ALL POSTS - 12-volt battery replacement

[miimura]

Yes. The car has a larger than usual drain on the 12V when parked. This was evident from the start when cars would be dead sitting on dealer lots. This situation also caused many people to have a factory 12V battery that had a short life due to it being drained dead before even being sold.

Thanks for that. I'd only read about the many premature 12v battery failures, hadn't seen this before.

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I run the Odyssey 34R-PC1500T + the Group 34 height spacer to correct the fit. The combo is a bit over $300. I own three of them for some of our vehicles (RAV4 EV, Sienna, another Sienna), they seem OK so far. The oldest one is in the RAV4 EV, and will be three years old in August.

If you drive the car every day or leave it parked for max 2-3 consecutive days, you won't see the problem and the factory battery will last the normal 4-5 years for a starter battery. However, if you regularly leave it parked for a week at a time, the factory battery will only last 2-3 years. This is why people have been recommending deep cycle batteries and higher capacity batteries. I still can't figure out why Toyota put the smaller Group 35 battery in from the factory when the ICE variants like the V6 uses the 24F. Maybe they were stuck in the ICE thinking and the EV doesn't need the cranking amps of the 24F.

 

[chrisspy]

Search 'ev vampire drain' & this is a common issue - especially when either things malfunction or settings are chosen that take the normal vampire drain & cause it to be 3-5X.
There's vampire loads on the 12V & on the big battery. Most people complain about the big battery losing (1-3%) range per day. Personally I don't have an issue with a load that maintains big battery or other car features (proximity alert, temperature sweet spot). It's the 12V, just like in an ICE car, that may need to be jumped. The assumption (that there's so much electric capacity in the big battery that they must have designed the EV/PHEV to trickle charge the 12V) is wrong.
So, we have to know what normal vampire loads are & get alerted when they become excessive. Killawatt type meter on Level 1 charger should do this if reset after big battery is full.
Carrying a small paperback book sized jump battery would avoid waiting for AAA. Instead of buying new batteries for the snowblower & lawn tractor, I use it there & elsewhere. $40+ Amazon. Would this work on a dead 12V or just a weak one in the RAV4EV? Once the car's back, I can disconnect & see if mine can. The jump battery may need to sense some minimal voltage to work.
asavage, thanks for the measurements

 

[davewill]

If you drive the car every day or leave it parked for max 2-3 consecutive days, you won't see the problem and the factory battery will last the normal 4-5 years for a starter battery. However, if you regularly leave it parked for a week at a time, the factory battery will only last 2-3 years. This is why people have been recommending deep cycle batteries and higher capacity batteries. I still can't figure out why Toyota put the smaller Group 35 battery in from the factory when the ICE variants like the V6 uses the 24F. Maybe they were stuck in the ICE thinking and the EV doesn't need the cranking amps of the 24F.

I don't know why they didn't pay more attention to charging the 12v so this wouldn't happen. Then the smaller battery would have been just ducky. It's not rocket science, they just needed to fire up the DC-DC converter more often.

Anyway the best way to handle it if you know you're going to park it a while is to get an inexpensive battery maintainer.

 

[davewill]

If you drive the car every day or leave it parked for max 2-3 consecutive days, you won't see the problem and the factory battery will last the normal 4-5 years for a starter battery. However, if you regularly leave it parked for a week at a time, the factory battery will only last 2-3 years. This is why people have been recommending deep cycle batteries and higher capacity batteries. I still can't figure out why Toyota put the smaller Group 35 battery in from the factory when the ICE variants like the V6 uses the 24F. Maybe they were stuck in the ICE thinking and the EV doesn't need the cranking amps of the 24F.

Now I've done it. Between COVID and my wife's semi-retired work schedule, she has been letting it sit for 4-5 days at a time intermittently. A couple of days ago, the car wouldn't power up all the way and wouldn't go into gear when she tried to go to work. When I got home, The battery read 11.97v. I disconnected the battery, put it on the tender and let it charge for for several hours. It got up to 12.6, so I reconnected and the car gave the same symptoms. Plugging in the J1772, and trying to charge worked, and the charging system started putting out a higher voltage. I disconnected the J1772, and the car seemed happy to power up and go into gear. I left the tender on it that night, and the resting voltage made it up to 12.6v. She drove it to work that day.

So the upshot is that the new group 35 Interstate battery I put in in Dec 2019, is barely holding a charge, reading 12.1v shortly after being driven for a time. Replacing it is a given, but with what? I either need to replace it with something that will handle the new driving pattern, which isn't going to change, or I need to plug it into the tender every night. I don't mind spending some money on a solution, as long as it lasts and protects my RAV.

 

[miimura]

If you drive the car every day or leave it parked for max 2-3 consecutive days, you won't see the problem and the factory battery will last the normal 4-5 years for a starter battery. However, if you regularly leave it parked for a week at a time, the factory battery will only last 2-3 years. This is why people have been recommending deep cycle batteries and higher capacity batteries. I still can't figure out why Toyota put the smaller Group 35 battery in from the factory when the ICE variants like the V6 uses the 24F. Maybe they were stuck in the ICE thinking and the EV doesn't need the cranking amps of the 24F.

Now I've done it. Between COVID and my wife's semi-retired work schedule, she has been letting it sit for 4-5 days at a time intermittently. A couple of days ago, the car wouldn't power up all the way and wouldn't go into gear when she tried to go to work. When I got home, The battery read 11.97v. I disconnected the battery, put it on the tender and let it charge for for several hours. It got up to 12.6, so I reconnected and the car gave the same symptoms. Plugging in the J1772, and trying to charge worked, and the charging system started putting out a higher voltage. I disconnected the J1772, and the car seemed happy to power up and go into gear. I left the tender on it that night, and the resting voltage made it up to 12.6v. She drove it to work that day.

So the upshot is that the new group 35 Interstate battery I put in in Dec 2019, is barely holding a charge, reading 12.1v shortly after being driven for a time. Replacing it is a given, but with what? I either need to replace it with something that will handle the new driving pattern, which isn't going to change, or I need to plug it into the tender every night. I don't mind spending some money on a solution, as long as it lasts and protects my RAV.

If you don't have JdeMO or leave the car ON and READY for long periods of time in situations like camping, a Group 24F AGM will have the most reserve capacity for leaving the car parked for extended periods. The only downside is that if you leave the car on for many consecutive hours, the AGM battery can overheat due to the RAV4 EV's programmed float voltage. In that case, a larger traditional maintenance free flooded battery is the way to go. That is what I decided to do after my Bosch AGM overheated a couple times. I got the Group 24F Interstate battery from Costco.

The Group 24F is the size used in the RAV4 V6 and fits the battery tray perfectly.

 

[davewill]

If you don't have JdeMO or leave the car ON and READY for long periods of time in situations like camping, a Group 24F AGM will have the most reserve capacity for leaving the car parked for extended periods. The only downside is that if you leave the car on for many consecutive hours, the AGM battery can overheat due to the RAV4 EV's programmed float voltage. In that case, a larger traditional maintenance free flooded battery is the way to go. That is what I decided to do after my Bosch AGM overheated a couple times. I got the Group 24F Interstate battery from Costco.

The Group 24F is the size used in the RAV4 V6 and fits the battery tray perfectly.

Yeah, I do have JDemo. After reading back through the thread again, I decided to go with the Costco 24F, and try your earlier idea of running the Pre-climate on a schedule to make sure the DC-DC runs every day. Maybe I will scale that back to a few days a week, I don't know. I plan to keep an eye on the resting voltage for a while and see if the battery is being run down.

Another issue is that I schedule charging using my EVSE. However, I sometimes find the car running it's cooling pumps (BUZZZZ!) in the middle of the day when the timer is off. Can't be good for their longevity. I'd use the scheduling in the car instead, but I remember that it wasn't reliable (something about the end of some months?) and I can't afford to have my wife come out and find her car didn't charge when it was supposed to. Did that ever get fixed?

Edit: OK I did the research I should have done before. The 31st of the month bug is fixed, but people complain about the charge starting too early. I think I will try a combo of the car's charge schedule and the EVSE's and see if that reduces the pump running while keeping my charging starting within my TOU window. That's what I end up doing with my Model 3. The EVSE timer keeps the car from cycling my EVSE on and off (KLUNK!) every time I plug, unplug, or open a door, and the car's schedule makes sure the car wakes up to charge when the EVSE timer turns on.

 

[TonyWilliams]

12 volt battery issues remain the NUMBER ONE issue with owners of the RAV4 EV.

We are now an Interstate battery dealer, and have the GROUP 24F size 12 volt battery that we recommend in the AGM construction. We can ship these batteries to you, if you don't want to go hunting one down.

We recommend a maximum of 3 years on the battery, unless you are in an extreme hot location like Las Vegas or Phoenix (regularly over 104F / 40C temperatures for long periods at a time), where we recommend a maximum of 2 years. Also, if you are in extreme heat locations, we suggest a traditional lead acid battery over an AGM. Always use the Group 24F. AGM has a "deep cycle" quality that is desirable with any EV.

It is possible to install a Group 24DC lead acid deep cycle battery (usually used for RVs and motorhomes), but the terminals are reversed. That will take a bit of ingenuity to sort out, but it can be done (and I've done it). Those are really cheap (usually less than $100) and very well suited to the RAV4 EV. Again, don't get one of these unless you have the skill to put it in, or know somebody who does.

If you let the 12 volt battery go bad, it may require a trip to the Toyota dealer to clear the "CHECK EV" code from the car.

A good 12 volt is fully charged at 12.7 volts resting voltage. That means it wasn't being used AT ALL for at least 15-30 minutes, and preferably 2+ hours. Charging the "traction" battery also charges the 12 volt battery, so that would be "use". Obviously, any time the car is in READY, it is charging the 12 volt battery.

12.7 = 100% capactity
12.4 = 75% capacity (CHANGE THE BATTERY)
12.2 = 50% capacity (HOW DID YOU LET IT GET SO LOW???)

The original Toyota battery is really inadequate for the job.

Don't let the 12 volt battery be your nemesis!!!

 

[alflash]

12 volt battery issues remain the NUMBER ONE issue with owners of the RAV4 EV.
...

Note. Indeed, many problems of these vehicles are caused by the poor condition of the 12V battery.
Using this diagnostic mode allows you to check it (and not only) both in the ignition on mode and in the READY mode. That is, to determine "whether he is tired of living" how big this "fatigue" is.

https://youtu.be/QpiwFtov26Y

HTH,

 

[Lido]

Hello any RAV4 EV users. Just wanted to add a recent experience (to go with all the other posts here about the same subject) with a venting 12v battery in my 2014 Rav4 EV. I've had the car for two years with no trouble at all until last week when I stopped at a red light and noticed a really strong sulfur / rotten egg smell. The smell continued and didn't go away even when the car was off (though plugged in). A couple of web searches led me to think the likely cause was the 12v battery under the hood.

The 12v battery that came with my (used) Rav4 EV was an 84 month Toyota branded battery with a late 2017 sticker date on it. It technically should have lasted another couple of years, but it started venting with a nasty sulfur smell. I popped the caps on the battery and there was steam rising and no visible liquid in the battery left at all. I "topped off" the battery with distilled water once the car had cooled down. That was a mistake. When I plugged the car in to charge, the battery just kept venting, now with acidic water dripping from the battery into the tray. Long story short, I decided to replace the battery, which I should have done earlier - before I'd inhaled quite a bit of sulfuric acid vapor.

After reading some posts here I decided to follow one particular post's advice that said to get a cheap battery (I put a reminder in my phone to check it periodically). Then I followed a separate post's advice that suggested a 24F size battery instead of the 35 size because 1) it will fit and 2) it's bigger and might handle the stress better.

In short, if your Rav4 EV starts making a rotten egg sulfur smell, consider replacing the battery.