Limiting the Charge to 80%

[Reddy]

Interesting thing happened to me yesterday. It's finally warming up, so I've turned off all climate control timers. I charge from 1 am to 4 am with the 80% timer set (still have the 2011). When I started the car, it was showing ELEVEN battery bars. I confirmed both climate timers were OFF. Strange, but I highly doubt the battery is getting bigger :roll: Probably just another one of those weird issues with the coarse 12 bar readings.

 

[theds]

So today I have my first drive leaving our home all the way down hill for ~2.5 miles and descending ~1500 feet. I put it in the "B" mode and didn't use the brake too much. On the bottom of the hill, the SoC increased by mere 3%, from 88% to 91%, much less than I hoped for.

 

[TomT]

You get back around 35% of what it would have taken you to climb that same hill...

So today I have my first drive leaving our home all the way down hill for ~2.5 miles and descending ~1500 feet. I put it in the "B" mode and didn't use the brake too much. On the bottom of the hill, the SoC increased by mere 3%, from 88% to 91%, much less than I hoped for.

 

[theds]

Is this a statement of a general rule? Or is it about my particular drive this morning?

I did a calculation this way: To drive 2.5 miles on flat surface it takes ~2% of charge. On my way to home, I consumed ~12% of charge to climb the 2.5 miles/1500 feet. So ~10% was due to the elevation gain. On my way down, I probably re-generated ~5% and spent 2% on driving and the remaining 3% was charged back into the battery.

You get back around 35% of what it would have taken you to climb that same hill...

So today I have my first drive leaving our home all the way down hill for ~2.5 miles and descending ~1500 feet. I put it in the "B" mode and didn't use the brake too much. On the bottom of the hill, the SoC increased by mere 3%, from 88% to 91%, much less than I hoped for.

 

[TimLee]

So today I have my first drive leaving our home all the way down hill for ~2.5 miles and descending ~1500 feet. I put it in the "B" mode and didn't use the brake too much. On the bottom of the hill, the SoC increased by mere 3%, from 88% to 91%, much less than I hoped for.

The issue is you started at 88%.
On 2011 you don't get substantial regeneration until below 80%.
2013 and 2014 may be a bit different and I haven't seen detailed #s provided, but still likely pretty limited till you get below 80%.
Try again starting at 80%.
But even then you won't get back but around 35% of the kWh it takes to climb the hill.

 

[Vorter]

Hmm, my dealer said it didn't matter how it was charged whether it was from 0 or 90 or up to 80 or 100.

 

[cwerdna]

Hmm, my dealer said it didn't matter how it was charged whether it was from 0 or 90 or up to 80 or 100.

See page EV-24 (page 43) of the '13 Leaf owner's manual...

You can get them from https://owners.nissanusa.com/nowners/navigation/manualsGuide" onclick="window.open(this.href);return false;. https://owners.nissanusa.com/content/techpub/ManualsAndGuides/LEAF/2013/2013-LEAF-owner-manual.pdf" onclick="window.open(this.href);return false; should be right.

 

[Vorter]

Hmm, my dealer said it didn't matter how it was charged whether it was from 0 or 90 or up to 80 or 100.

See page EV-24 (page 43) of the '13 Leaf owner's manual...

You can get them from https://owners.nissanusa.com/nowners/navigation/manualsGuide" onclick="window.open(this.href);return false;. https://owners.nissanusa.com/content/techpub/ManualsAndGuides/LEAF/2013/2013-LEAF-owner-manual.pdf" onclick="window.open(this.href);return false; should be right.

Oh okay. Only charge when below 80% and don't keep it above 80% for long periods of time. I don't think it'll affect me much either way as my lease is for 3 years.

 

[dgpcolorado]

So today I have my first drive leaving our home all the way down hill for ~2.5 miles and descending ~1500 feet. I put it in the "B" mode and didn't use the brake too much. On the bottom of the hill, the SoC increased by mere 3%, from 88% to 91%, much less than I hoped for.

The issue is you started at 88%.
On 2011 you don't get substantial regeneration until below 80%.
2013 and 2014 may be a bit different and I haven't seen detailed #s provided, but still likely pretty limited till you get below 80%.
Try again starting at 80%.
But even then you won't get back but around 35% of the kWh it takes to climb the hill.

Regen can also vary with battery temperature (at low battery temperatures it is essentially zero in the older LEAFs) and speed (at higher speeds regen is less than lower speeds, which is weird and annoying; again on the older LEAFs). This may have been improved somewhat in 2013/2014 LEAFs.


Anyway, the relative inefficiency of regen is why coasting is more efficient in situations where it is practical and safe to do so. For those of us who live on mountains, keeping the battery level low can help with regen braking, as opposed to friction braking, during descents. Controlling speed and reducing use of friction brakes in such situations is more important than the energy put back in the battery.

One thing I long ago noticed on my 2012 LEAF is that it is impossible to regen my way anyway near "100%". It just doesn't happen that way, no matter how long the hill, because regen goes away long before that SOC level.

 

[TomT]

It is a general rule.

Is this a statement of a general rule? Or is it about my particular drive this morning?

 

[DougWantsALeaf]

Our 13 will allow some regen even at 99% SOC in summer. I'm winter you need to discharge lower, maybe 96 or so

 

[lion]

Wouldn't using a timer affect the balancing process of the LEAF battery cells, or does it not matter when SoC is around 80%?

 

[LeftieBiker]

Wouldn't using a timer affect the balancing process of the LEAF battery cells, or does it not matter when SoC is around 80%?

Many of us think it's best to charge to 100% (and then drive the car) at least a few times a month, to keep the cells balanced. It isn't necessary every time you charge, though.

 

[muus]

I've seen several suggestions on using an end timer on 2013-14 Leafs to get an 80% charge but no-one seems to be speaking from experience. I have a 2014 Leaf and have been using an end timer from the day I got it. I experimented with it a little until I settled on an end time 2 hours after my departure time. (I set the end time for 9 AM yet I leave at 7 AM). This gets me an 88%-92% charge. Not sure if this will help extend the life of the battery but it does give me full regen from get-go.

 

[dgpcolorado]

I've seen several suggestions on using an end timer on 2013-14 Leafs to get an 80% charge but no-one seems to be speaking from experience. I have a 2014 Leaf and have been using an end timer from the day I got it. I experimented with it a little until I settled on an end time 2 hours after my departure time. (I set the end time for 9 AM yet I leave at 7 AM). This gets me an 88%-92% charge. Not sure if this will help extend the life of the battery but it does give me full regen from get-go.

I've been hoping that someone with a 2014 would give it a try and post results.

One thing you might watch out for is that with the 2011/2012 LEAFs, having the climate control timer on increases how early the car will finish charging. Don't know if that's true for 2014 models but, if it is, you may find that your numbers change a bit if preheating/precooling.

 

[joergheilig]

I live on top of a hill and I'd like to leave some room for regen charging going down hill. I couldn't figure out a way to stop charging at 80% or 90% on my 2014 SV. Nissan really should add this option.

As somebody else on this thread correctly said, the only way seems to be to:
1. Set a charge timer with no start time and an end time a good hour after your charging station turns off
2. Set your charging interval at your charge station to turn off a good hour before the end time of your charge timer

Now, if you want a full charge, just turn off the charge timer in your car temporarily.
If you want to charge during the day when you are back home and need a top off just turn off the charge timer in your car temporarily and hit the "charge now" (or equivalent) button on your charge station.

Hope this works for you. It does for me.