I suspect it’ll be a Toyota battery if they replace yours.
When mine fails I am looking at an Odyssey AGM deep cycle replacement.
Arggh! Issues with starting battery in winter - any solutions?
- Thread starter swampdog
- Start date
I suspect it’ll be a Toyota battery if they replace yours.
When mine fails I am looking at an Odyssey AGM deep cycle replacement.
Three ways that I know work......
Hook a jumper box to the under hood jump point and press the hatch button.
Hook a jumper box to the under hood jump point and press the glass hatch button and craw in through the glass opening.
Climb over the seats remove the rearmost storage tray cover and the tray (held on by plastic fasteners so ya gotta yank it). Remove the manual hatch mech trim panel (very difficult if you've never done it before) use the phillips screwdriver (one is include in your jack handle storage pouch) to loosen the screw that secures the white plastic guard and swing it out of the way, insert the screwdriver and manually trip the lock (almost impossible if you've never done it before). Once the hatch opens, immediately remove the screw fully and throw it and the white plastic guard in the trash.......lol Seriously, when it first happened to me, it was daunting trying to get it open, now having done it a few dozen times, not so much.
I have since installed a 12v trickle charger (semi-prem) and a 110v ext cord pass through, while I haven't had to use it yet, I assume in my case it'll be as easy as plugging in the trickle charger (if an outlet is available (at home). If I'm out in the boonies, I'll plug it into my power bank.
Take a look at this paper another LC owner posted about the charging system maybe being the problem - My battery failed after 16 months and I'm thinking this could be the problem with so many complaints about battery failure. Mine was so discharged that it froze when we had minus 30C weather and to make matters worse to get it towed the electronic brake wouldn't release because the battery was dead - so 3 tow trucks later got one with a dolly heavy enough to hold the LC and take it to the dealer.
docs.google.com
Toyota/Lexus 12v Battery Failures - Analysis of Charging Issues - Deep Dive Analysis & Workaround by /u/andy_why
Toyota/Lexus 12v Battery Failures - Analysis of Charging Issues - Deep Dive Analysis & Workaround Compiled by /u/andy_why First published: September 2025 Last updated: March 2026 Version: 2.0 This document may receive periodic updates for clarification and additional observations...
docs.google.com
WookieBait
Active member
Has anyone tried disconnecting the solution recommended in this document?Take a look at this paper another LC owner posted about the charging system maybe being the problem - My battery failed after 16 months and I'm thinking this could be the problem with so many complaints about battery failure. Mine was so discharged that it froze when we had minus 30C weather and to make matters worse to get it towed the electronic brake wouldn't release because the battery was dead - so 3 tow trucks later got one with a dolly heavy enough to hold the LC and take it to the dealer.
Toyota/Lexus 12v Battery Failures - Analysis of Charging Issues - Deep Dive Analysis & Workaround by /u/andy_why
Toyota/Lexus 12v Battery Failures - Analysis of Charging Issues - Deep Dive Analysis & Workaround Compiled by /u/andy_why First published: September 2025 Last updated: March 2026 Version: 2.0 This document may receive periodic updates for clarification and additional observations...
Started this morning with no issues. And it was way colder last night than the night before.
Could be a fluke?
Stopped by the dealership, they told me the ONLY way they'll do something about it is if next time it happens, I have to call roadside assistance and get it towed in... Turning a 5 minute jump into a potential 5 hour debacle. They said don't even let the tow truck driver jump it to get it on the truck. Didn't care that I have a video.
I guess I'll wait and see...
Could be a fluke?
Stopped by the dealership, they told me the ONLY way they'll do something about it is if next time it happens, I have to call roadside assistance and get it towed in... Turning a 5 minute jump into a potential 5 hour debacle. They said don't even let the tow truck driver jump it to get it on the truck. Didn't care that I have a video.
I guess I'll wait and see...
I just disconnected mine, I'll let you guys know if I have any ill effects, but for what it's worth I haven't had any battery problems yet either.
I've had that exact thing happen to me...... no start then 6 hours later started right up.
I have installed a digital voltmeter off the jack cradle, that's activated with a momentary switch. My routine when a have a "no start" is to see what the actual voltage in the battery by checking the voltmeter and if it's below 11v....... hook up the trickle charger or the jump box if I'm not at the house. If it's above 12v, I disconnect the neg battery cable for a few minutes for a hard reset and try again. Normally this cures all ailments.......LOL
I noticed that after this, my seat memory is gone, heads up display was turned off, and my android auto defaults to the phone for the "hey Google" detection.
Haven't taken the time to reset all the settings and reprogram everything, but it definitely puts a bad taste in my mouth with a new car.
Haven't taken the time to reset all the settings and reprogram everything, but it definitely puts a bad taste in my mouth with a new car.
Stranded again today. Parked for 4 days in the garage. No response whatsoever from the start button. Took about 6 attempts to jump via jump pack. It's like the first 5 tries get to partially power on the electronics, then it trips something, and then eventually after 5 tries and unplugging the jump pack in between each it starts.
Had to go directly to the battery.
Pulse charger did not work at all and was doing some trippy shit with the electronics inside, like everything was pulsing on and off.
Didn't want to call Toyota roadside as I didn't want to deal with the tow truck trying to yank it out of the garage.
I unplugged the voltage sensor on the battery and parked outside. We'll see what's it like tomorrow. I think I'm gonna get an optima instead of dealing with dealership as they're just gonna put another shitty lead acid in there and ain't nobody got time for that.
I wonder if Toyota will ever do a TSB to update the charging programming?
Video
Had to go directly to the battery.
Pulse charger did not work at all and was doing some trippy shit with the electronics inside, like everything was pulsing on and off.
Didn't want to call Toyota roadside as I didn't want to deal with the tow truck trying to yank it out of the garage.
I unplugged the voltage sensor on the battery and parked outside. We'll see what's it like tomorrow. I think I'm gonna get an optima instead of dealing with dealership as they're just gonna put another shitty lead acid in there and ain't nobody got time for that.
I wonder if Toyota will ever do a TSB to update the charging programming?
Video
Curious if anyone has tried the battery monitoring disconnect?
Im thinking about upgrading to an AMG battery and wondering if this work arround would alleviate the necessity to top it off periodically.....
I read the whole Google doc above, and this work-arround would keep the charging voltage at 14.1. I know a bit below what an AMG would prefer, but would appreciate everyone's opinion....
Thanks
Im thinking about upgrading to an AMG battery and wondering if this work arround would alleviate the necessity to top it off periodically.....
I read the whole Google doc above, and this work-arround would keep the charging voltage at 14.1. I know a bit below what an AMG would prefer, but would appreciate everyone's opinion....
Thanks
There is one way to find out- install an AGM and monitor how it is doing. If you go with a quality AGM deep cycle battery the pros outweigh the cons IMHO. You’ll see greater capacity, likely a marginally higher voltage, with the main benefit being no lasting damage if it does get discharged. Top it off, rinse & repeat.
Flooded lead acid starting batteries (and AGM starting batteries that are not deep cycle) become permanently degraded each and every time they become deeply discharged i.e. below 10V. If your pattern of use and load from extra accessories is likely to cause periodic deep discharges, then it makes sense to use an AGM deep cycle.
Some screen shots from a voltage check just now (Carista, OEM battery):
^^ voltage shown top left in “Ready” mode
^^ voltage in accessory mode showing slight discharge
^^ voltage shown when back in ready mode
A digital multimeter set to read DC voltage with probes on battery terminals or on jumper terminal and ground under the hood would show you what voltages you see under various conditions. Easy enough to check with a DMM or an app.
If you want to drop in a battery and let nature take its course without monitoring or maintaining its state of charge and your use isn’t going to discharge it much, maybe stay away from a really expensive deep cycle AGM and just go with an upgraded battery- AGM or flooded lead acid with a good warranty. If you need more from a battery and want the ability to bring it back with a charger after deep discharges without harming the battery then a really good AGM deep cycle would be perfect, but they live longest when you avoid partial state of charge conditions long term. That means monitoring regularly and topping off when needed.
I have wondered the exact same thing, but was waiting on some inmates to try this. It seems like it would work great, or at least better than OEM configuration..
Thank you for your thoughtful response....exactly the insight I was hoping for.
I don't plan to run any additional accessories off the battery (so far, prob change in the future).
I do go places where I reallllly dont want to have a dead battery, but it's never life or death and I always have a Noco. Not sure if I really need a AMG battery. I just believe in buy once cry once.....
Curious everyone's thoughts on whether I'd still have top off w the 14.1 charge or that'd be a healthy setup for AMG ...
I unplugged
I disconnected mine after I finally got it started and drove it like that for 2 days now. I'll update this thread if I have another no start event.
I've now got the Odyssey battery in, I have the voltage sensor disconnected from the negative, I'm using an Optimate smart charger now and then, yesterday I drove 160 mi and last night I hooked up the Optimate and it showed that the battery was not fully charged, it only tells you whether it's fully charged, partially charged or near-dead under charged... But apparently driving 160 mi with the voltage sensor disconnected so that it would get the maximum 14.1v charge, still wasn't enough to keep the battery topped off. So it sounds like topping off from time to time with a trickle charger might be necessary in general. As for swapping the battery itself, what a massive pain, the biggest challenge was the small nut behind the battery, once I finally got that off I ended up losing it behind the battery, it fell deep and I could not find it. Luckily I don't have a rattle from that, but I replaced it with a wing nut, raised a little higher with a plastic bushing. The wing nut will be easier to get on and off by... hand no tools needed in that cramped area, and using nylon twine, I put a slip knot around one of the wings on the wing nut and had about a foot or two of slack and then tied it to something so I can never lose that nut down the same chasm. Lastly I put another wing nut on the negative terminal in place of the OEM nut, that way if I ever need to disconnect the negative, I can do it by hand with no tools needed. I believe the wing nuts were M8-1.25.
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I did that a good while ago. Ended up having to buy a Milwaulkee bore scope to find the nut. In order to retrieve the nut, I taped a rare earth magnet onto the end of the borescope and advance it down to the lost nut.
I couldn’t jsut leave it behind. It was an expensive mistake..
A tight loop of tape, sticky side out, on the end of a folded coat hanger works well for retrieving lost fasteners..........
I tried multiple hacks like that, for 2+ hours. Nothing worked, since I had NO idea where the nut was. The fiber optic bore scope enabled me to locate it, in a crevice that I hadn’t suspected, and easily retrieve it.
A day later I dropped a plastic fastener from the underside of the hood, and it fell somewhere down into a hidden and unknown crack or crevice of Miss Daisy’s engine. I tried and tried to locate the fastener but couldn’t. I didn’t want it melting somewhere and stinking up the cabin air. Again the borescope enabled me to find it. I still couldn’t retrieve it, with any tool that I had. Your method may have worked for that, but I used compressed air to make it fly out of the hole which swallowed it.
Luckily I got the borescope on sale at Home Despot, and free delivery to boot! I’ll prolly never find a use for it again.
For sure, borescopes are the way to locate a dropped item! I use my scope all the time, mostly for determining if I could route a wire behind/under something.......LOLI tried multiple hacks like that, for 2+ hours. Nothing worked, since I had NO idea where the nut was. The fiber optic bore scope enabled me to locate it, in a crevice that I hadn’t suspected, and easily retrieve it.
A day later I dropped a plastic fastener from the underside of the hood, and it fell somewhere down into a hidden and unknown crack or crevice of Miss Daisy’s engine. I tried and tried to locate the fastener but couldn’t. I didn’t want it melting somewhere and stinking up the cabin air. Again the borescope enabled me to find it. I still couldn’t retrieve it, with any tool that I had. Your method may have worked for that, but I used compressed air to make it fly out of the hole which swallowed it.
Luckily I got the borescope on sale at Home Despot, and free delivery to boot! I’ll prolly never find a use for it again.
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