12V battery problems 24 TrailHunter

[TacoFreak]

I'm the opposite...I don't think I'll ever buy a non-hybrid!

I agree! I said that I wouldn't buy a hybrid before I realized that some non-hybrid Toyotas have the same problem with charging their batteries. Some people think it might be related to improving Toyota's CAFE numbers. I love the hybrid drivetrain and since the charging problem exists for non-hybrids also, I would definitely get another hybrid.

My issue with the charging is that the problem is not just with short drives. No matter how much I drive my truck the 12V always settles to 12.1-12.2 volts resting state of charge. I can make a round trip of 200-300 miles and it will still be at 12.2 volts or lower. That is around 50% charged and will kill a battery that is not deep discharge capable. That level is 15 minutes after shutting the truck off, and then with all of the parasitic drains it will get low enough to not even turn on if it sits for very long.

I charge mine with a maintainer, so I know that the battery can be fully charged. If I do that for a few days every week it settles in at around 12.5 volts. A deep discharge battery should fix that problem, although my wife's battery electric SUV's 12 volt discharges to the point where the car won't even turn on unless I put it on my maintainer from time to time.

Since some trucks seem to keep their batteries charged to a higher level, so I think something is wrong with my truck. But the dealers just tune you out when you ask about battery charging and say buy a trickle charger. They should at least update their BS to tell us to buy a maintainer. lol

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[shackley]

I agree! I said that I wouldn't buy a hybrid before I realized that some non-hybrid Toyotas have the same problem with charging their batteries. Some people think it might be related to improving Toyota's CAFE numbers. I love the hybrid drivetrain and since the charging problem exists for non-hybrids also, I would definitely get another hybrid.

My issue with the charging is that the problem is not just with short drives. No matter how much I drive my truck the 12V always settles to 12.1-12.2 volts resting state of charge. I can make a round trip of 200-300 miles and it will still be at 12.2 volts or lower. That is around 50% charged and will kill a battery that is not deep discharge capable. That level is 15 minutes after shutting the truck off, and then with all of the parasitic drains it will get low enough to not even turn on if it sits for very long.

I charge mine with a maintainer, so I know that the battery can be fully charged. If I do that for a few days every week it settles in at around 12.5 volts. A deep discharge battery should fix that problem, although my wife's battery electric SUV's 12 volt discharges to the point where the car won't even turn on unless I put it on my maintainer from time to time.

Since some trucks seem to keep their batteries charged to a higher level, so I think something is wrong with my truck. But the dealers just tune you out when you ask about battery charging and say buy a trickle charger. They should at least update their BS to tell us to buy a maintainer. lol

My 2026 TH has an alternator, and so far (built December 2025) the battery is holding. Are most of the problems due to the earlier TH not having an alternator? I know this has been discussed, but I'm wondering. I plan on getting a deep discharge battery at about 1 years. I'm retired and don't always drive any distance much of the time, but use a maintainer. It sat for 9 days and the battery was at 12.3-12.4 when I got home, but had it on a maintainer when we left 9 days earlier.

 

[TacoFreak]

My 2026 TH has an alternator, and so far (built December 2025) the battery is holding. Are most of the problems due to the earlier TH not having an alternator? I know this has been discussed, but I'm wondering. I plan on getting a deep discharge battery at about 1 years. I'm retired and don't always drive any distance much of the time, but use a maintainer. It sat for 9 days and the battery was at 12.3-12.4 when I got home, but had it on a maintainer when we left 9 days earlier.

A lot of us assumed that they added the alternators to fix the charging problem, but a number of people complaining about charge levels have newer trucks with them. Toyota indicated that they added the alternator to support the 4th aux output. Some non-hybrids, which obviously have alternators have the same issues.

I have given up trying to figure it out partly because other than this I love my truck. So I put it on a maintainer on a regular basis, I will get a deep discharge battery when the OEM one dies, and I carry a jump pack so I can't get stranded. I obviously really like the truck or I wouldn't go through all of that rather than just sell it and move on.

 

[shackley]

A lot of us assumed that they added the alternators to fix the charging problem, but a number of people complaining about charge levels have newer trucks with them. Toyota indicated that they added the alternator to support the 4th aux output. Some non-hybrids, which obviously have alternators have the same issues.

I have given up trying to figure it out partly because other than this I love my truck. So I put it on a maintainer on a regular basis, I will get a deep discharge battery when the OEM one dies, and I carry a jump pack so I can't get stranded. I obviously really like the truck or I wouldn't go through all of that rather than just sell it and move on.

As I mentioned in another post, our 2023 RAV 4 Prime PHEV has the same problem.

 

[Porwal22]

As long as you have the room to install one, buy a battery disconnect post. They work great, and you never have to carry tools.

https://m.media-amazon.com/images/I/51JgRJK7oLL._AC_SL1200_.jpg

 

[shackley]

As long as you have the room to install one, buy a battery disconnect post. They work great, and you never have to carry tools.

https://m.media-amazon.com/images/I/51JgRJK7oLL._AC_SL1200_.jpg

Something useful when going away for a time.

 

[Porwal22]

Something useful when going away for a time.

Yes. I can’t see it where it’d be useful on a daily driver. If you were not driving your truck for two or more weeks, then it’s a good idea.

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