM in boat because location makes it hard to access. It does not crank the big Mercury like the flooded cell battery did. I would stick with a good flooded cell in truck.

 

Thanks for the advice, I'll put in a new flooded battery.

But does anyone understand how the mechanism for cutting off the power works? Is that normal these days?

For example: if the power is cut at a certain battery voltage, that should mean that potentially I can add 0.1V to it by some means, and then easily crank the engine?

 

Dont make this too hard.
Replace the battery and if you feel like you need a "backup" just get a

$100 Noco GB40 1000A UltraSafe Car Battery Jump Starter, 12V Jump Starter Battery Pack, Battery Booster, Jump Box, Portable Charger and Jumper Cables for 6.0L Gasoline and 3.0L Diesel Engines

Noco GB40 jumpstarter and keep that in the truck. GB40 stays charged for several months before it need a recharge, so it will start the truck if you have a battery problem in the future.

 

I keep a jump starter in the truck for those kinds of situations. If the battery doesnt check out, just get a new one...four years was a good run. I like topping off my batteries once a month with a trickle charger. I just plug it in overnight and let it top it off. Seems like newer vehicles will keep the bare minimum voltage to help with mpg, so toping it off is a must for me on my 22