Slower charge rate.

[4wardthinking]

Seemingly an odd question, but I have my reasons.

Does anyone know of a way to reduce the EVSE charge rate to less than 1kw?.

I'm looking to trickle charge the pack so its self balancing can have greater effect.

I have 10 & 15 Amp capability, just wondered if there was a slower rate method.
The EV generally gets to rest at week-ends, the Prius gets an airing then.

[hieronymous]

Sept 30, 2016 22:13:36 GMT 11 4wardthinking said:

Seemingly an odd question, but I have my reasons.

Does anyone know of a way to reduce the EVSE charge rate to less than 1kw?.

I'm looking to trickle charge the pack so its self balancing can have greater effect.

I have 10 & 15 Amp capability, just wondered if there was a slower rate method.
The EV generally gets to rest at week-ends, the Prius gets an airing then.

Something like this would do...

[4wardthinking]

Well, it appears the capability was there all the time, and I just had the epiphany!.

Simple logic really.

1. Put car on a limited charge, like the brick that comes with the car.
2. Carwings or Nissan App.
3. Use the cars settings to prioritise climate control over charging.
4. Turn on climate control remotely.

That's how I did it. Now all you have to do is set charging and climate control to coincide, and plug in for normal charging. Admittedly the car still takes 2.4KW feed, but apportions most of the power it's fed with to climate control, and feeds the residual 'spare' power across the battery pack.... still takes 2.4KW, but it's far gentler on the pack. Now I'm setting ours to charge this way at home permanently.

Normal charging elsewhere, but I like the idea of charging the pack slower when it's convenient. It will certainly help the longevity of the pack, which is one of my aims.
Now... On to stopping the heater coming on every time!! The fan is used for simple cabin ventilation. Looks easy to me, and the heater can reduce distance by anything around 20kms.... If it's allowed to pillage the available power.
I also disconnected the Diesel noise maker under the near-side front wing, that annoying thing is gone, and no CAN-BUS alarms set.

[EVtricity]

Yes, there are a few EVSEs on the market that allow you to dial the current down to 6 amps. Below that the Leaf automatically shuts off - I know, I've tested it (unsuccessfully ) under 6 amps on a unit where I can set the available current from 1-32 amps.

If you're looking to charge at a lower rate I think a 6 amp EVSE that would be a better and cheaper option in the long run than running the climate control (which wastes electricity and causes wear on the A/C components).

[stewartm]

If u want to knock up your own, there is a simple three position switch, gives 6,10 or 16 amps.
gwl-power.tumblr.com/tagged/EVSE
It uses the open source EVSE kit that you build into the handle.
Great concept really, just a j 1772 plug, 15 amp lead, and you have a very flexible portable EVSE
This is the main page..
www.ev-power.eu/Connectors-Cabling-1-1/EVSE-kit-for-EV-charging-station.html

[4wardthinking]

Fair point on the wasted power using the CC. It doesn't sit that comfortably with me either.

I also note the 6-10-15a open source item.
I think I'm going to make myself one of the switchable items, order goes in Monday.
It's far quicker then dragging the PCB masking gear out. I'd like to use SMD, but if I can(great chance I can) squeeze it all in the plug handle, PSU included, then I'd be left with a very useable cable all-in-one for the cars boot. Wife would find this more easy to use.
Maybe, thinking forward. I should be able to create a pull-out and plug in version, which looks a feasible possibility once proven.

The reason for this is I don't like to torture the battery just because it's possible, but not really necessary. The pack is a higher out than in charge/discharge unit. Admittedly a quick charge is an important asset with EV's also.
I'm actually sat watching the charging at the 50% mark, listening to the car. I note that the pack does appear to respond better to the lower rate of charge, it's charging with a 10mV cell difference, which the lower this number will ultimately dictate charge quantity absorbed before it halts itself. Balanced out with fewer high cell than the rest gives a better balance and more even heat distribution for power extracted. I note the histogram on the charge screen of LSP being regulated down to suit loading. Wanted power, but will be beneficial in the long run I feel.


Anyone else up for having a go at the open EVSE?. I'll order a few kits at the same time if enough takers.

[EVangelist]

Oct 15, 2016 22:53:39 GMT 11 4wardthinking said:

The reason for this is I don't like to torture the battery just because it's possible, but not really necessary.

How much evidence is there that a slower rate of charge will make a material difference to battery life?  "Wizzy" the taxi Leaf in Cornwall has done 160,000 km in 2 years, been rapid charged over 1700 times, yet retains near full battery health.  Drivers on the Tesla forums also report no material degradation from supercharging their cars - and that's at 120 kW!

[Feng]

That was actually incorrectly reported by a few sources. Wizzy turned out to have 12.5% capacity loss at 100k miles. Not enough to lose its first bar but getting close. Teslas have active cooling so that gives them an advantage. There was a comparison between two sets of LEAFs, one only using regular charging and the other using fast charging. After 40,000 miles there was 3% difference.

I was under the impression the balancing occasionally happens after a full charge if you leave it plugged in for a few hours.  Not sure if charging speed has any effect on it.

This one goes down to 6A but it's in NZ: bluecars.nz/shop/spark/?v=d76c77a873e2

[4wardthinking]

According to what we read, that is correct.
First factual evidence is heat is the main destroyer of battery cells.
So I have taken the first known as a basis to begin with.
Another proven aspect is constant use, epitomised by almost all battery assisted or propelled vehicles.
And another I have noted in the time we've had the leaf is the full charge, and it's self balancing. It appears more prevalent at higher states of charge.
I've also taken the parts I know, and taken them into account.
Over the years I do note that the Internet and the information it has brought together is just like a library. You can be in the wrong section, which is near fiction, or factual.
A lot of times para-phrasing is a favourite way writers display their knowledge, and it can be from the wrong section at times.

So applying that heat in the pack is a direct product of voltage and current, be it charging it discharging. We tend to have greater control of charging than discharging. There's my first logical reason.
Ambient temperatures are going to have a major effect on this at any time of course.
The guy in Cornwall, UK, has more cell favourable ambient temperatures, which can be directly attributed to the news we hear. Another facet of his use is constant charging, as it's a 'working car'. There are Prii here in Australia with in excess of 700,000kms on them, and continuing. I also note that our Prii's batteries respond better when tested to more constant use. So there has to be a point to be drawn from this. Yes, the chemistry is different, but I notice a trend. Interesting.
The product could be that the chemicals are more reactive in the cells at elevated temperatures if this is held constant. Constant use could be the key. Now to throw into this mix is the old, but not proven reputation of a EV being stock piled for extended periods of time, and how it affects the battery pack. I note that mobile devices have a 'use by' date too, mostly they are lithium technology. This could be the much discussed dendrites we hear of.
So I think that there is a middle ground personally. Too much and heat, too little and "dendrites".
Now I muttered about my famous three 18650 cells I consigned to the bin, and how I resurrected them. It still stands testament to a theory that they can be resurrected.
Part, or the biggest part of the 'pack repair' on the LEAF is the charge/discharger used. It tends to slowly charge the cells, and rapidly discharges them. I'm still trying to get one myself!. A very important part of the cycle it uses is temperature.
The balance side of the pack is clear, but as yet I'm not at the 100% certain mark yet, but is looking correct.
The sheer filling of the pack at, or close to 100% will generate heat, but will also push every cell to its limit if charging is left long enough, but it's holding that is the difficult part. The car stops charging. The mystical dismantle & balance method takes each of the 96 cells to their limit. It is very likely that if this is done in a timely manner to all the cells, the imbalance will be reduced. They will be totally discharged, and then fully charged repetitively, and should be capacity monitored. It's fascinating to witness cells come back to useable life when doing this. Personally, the self balancing of the pack lacks this, and goes more for use of the energy, which is unpredictable at any time.
So, in as much as the energy is wasted with what I'm doing, it doesn't do anything out of the scope of normal use of the pack, which is important if warranty is to be invoked
I 'could' dismantle the pack & balance it, which if done as early as possible at imbalance, will preserve the longevity.. but it's a trade-off.

My pack and car was bought at 74%. It's increased. Distance travelled against residual charge had increased also. So I'm moving on to be delicate with the pack when I can, but point out that the increase was brought about by fully charging the pack when it had rested between attempts to charge it to 100%.
I'm now noting that the 'GID' count is increasing with slower charging on a heat balanced, & cooler pack.
This morning I'm taking the pack slowly to 60%.
It's interesting.

[4wardthinking]

Oct 16, 2016 1:09:57 GMT 11 Feng said:

That was actually incorrectly reported by a few sources. Wizzy turned out to have 12.5% capacity loss at 100k miles. Not enough to lose its first bar but getting close. Teslas have active cooling so that gives them an advantage. There was a comparison between two sets of LEAFs, one only using regular charging and the other using fast charging. After 40,000 miles there was 3% difference.

I was under the impression the balancing occasionally happens after a full charge if you leave it plugged in for a few hours.  Not sure if charging speed has any effect on it.

This one goes down to 6A but it's in NZ: bluecars.nz/shop/spark/?v=d76c77a873e2

Nearly 2500 low power charges, and 30+ DCFC's, 44,000kms, and was!! 74%.
The best results don't define the median remember.
The question is can! I bring it back?.
Owners around AU have differing results to the best touted figures. Is it the battery or the control logic that's actually the defining data.
I've dragged out more performance already. The previous owner of ours will agree that he wasn't exactly the most gentle on the car. Are the cells being pushed to say they are weakening, or could it be the monitoring logic that's deciding. I'm waiting for the next random assessment to see the results. The only thing I can use to judge product by is the GID count at present.
Admittedly Nissan may get off lightly, but I keep my car away from hams, that can fudge the pack, which is where the problem really lies. What happens if it falls over again?.
If our pack fails, I will settle for no less than a professionally repaired item, or replacement. AU law can force this point.

[EVangelist]

Oct 16, 2016 1:09:57 GMT 11 Feng said:

That was actually incorrectly reported by a few sources. Wizzy turned out to have 12.5% capacity loss at 100k miles. Not enough to lose its first bar but getting close. Teslas have active cooling so that gives them an advantage. There was a comparison between two sets of LEAFs, one only using regular charging and the other using fast charging. After 40,000 miles there was 3% difference.

Thanks for the links Feng, very interesting reading.  These seem to indicate that other variables like ambient temperature and the amount of discharge before recharging are much bigger contributors to capacity loss, charging method is relatively small variation on top of that.

What I found very interesting is the calculation GBEV made that Wizzy had a charge every 18km on average, so a very low average depth of discharge.  In contrast, the cars used in the test in Arizona were driven until LBW (less than 10km) then recharged (although not clear whether to 80% or 100%, I suspect the latter) - so very high level of average discharge.  Result?  Relatively little degradation for Wizzy (12.5% after 160 Mm) but a lot (25% after 64 Mm) in the Arizona cars.  So capacity loss rate was 5 times faster for the latter - now THAT is significant!

Info like that made me change my charging behaviour to plug in every time the Leaf is in my garage, even if I've only used a bar, and charge only to 80% unless I really need 100%.

I used to not plug in until it was down to 2 bars, basically so that I could say when people asked me how often I charge it that I only charge it once every 2-3 days. That turned out to be a dumb rather than scientific reason.

Good stuff!

[4wardthinking]

I note evtricity's information about the six Amps or less the car refuses to charge.
Is there a reason for this?.
I would have thought it would be beneficial for the car to take any power it is fed from external sources.
Any quantity of solar panel power would help complete "The Circle".
It's revealing that the pack will take anything it's offered IF the climate control is activated.

Is this a country specific issue. The US charger at 110vac puts in half the power ours do at 240vac. We put in theoretically 10amps.

Worth investigating I think. Imagine the power supplies if the CC was on with a 110vac supply?,

Odd!.

[4wardthinking]

Oct 16, 2016 8:52:18 GMT 11 EVangelist said:

Oct 16, 2016 1:09:57 GMT 11 Feng said:

That was actually incorrectly reported by a few sources. Wizzy turned out to have 12.5% capacity loss at 100k miles. Not enough to lose its first bar but getting close. Teslas have active cooling so that gives them an advantage. There was a comparison between two sets of LEAFs, one only using regular charging and the other using fast charging. After 40,000 miles there was 3% difference.

Thanks for the links Feng, very interesting reading.  These seem to indicate that other variables like ambient temperature and the amount of discharge before recharging are much bigger contributors to capacity loss, charging method is relatively small variation on top of that.

What I found very interesting is the calculation GBEV made that Wizzy had a charge every 18km on average, so a very low average depth of discharge.  In contrast, the cars used in the test in Arizona were driven until LBW (less than 10km) then recharged (although not clear whether to 80% or 100%, I suspect the latter) - so very high level of average discharge.  Result?  Relatively little degradation for Wizzy (12.5% after 160 Mm) but a lot (25% after 64 Mm) in the Arizona cars.  So capacity loss rate was 5 times faster for the latter - now THAT is significant!

Info like that made me change my charging behaviour to plug in every time the Leaf is in my garage, even if I've only used a bar, and charge only to 80% unless I really need 100%.

I used to not plug in until it was down to 2 bars, basically so that I could say when people asked me how often I charge it that I only charge it once every 2-3 days. That turned out to be a dumb rather than scientific reason.

Good stuff!

Good points. I went three weeks with power on as soon as the car got home.
I'm trying to separate the information gleaned from the routine.
Like it has been said, "An EV is driven differently than an ICE. With an EV one charges when the opportunity presents, not when the battery is getting low. ".
It could be that catching the cells chemistry as it is more reactive, usually after use is the best point in time, and would support the regular use theory for good battery longevity.

[hieronymous]

Oct 16, 2016 8:58:58 GMT 11 4wardthinking said:

I note evtricity's information about the six Amps or less the car refuses to charge.
Is there a reason for this?.

According to this link I read recently, the J1772 protocol requires a minimum of 6A (see the Signalling section).

[4wardthinking]

Ok, the protocol & definition. This has to be in-feed power, so internally, the distribution of the power is vehicle specific.
It's bad in one respect. Take a hypothetical circumstance, with environmental consideration.
I have three KW of solar panels, harvesting 80%(hypothetical!).
I would like to complete the circle, and use this to power my transport.
For some, space, money or position, 3KW is just achievable.
It appears that conversion to DC is the only route. I haven't studied the DC allowed protocol as yet though, but casting aside all the control logic, a higher enough voltage above pack PD would cause charge to be retained in it.
It's quite straight forward to bypass the logic, and terminal charge if it was low enough. It appears the shunting is self powered.
A possibility, and the circle would be complete. Transport without depending on the power-grid and its costs from many angles. A quick stab would suggest around 450vdc.

[4wardthinking]

Oct 16, 2016 8:52:18 GMT 11 EVangelist said:

Oct 16, 2016 1:09:57 GMT 11 Feng said:

That was actually incorrectly reported by a few sources. Wizzy turned out to have 12.5% capacity loss at 100k miles. Not enough to lose its first bar but getting close. Teslas have active cooling so that gives them an advantage. There was a comparison between two sets of LEAFs, one only using regular charging and the other using fast charging. After 40,000 miles there was 3% difference.

Thanks for the links Feng, very interesting reading.  These seem to indicate that other variables like ambient temperature and the amount of discharge before recharging are much bigger contributors to capacity loss, charging method is relatively small variation on top of that.

What I found very interesting is the calculation GBEV made that Wizzy had a charge every 18km on average, so a very low average depth of discharge.  In contrast, the cars used in the test in Arizona were driven until LBW (less than 10km) then recharged (although not clear whether to 80% or 100%, I suspect the latter) - so very high level of average discharge.  Result?  Relatively little degradation for Wizzy (12.5% after 160 Mm) but a lot (25% after 64 Mm) in the Arizona cars.  So capacity loss rate was 5 times faster for the latter - now THAT is significant!

Info like that made me change my charging behaviour to plug in every time the Leaf is in my garage, even if I've only used a bar, and charge only to 80% unless I really need 100%.

I used to not plug in until it was down to 2 bars, basically so that I could say when people asked me how often I charge it that I only charge it once every 2-3 days. That turned out to be a dumb rather than scientific reason.

Good stuff!

[



Aparrently. Ever been to Cornwall or Arizona?.

The ambient temperatures are no where near each other.

It's a comparison between Apples & Oranges really, and there's a finite list of similarities that can be drawn. Most importantly is the 50%+ temperature figures.