CTEK Vs Ready Mode Charging

[Corolly Poly]

After suffering a dead car yesterday I left it in ready mode for about 4 hours whilst I went out (wife was still at home). All seemed good and everything was working as expected.

Bought a new CTEK MXS5 a while ago so thought I would stick that on just to check the level of charge.

Connected it to fuse box connector and to a nearby bolt.

All looked good except the charge level was only at 3. I would have expected after 4 hours in ready mode the Battery level would have been much better. Makes me wonder if its much better to use a charger than ready mode to obtain a decent charge.

Anyone else getting more charge out of ready mode?

[forkingabout]

If the 12 volt Battery has gone that flat then it would be best to recovery charge it using a charger connected to the mains. 

Once a modern 12 volt Battery goes that flat its difficult to nearly impossible to get it back to its full potential. 

[Mojo1010]

4 hours are good for those that cannot connect a charger, though it's not enough to bring it back to a high level. It has sustained a discharged so will have some effect to the level of capacity it can reach. Overnight with a charger in cases like yours is best. 

[Corolly Poly]

Its crept up to 4 so will leave it to see if it can get it to 7. Might do a recon if it doesn't make it.

[Hybrid21]

Hi Corolly, find it strange you got a flat Battery on a 24 reg vehicle.

Did you do something to make it go flat ?

[Corolly Poly]

1 hour ago, Hybrid21 said:

Hi Corolly, find it strange you got a flat battery on a 24 reg vehicle.

Did you do something to make it go flat ?

Don't think it's unusual.  Had not been used for 10 days and Valet left doors open for some time and used the powered boot a few times. 

[yossarian247]

I've used a CTEK charger on various vehicles (petrol, diesel and hybrid) over the past decade or so, and I've found the charger will often spend a while on stage 3 then 4 when first connected, even if the car has been on a longish run shortly before connecting it. CTEK chargers just seem better at fully charging a 12V Battery than most cars own charging systems. 

[Red_Corolla]

If you've got a charger, use it!

Any kind of charger, whether it be mains or solar, is a much better strategy for looking after the Battery than simply sitting in the car in ready mode IMHO.

[Derek.w]

It possible with a full 12v Battery to forget the HV Battery maybe needs topping up using Ready Mode.

[Corolly Poly]

6 hours and the CTEK had it fully charged.  Hopefully no major damage done and I'll be ready next time 😁

[Pannett]

Our Corolla has the same issue with the 12v Battery losing voltage. The car had a software update and the Battery now loses around 0.1 volts overnight. Oddly, after a 260 mile journey on July 21st, the resting voltage was 11.6v on the 22nd July. I know how to start the car if the 12v Battery is too low, using a booster pack, so I'm putting up with it for now. It's reminiscent of when we had a diesel-engined Yeti during lockdown, so our mileage was limited. Every so often I went for a drive to regenerate the DPF when the soot level was high. Now I do the same in the Corolla except this is to recharge the battery. Does anyone know whether a larger battery would fix the problem, would it fit and could it affect the warranty?

[Mojo1010]

All modern cars lose some voltage overnight. My Yaris lose about 0.2 each day for 4 days once during the winter this year. A bigger capacity will help with the buffer and it does not affect warranty. This is the route I would take if my car Battery starts failing.

What was your method of measuring the resting voltage?

[TonyHSD]

1 hour ago, Pannett said:

Our Corolla has the same issue with the 12v battery losing voltage. The car had a software update and the battery now loses around 0.1 volts overnight. Oddly, after a 260 mile journey on July 21st, the resting voltage was 11.6v on the 22nd July. I know how to start the car if the 12v battery is too low, using a booster pack, so I'm putting up with it for now. It's reminiscent of when we had a diesel-engined Yeti during lockdown, so our mileage was limited. Every so often I went for a drive to regenerate the DPF when the soot level was high. Now I do the same in the Corolla except this is to recharge the battery. Does anyone know whether a larger battery would fix the problem, would it fit and could it affect the warranty?

Healthy Battery will fix the problem if the problem is down to the Battery which seems it is as the Battery  goes down to 11.6v after one day of inactivity. 
Larger battery will not help much, just extend a little bit standby time due to its larger capacity. However if you buy larger don’t jump too large, actually best is to stay close as possible ( 45Ah to 55Ah) , otherwise the new larger battery might not get properly recharged by the car and after some time you will end up with the same problem.
You did longer journey and next day the battery was low, well when the battery is not healthy it can even die on you while you are driving, or shortly after a long journey of hours., because the chemistry can not hold charge anymore. If the car is one year old or less you can argue with the dealer where you bought it from for new battery replacement under warranty as premature wear, any new or used car should be able to start after week or two without use.