12v battery maintenance, issues, etc.

[Roy124]

John, quite.  Just posting a figure FWIW

[Max_Headroom]

With an ICE you need the Battery to be above 12.6v  you also have to test cold cranking amps (see video) 

My question is as the 12v hybrid Battery doesn't have to crank the engine is there a known figure stating how low can the voltage can drop before it will not power the 12v side of things allowing the car to start?

I don't own a hybrid so can someone tell me if the 12v Battery voltage can be shown on the info screen or elsewhere?

 

 

 

 

[AisinW]

The nature is different in Lead acid Battery. It is happy when fully charged. It degrades as the voltage below 12V from sulphation process. That's why Tesla and BEV still use lead acid Battery for starter. 

Li Battery does not like to be fully charged and fully empty from mechanical stress.  the anodes degrade when fully charged and in conjunction with the formation of solid electrolyte interface. 

So, don't let the auxiliary battery discharged too low below 12V. 

[Max_Headroom]

Thanks for answering but that is not what i was asking -

With an ICE you need the Battery to be above 12.6v  you also have to test cold cranking amps (see video) 

My question is as the 12v hybrid Battery doesn't have to crank the engine is there a known figure stating how low the voltage can drop before it will not power the 12v side of things allowing the car to start?

I don't own a hybrid so can someone tell me if the 12v Battery voltage can be shown on the info screen or elsewhere?

[Roy124]

Max, I did not try to find of under controlled conditions, ie wait till the Battery was 11.5v, check.  Then let the Battery voltage decay to 11v, check etc.  

I know at around 10v all the lights light up, flash and do strange things but not go to Ready mode. 

At 8v the door remote will not work and it all remains pretty dead if you press ready mode. 

We need some brave soul to connect a voltmeter and allow the Battery voltage to drop, check, rinse and repeat. 

[Max_Headroom]

10 minutes ago, Roy124 said:

We need some brave soul to connect a voltmeter and allow the battery voltage to drop, check, rinse and repeat. 

It would be interesting to see at what point the 12v Battery will not do its thing.

[anchorman]

38 minutes ago, Max_Headroom said:

Thanks for answering but that is not what i was asking -

With an ICE you need the battery to be above 12.6v  you also have to test cold cranking amps (see video) 

My question is as the 12v hybrid battery doesn't have to crank the engine is there a known figure stating how low the voltage can drop before it will not power the 12v side of things allowing the car to start?

I don't own a hybrid so can someone tell me if the 12v battery voltage can be shown on the info screen or elsewhere?

No it can’t but Battery condition “status” did on the app for my Lexus NX.  

[Cyker]

It's a bit more complicated than that as the Battery voltage will 'sag' under load, depending on charge level and Battery condition, so one Battery could read 12v but then drop to, say, 8v when you put a load on it, while another only drops to 11v, so it's quite hard to nail down a specific voltage as the 'cut-off' level.

 

[SinglePointSafety]

As Cyker says.... the Battery will have an internal resistance, so the voltage drop at the terminals when a given current flows = (internal resistance) x (current)

[AisinW]

2 hours ago, Max_Headroom said:

Thanks for answering but that is not what i was asking -

With an ICE you need the battery to be above 12.6v  you also have to test cold cranking amps (see video) 

My question is as the 12v hybrid battery doesn't have to crank the engine is there a known figure stating how low the voltage can drop before it will not power the 12v side of things allowing the car to start?

I don't own a hybrid so can someone tell me if the 12v battery voltage can be shown on the info screen or elsewhere?

Unfortunately, £10 Voltmeter is probably the best way to read "open circuit" voltage. 

The OBD2 reader + Torque Pro App need to be powered by switching the key to ACC (ignition on).  At this point, the healthy voltage is 11.5V, headlights On 11V or above is good. 

To test any 12V Battery with load test https://amzn.eu/d/gIvPBeu

Sometimes, the check engine lights will only be ON whenever the voltage drop below 10V. It happens when we start the starter motor. 

[Poohs]

My wife's 2021 Launch edition Yaris is a very impressive little car and a pleasure to drive, but, a bit of a pain to live with !

We spend a lot of time travelling, so the car regularly spends weeks at a time in the garage going nowhere.  Sometimes when we go to use it it's fine, but sometimes it isnt and as others have said, it's that uncertainty that's the problem.

Having lived with the issue for nearly two years, I'm now using a Battery maintainer / float charger that I connect to the car when the car hasnt been used for a few weeks.  Although a bit of a pain, at least that way when we do go to use the car, it will start-up.

Picking up on a discussion early on in the thread, the "jump start" point in the fuse box under the bonnet does appear to be permanately connected to the Battery because this is where I connect the Battery maintainer, as this is a lot easier and quicker to get at than removing the access panel to get to the battery under the rear seat.  There are gaps in the seals at the windscreen edge of the bonnet that enable you to run the connection to the fuse box without trapping the cable and risking damaging it.

I've also discovered that when using a battery maintainer with a low maximum output (in my case 1 amp) to recover a completely flat battery, you must make sure all doors (including the bonnet) are closed because if not, once the battery accumulates enough charge for the electronics to work, various items start-up and flatten the battery again.

[Gray86]

32 minutes ago, Poohs said:

My wife's 2021 Launch edition Yaris is a very impressive little car and a pleasure to drive, but, a bit of a pain to live with !

We spend a lot of time travelling, so the car regularly spends weeks at a time in the garage going nowhere.  Sometimes when we go to use it it's fine, but sometimes it isnt and as others have said, it's that uncertainty that's the problem.

Having lived with the issue for nearly two years, I'm now using a battery maintainer / float charger that I connect to the car when the car hasnt been used for a few weeks.  Although a bit of a pain, at least that way when we do go to use the car, it will start-up.

Picking up on a discussion early on in the thread, the "jump start" point in the fuse box under the bonnet does appear to be permanately connected to the battery because this is where I connect the battery maintainer, as this is a lot easier and quicker to get at than removing the access panel to get to the battery under the rear seat.  There are gaps in the seals at the windscreen edge of the bonnet that enable you to run the connection to the fuse box without trapping the cable and risking damaging it.

I've also discovered that when using a battery maintainer with a low maximum output (in my case 1 amp) to recover a completely flat battery, you must make sure all doors (including the bonnet) are closed because if not, once the battery accumulates enough charge for the electronics to work, various items start-up and flatten the battery again.

A smart charger (like CTEK MXS 5.0) would be great for your circumstances, you can leave it for months on a trickle charger and the car is always ready to go. My dad used airport parking for 2 weeks over autumn with his CHR hybrid. Charged the Battery fully with CTEK charger beforehand, no issues at all at collection time 

[AisinW]

CTEK is too expensive for what it offers.  Aldi and Lidl offer much better value and do the same thing with microcontroller and regulated current. £20 or less today in local Lidl. The fully charge reading is 12.6V or higher. 

You can remove D/C cut on fuse box when leaving it for 1 month in airport.  You do not need to crawl under the seat. 

Below is TSB from Toyota that dealership do in practice. It is from USA gov. Website

https://static.nhtsa.gov/odi/tsbs/2019/MC-10154807-9999.pdf

There is an update for fixing the EMERGENCY CALL standby that  is too long and deplete the Battery. So ask dealership update this fix and probably you need new 12V Battery. Once it is depleted below 12V the capacity drop below 50% even after you fully charge it. Sulphation damage is not reversible below 12V. 

[Dala]

measured about 0.5 years ago
after 7 hours from the end of the ride
outside temperature 14°C
when measuring the cranking test, the correct value is 392.6

 

[AisinW]

@Dala thanks for sharing. Yes, the health state depends on the charged state too. However, the 3rd and 4th pictures are scary. 14V is like the DC/DC converter supplies current. Are you testing it in Ready mode?  

You should never do load test on READY mode. It can blow and overheat the DC/DC converter. 

I think the maximum voltage on auxiliary Battery is only about 13V after the surface charge is removed.

[Mooly]

I think you will find these small portable tester deduce or 'calculate' the CCA value using a round about method. They don't actually load the Battery in the way the CCA test dictates.

You can infer the CCA value by measuring the internal resistance (which is how some of these testers work) or you can do a very very short high load pulse test on the Battery.

If the tester were to actually draw a current of say 300A and the voltage really did hold up at say 10 volts then the tester would be dissipating 3kW of heat. That's as much as a fast boil kettle. It would melt in literally a second or two.

I don't know how a Hybrid would respond to this but why not try a real load test by for example holding the high beam on (assuming filament bulbs) for say a minute and see how the voltage hold up.

Also try putting it in whatever mode is needed to get the headlights and heated window on (engine not running) and see if and when the DC/DC convertor kicks in and whether it can hold the Battery above its normal resting voltage (meaning it is not being discharged).  

 

 

 

[Dala]

Before opening the car - the car Battery has a voltage of 12.3V

1/ open car, open rear door + driver door, lifting the rear seat and connecting the tester directly to the car Battery - the car Battery has a voltage of 12.11V - photo number 1
2/ load test - without starting the engine - no accessories - without ignition on - without Ready mode - photo number 2
3/ Test Cranking  - launched Ready mode - photo number 3
4/ Car still in Ready mode - launched Charging Test - Photo number 4

Load test was not performed in Ready Mode

"The 3rd and 4th Pictures Are Scary" - Why?

Pictures number 3 - Cranking Test (engine start test) - at the start of the unit to reduce the voltage to 11.32V and then after starting an increase to 14.25V.
Pictures number 4 - Charging test - 14.1V to 14.15V.

In my opinion, these values are fine.

[Derek.w]

Once you open the car door a lot of electronics wake up plus door solenoid operated & some lights turn on internal and external this will all pull the voltage down.

Once you press the start button with brake on then the dc to dc converter start charging the Battery hence a reading of 13.5 or 14.4 volts volts depending on 12 volt Battery load ie headlights on.

The 11.32 voltage reading is a little low showing Battery capacity is low but this drop is only for a second or two otherwise it will fail to start.

Recharge battery then complete the test again it will not drop below the 12 volts!.

[RobertR]

Is the jumpstart "+" terminal in the fuse box permanently connected to the 12V Battery? Because I have no voltage reading on this pin, the car was completely off.

Also, do you have a rubber seal on your fusebox cover? Because I don't. Maybe it's ok, but my previous car has a sealed fusebox.

[Dala]

[anchorman]

3 hours ago, RobertR said:

Is the jumpstart "+" terminal in the fuse box permanently connected to the 12V battery? Because I have no voltage reading on this pin, the car was completely off.

Also, do you have a rubber seal on your fusebox cover? Because I don't. Maybe it's ok, but my previous car has a sealed fusebox.

It is permanently connected, try again in case you got a bad earth.  The lid is a very good fit to the point it will only lift off dead square and the lip overhangs the base so water can’t get in.  Didn’t notice if there was rubber, probably not if yours doesn’t.  

[Roy124]

Did you probe both sides of the 'pin'. Mine is a blade and I was told only one side was live and the other insulated. 

[RobertR]

Yes, I did notice only one side of the "connection point" is made from metal, and a pretty thin piece of sheet metal actually, I was surprised. I tried several metal spots under the bonnet to find good ground but the multimeter showed no voltage. Also, that metal looks like it has some movement, hope there is no loose connection.

I will try to put the car into the "accessories" or even into "Ready" if that makes any difference.

[Derek.w]

Its a jump start terminal so goes to Battery. Check your Meter see next line.

Is your meter on the 20 volt scale DC then check its working with a 1.5 volt cell

Your Yaris will have another jump start blade at the 12 volt Battery but for access you have to remove the plastic rear seat side panel.

The smaller panel of the two remove two 2 part rivets then it pull up and away.

[Hibird]

I came across the website below while doing some reading on Toyota AGM batteries. It is interesting and informative and if you follow up with a google of 'SST P/N 00002-MCGR8' which is the part No of the Toyota Battery diagnostic tool there is further insight and information on what should/may happen at you local dealers when they evaluate your Battery. There is also at least a suggestion that a 10 amp charge rate from a smart charger that mere mortals may have is OK but intrestingly talks about 14.4 Volts not the 14.7 volts linked with AGM (a question often asked and pondered over here)

There has clearly been various iterations of this diagnostic tool  and the early ones would appear to use the 10 amp figure refered to as a 'Low Charge Rate' while later models offering more sophistication and targeted use offering higher charge rates.

You may or may not find it of use and apologise if this has already been shared.

https://www.brakeandfrontend.com/toyota-tech-tip-absorbed-glass-mat-agm-battery-information/