Does regen braking need to "warm up"?

[jamerg]

Hi All

Have had the PHEV back for a few weeks following its repair due to some idiot smashing into the back of it :evil:

One thing I've noticed, which I hadn't before, is that it now takes a few miles into each journey before the regen braking starts to work. Is this normal? As I say, I'd not noticed it before, but then we hadn't had it long prior to the smash :?:

 

[ChrisMiller]

Yes, it's normal - when the battery is close to fully charged, it can't 'take' the full current generated by regenerative braking. Once the state of charge has dropped after a few miles, the regenerative braking will operate normally.

 

[jamerg]

Yes, it's normal - when the battery is close to fully charged, it can't 'take' the full current generated by regenerative braking. Once the state of charge has dropped after a few miles, the regenerative braking will operate normally.

Cheers Chris. That probably also explains why I hadn't noticed it before, as I imagine in the depths of winter the pre-heating function was slightly draining the battery before I got in the car.

 

[CJ1045]

Think it has to drop below 80% full charge before it works but I may be wrong.

CJ

 

[anko]

Think it has to drop below 80% full charge before it works but I may be wrong.

CJ

To feel it work: yes. To work: no.

I can monitor battery power in/out to 1/10th of a kW and SOC at 1/100th of a percent. Even at a very high SOC there is a little incoming current during regen braking. But indeed I cannot feel it.

 

[greendwarf]

Think it has to drop below 80% full charge before it works but I may be wrong.

CJ

To feel it work: yes. To work: no.

I can monitor battery power in/out to 1/10th of a kW and SOC at 1/100th of a percent. Even at a very high SOC there is a little incoming current during regen braking. But indeed I cannot feel it.

+1 - I do a round trip of about 2 miles most mornings straight from overnight charge and only notice a lack of Regen on the outward journey. By the time I get back home it seems to be working fully.

 

[AndyInOz]

I do a round trip of about 2 miles most mornings straight from overnight charge and only notice a lack of Regen on the outward journey. By the time I get back home it seems to be working fully.

I hope I'm reading too much into the above, i.e. you do a lot of other driving after the 2 mile round trip, but if you're recharging the battery after every 2 miles, I suspect that will reduce the life of your battery.

 

[greendwarf]

I do a round trip of about 2 miles most mornings straight from overnight charge and only notice a lack of Regen on the outward journey. By the time I get back home it seems to be working fully.

I hope I'm reading too much into the above, i.e. you do a lot of other driving after the 2 mile round trip, but if you're recharging the battery after every 2 miles, I suspect that will reduce the life of your battery.

Correct - eldest granddaughter is too tired first thing in the morning to walk to the station But, as part-retired I don't need to go to work myself until later, when the Bus Lanes are no longer in force, to enjoy the free parking & no Congestion Charge in Central London. Overall I use about "half a tank" on these regular daily trips but prefer to be topped up each night in case I have to do any unexpected extra mileage.

 

[ChrisMiller]

I hope I'm reading too much into the above, i.e. you do a lot of other driving after the 2 mile round trip, but if you're recharging the battery after every 2 miles, I suspect that will reduce the life of your battery.

It's only anecdata, but the Li-ion battery on my Missus's 10-year-old laptop has just given up the ghost after spending 99.9% of its life on mains power (it was really a luggable desktop replacement). I don't think they develop a 'memory' of their recharge state like the old NiCads used to, but I'm sure others on here know more about it than I do.

But FWIW, I wouldn't recharge after 2 miles, either.

 

[HHL]

I hope I'm reading too much into the above, i.e. you do a lot of other driving after the 2 mile round trip, but if you're recharging the battery after every 2 miles, I suspect that will reduce the life of your battery.

It's only anecdata, but the Li-ion battery on my Missus's 10-year-old laptop has just given up the ghost after spending 99.9% of its life on mains power (it was really a luggable desktop replacement). I don't think they develop a 'memory' of their recharge state like the old NiCads used to, but I'm sure others on here know more about it than I do.

But FWIW, I wouldn't recharge after 2 miles, either.

From what I have read, Li-ion batteries are stressed at full charge and of course should never be discharged below a certain cell voltage at all. I think the BMU in the PHEV takes care of it pretty well.

I probably would not leave the car at full charge sitting for a month, but day to day it should not matter.

 

[Grigou]

Owners Manual in English language, Note page 3-4 (charging) :

"To maintain the capacity of the drive battery the following is recommended :

° Fully charge the vehicle in normal charging every two weeks
° Do not repeat charging near the full charge level"


I think it's the third time that I write this in the forum :roll:

 

[Claymore]

The experience, after a couple of months, is probably less exciting than that of a hamster in it's exercise wheel.

:shock:

JimB