Battery 'whistling' and B5 effectiveness

[THE]

Evening all,

Potentially two separate issues but they both appeared at the same time, so...

1. Anyone noticed a high-pitched whistling appearing after the battery is about halfway in the green bar? It isn't the usual welcome background hum (less spaceship taking off and more gnome under the bonnet starting a tune). It has only appeared in last few days and kicks in halfway through accelerating (with both EV and save/charge activated).

2. Anyone notice lower effectiveness of B5 in cold weather? Been chilly here lately and it seems to have tapered off its tightness (and no, the battery isn't anywhere near full...). However, even when warmed up it seems lighter and I wonder if this is related to the brake pads issue I've raised elsewhere. Are brake pads and regen system possibly afflicting each other?

The two have appeared together. All might be related (or not) but if anyone can offer potential clarification, I'd be grateful.

 

[greendwarf]

No & No on my 2014 car

 

[jaapv]

No & no too. 2014.

 

[michael8554]

No & No, 2014.

Assuming the ICE is running and accelerating, the whistle could be from a hole, or loose connection, in the air intake.

 

[Mitch]

1. No

2. No, but this could happen. In cold weather, the battery can not be charged with the same energy like if it would be warm. Normal behaviour.

 

[littlescrote]

No and Yes (perfectly normal to have reduced max Regen rate in colder, say < 10degC, weather)

 

[Nibbo]

perfectly normal to have reduced max Regen rate in colder, say < 10degC)

I though I was imagining it but it definitely felt less in cold weather for the first few miles at least.
Anyone got any idea why this would be? Seems strange to waste regen especially when it is cold where we need extra battery power for demist fans/lights etc.?!

 

[THE]

Thanks all so far, particularly recent comments regarding regen as that's helpful to bear in mind. Whistling is still apparent (it's not loud, but loud enough to sound unintentional)) and is accompanied by another different but high frequency squeal at speeds above forty. Car in next week (need screen heater fixing too!) so will update if anything out of the ordinary.

 

[littlescrote]

I though I was imagining it but it definitely felt less in cold weather for the first few miles at least.
Anyone got any idea why this would be? Seems strange to waste regen especially when it is cold where we need extra battery power for demist fans/lights etc.?!

the same reason that excess power rate is not taken from the battery in the cold - the chemistry doesn't like it.

it's like asking your cold muscles to suddenly run fast. you can do it, but you'll probably get an injury.

 

[ThudnBlundr]

No idea what the charge rates are for the PHEV wrt temperature, but the bloke who wrote CanZE (the Zoe equivalent of the WatchDog app) did some calculations and they're in this spreadsheet. The different tabs are for the 22kWh and 41kWh cars. It's not quite as simple as the rate dropping below 5C, but you can see the effect of temperature on charging rate. Of course the PHEV battery is different to the Zoe's, but it should display similar characteristics

 

[THE]

UPDATE:

Dealer said the whistling is tyre noise.

(silence)

I have my doubts, but we'll see what happens come the motorway next week...