Prius dead battery - advice

[Artsy]

Hi All,

Got a question that is sort of electronic I guess.

My 2010 Prius has a dead 12v battery due to an internal light being left on by a passenger...

Can't even get central locking to work.

I've sourced a replacement battery from Toyota which is £140 or so which is ok.

My question is - is it worth getting the AA or similar to come and have a look at the existing battery and attempt to charge it outside the car or is it likely to have been killed off anyway?

Battery is probably old enough to warrant a fresh one it's just that everything was working fine before the incident so I'm thinking is the original 12v battery salvageable?

Edited by Artsy on Friday 31st May 10:41

[Ken_Code]

What do you want the AA to do? I’m assuming that as a very first step you charged the battery fully, would that be right?

[Artsy]

Unfortunately not - I don't have the equipment to do so.

The question is more along the lines of is it worth me getting the AA out to have a look at the battery or just get a new one on the basis that it would have to be changed anyway?

[Alickadoo]

Well, if you are a member of the AA and it is going to cost you nothing to call them out - what have you got to lose?

[Ken_Code]

Artsy said:

Unfortunately not - I don't have the equipment to do so.

The question is more along the lines of is it worth me getting the AA out to have a look at the battery or just get a new one on the basis that it would have to be changed anyway?

It’s not worth calling the AA, no.

A battery charger is £15 from Amazon. Buy one and charge the battery up.

[Master Of Puppets]

Or get a jump start from someone with leads or a booster pack, drive the car a few miles and see if it charges back up, you might
not need to spend anything.

Edited by Master Of Puppets on Friday 31st May 09:12

[Artsy]

I can't connect jump leads to a Prius - it's apparently very easy to damage the hybrid battery by doing so.

I'll have a look at battery chargers online and see how it goes.

Can I trust a £15 charger?

[Ken_Code]

Artsy said:

I can't connect jump leads to a Prius - it's apparently very easy to damage the hybrid battery by doing so.

I'll have a look at battery chargers online and see how it goes.

Can I trust a £15 charger?

I can’t really say what you can trust or not, that’s more down to you than to the equipments

The best I can do I suppose is to say how I view it.

I used to teach electronics at Imperial College. I use a £15 charger on my McLaren 650s when it’s completely dead.

[Artsy]

Ken_Code said:

I can’t really say what you can trust or not, that’s more down to you than to the equipments

The best I can do I suppose is to say how I view it.

I used to teach electronics at Imperial College. I use a £15 charger on my McLaren 650s when it’s completely dead.

I think I can risk it on a Prius then

Thanks!

[LordLoveLength]

Probably killed the battery. They don’t like being deep discharged, even if it did ‘recover’ it won’t have it’s original capacity and will let you down again in the near future.
If it was a relatively new battery it may be worth a try but an old one? Forget it!

[Master Of Puppets]

LordLoveLength said:

Probably killed the battery. They don’t like being deep discharged, even if it did ‘recover’ it won’t have it’s original capacity and will let you down again in the near future.
If it was a relatively new battery it may be worth a try but an old one? Forget it!

That isn't necessarily always the case though, I've seen it many times where a battery was discharged and recovered to run for years after,
older and newer ones.

Also jump started Prius before with no issues, video here showing how it's done.... https://www.youtube.com/watch?v=rtM8OsH_h4o

[dingg]

PRIUS DEAD BATTERY - ADVICE

Set fire to it.

[Artsy]

I should add I'm referring to the 12V battery.

I'll consider next steps about setting fire to it as I'm currently undecided.

[Ken_Code]

To add context to my above reply; my car battery shuts off when nearly dead, and an expensive charger which looks to see what it’s attached to will likely refuse to charge it when in this state.

A cheap charger just works.

Stick it on in the morning, leave it for four or five hours, and then see if it starts and runs OK.

If after a couple of weeks of normal use (as in driving it regularly) you notice that the battery is still struggling then change it.

[paintman]

Alickadoo said:

Well, if you are a member of the AA and it is going to cost you nothing to call them out - what have you got to lose?

^^^^^That.
If you don't know what you're doing, mess about with it & mess it all up then you might have an expensive problem.
If you are an AA (or other breakdown service) member get them to come & sort it out. Hopefully they will know what they're doing & save you all the bother.
Who knows, they might even fit the new battery for you.

[Ken_Code]

paintman said:

^^^^^That.
If you don't know what you're doing, mess about with it & mess it all up then you might have an expensive problem.
If you are an AA (or other breakdown service) member get them to come & sort it out. Hopefully they will know what they're doing & save you all the bother.
Who knows, they might even fit the new battery for you.

They won’t “sort it out” though. They will either offer a jump start or to charge quite a lot to fit a new battery.

[Artsy]

This is the thing.

I worried it would be a waste of time to ask them to unhook the battery for testing and as I'm reluctant to let them attempt a jump start they won't hang around to charge the battery after it's unhooked.

No idea what the charge would be for a battery as they wouldn't tell me on the phone so I'll attempt the DIY first and if it fails the new battery from Toyota.

All I have to do now is get in through the front door, unlock the rear door, remove child seats, fold rear seats, empty the boot through the back doors, lift the floor in the boot, unlock the boot from the inside and then eventually remove the battery.

Amazon charger on the way meant to arrive tonight.

And it looks like rain outside...

[Artsy]

Well...

Battery is out which was more fun than expected as the rear doors wouldn't open from the inside due to deadlocks.

So I emptied the boot from the front door before I could access the boot latch.

Battery is a large Yuasa so hopefully salvageable.

It says recommended charge rate is 3A but charger I've bought is 10A so not sure how this will pan out but from what I can see online it's ok. I hope sonat least.

[5s Alive]

Artsy said:

Well...

Battery is out which was more fun than expected as the rear doors wouldn't open from the inside due to deadlocks.

So I emptied the boot from the front door before I could access the boot latch.

Battery is a large Yuasa so hopefully salvageable.

It says recommended charge rate is 3A but charger I've bought is 10A so not sure how this will pan out but from what I can see online it's ok. I hope sonat least.

10a is fine when the battery is disconnected from the car but not recommended insitu. Note that Prius batteries are AGM and not wet acid and require a different charge setting to fully charge - slightly higher voltage.

Your charger might also have a lower current motorbike setting that can be safely be used while the battery is in the car.

[Artsy]

I've put it onto a repair cycle.

Stopped it earlier and the battery is up to 10v from the 6.4 it was showing earlier sonim hoping something is happening.


Battery is a HJ-S46B24R which is showing online as an AGM battery.


Will find out tomorrow when I reinstall it in the car.

Edited by Artsy on Friday 31st May 19:50