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Quick question about battery charging

Posted: Wed Nov 16, 2022 6:43 pm
by tomasblas
Hi everyone!

Quick one. I use about 30% battery everyday.

What is better for battery degradation:

a) Charging everyday to 80% (so plugging when it's at 50%), or

b) Charging every second day to 90% (so plugging when it's at 30%)?

Thanks!!

Re: Quick question about battery charging

Posted: Wed Nov 16, 2022 9:24 pm
by FDAD
tomasblas wrote: Wed Nov 16, 2022 6:43 pm Hi everyone!

Quick one. I use about 30% battery everyday.

What is better for battery degradation:

a) Charging everyday to 80% (so plugging when it's at 50%), or

b) Charging every second day to 90% (so plugging when it's at 30%)?

Thanks!!
If you can, to 80% and you can get to 30% if you want to, you don't need to keep it a 50%.

Re: Quick question about battery charging

Posted: Wed Nov 16, 2022 9:48 pm
by tomasblas
The problem is that I use 30% of the battery for commuting and I can only charge it at home.

So if I charge it to 80% and use it for two days, then the battery will go down to 20% level before charging. I couldn't charge it when it's 30% level.

I didn't put this option c) as I assume it's worse than b) but also because I want to have some more battery left in case I need some extra miling.

Cheers!

Re: Quick question about battery charging

Posted: Wed Nov 16, 2022 11:37 pm
by londiniumperson
tomasblas wrote: Wed Nov 16, 2022 9:48 pm The problem is that I use 30% of the battery for commuting and I can only charge it at home.

So if I charge it to 80% and use it for two days, then the battery will go down to 20% level before charging. I couldn't charge it when it's 30% level.

I didn't put this option c) as I assume it's worse than b) but also because I want to have some more battery left in case I need some extra miling.

Cheers!
In your case I'd prefer to charge every day just in case I forgot to plug in every second day & also charge to 85%, that way if for some reason you couldn't charge for 2 days then you can still get to work on the 3rd day and find a charger at/near work to top up enough to get back home.

Have you purchased outright/loan or leased/PCP?
If on a lease or PCP, then charge to 100% and don't worry because any potential battery degradation isn't going to affect you then you'll have 3 days' worth & 10% in reserve.

Re: Quick question about battery charging

Posted: Thu Nov 17, 2022 8:35 am
by tomasblas
Thanks! I own the car, no lease or PCP.

I'm not worried of forgetting to charge the car as I could use a petrol car if I do.

No chargers near work and I don't want to have range anxiety so I prefer not going down to 10% (besides of the additional battery degradation).

Re: Quick question about battery charging

Posted: Thu Nov 17, 2022 10:37 am
by EEEE
I try not to worry about it too much. Most of the manual is garbage anyways so I try not to follow it religiously.

My journeys are similar - about 10% each way in the summer, maybe 12 or 13% if I pop out for lunch from work in the day. More recently now it's dark and road closures etc.

I charge after 2 or 3 days to 100% (so that's from either 60% -> 100% or ~40% -> 100%). If the battery degrades below the specification limit by the end of the battery warranty, Honda will give you a new battery so you're probably better off not caring for your battery on purpose almost to take advantage of the warranty.

I think its 5 years? After 5 years, better to have an old car with new battery, than an old car with an old battery!

Worrying about charge %age is just one way to reduce the enjoyment of the car in my view. I'm sure the grid would prefer smaller more frequent charges however, rather than ending up with human patterns doing big charges on a Friday night only for example.

Re: Quick question about battery charging

Posted: Thu Nov 17, 2022 11:14 am
by mesa
As the battery becomes more charged the charge rate drops so if you are paying for charging time rather than energy it gets more expensive. I think that that has stopped in Sweden but I am unsure, I know that one supplier charges after 45 minutes.

The grid would prefer longer slower charges rather than more frequent. One of the problems that they have is handling the short peaks and dips. One of the Swedish suppliers has recently added 2MWh of batteries to smooth the supply. Not that much but we only generate about 20MW.

Re: Quick question about battery charging

Posted: Thu Nov 17, 2022 7:12 pm
by tomasblas
Thank you both!

I understand the approach regrading the guarantee but they will only replace it with a new one if it reaches certain level of degradation. So if you don't care the battery you can find yourself with a somewhat degraded battery and no manufacturer's replacement.

Where I live the cost is based on kWh and not on time plugged. Actually I'm charging it at a relatively low power of about 4 kW.

Re: Quick question about battery charging

Posted: Fri Nov 18, 2022 12:08 pm
by Reuben80
You are same as me. I try to keep it between 35% and 65%. right in the middle, not too high, not too low.

Re: Quick question about battery charging

Posted: Fri Nov 18, 2022 4:28 pm
by DonJohnsonJr
I charge to full every night. No matter how much I used it during the day. Sometimes I keep the car plugged in for many days in a row, I trust the cars BMS can handle all use cases.

Honda provides a 8 year / 160 000 km / 70 % guarantee for the cars battery. Honda wouldn't provide that if they weren't confident the battery will stay at above 70% for that time no matter how you use and charge it. That's my opinion.