Successful charge today using CTEK. I did not disconnect the battery but did switch off the 12V battery saver temporarily to avoid any possibility of clashing with the CTEK.

 

After going to the car yesterday and finding that I couldn’t unlock it, I used my manual key and my jump start pack, then left it on charge using my trickle charger overnight. When I got back from work I rigged up my 12V solar trickle charger and left it topping up.

Background…i’d not used the car for 10 days due to being unwell with the dreaded C virus. Not checked it, not opened the car. It worked fine today and it’s saying it is okay now. I keep the battery pack in the car in case of emergencies.

I do not monitor the 12V. I don’t want to either. The 12V is now out of warranty. I’ll replace it when it don’t work no more

 

Keeping a battery pack handy is great advice and a must really - especially for EV owners.

 

Can anyone please recommend a battery pack from Amazon /ebay

 

I bought this one. Seems good.

 

Since last posting - and in view of the various comments I've read in relation to 12v battery longevity concerns - I picked up a battery monitor. It's a small device that's permanently attached to the battery and tracks it's state of charge. It'll also show stuff like cranking power and idle charge on ICE cars but there's not much call for those features with EVs . . .

. . . anyways, when left standing, the battery charge sits at a fairly constant 12.7-12.8v. As you'd expect, the voltage dips every time the doors/boot/whatever are opened but those dips are only momentary. Going the other way, the voltage has spiked up as far as 14.7v on a few occasions over the past week - with the most obvious occurrences being every time the car has been driven. Journeys have only been short and lasted around 10 minutes or so but during those periods, charge is up over 14v.

There's also a relatively regular spike between 6-7pm every day that also pushes the charge to above 14v and lasts for between 10-20 minutes. So I'm pretty sure the auto top-up is working the way it should.

 

Which BM?

 

This thing.

 

Are my assumptions correct?

I go on holiday for a week
.
Option 1
My FE is charged to 75% and battery saver is on and car is NOT pluuged into charger. The HV battery will keep the 12v fully charged because battery saver is on.

Option 2
With the car plugged in, charging would stop almost immediately as % Charge Limit is reached. The few mins the 7Kwh charger is ON, would be too little time for 12v to be topped up to adequate level, and to make it worse the battery save will not try again for 24 hours.

 

For a week's holiday I will not bother.

I'm going away for a month in August and I will leave the car as is, based on my last year's experience of 3weeks away/no issues.

Reading your Option 2: What is going to start your charger again? Once it stops, that is it. It will not (should not) start charging ever again, no matter what the SOC is. It could be my charger Hypervolt though. What charger do you have?

 

Old non smart chargemaster

 

So, once your car is charged up to the limit and charging stops, who/what is going to start it again?

 

I didn't matter at the end. Left it unplugged and looks like the battery saver did its job. The 12v was 13.2 when I started the car and range was about the same.