Do Not Sell My Personal Information Jump to content


Help about hybrid battery after jump start


Recommended Posts

Hi everyone. Im in the UK (just outside of Manchester) and I need a bit of advice please. I’ve put a deposit down on a used LC 300h, 2016 registration and it’s down circa 30k miles. 

As part of the deal I insisted the car pass a Hybrid health check at Lexus. On Friday, the day befoee I was scheduled to pick up the car I got a call from the independent dealer who’s selling the car, and they were at the Lexus dealer where the health check had just been carried out. It had failed, because the car was sat on their forecourt for 3 months, and they had jump started it a few weeks ago, and apparently the hybrid Battery wasn’t charged enough. The Lexus garage said that the remedy was to drive to the car for 500 miles and then repeat the hybrid health check in 2 weeks. 

So the independent dealer now has the car and is going to drive it over the next two weeks to get to the 500 mile requirement and has booked the re-test for 2 weeks time.

What I’d like to know is that has anyone been in this position where they’ve jump started a hybrid and has it caused any issues with the hybrid Battery? Does driving it 500 miles really remedy it, or is the Battery now damaged/not at its best in any kind of way, due to leaving the car not driven for 3 months and jump starting it?

You words of wisdom are appreciated. 

Sorry for the long post and thanks in advance :)

Link to comment
Share on other sites

It's nothing to worry about Zuby, and it's nothing to do with jump starting it either.

It's simply how the hybrid system works. Having been stood for so long the traction Battery wouldn't be flat but all the measurable parameters will have lost their settings and such like. The 500 miles is needed to reset and recalibrate the system and to let the Battery cells balance and normalize as they should. If the dealer was to carry out the health check now, the readings would be meaningless.

  • Like 1
Link to comment
Share on other sites

1 hour ago, zubysan said:

Thanks for the comment Herbie. So the next two weeks is all about recalibration? Thank goodness as I thought the battery may have been impacted some way 

Yes, that's right.

You'll find that the 12V Battery will quickly lose its charge if the car isn't used regularly because they're small and only have a low capacity, but the high voltage traction Battery is very robust with many of them going to 250 or 300,000 miles and beyond.

Link to comment
Share on other sites

Herbie's right, nothing unsuaal and nothing to worry about. Mine failed a hybrid health check after the 12v Battery was replaced and so they asked me to come back for a re-test after 500 miles,  where it passed with flying colours.

Link to comment
Share on other sites

Exactly the same experience as Bill. I left my ignition on for many hours and flattened the 12 volt Battery. I charged the 12 volt and a few days later at service time it failed its hybrid Battery check. Drove the obligatory 500 miles, re-tested, and it passed. Its carried on "passing" ever since, and simply because the ignition doesn't get left on nowadays!

Link to comment
Share on other sites


18 hours ago, zubysan said:

Hi everyone. Im in the UK (just outside of Manchester) and I need a bit of advice please. I’ve put a deposit down on a used LC 300h, 2016 registration and it’s down circa 30k miles. 

As part of the deal I insisted the car pass a Hybrid health check at Lexus. On Friday, the day befoee I was scheduled to pick up the car I got a call from the independent dealer who’s selling the car, and they were at the Lexus dealer where the health check had just been carried out. It had failed, because the car was sat on their forecourt for 3 months, and they had jump started it a few weeks ago, and apparently the hybrid battery wasn’t charged enough. The Lexus garage said that the remedy was to drive to the car for 500 miles and then repeat the hybrid health check in 2 weeks. 

So the independent dealer now has the car and is going to drive it over the next two weeks to get to the 500 mile requirement and has booked the re-test for 2 weeks time.

What I’d like to know is that has anyone been in this position where they’ve jump started a hybrid and has it caused any issues with the hybrid battery? Does driving it 500 miles really remedy it, or is the battery now damaged/not at its best in any kind of way, due to leaving the car not driven for 3 months and jump starting it?

You words of wisdom are appreciated. 

Sorry for the long post and thanks in advance 🙂

Hi Zuby.. When the car Had the Hybrid Battery checked and it failed..WHAT DID The Lexus dealership say as to the reason why it had failed. ( you did not mention the reason it had failed the test ) Was It Perhaps Faulty cells or corrosion in the main leads connecting The power to the car etc.. Perhaps the cooling fans on either side of the hybrid Battery needed a good clean or replaced..You Need to check this..!! Also i suspect the 12v Battery has been replaced And that would also indicate why you are having problems with the hybrid Battery..There is a strong possibility that the car has been sitting idle a lot longer than 3 Mths for these problems to arise.. I Personally think jump starting a lexus can in some cases cause problems with The dynamics of the electrical system and thats why a have a Noco gb40 booster that connects on the special link in the fuse box  Engine compartment and is a lot safer...Would be a good idea to book a full service at your local lexus dealership and let them FULLY evaluate the car assuming you still want to buy it..

Link to comment
Share on other sites

1 hour ago, RONNIE W HODGEKINSON said:

There is a strong possibility that the car has been sitting idle a lot longer than 3 Mths for these problems to arise.. I Personally think jump starting a lexus can in some cases cause problems with The dynamics of the electrical system and thats why a have a Noco gb40 booster that connects on the special link in the fuse box  Engine compartment and is a lot safer...

With the greatest of respect Ronnie, I think your post may be filling Zuby with apprehension when there really is no reason to worry and you also seem to be a bit confused about how jump starting works.

First of all, you may be correct in that the car may have stood for more than 3 months, but it doesn't matter because the 12V Battery would be flat well before then anyway, thus necessitating the 500 mile recalibration for the hybrid health check no matter what.

Secondly, you talk about jump starting a Lexus and how it may cause problems and that's why you have a Noco GB40 that connects to the dedicated jump start terminal in the engine bay fuse box.

Well, (a) jump starting a Lexus is perfectly fine, doesn't cause any problems, and is just like jump starting any other car; and (b) a Noco GB40 is a jump start Battery pack. Whether you use that or a traditional set of jump leads with another car as the donor power source, the process is still jump starting; and (c) whether you use the dedicated terminal in the engine bay fuse box or connect directly to the Battery it doesn't matter; 12V is 12V no matter where it's coming from. When jump starting all you're doing is piggy-backing one good 12V source onto a bad 12V source.

No offence meant Ronnie, just felt I should post this for clarification.

  • Like 2
Link to comment
Share on other sites

1 hour ago, RONNIE W HODGEKINSON said:

WHAT DID The Lexus dealership say as to the reason why it had failed. ( you did not mention the reason it had failed the test )

 

20 hours ago, zubysan said:

It had failed, because the car was sat on their forecourt for 3 months, and they had jump started it a few weeks ago, and apparently the hybrid battery wasn’t charged enough.

Quite possibly didn't do (or complete) the test once they saw the traction Battery charge level, it takes a significant time to complete the test

  • Like 2
Link to comment
Share on other sites

15 hours ago, Herbie said:

With the greatest of respect Ronnie, I think your post may be filling Zuby with apprehension when there really is no reason to worry and you also seem to be a bit confused about how jump starting works.

First of all, you may be correct in that the car may have stood for more than 3 months, but it doesn't matter because the 12V battery would be flat well before then anyway, thus necessitating the 500 mile recalibration for the hybrid health check no matter what.

Secondly, you talk about jump starting a Lexus and how it may cause problems and that's why you have a Noco GB40 that connects to the dedicated jump start terminal in the engine bay fuse box.

Well, (a) jump starting a Lexus is perfectly fine, doesn't cause any problems, and is just like jump starting any other car; and (b) a Noco GB40 is a jump start battery pack. Whether you use that or a traditional set of jump leads with another car as the donor power source, the process is still jump starting; and (c) whether you use the dedicated terminal in the engine bay fuse box or connect directly to the battery it doesn't matter; 12V is 12V no matter where it's coming from. When jump starting all you're doing is piggy-backing one good 12V source onto a bad 12V source.

No offence meant Ronnie, just felt I should post this for clarification.

No Offence Taken Herb.. And Thanks for Clarifying The points you Raised..I should have given it a bit more Scientific Thought..Reason I suggested that was my Good friend who has a Volkswagon Jetta Had a problem with the Battery and got a jump start from another colleague.. Whatever happened The jump start had adversely affected some of the components in the fuse box..hence the reason i thought is safer to use the Noco  boost in that event... But Thanks again for that information...

  • Like 2
Link to comment
Share on other sites

I know that some vehicles (Jag XJ for example) have Battery monitoring software that doesn’t like it if you connect direct to the Battery terminals, bypassing the software. For that reason, they insist you connect to specific connection points rather than directly to the Battery

I don’t know if your friend’s Jetta had a similar system which caused it to fritz but the RC is much more straightforward. What Herbie says makes perfect sense and I don’t think the OP has anything to worry about.  

On a different but related note. I’ve been paranoid about Battery life since a BMW X5 let me down in Manchester some years ago so I plug mine into a Battery conditioner overnight when I put it in the garage.

  • Like 1
Link to comment
Share on other sites

I too am paranoid (although in practice without cause to be) and so keep a small jump start pack in the car.

I should add that whilst it's fine to jump start a hybrid from another car, or Battery pack, it's not recommended to jump start other cars from a hybrid. I assume it's because the 12v Battery is only really large enough to fire up the electrics and not for cranking an engine.

  • Like 1
Link to comment
Share on other sites


Thanks for all your replies and wisdom guys; it’s really appreciated. I’m holding all goes well a week on Friday when the car goes for a retest. I’ll keep you kind people all posted for sure.

  • Like 3
Link to comment
Share on other sites

On 5/1/2023 at 6:01 PM, Herbie said:

With the greatest of respect Ronnie, I think your post may be filling Zuby with apprehension when there really is no reason to worry and you also seem to be a bit confused about how jump starting works.

First of all, you may be correct in that the car may have stood for more than 3 months, but it doesn't matter because the 12V battery would be flat well before then anyway, thus necessitating the 500 mile recalibration for the hybrid health check no matter what.

Secondly, you talk about jump starting a Lexus and how it may cause problems and that's why you have a Noco GB40 that connects to the dedicated jump start terminal in the engine bay fuse box.

Well, (a) jump starting a Lexus is perfectly fine, doesn't cause any problems, and is just like jump starting any other car; and (b) a Noco GB40 is a jump start battery pack. Whether you use that or a traditional set of jump leads with another car as the donor power source, the process is still jump starting; and (c) whether you use the dedicated terminal in the engine bay fuse box or connect directly to the battery it doesn't matter; 12V is 12V no matter where it's coming from. When jump starting all you're doing is piggy-backing one good 12V source onto a bad 12V source.

No offence meant Ronnie, just felt I should post this for clarification.

Erudite, lucid and informative.

As ever, Herbie.

  • Like 2
Link to comment
Share on other sites

Latest Deals

Lexus Official Store for genuine Lexus parts & accessories

Disclaimer: As the club is an eBay Partner, The club may be compensated if you make a purchase via eBay links

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share






Lexus Owners Club Powered by Invision Community


eBay Disclosure: As the club is an eBay Partner, the club may earn commision if you make a purchase via the clubs eBay links.

DISCLAIMER: Lexusownersclub.co.uk is an independent Lexus forum for owners of Lexus vehicles. The club is not part of Lexus UK nor affiliated with or endorsed by Lexus UK in any way. The material contained in the forums is submitted by the general public and is NOT endorsed by Lexus Owners Club, ACI LTD, Lexus UK or Toyota Motor Corporation. The official Lexus website can be found at http://www.lexus.co.uk
×
  • Create New...