12v battery maintenance, issues, etc.

[Derek.w]

Think of booster packs as peace of mind just to get you going its a situation you dont want to repeat to often or you be needing a new Battery.

If you do use a booster pack then its also time to connect a mains charger once you return home.

I use a bluetooth Battery Monitor it has short circuit protection built into it.

CTEK MXS 3.8 charger but some people use a 5amp version.

Regarding a jump starter that I can do from a spare batterys that I have at home.

[Roy124]

As @Derek.w says, these are all useful tools and are essentially one-off purchases that can last many years.  I changed my Battery charger after 60 years.  I still have a snow shovel bought 55 years ago for 10/-.  I have retired my jumper cables after 40 years.

Don't look on such purchases as needed for you Hybrid but as insurance for the future.

Oh, I also kept a jungle boot lace for 30 years before I used it to refit a side window in once car.  That has been retired too as car windows are different now.

[Sunflowers]

Thank you @Derek.w and @Roy124, I really appreciate the advice

[hind]

11 hours ago, Roy124 said:

If, for instance, you did numerous short time journeys and switched off at each stop you will be using more power from the battery than the HV DCDC Converter puts back. 

11 hours ago, Roy124 said:

but every start sees the battery voltage drop by 1v before recovering

Do you have diagrams for that? Can't find it in this huge thread 😄 The drop from what you say seems huge and I guess it's rather short lasting - should be the time between pushing the Start button / turning on Ignition and the DC/DC kicking in. I don't think it takes more than a minute of Ready state to compensate for that. Of course we don't know the charge rate unless we monitor the current too and count the balance. 

[Roy124]

57 minutes ago, hind said:

Do you have diagrams for that? Can't find it in this huge thread 😄 The drop from what you say seems huge and I guess it's rather short lasting - should be the time between pushing the Start button / turning on Ignition and the DC/DC kicking in. I don't think it takes more than a minute of Ready state to compensate for that. Of course we don't know the charge rate unless we monitor the current too and count the balance. 

Dala has posted several BM screen shots that demonstrate the effect.  The BM only records data at 2 minute intervals. You are right it is a momentary dip.

It does not need much imagination to think what might happen if the prestart voltage is 'ok' but minimal,

E2A

Checked this week's data.  Haven't caught the data dip but noted a 5 point drop in state of charge and a 1.6v increase in the following 2 minutes after start and a further 0.3v in the following 2 minutes.

I looked at about 5 start points and the graph clearly shows this drop, the data gathering has not captured it from which we might surmise the drop is definitely less than 2 minutes duration and is probably much less than even one minute.

 

[G L J]

In case anybody is after a portable power pack there is one al Lidl at the moment.https://www.lidl.co.uk/p/ultimate-speed-portable-jump-starter-with-power-bank/p10010233

[Roy124]

Further to the voltage drops shown on my BM6.  I checked with the OBD meter plugged in.  The voltage reading 12.25v.  When I pressed the brake pedal the voltage dropped to 12.09v (brake lights).  Pressing Start it dropped immediately to 11.75v before jumping up over 13v as the HV energised.

From my earlier BM6 data, voltage measured from 30 minutes after last use (about 1730) and pre-start on the following morning at 0700 gave the following drops 0.21v, 0.31v and 0.3v.  

This appears to show an alarming 6v drop in 10 days but in practice the rate of voltage drop tails off significantly over time.

All these figures are over 4 days this week with the car being used for short 10 minute journeys morning and evening with some longer runs during the days.

[hind]

5 hours ago, Roy124 said:

It does not need much imagination to think what might happen if the prestart voltage is 'ok' but minimal,

You are right, just wanted to point out that the start/stop (or rather ready off/ready on) cycle in hybrid engine is not that much of an issue as with regular non-hybrid ICU engine when the starter takes hundreds of amps and it takes a fair amount of time to recharge.

I did some calculations, based on Dala's data from the clamp meter and calculated, that the first 2 minutes prior to kicking in the DC/DC consumes around 221 As (ampere-seconds) of power = 0.06Ah. Almost half of it is covered in the next 12 seconds (when the provided log ends) but assuming (maybe wrong) that the DC/DC would continue delivering 6 amps to the Battery, it should be replenished with the next 50 seconds. 

So this isn't that bad, doing 2 minute drive should cover the 2 minute preparation to drive time.

Of course you have to recharge what was wasted during earlier parking phase but that's a separate story.

[Roy124]

Here is today's graph from BM6

 

[Chas G]

Toyota Yaris Cross - had a long Ctek 5 charge on Sunday and it seems to have kicked my Battery up the Harris. It's charging properly now even on short runs. To say I am pleased is an understatement.

After standing idle over 4 nights, 1 local trip to doctor, 1 trip to Watford and local trip to Asda the Battery is showing fully charged at 12.76 volts.

Long may this continue.

[Chas G]

I think my car had probably been sitting on the forecourt for a few weeks before I bought it and was jump started for my test drive and delivery.

It then took a really good long charge to kick it back up to full capacity despite showing 12.6 volts after shorter charges.

I had pondered the question whether Toyota would have produced a car with a charging system which wasn't capable of keeping the 12 volt Battery charged after relatively short journeys and I think the answer is no otherwise they would be inundated with complaints and a disappearing customer base.

[skidlid]

8 hours ago, G L J said:

In case anybody is after a portable power pack there is one al Lidl at the moment.https://www.lidl.co.uk/p/ultimate-speed-portable-jump-starter-with-power-bank/p10010233

Thanks for the heads up, been and picked one up.

Been considering one for a while now and the new Yaris is due in March and do not want to end up with a non-starting anything blocking the other 2 in (too old to push them about). One is the 6 year old Fabia with original Battery (that goes when the Fabia arrives), a Superb PHEV but still has a 3.5 year old 12v Battery that could let us down and finally a 31 year old with a Battery that is almost 7 years old (never got more than that out of one) and its inevitable that will let us down this year.

Hopefully we are covered now with the smart charger as well.

[Roy124]

49 minutes ago, Chas G said:

It then took a really good long charge to kick it back up to full capacity despite showing 12.6 volts after shorter charges.

12.6v is my normal.  However, I want to make a point.   It is not the absolute value that is important but the change from your norm.

The BM6 gives a steadier value than the OBD but is slightly lower.   A hand held voltmeter gives a slightly less precise reading but differs from both.  The different readings are probably within the individual specs. 

It is the rate of change from a particular device that will give you a better indication of your Battery performance. 

[Chas G]

1 hour ago, Roy124 said:

12.6v is my normal.  However, I want to make a point.   It is not the absolute value that is important but the change from your norm.

The BM6 gives a steadier value than the OBD but is slightly lower.   A hand held voltmeter gives a slightly less precise reading but differs from both.  The different readings are probably within the individual specs. 

It is the rate of change from a particular device that will give you a better indication of your battery performance. 

I am using the same voltmeter on the jump terminal and aluminium bracket under the bonnet each time.

[Roy124]

Chas, that eliminates some potential variances, but my point was don't compare my set of readings with yours and think them better or worse.  Look at how your readings compare, one with another over a period.

My 'shocking' drain measured over half a day was I significant when calculated after 2 weeks out of use.

[Chas G]

47 minutes ago, Roy124 said:

Chas, that eliminates some potential variances, but my point was don't compare my set of readings with yours and think them better or worse.  Look at how your readings compare, one with another over a period.

My 'shocking' drain measured over half a day was I significant when calculated after 2 weeks out of use.

Roy, I understand what you are saying.

I am only comparing my own readings taken in exactly the same way and since a long charge last Sunday they are all significantly better. Its like the Battery has woken up. I just hope it stays that way.

[Cyker]

4 hours ago, Chas G said:

I think my car had probably been sitting on the forecourt for a few weeks before I bought it and was jump started for my test drive and delivery.

It then took a really good long charge to kick it back up to full capacity despite showing 12.6 volts after shorter charges.

I had pondered the question whether Toyota would have produced a car with a charging system which wasn't capable of keeping the 12 volt battery charged after relatively short journeys and I think the answer is no otherwise they would be inundated with complaints and a disappearing customer base.

My personal theory is the Mutley batteries suffer excessive degradation if they're discharged too low, and as you say it's likely that's happened once or twice while it was in storage, so the Battery starts off degraded when it gets to the customer. Customer then doesn't use the car so much and Battery degradation accelerates.

That's why I reckon the Yuasa seems to solve the problem, as it seems to be much more resistant to degradation from partial charge and doesn't just drop all its capacity off a cliff so readily.

My Mk4 is a workhorse so it gets heavy use, but I think that's staved off the degradation in the OE Battery (Which still hasn't died on me!)

 

[Dala]

51 minutes ago, Cyker said:

My personal theory is the Mutley batteries suffer excessive degradation if they're discharged too low, and as you say it's likely that's happened once or twice while it was in storage, so the battery starts off degraded when it gets to the customer. Customer then doesn't use the car so much and battery degradation accelerates.

That's why I reckon the Yuasa seems to solve the problem, as it seems to be much more resistant to degradation from partial charge and doesn't just drop all its capacity off a cliff so readily.

My Mk4 is a workhorse so it gets heavy use, but I think that's staved off the degradation in the OE battery (Which still hasn't died on me!)

 

I agree
only one jump in three years
I regularly drive approx. 18 thousand km/year
since the first jump, I regularly charge the Battery approx. 1x/14 days
after 3 years, a larger "desulfation" value to appear during charging

today :

  

[Mojo1010]

Just for interest, over the past month leading up to Xmas, have not used the car much and for short trips 2x a week of 25mins returns to the shops (2 starts). 

Today measured the voltage, reads 12.08v, 1.5 day without using the car. I usually walk to the park to do exercise, though need to top up the Battery so drove there. 9 mins journey and park up in ready mode for another 5mins = 14 mins. About 2 hrs later done 11 km walk, voltage is 12.10v. 

So needed to leave it on ready mode for longer on the return journey home. Been meaning to top up on tyre pressure for a while, so perfect time to do it while the car is in ready mode. Total time 33 mins back home, 12.67v. 

[Roy124]

A thought:

Buying a Battery charger and looking after your Battery is no different from buying a tyre inflator and looking after your tyres.

Thanks @MOJO for the prompt. 

[Jules88]

Difference is you can easily find out the tyre pressure readings and even a warning light pops up to remind you. Yet for the Battery.. you're on your own.

[Max_Headroom]

16 minutes ago, Jules88 said:

Difference is you can easily find out the tyre pressure readings and even a warning light pops up to remind you. Yet for the battery.. you're on your own.

I bought one of these recently peace of mind for little money - 

 

[Roy124]

Please, someone put confused of Durham our of his misery.

[Rhymes with Paris]

26 minutes ago, Roy124 said:

Please, someone put confused of Durham our of his misery.

Maybe it's a bit like the perpetually surprised, some I know in real life bemoan the expense of Christmas for instance, when I point out it happens on the same day every year, they get all bewildered.

[Derek.w]

A slow charger is just going to be slow but hopefully a regulated voltage some are not.

A smart charger as it name suggest is microprocessor controlled so more protection for your car electronics. Then you have the option of using it as a slow charger IE bike mode.