2011 RX450h 12V battery - a possible solution

[Walus]

I charged both batteries (the original Panasonic 51Ah, and Yuasa 65Ah) using CTEK charger. Starting off at 12.25V for both batteries the new Yuasa charged up to full around 25% quicker than the Panasonic - 6h vs 8h. 

[Barry14UK]

An old sulphated Battery V a new one?  In any event AGM batteries are designed to charge up more slowly and take an even slower charge as they they near full charge than standard flooded acid ones. The recommended maximum charge for a new Yuasa 9000 series AMG stop start 60Ah Battery is 4amps for example. Actually I have been looking into this Battery (YBX9027) and a couple of others with some small mods for my car but will only recommend if some other things are resolved and it is proved to work well with mine. https://cdn.tayna.com/datasheets/YBX9027_DATASHEET.pdf

Hope your solution serves you well.  Interested to learn how it performs in a couple of years time.    

[Walus]

Barry14UK, at the technology level AGM are supposed to have lower internal resistance and therefore charge faster than standard batteries of comparable Ah capacity. Of course, in my case the Panasonic 51Ah is 5 years old and one would expect ageing to have its effect, as it indeed does at this point. The new Battery that I fitted as an experiment also has 4A as a recommended charge current, and I will monitor how it performs in a regular use. 

The YBX9027 is a nice match when the electrical spec is concerned and I looked at it as well. However, it is a bit longer and lower in height, and needs a custom bracket to securely hold it in place, and I opted against it after all. The one I fitted is of the same case as the original (D23) and fits like a glove. 

also, one interesting thing is that with the car turned on and stationary the charge voltage from a dc-dc converter is 14.3V, but when the traction Battery is in use this drops about 0.5V, which in turn may suggest that the 12V Battery gets best recharged by the dc-dc converter when the vehicle is stationary with all the auxiliary stuff turned off. When my Battery died I jump started the car and took it for an hour drive, only to discover that the Battery did not charged up as much as I thought. Now, I understand why that is.

[Walus]

On 12/20/2020 at 11:07 PM, miti said:

where did you buy Yuasa YBX 5005 battery? Now I am tempted to cancel my tomorrow's slot for replacing the battery at the dealership!

miti, which battery did you go for at the end?

[Herbie]

2 hours ago, Walus said:

one interesting thing is that with the car turned on and stationary the charge voltage from a dc-dc converter is 14.3V, but when the traction battery is in use this drops about 0.5V, which in turn may suggest that the 12V battery gets best recharged by the dc-dc converter when the vehicle is stationary with all the auxiliary stuff turned off.

Not so interesting really as that's how it's supposed to work.

The DC/DC converter, just like an alternator in a conventional car, will supply all of the electrical demands once the car is running. If there's enough energy 'left over' so to speak, then it will also keep the 12V Battery charged up.

Whether conventional or hybrid, the 12V Battery is only used for starting then the alternator/converter takes over.

[Barry14UK]

36 minutes ago, Herbie said:

 

Whether conventional or hybrid, the 12V battery is only used for starting then the alternator/converter takes over.

What I found was that in auxiliary mode on my RX the radio cut out after about 15 mins so I assume you have to be in the 'Go' mode and have engine cut in to play radio or video screens for longer.  I appreciate need to protect Battery and maybe this is something that has to be with the Lexus system. (With my old BMW with large single Battery, before they changed the TV format, I could watch TV or listen to the radio for ages without running engine).

[Illogan]

7 minutes ago, Barry14UK said:

What I found was that in auxiliary mode on my RX the radio cut out after about 15 mins so I assume you have to be in the 'Go' mode and have engine cut in to play radio or video screens for longer.  <>

Aye Barry - - they are programmed to do that - just to avoid the 12v Battery losing too much charge

 

[Herbie]

1 hour ago, Barry14UK said:

What I found was that in auxiliary mode on my RX the radio cut out after about 15 mins so I assume you have to be in the 'Go' mode and have engine cut in to play radio or video screens for longer.

Yep, as Dave says above, whenever you're parked up with the radio or whatever on, always have the car in 'P' and READY mode so that the engine can fire up and stop the Battery from depleting too much.

[Barry14UK]

3 hours ago, Walus said:

 

The YBX9027 is a nice match when the electrical spec is concerned and I looked at it as well. However, it is a bit longer and lower in height, and needs a custom bracket to securely hold it in place, and I opted against it after all. The one I fitted is of the same case as the original (D23) and fits like a glove. 

 

As you rightly imply, the main problem stems from the inadequate length of the allocated space in the boot of the RX 450h to accommodate some larger capacity batteries.  Even the type 027 is a tight fit.  However, it is not as tall as the D23 so it could be raised.  This would not only enable the existing holding down retainer to be used albeit with another packer but would provide greater length as one side of the formed Battery space effectively increases in length as it is raised.  The positive terminal is not affected but a modification needs to be made to bring the negative back over the Battery to the present earthing point.  I have ordered a part to achieve this as I would like to keep this looking as near to original as possible.  It may be necessary to move the spare wheel over slightly along with its fixing point.

I plan to make a wooden buck to check out how this will work before going into more detail .  However, if it works it will have the following advantages:- 

- be an AGM Battery offering 60Ah with the anti vibration/safety and of similar type to existing.

- less expensive than the D23 original.

- readily available from many stockists so no need to have to be near a Lexus dealer for replacement when it fails.

I did find some alternative batteries in the USA but when you consider time lag and extra costs of importing these along with what is involved in returning for warranty replacement if needed, I think you have to rule these out and limit choice to what is available in the UK.

I will revert to this subject under the possible alternative 12v Battery thread I started previously, as this thread is about using a non AGM Battery.

 

[AnthonyW]

I replaced the 12v Battery on my RX450h in Dec 2016 with a Yuasa YBX9012.  I installed a rubber spacer across the top of the Battery cos it wasn't as high as the original for the bracket, otherwise a very easy fit and vented ok also.  No issues since after the original was quickly loosing its charge.  

[Barry14UK]

 At around £130 and an AGM Battery with almost identical Ah but not quite a deep cycle HEV (Hybrid Electric Vehicle Battery) like Panasonic. Anybody intent on this sort of Battery would do well to check if they could fit the same Yuasa version but in 027 size where it provides 60Ah.  GSF have it on offer for £113.98 inc VAT at present.  The spare wheel may need to be moved over slightly too. https://www.gsfcarparts.com/971na0320?auto_apply_coupon=SHOP60&gclid=CjwKCAiA_9r_BRBZEiwAHZ_v1xh1HPvZGsFx3dFtc3b_dvi5N8yGqh-tc0Ux4asfBilJ4g-_xd2qtxoCO_IQAvD_BwE   (Not been able to check with mine as it's back with repairers again and I am looking into another possibility also)

[MrChemist]

For a few pounds, I bought a Bluetooth transmitter that plugs into the OBDII connector, it will tell you the voltage of the 12V Battery.  You need the Torque app on your smartphone to see this.  It will tell you other things that you don't want to see when you're driving, like whether you're accelerating and the actual engine revs.

I had occasion to need it in April 2020; after suffering from Covid for a fortnight, I went to the car and found the Battery on 8V. It was clearly not charged much when the car was last run. The dealer has just checked it for me and found no excuse to take the arm, having already taken the usual leg for a service. (Like vultures, they can afford to wait for their meat, I have air suspension!)  It's still the original Battery, it's got code 09 on it.

[GSLV6]

I simply replaced mine with a leisure (deep cycle) Battery which from memory was about 60Amp Hours, for way less than the Panasonic.  It's lasted 2 years so far.  My original Panasonic died after 2 years from new.

[TouringRob]

Barry I think you are massively overthinking this. 

I would have absolutely no hesitation in fitting a wet Battery in place of the AGM in this particular application. The Battery doesn't have a hard life if you don't let it go flat (deep cycle), in fact it has the easiest life of all given that its being charged at a low rate and is never subjected to high current draw a normal stop/start car would be. 

Worried about Battery acid inside the car? Remember that until mid 2000's there were a great many cars with a Battery in the cabin (some with two!) without issue (BMW E36/E46 etc). This will be a change driven by legislation rather than being a practical requirement. 

There is nothing else to consider, the charge methodology used for and AGM type Battery is compatible with wet lead acid (not necessarily the other way round!). My 400 Battery is the original (12 years old now) and when it finally dies I will use a wet Yuasa, the 400 has gives the Battery a harder life as it is within the engine compartment.   

Yuasa is great choice, for good deals check out Tanya on eBay, I have bought several batteries from them recently all have arrived within a day and are superbly packaged/keenly priced. 

[GSLV6]

+1 to all of that (being a past E46 owner too!)

added to which most of the latest chargers work on a maximum 4A dropping to a fraction of that as they approach full charge.  In reality most Battery types will work but a deep cycle of any description will have a longer life...or so you'd like to think.  2 years from my Panasonics was pitiful!

[TouringRob]

Yes indeed, a deep cycle will be more tolerant to being left to go flat. If you never let the Battery go flat a deep cycle will have a similar life time to a good quality normal Battery I believe.... but seeing as these cars seem to like to flatten their batteries a deep cycle wasn't a bad decision at all. 

And agree with the 4A point, that is actually a fairly low figure compared to the capacity, its fine to charge either type at 4A. The Battery will self regulate as it reaches float voltage so you only need to current limit during the first part of the charge cycle. Where you can hurt batteries is if you allow them to draw an excessive amount of current when they are flat. 

Still miss the E46! 

Rob

[Barry14UK]

Of course safety and legislation plays an ever increasing part in the automotive industry.  I am sure some people would not wear seat belts were it not for legislation, (a small number, at least on some occasions, don't wear them even so).  There is not any legislation of which I am aware, that requires that when a Battery is within the cabin it should be an AGM or Gel type if that was fitted by the manufacturer.  So it is very much the choice of the owner/driver, whether s/he replaces the manufacturer's safer type Battery in these circumstances with a less safe one,  a decision that would doubtless be much regretted in retrospect if injury from spilled acid happened in an accident.  If you check with manufacturers, the Battery industry AA or RAC or anybody knowledgeable on the subject says you should replace a Battery with the more advanced type as fitted by the car make/model and for additional reasons other than safety too.  You can of course fit a larger capacity Battery of the same type.  Incidentally, I have a standard Battery in my E39 BMW which has optional fold down rear seats so lacks the extra protection of a fixed rear bulkhead and if I was keeping it I would check whether a safer Battery option was available.

As we know, the Battery compartment in the rear of some of our RX models is small and the AGM batteries have only small capacity which is inadequate in some situations.  Standard lead acid are cheaper and as available in more sizes can be had with greater Ah and still be accommodated within the Battery compartment.  However, it may be possible to fit a larger AGM HEV Battery by modifying the Battery compartment and I will investigate this when circumstances permit.  Over thinking this issue - I don't think so but in any event I would rather this be the case than under thinking it.  Suggest you watch this video by Professor Kelly if you have not yet done so and note the salient points as similar system on RX as Prius. 

     

[TouringRob]

Barry, I have indeed watched the video and several others by Proff Kelly, as an EE I do not find myself so in awe of him as you seem to be, he makes no comparison between a regular lead acid and agm for example, and only touches on some minor benefits of having an agm. 

Yuasa themselves state that the only benefit of AGM in a hybrid vehicle with charging systems such as ours is that an AGM is able to survive deep cycling better than a lead acid. My guess is that Toyota/Lexus were concerned about long term reliability of a regular wet Battery (sealed or not) - it is technically the better solution and I am not surprised that Toyota who are very mindful of long term reliability would choose the better technical solution. 

A good quality, appropriately vented wet Battery that the owner does not leave to go flat has zero disadvantages in this application. You are naturally free to do as you will but I just wanted to make that point clear for other future viewers who might feel obligated to spend £300 with Lexus on a Battery. 

PS. You should keep the E39! They are appreciating. 

[ColinBarber]

1 hour ago, TouringRob said:

My guess is that Toyota/Lexus were concerned about long term reliability of a regular wet battery (sealed or not) - it is technically the better solution and I am not surprised that Toyota who are very mindful of long term reliability would choose the better technical solution.

Did the 450h move to AGM because of better cycling capabilities, which does get tested on a small capacity Battery when owners go on holiday for two+ weeks, or because it moved into the boot? Toyota seem to state both a reasons.

The 400h never really had a problem of the Battery going flat as it had a relatively large Battery, so the fact it was wet wasn't an issue.

Like you I would probably put in a wet Battery. The new ES300h has a wet Battery in the boot (which isn't sealed from the cabin) so it seems Toyota don't think it is an issue now either.

[TouringRob]

3 hours ago, ColinBarber said:

Did the 450h move to AGM because of better cycling capabilities, which does get tested on a small capacity battery when owners go on holiday for two+ weeks, or because it moved into the boot? Toyota seem to state both a reasons.

The 400h never really had a problem of the battery going flat as it had a relatively large battery, so the fact it was wet wasn't an issue.

Like you I would probably put in a wet battery. The new ES300h has a wet battery in the boot (which isn't sealed from the cabin) so it seems Toyota don't think it is an issue now either.

I believe both. The AGM for in cabin seems to be a popular modern choice which is why I suspect it is legislated somehow, or possibly counts towards crash test safety ratings in some way. Was under the impression the 400 used AGM also, but have never looked and would not be amazed if it was wet given its in the engine bay which AGM doesn't typically like (heat). 

I haven't actually seen the Battery location for the 450 in person but do know that 10 years ago a wet Battery in the boot was the norm. Another consideration is that an overcharged Battery which is able to vent can become a fire/explosion risk, that may have counted towards their original decision, AGM on paper should be more reliable full stop (although owners say different). 

But lets face it, a leaking Battery after an accident would be the least of my concerns given how severe the impact would need to be! Battery is presumably under the floor/carpet, after looking over a terribly rear ended E36 touring some years ago which had the Battery about as exposed as you could get for that type of accident the Battery was cracked, all of the acid had leaked - none of it was in the cabin (beyond the Battery box). Id likely choose an AGM or gel Battery if the car was used offroad or on track lots due to vibration and the risk of turn over. 

I would trust a conventional lead acid in the boot of any car over say charging a Tesla in my garage which many seem very happy to do. Not trying to convince people either way but just wanted to put peoples minds at rest that replacing their original Battery with a cheaper standard alternative isn't going to damage their vehicle and in my opinion is very unlikely to represent any real world safety trade offs.... Put the money saved towards some good tyres! 

[TouringRob]

Interesting that the ES has a conventional Battery in the boot. I would love to know their rational for making choices like this but would imagine that Toyota who are fond of over-testing would have good reasons, while other manufacturers I am positive under-test which makes me doubt many of their engineering choices.

[GSLV6]

My current Battery is a conventional deep cycle wet Battery Rob. I saw little advantage in paying the extra for an AGM and equally little disadvantage to my current wet Battery.

 

[Barry14UK]

I am neither massively overthinking anything nor am I in awe of Professor John Kelly.  You are too too free with hyperbole Rob.  I do respect him as an official instructor though.  The point is he took the same view as Toyota, the Battery manufacturers, and everybody else of any standing that a replacement Battery should be the same type as the original Battery.  Even Scotty Kilmer explained the need for this in one of his many videos.  (Assume you will have found Scotty, a mechanic with over 50 years experience).

Every car I have had and sold has been up to the spec it came with or is better, eg, full upgraded lighting on my E39 to retrofitted genuine BMW Xenon lighting system, not just added  aftermarket HIDS.   I would not buy rubbish tyres either to save a few pounds as some do.  So I will stay with the original  AGM type Battery.   The Panasonic  costs nothing like £300 (more hyperbole) from Lexus Parts Direct but there are other potential options which I hope to explore as my Pan Battery needs smart charging every 8 or 9 days now if not used.

The chances of your having an accident in which you are injured by acid may well be small and you are happy to accept the risk, but how would you feel if somebody had been injured in this way following your advice to go for the cheaper flooded lead acid Battery?  Insurers may also have something to say in such an event too.

I don't know why the new ES300h apparently has a flooded lead acid Battery within the cabin, as apart from personal injury, AGM batteries with low internal resistance were said to be more suited to regeneration from braking and stop/start.  I would be interested to learn more about this if anybody cares to elaborate/research.

[ColinBarber]

51 minutes ago, Barry14UK said:

AGM batteries with low internal resistance were said to be more suited to regeneration from braking and stop/start.  I would be interested to learn more about this if anybody cares to elaborate/research.

That is for conventional stop/start vehicles where the 12v Battery is being cycled heavily due to continuous starting and then recharging either via alternator or some form of energy recovery. Most start/stop vehicles use an AGM Battery because of this.

It is irrelevant for a Toyota hybrid, 12v Battery has no part to play in the starting of the petrol engine or energy recovery/recharge because the hybrid traction Battery is the energy store. 

[GSLV6]

1 hour ago, Barry14UK said:

I am neither massively overthinking anything nor am I in awe of Professor John Kelly.  You are too too free with hyperbole Rob.  I do respect him as an official instructor though.  The point is he took the same view as Toyota, the battery manufacturers, and everybody else of any standing that a replacement battery should be the same type as the original battery.  Even Scotty Kilmer explained the need for this in one of his many videos.  (Assume you will have found Scotty, a mechanic with over 50 years experience).

Every car I have had and sold has been up to the spec it came with or is better, eg, full upgraded lighting on my E39 to retrofitted genuine BMW xenon lighting system, not just added  aftermarket HIDS.   I would not buy rubbish tyres either to save a few pounds as some do.  So I will stay with the original  AGM type battery.   The Panasonic  costs nothing like £300 (more hyperbole) from Lexus Parts Direct but there are other potential options which I hope to explore as my Pan battery needs smart charging every 8 or 9 days now if not used.

The chances of your having an accident in which you are injured by acid may well be small and you are happy to accept the risk, but how would you feel if somebody had been injured in this way following your advice to go for the cheaper flooded lead acid battery?  Insurers may also have something to say in such an event too.

I don't know why the new ES300h apparently has a flooded lead acid battery within the cabin, as apart from personal injury, AGM batteries with low internal resistance were said to be more suited to regeneration from braking and stop/start.  I would be interested to learn more about this if anybody cares to elaborate/research.

The regeneration though I thought had nothing to do with the Battery.  It is not directly hooked up.  The effect on any Battery is the same...they can only be  charged via the inverter and charging circuit or direct from the hybrid Battery via a charging circuit II'm not sure which in this cas e to be honest but it has to be one of those) which steps down and regulates the voltage.  Any differences will be purely down to the charging efficiency of the Battery type under deep cycle load conditions.  There is no good argument for insisting that the OEM Battery will be the best...that's a misleading statement and simply is not true as many alternatives will meet or exceed those specifications.  ANY Battery that meets the specifications required ie deep cycle of sufficient AH will be more than adequate and I've already proved the life of the wet Battery I replaced my panasonic with has been longer.  The incidences of anyone being injured by a lead acid Battery in the cabin I suspect are probably so low as to be statistically irrelevant, and whilst the outcome could be locally serious but still relatively minor, the risk is so low as to be negligible.  There are many other outcomes of serious accidents that are likely to cause far greater injuries or risks to long term health.  I speak as someone involved in a very serious accident whilst a passenger.

You accuse Rob of Hyperbole Barry but you have to admit that your viewpoint has little factual basis to support it and the risks you mention are much exaggerated.  Just saying. no offence intended.