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Planned replacement of 12v battery


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4 hours ago, reeac said:

I own a 1958 MGA sports car which has two 6 volt batteries in series to power the 12 v system. After restoration between 1981 and 1983 the first pair of batteries lasted 11 years and the second pair 10 years. After that I started having trouble with batteries which was eventually cured by converting to using a single 12 v battery. I believe that the problem was that the more recent 6 v batteries were intended for use in golf buggies and so were deep cycle and couldn't supply enough current for cold starts. I expect that true car type 6 v batteries are still obtainable but it's a possible pitfall if choosing deep cycle batteries. So called leisure batteries provide enough CCA (cold cranking  amps) and have reasonable deep cycling ability and I always used them on my boat, finding that they lasted about 10 years.

I have owned two MGA's a 1600 and a 1600 twin cam. After those I had an MGB-GT "a pre-production model chassis no 11. All had two 6 volt batteries of the flooded variety that lasted well. I believe that later 6 volt batteries possibly because of the small demand are not as well made as there early counterparts.

The problem with using AGM batteries in a normal car be it with a dynamo or alternator is that the charging currents are to high. The old Lucas dynamo was designed to output 22 amps maximum, and alternators 4 or 5 times that figure. Looking at the Toyota/Lexus 45 AH Battery it has a label on the top that states maximum charge rate 4.5 amps.

Most so called leisure batteries "but not all" are of the flooded type, but the plate chemistry is slightly different to car batteries. 

John.

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I believe so. There are possible alternatives for being able to reasonably see the condition of the hybrid 12 volt Battery by using the built in volt meter on the hidden menu screen or by using a ci

Well Matt this is not as simple a question as it may sound, but I will keep it as brief as I can. All lead acid batteries have one thing in common. They do not like to be stood partially charged.

Having a 2007 Prius, and previously using it as a Taxi for 5 years, I would say yes, replace it. The inconvenience of getting into the car and seeing the 'red triangle of death' is annoying, especiall

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38 minutes ago, BigChange said:

With a hybrid the first sign of problems is usually a failure to boot into ready mode possibly with false codes.

Can the hybrid car then be jump started, to get to a (lexus) garage to buy a new battery ?

Yes the hybrids can be jumped ether at the battery the "generally in the rear of the car" or at a jump point provided under the bonnet. The car you are jumping from should not be running to avoid voltage spikes damaging the electronics. Only low current is required to get the car to boot the computers to ready mode.
More often than not a second or third try will get the car to ready without a jump providing the Battery has not been discharged to much.

A small 12 volt Battery such as used in fire and burglar alarms can also be used or a jump pack. The 12 volt Battery is not used to turn the engine as in a normal car.

John

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Interesting thread with lots of impressive technical information but, as the driver of a Lexus hybrid who places no abnormal demands on it, I am still none the wiser as to if or why or when I might need to worry about an old or ageing 12v Battery.  As far as I can gather, provided that cost is not an issue, nobody disagrees with the idea of replacing the Battery after five years even if it is showing no untoward symptoms, the sole disincentive being the undemonstrable risk of replacing what may be a perfectly good Battery with a faulty one.  Is this a fair summary interpretation of the opinions so far expressed in the thread?

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27 minutes ago, Rabbers said:

Interesting thread with lots of impressive technical information but, as the driver of a Lexus hybrid who places no abnormal demands on it, I am still none the wiser as to if or why or when I might need to worry about an old or ageing 12v battery.  As far as I can gather, provided that cost is not an issue, nobody disagrees with the idea of replacing the battery after five years even if it is showing no untoward symptoms, the sole disincentive being the undemonstrable risk of replacing what may be a perfectly good battery with a faulty one.  Is this a fair summary interpretation of the opinions so far expressed in the thread?

I believe so.
There are possible alternatives for being able to reasonably see the condition of the hybrid 12 volt Battery by using the built in volt meter on the hidden menu screen or by using a cigar socket volt meter available cheaply. The readings should be taken after pushing the start button twice without your foot on the brake pedal. If the reading after sitting over night is down to 12 volts or mid 11's the Battery is getting tired. At 11 volts and below expect trouble sooner than later. Lower than 10.6 volts and the Battery is toast.
On entering ready mode the voltage should rise to 14/14.2 volts as the Battery is being charged.

John

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7 hours ago, Britprius said:

.....
There are possible alternatives for being able to reasonably see the condition of the hybrid 12 volt battery by using the built in volt meter on the hidden menu screen or by using a cigar socket volt meter available cheaply....

John:   Thank you very much.  That’s precisely the sort of guidance I was looking for.... 👍

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8 minutes ago, darrude said:

That's exactly the sort of item I was talking about. They do have the advantage of giving an instant reading over the built in hidden menu that is somewhat cumbersome to use.

The voltage being checked "pushing the start button twice with no brake pedal" is under load so giving a good indication of Battery condition. The unit can be left plugged in as the power outlet is turned off with the stop button. So there is no extra Battery drain.

John. 

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That's exactly the sort of item I was talking about. They do have the advantage of giving an instant reading over the built in hidden menu that is somewhat cumbersome to use.

Sorry if I am missing something but how do I access this “built in hidden menu” to check my Battery voltage?

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14 minutes ago, Pompeyscouser said:

Sorry if I am missing something but how do I access this “built in hidden menu” to check my battery voltage?

I was wondering that too.

And a second question: if the car knows the voltage of the 12v Battery, does it put up a warning if the voltage is getting too low? I've seen comments that say it warns if the keyfob Battery needs replacing; it would also make sense to put up a warning saying the 12v Battery needs replacing. 

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58 minutes ago, darrude said:

Could you report back on whether it works ok? I've seen similar ones on the internet but I thought they might be too wide to fit in the central box where the socket is.

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38 minutes ago, Pompeyscouser said:

Sorry if I am missing something but how do I access this “built in hidden menu” to check my battery voltage?

If you push the start button twice with no brake pedal or even if you go to ready mode. Turn the lights on and off 3 times inside 2 seconds a menu will appear. Choose vehicle signal check, and a number of items will appear including the Battery voltage. If you are in ready mode this will be the voltage of the Battery on charge not the real Battery voltage.

An alternative method is to push start button twice, and on the touch screen press display then on the lefthand side of the screen just inside the top, and bottom displayed lines starting at the top press an imaginary button at the top then the bottom then top then bottom then top then bottom in quick succession. The hidden menu will appear. 

John.

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50 minutes ago, Pompeyscouser said:

My car is the is300h and the above operations did not work for me. Is the above applicable to my vehicle?

Paul. I have not tried this on an is300h, and I am sorry if this does not work for you. It does work for the great majority of Lexus/Toyota hybrids, and maybe there is some other way to entre this menu on your model that someone else will know. These menus are not in the cars hand book so do not waste time trying to find it there.

John.

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John, thanks for responding. I wonder if anyone else has tried this on the is300h or has an alternate method. In any event, my Battery appears to be working ok and is only 3 years old. I was just interested because of the thought of “hidden menus” and not knowing all the Lexus “secrets”. Love this forum as (on the whole) everyone is so helpful and informative.

If anyone knows anymore secrets it might be useful to compile a list for all to take advantage of.

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22 minutes ago, Thackeray said:

It seems that the Hybrid Assistant phone app also shows the 12v battery voltage. I haven't used it myself but it was recommended by someone in another thread. Here's a video showing the battery voltage display.

There are many applications that use the OBD (on board diagnostics) port if you buy the required plug in units. This includes Techstream the complete diagnostic system used by Toyota/Lexus. The volt meter that just plugs in to one of the power outlets is probably the simplest, and cheapest method without loosing accuracy.

John.

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On 9/11/2018 at 1:08 PM, Pompeyscouser said:

Sorry if I am missing something but how do I access this “built in hidden menu” to check my battery voltage?

I've just noticed another thread about firmware updates and one of the messages says you should hold down the Menu button while turning the lights on and off three times. Is that the way to display the hidden menu?

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On 9/11/2018 at 4:26 PM, Britprius said:

There are many applications that use the OBD (on board diagnostics) port if you buy the required plug in units. This includes Techstream the complete diagnostic system used by Toyota/Lexus. The volt meter that just plugs in to one of the power outlets is probably the simplest, and cheapest method without loosing accuracy.

John.

Techstream can read the Battery voltage?

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2 minutes ago, BrunoLeal said:

Techstream can read the battery voltage?

Yes it does, but it is not the cheapest or the easy option requiring a laptop set up to use. A simple multi meter would be better.

John

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Returning to the original post, 5 years changeover is probably ok. I had a Prius Gen II for 10 years and the only thing that ever failed on that car was the Battery at 7 years, which I thought was pretty good compared to other cars batteries.

Admittedly it was a royal pain on a cold winter morning to find the Battery flat, but got a rescue start from home and went to the garage for a quick replacement. I drove the car 5 days a week, occasional weekend, and covered under 7000 miles a year, so the Battery was in regular use, even if it was short 7 mile trips.

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On ‎9‎/‎11‎/‎2018 at 3:57 PM, Pompeyscouser said:

John, thanks for responding. I wonder if anyone else has tried this on the is300h or has an alternate method. In any event, my battery appears to be working ok and is only 3 years old. I was just interested because of the thought of “hidden menus” and not knowing all the Lexus “secrets”. Love this forum as (on the whole) everyone is so helpful and informative.

If anyone knows anymore secrets it might be useful to compile a list for all to take advantage of.

I decided out of sheer curiosity to find the "hidden menu" - I have a 64 reg IS 300h Executive (so standard nav). The combination on mine is to hold the menu button down (on the centre console) and then do the lights on/off three times quickly - it then pops up the "hidden menu". I also had a look at the Battery voltage - with the aux on but the engine off it was showing between 11.7V and 12V - seemed to fluctuate up and down in this range. Not sure what that tells me! As far as I know the car has the original Battery (I bought it just under two years ago at 41,000 miles from Lexus - always serviced at Lexus and no Battery replacement in the online service notes) and it's now done about 63,000 miles. It's used most days on short runs with longer runs on average once a week. Never had any sign of problems with the 12V Battery. There didn't seem to be anything else of much use in the "hidden menu" unless someone knows what else can be accessed...

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2 hours ago, wharfhouse said:

I also had a look at the battery voltage - with the aux on but the engine off it was showing between 11.7V and 12V - seemed to fluctuate up and down in this range.

Which menu option do you choose? I had a look too but couldn't see anything that looked as though it would show Battery voltage.

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16 minutes ago, Thackeray said:

Which menu option do you choose? I had a look too but couldn't see anything that looked as though it would show battery voltage.

It was as per a previous part of this thread "Choose vehicle signal check, and a number of items will appear including the Battery voltage" - I went through most of the menus to see what was there but couldn't find much else of any use... 

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