Dead Battery

Paul-B · March 13, 2021

I have a 2014 IS300H which rarely leaves the driveway lately as I am working from home and we're still in lockdown.

As a result the Battery goes flat after about 2 or 3 days when it's not in use.

What is my best option?

Could I buy this 12v charger from amazon and disconnect the Battery to recharge it or should I buy a new Battery?

Cheers

https://www.amazon.co.uk/dp/B07T6GV32V/ref=cm_sw_r_cp_apa_fabc_BAVWC7JBXH242TGEX148

m4rkw · March 13, 2021

It should last more than 2-3 days, Halfords will test the Battery for free for you.

wharfhouse · March 13, 2021

1 hour ago, Paul-B said:

I have a 2014 IS300H which rarely leaves the driveway lately as I am working from home and we're still in lockdown.

As a result the battery goes flat after about 2 or 3 days when it's not in use.

What is my best option?

Could I buy this 12v charger from Amazon and disconnect the battery to recharge it or should I buy a new battery?

Cheers

https://www.amazon.co.uk/dp/B07T6GV32V/ref=cm_sw_r_cp_apa_fabc_BAVWC7JBXH242TGEX148

It either a) needs the Battery properly charging and then kept charged as per Lexus / Toyota instructions of running the car for an hour a week or b) a new Battery and then maintaining it properly or c) you have a parasitic drain (but this is probably the leat likely).

See: https://blog.lexus.co.uk/lexus-hybrid-parked/?utm_source=LexusOwnersClubUK&utm_medium=ForumLinks

Herbie · March 13, 2021

3 hours ago, Paul-B said:

I have a 2014 IS300H which rarely leaves the driveway lately as I am working from home and we're still in lockdown.

As a result the battery goes flat after about 2 or 3 days when it's not in use.

That makes it sound like it's happened more than once, so how many times has it been flat and how long have you left it flat for? Each time it goes completely flat it'll lose a bit of its capacity so it won't reach full charge when you do charge it.

If it's the original Battery it could be 6 or 7 years old so it may well be worth just cutting your losses and buying a new Battery now and then keep it charged as per the link that Phil provided above.

If you have a multimeter then the chart below shows Battery 'standing' charge at the Battery terminals. If you then bring the car up to READY and test again, you should see somewhere in the region of 14.2-14.5V.

Paul-B · March 14, 2021

Thanks for the replies.

I think a new Battery is probably the best way to go but I seem to have a problem finding one for my car.

My car details are below so when I add in my registration on a number of websites including Halfords it states there are no batteries available for my car. But if I change the engine capacity rating to 2494 there ate lots of batteries available.

Am I to assume its OK to use batteries for the 2494 cc model?

Make & Model - LEXUS IS 300H

Description - 300 H SE 4DR AUTO 2.5

Engine Capacity - 2493

wharfhouse · March 14, 2021

10 minutes ago, Paul-B said:

Thanks for the replies.

I think a new battery is probably the best way to go but I seem to have a problem finding one for my car.

My car details are below so when I add in my registration on a number of websites including Halfords it states there are no batteries available for my car. But if I change the engine capacity rating to 2494 there ate lots of batteries available.

Am I to assume its OK to use batteries for the 2494 cc model?

Make & Model - LEXUS IS 300H

Description - 300 H SE 4DR AUTO 2.5

Engine Capacity - 2493

This is the Lexus Battery - on back order here but your local Lexus dealer may be able to get you one: https://lexuspartsdirect.co.uk/parts/lexus-is/lexus-is-phase-iii-2013-present/lexus-is-3-engine-service-kits/lexus-is-phase-3-12v-starter-battery/

Thackeray · March 14, 2021

If your car is from 2014, you might be affected by the issue described in the following thread. If you are, the best option may be to get a dealer to change the Battery to avoid any problems.

https://www.lexusownersclub.co.uk/forum/topic/126933-screen-black-after-battery-change/#comments

royoftherovers · March 14, 2021

16 hours ago, Paul-B said:

I have a 2014 IS300H which rarely leaves the driveway lately as I am working from home and we're still in lockdown.

As a result the battery goes flat after about 2 or 3 days when it's not in use.

What is my best option?

Could I buy this 12v charger from Amazon and disconnect the battery to recharge it or should I buy a new battery?

Cheers

https://www.amazon.co.uk/dp/B07T6GV32V/ref=cm_sw_r_cp_apa_fabc_BAVWC7JBXH242TGEX148

Paul, The best option is to follow the free advice contained in the Owners Manual/Handbook.

The next best is to buy one of these and keep it handy https://www.amazon.co.uk/NOCO-GB20-UltraSafe-Lithium-Gasoline/dp/B015TKPT1A/ref=sr_1_11?crid=20470Z3DEZDF2&dchild=1&keywords=car+jump+starter&qid=1615716654&sprefix=car+jump%2Caps%2C201&sr=8-11

Brechin Slate · March 15, 2021

Whilst waiting for your new Battery it's worth knowing (if you don't already) that your car doesn't need a big Battery to jump start from. I discovered that my car starts just fine when jumped from my 12v lead acid golf cart Battery. It just needs enough power to wake everything up, no cranking amps needed.

Paul-B · March 15, 2021

5 hours ago, Brechin Slate said:

Whilst waiting for your new battery it's worth knowing (if you don't already) that your car doesn't need a big battery to jump start from. I discovered that my car starts just fine when jumped from my 12v lead acid golf cart battery. It just needs enough power to wake everything up, no cranking amps needed.

Yeah I jumped it yesterday off my partners car and started straight away. I don't a few km in it to give the Battery a chanrge and plan to start it every day until normal life resumes.

paulrnx · March 16, 2021

On 3/15/2021 at 11:10 AM, Paul-B said:

Yeah I jumped it yesterday off my partners car and started straight away. I don't a few km in it to give the battery a chanrge and plan to start it every day until normal life resumes.

I’d recommend more than a few km to charge the Battery if you can

Thackeray · March 17, 2021

On 3/15/2021 at 11:10 AM, Paul-B said:

Yeah I jumped it yesterday off my partners car and started straight away. I don't a few km in it to give the battery a chanrge and plan to start it every day until normal life resumes.

Unlike a conventional car with an alternator, driving the car makes no difference to the rate of charge of the 12v Battery. As long as the car is in the Ready state, there's a feed of around 14.5v to the 12v Battery from the high voltage Battery whether the engine is running or not. If you don't feel like going for a drive, it will use less petrol just keeping the car stationary. The engine will start from time to time when the high voltage Battery needs topping up.

Paul-B · March 17, 2021

11 minutes ago, Thackeray said:

Unlike a conventional car with an alternator, driving the car makes no difference to the rate of charge of the 12v battery. As long as the car is in the Ready state, there's a feed of around 14.5v to the 12v battery from the high voltage battery whether the engine is running or not. If you don't feel like going for a drive, it will use less petrol just keeping the car stationary. The engine will start from time to time when the high voltage battery needs topping up.

Great information, thanks!

Brechin Slate · March 17, 2021

2 minutes ago, Paul-B said:

Great information, thanks!

Also makes sense not to have anything drawing power if you do the stationary charge

matt8 · June 8, 2023

On 3/13/2021 at 9:24 PM, Herbie said:

That makes it sound like it's happened more than once, so how many times has it been flat and how long have you left it flat for? Each time it goes completely flat it'll lose a bit of its capacity so it won't reach full charge when you do charge it.

If it's the original battery it could be 6 or 7 years old so it may well be worth just cutting your losses and buying a new battery now and then keep it charged as per the link that Phil provided above.

If you have a multimeter then the chart below shows battery 'standing' charge at the battery terminals. If you then bring the car up to READY and test again, you should see somewhere in the region of 14.2-14.5V.

After a couple of weeks of being away, car sat still and not started, I’ve come back to a Battery (which I fully trickled charged before leaving it for the 16 days), down to 11.81 volts. That’s about 30% in the AGM chart.

What is everyone’s verdict? Is it a dying Battery? I replaced it in Jun 2020 and fully trickle charged it every 6-8 weeks.

NemesisUK · June 8, 2023

Did the car start on your return?

Herbie · June 8, 2023

Well, first of all, as Peter asks above - did it start the car?

Secondly, you seem to be a bit confused about what a trickle charger is and how to use it.

A standard Battery charger can output up to about 5A as an example. You use it when you have a flat Battery and want to charge it up, and once charged you disconnect it and put it away.

A trickle charger usually outputs less than 1A and it's connected to the Battery when you know it will be stood for a long time. Some people call them a Battery maintainer because it keeps, or maintains, the charge in the Battery. There is always some current draw from the Battery and the trickle charger is used both to supply that and also provide more, so that the net effect is that the Battery doesn't discharge. Trickle chargers are both expected to be used, and are designed for, 24/7 continuous connection to the Battery when you know it won't be used for a good while.

matt8 · June 8, 2023

Thanks chaps.

I didn’t even start it, just put it straight back onto the trickle charger. Perhaps that was my mistake.

I have the CTEK MXS 5. I can’t leave it permanently connected as the car is not garaged. Otherwise I’d have left it on for the weeks away. However, it has different stages and applies a higher amperage during the bulk phase (5A as noted, @Herbie), but applies lower voltages at varying currents, as the Battery reaches full charge. I put it on to charge every so often just to fill it back up, allowing the charger to run its program.

This Battery, despite a low voltage today, has not failed me so far in the 3 years since I fitted it. It’s an AGM from Lexus Parts Direct so is “official” if that’s a fair term. It’s rarely left untouched for such a long time like it has been. I am wondering if seeing a drop so low (supposedly 30%) after a couple of weeks is deemed normal. Or am I likely to need a replacement soon.

Thanks for your responses.

ColinBarber · June 8, 2023

2 hours ago, matt8 said:

I put it on to charge every so often just to fill it back up, allowing the charger to run its program.

What is every so often? Every few days, every week, every two weeks?

I would have expected a slightly better charge level after 16 days. The next time it is left so long it will probably be even worse and does indicate some of its original capacity has been lost, but for normal daily use the Battery will probably last a few more years without issue.

matt8 · June 8, 2023

2 hours ago, ColinBarber said:

What is every so often? Every few days, every week, every two weeks?

I would have expected a slightly better charge level after 16 days. The next time it is left so long it will probably be even worse and does indicate some of its original capacity has been lost, but for normal daily use the battery will probably last a few more years without issue.

Thank you.

Every 6-8 weeks is my routine for trickle charging up to full.

ColinBarber · June 9, 2023

9 hours ago, matt8 said:

Thank you.

Every 6-8 weeks is my routine for trickle charging up to full.

If the car wasn't being used then that would be too long. By that time the Battery would have discharged too much, to the point where it would be causing small amounts of damaged to the Battery because they don't like being kept in a low discharge state. The damage manifests itself as a lowering of capacity which then becomes a vicious circle because it takes less and less time to cause further damage.

However, I assume you are actually using the vehicle? Is it being used frequently and for drives more than 15 minutes in duration?

matt8 · June 9, 2023

12 hours ago, ColinBarber said:

If the car wasn't being used then that would be too long. By that time the battery would have discharged too much, to the point where it would be causing small amounts of damaged to the battery because they don't like being kept in a low discharge state. The damage manifests itself as a lowering of capacity which then becomes a vicious circle because it takes less and less time to cause further damage.

However, I assume you are actually using the vehicle? Is it being used frequently and for drives more than 15 minutes in duration?

Thanks Colin. Yes, more than 15 minutes. Those 6-8 weeks is to charge it to a level where the car itself is not able to.

I do not drive long motorway journeys regularly but it is common for multiple 15 to 45 minute journeys three times a week at least. So indeed, it is not sat entirely unused for the 6-8 weeks.

I will keep an eye on it and report any failed starts here.