80% Leaf charge - cell balancing

Orebro

I normally set my timer during the week to just charge the Leaf battery to 80% (long life mode), since this gives me more than enough capacity for day to day usage, I then charge to 100% on a Friday for extra spins at the weekend.

Does anyone know if the Leaf does cell balancing & 12v battery charging with this method, or do these only happen after a 100% charge is complete?

ELM327

I am lead to believe that the cell balancing happens in the mid 90% and above SOC only.
I found, using leafspy and 80% mode, that the cells were not balanced.

(I use "long life mode" as "cheapskate mode", for home charging, as I charge to 100% at work!)

Cell balancing only really becomes an issue when you take the charge below 30% then weaker cells make themselves known and you can clearly see this on leafspy.

Cell balancing is only an issue if you regularly drive below 30% because it's at low charge % where the imbalance is noticeable, for instance you have 15% put the foot down for a few seconds and you could now have --- on the dash remaining but , you didn't loose 15% in that space of time but the weaker cells drop in voltage faster under load and they get to or close to low voltage cut off they will be taken out of the equation so the BMS thinks you have less in the pack, and the more out of balance the more this becomes apparent especially as the battery ages, all the cells don't age equally and they're not 100% equal from factory either. Drive slower again and the voltage creeps back up but --- will still be displayed and this is where having leaf spy really helps, it will go to turtle from 1 Kwh remaining and you better be at a charge point at that point, it will stop at 500 watt hrs remaining.

At lower charge % having a very light foot helps not only for conserving energy but to reduce stresses on the weaker cells.

If you charge to 80% and drive down to 40-50% then cell balancing shouldn't be needed at all, charge it to 100% once a week and it will be fine, don't set an end timer to give it a chance to fully balance.

In other words don't worry about cell balancing, if you need all the range of the car charge to 100% without and end timer.

Orebro

Nice one, that's a seriously comprehensive response!

Water John

Read some where before to balance maybe once a week. I presume that was in the context of charging everyday.

To be honest there's no need to care whatsoever about balancing, once a week is fine but not even necessary. Worst case is that you loose a bit of range or it takes much longer for a 100% charge if it's very out of balance.

The most important thing to remember when the charge % gets to 20% and less to be gentle with the throttle and no hard acceleration because no matter how balanced the cells are the weaker cells will still be just that, weaker but hard acceleration will make them reach low voltage cutoff faster.

KCross

Deleted User wrote: »

...and this is where having leaf spy really helps, it will go to turtle from 1 Kwh remaining and you better be at a charge point at that point, it will stop at 500 watt hrs remaining.

Low Battery at 4kWh and Very Low Battery at 2kWh.
Turtle is usually at 0.4kWh.

Could be, perhaps I got mixed up, I only deliberately got to turtle twice.

ELM327

Deleted User wrote: »

To be honest there's no need to care whatsoever about balancing, once a week is fine but not even necessary. Worst case is that you loose a bit of range or it takes much longer for a 100% charge if it's very out of balance.

The most important thing to remember when the charge % gets to 20% and less to be gentle with the throttle and no hard acceleration because no matter how balanced the cells are the weaker cells will still be just that, weaker but hard acceleration will make them reach low voltage cutoff faster.

When you are relying on the last 10% to make 11km to a fast charger you need to have balanced recently! I know... as I reached the fast charger on 0%

Yes as I said balancing only becomes an issue when you need to use most or all of the range and if taking a long trip you'd most likely be doing a 100% charge first and without an end timer set will ensure proper balancing.

If you frequently find yourself running the battery that low then you may as well just charge too 100% all the time.

ELM327

Deleted User wrote: »

Yes as I said balancing only becomes an issue when you need to use most or all of the range and if taking a long trip you'd most likely be doing a 100% charge first and without an end timer set will ensure proper balancing.

If you frequently find yourself running the battery that low then you may as well just charge too 100% all the time.

I do charge to 100% most of the time (at work, or when I need to go somewhere else the next day). I only ever use the 80% mode as a cheapskate mode so I arrive to work on VLBW and charge to 100% and balance there.

My point was the importance of the balancing if you intend to rely on the last few percent. A fact I very, very nearly learned the hard way!

when I don't need the range I charge to between 50 and 80%. Could be for a week or more then charge to 100 % for my commute and 100% again at work for the trip home.

Yes balancing is important for squeezing the extra few KWh but as important is being very gentle in the throttle for the last 20% especially.

cros13

I alway charge to 100% on all my EVs.... I don't see any reason not to and it increases the utility of the car by not effectively artificially limiting the range.

I couldn't be arsed when I don't need the range, why would I charge to 100% all the time ?

Water John

Well Mad, you're the only person who can answer that Q.
Others are just giving their opinion of what they do. Generally we charge overnight. Plug it in when we get home and let it cook away. We don't have night rate ATM.