Leaf in the tropical north

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JeffB
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Leaf in the tropical north

Post by JeffB »

We live in Kununurra where summer temperatures reach 40+ and don't drop much below 30 even at night. The batteries will obviously degrade just standing in the garage, but how important will the lack of active cooling be?
We have a 20km drive to town, about 80% of that at highway speed (say 80km/h) which may heat the battery too much.
It would only ever be slow charged overnight.
There are lots of Leafs for sale with 5-6 years and 50 000km, but if the battery fails after two years because of overheating they will be poor value.
Any thoughts?
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Re: Leaf in the tropical north

Post by antiscab »

Any chance of air conditioning your garage?

For the distances you propose. Maybe a conversion ev would be better.

Lifepo4 batteries used in most conversions (up until recently) are not as sensitive to heat as the nmc batteries used in production cars.

I note there's a BMW 318i up for sale at the moment.
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Re: Leaf in the tropical north

Post by JeffB »

"Garage" is a euphemism for any shady spot, though I have considered the possibilty. Since we only aircondition one room of the house it would be pretty funny airconditioning a garage.
I read the iMiev uses its airconditioner to cool the battery while charging, and there is a 2010 model for sale, but its battery must be getting close to the end of its life. I will look at it when I get to Perth.
The low km BMW looks very nice but out of my price range.

Currently we use electric bikes to commute but the wet season really boils us even with the assistance.
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Re: Leaf in the tropical north

Post by antiscab »

imiev only uses aircon to cool the battery when it's fast charging
Though given the hardware is there, it may be possible to modify it to run whilst charging or driving.
likely would just have to apply 12v to the right spots to get everything to start

the BMW I had in mind was this one:
viewtopic.php?f=34&t=6196

about the same price as an imiev, with the same range and possibility of attaching a tow bar to tow stuff
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Re: Leaf in the tropical north

Post by jonescg »

I was doing research on the sandalwood plantations up there during my PhD and post-doc. The latest I was ever there was October, and that was pretty rough! I agree it will be difficult to keep the battery cool. Matt's probably right - a conversion with LiFePO4 batteries will handle the heat much better than the chemistry's being used in all current production EVs. Some kind of cooling whenever the vehicle is charging or driving will also help the battery last a lot longer, but in these circumstances, short of an air conditioned garage, a more robust chemistry is probably the best solution.
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whimpurinter
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Re: Leaf in the tropical north

Post by whimpurinter »

Hi
I have learned not to have a "specialist" car unless I am a specialist.
If you are not a hobbyist in the appropriate fields, avoid like the plague any transport which cannot be repaired by a commercial organisation in your reasonable vicinity.
Aside from a non-commercial vehicle not having any of the "it just does it" ability, equipment for it is very specific and not conveniently available with regard to time or knowledge.
I tell you, people here go on about modifications but these are people who can, like to, and do this stuff. If you simply want an ev to drive and you are not one of those people (you will know), ignore any advice on how to "make it happen" regarding vehicle performance. This is one of the perils of mixing up tech people with modern people who, for various reasons, realise that an Electric Vehicle is the type of vehicle they would desire to drive.

I have a 2012 imiev. I don't even stress it with highway speeds most of the time. My slow speed range seems to be around 100 km with a 73% reported battery capacity after this time.
I have not learned the true range capability of the car because I just don't/won't use it that way. Also, without having tested anything, I'm going to guess that full-time use of air/con in the car while driving will significantly reduce your driving range. I'm pretending that you will drive flat roads but if you go up significant hills in high temperatures while using aircon, that could also be very significant for a 100km range vehicle. It seems, without having looked into it, that a better 2nd hand leaf, say, might be ok for you if you drive properly and really only want it for 20 km each way. It would go much further than that and you would know just how much further after having owned a car and learned about it. I'd say the imiev would work except that I do not know just how influential higher ambient temperatures Brisbane/vs/outback would be.

You'd need to ask yourself how far away Nissan or Mitsubishi service centres are and would they want to know if you have issues with the car. The odds are that the cars would go for a long time without problems, but there is that issue to remember.

If you really want an ev, obviously a kona type vehicle would be perfect (500km range?), though it is a little early to be very sure about the vehicle (and where is the Hyudai service centre). At the approx $50k price, it seems a lot. It might be better to buy a 4wd for $90k or $120k for REAL VALUE. They have their place, but not many of them do.

I've been a little bit silly at the end because only some of us really can afford those things and so I already said it at the start :)

Edit: Added the word "how"
Last edited by whimpurinter on Sun, 29 Sep 2019, 06:49, edited 1 time in total.
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Re: Leaf in the tropical north

Post by mikedufty »

I agree with most of the above, but wouldn't be concerned about running air con full time in an i-Miev. We pretty much did that with ours in Perth. I'm pretty sure it would be more in Kununurra. Knocks 10% off the guessometer range, but doesn't seem to reduce actual range that much. I'd be more concerned that if the air con is cooling the batteries it might not be available for cooling the cabin sufficiently, but admit I don't know how the system works. Only ever used a fast charger once for about 10 minutes just to try it out.
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Re: Leaf in the tropical north

Post by T1 Terry »

Something I've always wondered, if heat rises and cold falls, wouldn't blowing cold air above the battery pack and exhausting it below the battery pack a better method for cooling? I see all these cooling plates the cells sit on, but wouldn't that be the coolest part of the cell?
Tesla run pipes up one side of their cells to transfer the heat out of the cylindrical case, but doesn't that only cool the outer layers of the cell while the centre stays hot?
How effective is active cooling?

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Re: Leaf in the tropical north

Post by jonescg »

T1 Terry wrote: Sat, 28 Sep 2019, 12:17 Something I've always wondered, if heat rises and cold falls, wouldn't blowing cold air above the battery pack and exhausting it below the battery pack a better method for cooling? I see all these cooling plates the cells sit on, but wouldn't that be the coolest part of the cell?
Tesla run pipes up one side of their cells to transfer the heat out of the cylindrical case, but doesn't that only cool the outer layers of the cell while the centre stays hot?
How effective is active cooling?

T1 Terry
Convection (the rising of warmer, less dense air) is a pretty slow way to move heat compared to conduction, which is what all the EV cooling systems rely on. So a solid, highly thermally conductive (but critically, electrically insulating) material binding a large surface area with a big delta T between source and sink will result in the most effective thermal management system. In Teslas case they are cooling the side of a cell through a rubbery material with a thermal conductivity of about 1.0 W/m.K (typical for the job) but the fact that it's only touching 1/4 to 1/3 of the cells radius is not a big deal. The thermal conductivity of the cells in that plane is not great, but the flow of heat actually follows the conductors quite well.
radial heat conductivuty.png
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Re: Leaf in the tropical north

Post by antiscab »

bladecar wrote: Sat, 28 Sep 2019, 11:40 I have learned not to have a "specialist" car unless I am a specialist.
If you are not a hobbyist in the appropriate fields, avoid like the plague any transport which cannot be repaired by a commercial organisation in your reasonable vicinity.
This is solid advice
How comfortable are you working on electric vehicles? would you be willing to learn?
T1 Terry wrote: Sat, 28 Sep 2019, 12:17 Something I've always wondered, if heat rises and cold falls, wouldn't blowing cold air above the battery pack and exhausting it below the battery pack a better method for cooling? I see all these cooling plates the cells sit on, but wouldn't that be the coolest part of the cell?
That is precisely the method the iMiev uses, though I'm not sure where the exhaust comes out. Just pulls cabin air into the battery, and charging chademo tells the car to run the aircon.
I have heard of leaf being modified in this way too, at least to achieve battery warming.
Who want's to be the first to do the mod to achieve battery cooling?
I know of a leaf down to 60km range that may be a good candidate for testing some ideas out

20km round trip isn't overly onerous, it is a shame that all the vehicles that have active battery cooling have 300km range and cost $50k+
Matt
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Re: Leaf in the tropical north

Post by jonescg »

I hope to have a Leaf to play with soon. Only after a while though, Katherine would need to give her blessing :)
If nothing else, pulling air conditioned cabin air through the battery would make a world of difference.
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Re: Leaf in the tropical north

Post by JeffB »

Many thanks to all of you for you input.

Bladecar has hit the nail on (my) head - while I like the idea of engineering an electric car, the fact is I lack the time, inclination, and abilty to build such a vehicle. Thanks for the reality check.
However I do have some technical skill, and there are many people on this forum willing to share their knowledge. Which might be useful given the nearest Nissan dealer is 800km away in Darwin, and the nearest dealer with EV experience is probably 3000km away in Perth.

So I think the summary is:
I'm not a specialist so I need a production car with its less than ideal chemistry.
The battery will have a shortened life due to the high ambient temperature.
Active battery cooling will help but by how much?
With reduced life there is no point in buying more battery than I need.
My commute is 20km to town plus running around, say 40-60km. 20kWh is sufficient with a margin for degradation.
And I can still use the air conditioner. Phew!

I had not thought of trying to cool the Leaf's battery using it's air conditioner, I wouldn't have thought there was sufficient space between the cells to allow air flow, but if someone has managed to heat one then maybe I should have a crack at cooling one (except I'm not a specialist right).

We have to buy an EV because we rather blow our carbon budget flying to Perth for family. Also our other car is a Hilux - good for getting us into the bush, but bad form for shopping. When a serious 4WD EV becomes available we will have to get a mortgage and buy one.
Kununurra runs mostly on hydro power so home solar doesn't make much environmental sense, but an EV really does.
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Re: Leaf in the tropical north

Post by whimpurinter »

Hi JeffB

Of course the "specialist" term is not designed to be a put-down, but to work on ev's is to be a "jack-of-all-trades", but forget the "master-of-none" bit. This would be disastrous.
The way I have looked at it is to remember there are lots of older codgers who have continued to climb ladders to attach photos to walls, to clean their rooves etc and who have fallen off those ladders with disastrous consequences. This was because you don't ask someone to do these simple things, that you have done all your lives, and then you fall off the ladder.
This sort of argument sounds stupid but emergency services, the racq etc have treated ev's extremely seriously because they can't afford to benefit from the sort of voltage that ev-s use. Very rigorous methods have to always be adhered to, where underlying knowledge determines those methods. There's a video of a US ev drag racer (forget the name - White Something) with a dc drag car that was doing 9 second or 8 second quarters, who accidently dropped some metal across some terminals and was lucky to be able to push the vehicle out of the building before everything went up in flames. Injury was also avoided.
So, I decided that acquiring skills is only part of the scene. You have to have deeply ingrained understanding to deal with high voltages. Young people with new careers can do this, and determined any-other-agers also, if they so desire.

Here, I believe our best interest is served by freely giving up any relevant information about the new Electric Vehicles which will give us economical knowledge (we didn't have to give over thousands to learn these bits of knowledge), will help us determine which Makes to promote (buy, talk about), which Makes are old-world or simply continuing to look after themselves, and to properly serve the transported masses instead of contemporary business, ie expensive cars, accepted expensive services, no vehicle value after 10 years regardless of vehicle quality etc.

This is the hope :)
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Re: Leaf in the tropical north

Post by JeffB »

So we bought a Leaf!
2015 model second hand Japanese import (not imported by me). Has 11 bars on the battery condition meter. Drove around Perth for a couple of days then trucked it 3000km to Kununurra where it arrived on my wife's birthday. Nice timing. :D

I will order an OBD dongle and Leaf Spy to monitor the battery temperature while I figure out if airconditioning the battery is a feasible proposition. Meantime, when I can wrestle the keys from Di, I'm enjoying zooming around in a silent car.

Cheers
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Re: Leaf in the tropical north

Post by jonescg »

Was that the black one from Wangarra? I had my eye on it too ;)
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JeffB
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Re: Leaf in the tropical north

Post by JeffB »

Black!! We live in the tropical north - white is the only colour for a car. :D
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Re: Leaf in the tropical north

Post by coulomb »

JeffB wrote: Fri, 01 Nov 2019, 15:01 Meantime, when I can wrestle the keys from Di, I'm enjoying zooming around in a silent car.
Sounds like you need one of these T-shirts :)

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Re: Leaf in the tropical north

Post by JeffB »

After 12 months and 10,000km in our Leaf in the tropical north here are a couple of observations.
- Battery SOH has dropped from 83% to 78% with an equivalent loss of range.
- Even at our high average temeratures the GOM range was less in "winter" and has picked up again now it's really warming up.
- I don't believe active battery management would have made any difference. The thermal mass is so high that for the 20-25 minute drive to town the battery temperature dosen't change more than about 0.2 degrees. (An airconditioned garage might be good though).
- The auxillary battery failed while we were on holidays and now the onboard computer cannot caluculate how much time it requires to reach 80% charge. We set the timer to finish at 5am, and the charge level to 100%. At 5am it shuts off with about 84%. Doesn't seem to be relearning.
- And finally a key has died. It still operates but chews through a battery in about 3 days. Any ideas? Does the car need to go to a dealer.
We still love this car and in the abscence of an affordable replacement for the Hilux I'm doodling a Model 3 with a really high lift suspension job. :)
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Re: Leaf in the tropical north

Post by whimpurinter »

Hi,
It's really good to get the update on what has happened over the last 12 months.

I have tried to maintain constant power with the imiev when exchanging a new 12V battery for an old one but not because I know something about it. Just been very cautious around the possibilities around loss of settings. I do wish the imiev had a voltage reading for the low voltage battery on the dash somewhere (SINCE IT IS SUCH A CRITICAL COMPONENT THAT WILL REQUIRE REPLACEMENT FROM TIME TO TIME, BUT ALWAYS AHEAD OF TIME.) - Yes, I am annoyed. They have not been very helpful there.

I just accept there will be a drop in drive-battery condition on into the future so long as spacetime continues in only one direction. But the range of the car is known by an owner and won't under normal circumstances change rapidly over time so I consider it not important.

It's nice to have an ev and know that you're gaining knowledge about them as time goes by. I think it's a special though limited knowledge but current and useful.

p.s Do Teslas show the 12V battery voltage somewhere?

Edit: Added '12V'
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Re: Leaf in the tropical north

Post by brunohill »

JeffB wrote: Wed, 25 Nov 2020, 18:15 After 12 months and 10,000km in our Leaf in the tropical north here are a couple of observations.
- Battery SOH has dropped from 83% to 78% with an equivalent loss of range.
- Even at our high average temeratures the GOM range was less in "winter" and has picked up again now it's really warming up.
- I don't believe active battery management would have made any difference. The thermal mass is so high that for the 20-25 minute drive to town the battery temperature dosen't change more than about 0.2 degrees. (An airconditioned garage might be good though).
My Leaf in Wangaratta (inland NE Victoria) lost around 4% of capacity a year over 8 years. The climate is probably similar to Canberra with summer max (at the moment) at 46 'C and winter minimum around - 2'C (it used to be lower). I am not sure what the average is. On another note though I have noticed , that the average minimum temperature for every month,for every year (in the last 20 years here), has been higher than the previous year. Most people I have mentioned this to though, over the years, have told me this is absolute BS because they know the truth because they read it in the news paper.
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Re: Leaf in the tropical north

Post by JeffB »

Another 12 months and another 10,000km.
112440 km on the clock. SOH has dropped to 74%.
Interestingly the vehicle is a December 2014 build and when we bought it in October 2019 it the SOH was 84.5% - just shy of 4% degradation per year while in Japan. After two years in the tropics it has degraded 4.5% per year. Not as bad as I feared.
The average maximum temperature over the whole year in Kununurra is 35.2 degrees - it's been sitting at 41 all this week. As Brunohill notes: every year the temperatures get a bit further above average.

We had a good wet season this year so the creek crossing on our road was flooded quite often. We got pretty blase about fording 200mm, so on the way home and finding it just shy of 400mm we waded right in. I was possibly going a bit fast and the rear under car fairing ripped out taking the back bumper partially off, but otherwise OK. Repaired it all with Sikaflex and glass tape. It was pretty stupid and I worried for a few day about possible water ingress to the electronics.

There is a lovely Nissan video (that I cannot now find) on Youtube showing a Leaf fording 700mm. I'm not suggesting that they recommend it!
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Re: Leaf in the tropical north

Post by Rusdy »

Thanks @JeffB for the update! I love when people post their Leaf's battery stats (weird hobby of mine, I know :) ).

Your case is indeed another example that active cooling is simply unnecessary for city cars. Active cooling is indeed better, but the extra complexity and cost is just an expensive 'peace of mind', in my opinion.
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Re: Leaf in the tropical north

Post by antiscab »

Rusdy wrote: Mon, 18 Oct 2021, 20:12 Your case is indeed another example that active cooling is simply unnecessary for city cars. Active cooling is indeed better, but the extra complexity and cost is just an expensive 'peace of mind', in my opinion.
to give another anecdote point ( the old saying the plural of anecdote is not data)

The battery in our Zoe reduced from 100% to 96% SOH in 3 years and 95,000km. The first few years are supposed to be the steepest part of the capacity decline too.

btw - if the leaf went from 100% to 84.5% from Dec 2014 to Oct 2019, that'd be 3.3%/year in the steepest part of the capacity decline, vs 4.5%/year in the gradual decline part

Perhaps we should be recording our SOH somewhere central to see the difference between cooling strategies, climates and vehicles in general.
I wonder how many manufacturers are already doing this (taking a scan as part of the "service" they seem to think EV's need)
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Re: Leaf in the tropical north

Post by Rusdy »

antiscab wrote: Tue, 19 Oct 2021, 21:09 ...
btw - if the leaf went from 100% to 84.5% from Dec 2014 to Oct 2019, that'd be 3.3%/year in the steepest part of the capacity decline, vs 4.5%/year in the gradual decline part
...
Unless for the unlucky ones, i.e. owner of gen-1. My original battery dropped ~5% per year, and the new one from Nissan dropped 12% so far for the first year. Realistically, looking at the graph, same degradation path with original (i.e. 'canary' type):
Image
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Re: Leaf in the tropical north

Post by antiscab »

wow that's a pretty steep decline

do you poll the SOH every 3 months or more frequently?
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