Nissan Leaf (gen-1) Old vs New Battery

[UPDATE 06-May-2022: Updating battery degradation chart]

Comparison of battery degradation (Nissan Leaf gen-1), before and after battery replacement:

Note that the top x-axis is for the new replaced battery, both plotted on the same date scale for easy comparison. My mileage usage is consistent every week, so using date scale for convenience:

The bump above, that was when I had recall from Nissan for battery software update, which I'm guessing is this one.

Now, for the difference in kWh/km reported by dash vs LeafSpy reading, comparing old vs new battery:

From my old battery below, 0.13kWh/km (dash) vs 0.18kWh/km (LeafSpyPro):

From new battery, which both has same figure at 0.12kWh/km:

However, do note new battery also suffers some difference (maybe depends on SoC?), as example below. I forgot to take photo from the dash on the day, but it was 0.13kWh/km on the dash (compared to 0.18kWh/km from LeafSpyPro):

Issue above causes the battery meter seems reporting discharge quicker, and then slows down later.

Nissan Leaf 2012 Fast Charge Curve

Some data from my Nissan Leaf 2012 fast-charge sessions:

Before and after battery replacement. Both data are for gen-1 battery, a.k.a canary battery:

Not too far from out there:

eBike Long Term Reliability (2)

After clocking 54,000km since 2013, my DIY eBike conversion has indeed surpassed my expectation.

Photo of now and then.

Update since then:

Upgrade to a Bigger Battery:

The one on the photo above is my 3rd one (14Ah Tiger Shark Battery).

My 2nd set of battery has performed better compared to my first one by simply doing these:

1. Fill any gaps with silicon grease. No more water ingress!
2. Don't leave it fully charged and then leave it unused, especially on hot days.
   

Second bullet point above is important if you want to extend your battery life. My 2nd set of battery is now just under 9Ah capacity left (original 11.6Ah) after 1,000 deep cycles. Where as my first one degraded to just under 8Ah after same 1,000 deep cycles (see Note 1 below).

What happened to my previous batteries? Are they polluting the landfill?

Glad you ask! (of course you didn't)

They're joining my battery storage in my shed. I've upgraded my off-grid shed to include my ex-eBike batteries! Also, after getting an extra solar panel couple years ago (super cheap 2nd hand panel), my commute has been totally charged by the sun, even in winter cloudy days! Well, ok, half-lie there, as the other way charged at work, ha!

Note:

1. 'Deep cycle' here is 7Ah average per ride after 1,000 cycles. Individual rides vary between 6 to 9Ah, which highly depends on head-wind.

Sin of Early Adopters

Ah, the sin of early adopters. The consequence from Nissan Leaf's engineers bad choice for their first generation EV battery, is now felt years later: The wrath of increased internal resistance (see UPDATE below)!

So far, my first-gen Leaf (i.e. 2012 built) decreased battery capacity (originally 24kWh) is not my biggest problem, thanks to network of fast chargers. The degrading internal battery resistance is!

My real issue is, instead of being able to 'fill' my battery in 6 minutes for a quick top-up of 5kWh, or roughly 30-ish km of range (so I can quickly get back on the road), the degraded battery has also 'slows' down the quick charge capability considerably. More than twice as long!

Prodding into cells' battery voltage during fast charge, revealed that the BMS deliberately slows down the charger in order to maintain cell battery voltage under 4.1 Volt at any stage. Fair enough. One can expect this 'slowing down' when the battery is closer to fully charged (i.e. 80% SoC or above). Due to massive degradation of 'Hx', this now happens very early on mine (under 50% SoC). Yikes!! (see UPDATE below)

I just never thought the 'Hx' degradation griefs me equally as the 'SoH' degradation. Sad.

Looking at the bright side (so I can feel better), other than batteries, Nissan Leaf is such a good car (said me who treat cars like a fridge, i.e. purely utilitarian). Definitely no disappointment to date (except the battery...)!

My battery history so far:

Nomenclature buster:

BMS:
Battery Management System.

SoH:
State of Health is another indication of the battery's ability to hold and release energy and is reported as a percentage. When the battery is new SOH=100%.

SoC:
State of Charge indicates the amount of charge currently in the battery.

Hx:
The meaning of this number is not fully understood but it appears to be inversely related to the battery internal resistance. As the internal resistance of the battery pack increases it is thought this percentage decreases. As internal resistance increases more energy is lost within the pack and the pack heats up more under load.

UPDATE 24 June 2019:
I had another fast charge session from 20%SoC, and I was expecting the 50kW charge lasted longer. I was wrong. After self-research, I've just found out something called polarisation effect. So, the aging of my Leaf battery grief is mostly due to this, not internal resistance.

Presented below in equivalent circuit. There you go!

Powerwall 2 Time Base Control Algorithm

Since PW2 (Tesla Powerwall 2) introduced the new TBC (Time Base Control) algorithm, I had a great difficulty in trying to understand the actual algorithm, especially during shoulder period. Consulting forum (such as here and here) only confuses me further, especially when the forum started to discuss incentives and local regulations (US centric). This, however, makes me appreciate the herculean task for PW2 engineers. You simply can't make everyone happy.

The ever evolving nature of PW2 algorithm (typical Tesla my guess), makes any 'User Manual' writing attempt a futile exercise. Reverse engineering the algorithm also requires different permutation, such as state of charge, how much PV production during the day, etc that can affect the PW2 behaviour.

Still, little documentation is better than nothing. Since I don't have the stamina to try all permutations, I deliberately write down as much details below (trying to be as neutral as possible, i.e. no incentive and regulation jargon):

Off-Peak Cost Saving Mode:
In this mode, PW2 does try to aim a certain State of Charge prior entering shoulder and peak period (by charging from the grid if necessary). Based on the limited 2 days experiment (see screenshot below), this State of Charge (SoC) is not a fixed value. How does PW2 decides this SoC level? Me no idea.

Also, some charge from PW2 is used during off-peak period (see bubble number 1 in the screenshot). I don't know how PW2 decides when to use the battery. One thing for sure: it mostly uses the grid to conserve the SoC for peak period.

I haven't tested what happens when you have solar production during off-peak period.

Shoulder Cost Saving Mode:
Now this gets interesting. In day 1 of the test (see bubble number 2), my PW2 behaved as I wanted it, that is: no grid activity (i.e. to behave exactly like peak). Too bad I didn't record the SoC, but I remembered it was roughly 40-ish percent at this stage.

In day 2 (see bubble number 3), my PW2 started to be less agressive (despite higher SoC compared to the previous day), i.e. grid activity is allowed by importing and exporting. Uh oh, for me, who has a power provider that value exported PV close to zero (yup, zilch, nada), this is bad news. Also, why PW2 allows a significant grid import when the battery SoC is relatively high (roughly 60-ish percent at bubble number 3). Is this because PW2 hasn't learnt that I don't usually use lots during peak period? My guess at this stage, this is due to the PW2 algorithm is based on US-centric market, where they have incentive to export PV to the grid (such as net metering). Pure guess though.

At this stage, my panic mode was on, and I switched it back to 'Self-powered' mode (as commented by the red line), which explains why the screenshot is no longer showing peak/off-peak on the 14-th May, and also 100-ish watt grid consumption during solar production after the switch (see my previous post).

After 14th of May, I changed PW2 to 'TBC Balanced' mode and extended the peak period to also cover shoulder (i.e. only peak and off-peak, no shoulder). This has worked perfectly for me, but...

In the last 2 days, I haven't had enough PV production to cover my shoulder and peak. This has caused me grief since now I need to import from the grid during peak period (see bubble number 4). So, I changed it to TBC 'Cost Saving' mode, thinking that PW2 would've charged from the grid during off-peak to cover my PV production shortfalls. To my surprise, it didn't (although the SoC was just a tad below under reserve).

So, here I am, finding another quirk in PW2 algorithm. If you don't set the shoulder period,  PW2 will not charge from the grid (despite the PW2 SoC at the reserve level). What the??

In the screenshot below (see bubble number 5), you can see that as soon as I bring back the shoulder period, PW2 behaves as I expected again by start charging from off-peak grid (I've found this by coincidence).

In short, for those who want exporting to the grid at the very lowest priority, I recommend to use 'TBC Cost Saving' mode with a wee bit of shoulder period (just enough to activate 'charge from off-peak grid mode').

PS: Peak period behaviour is consistent as expected, i.e. no import from the grid.

My Observation of Tesla PowerWall2

My Tesla Powerwal 2 (PW2) summary, freshly installed just 3 days ago:
[UPDATED 7 May 2018: see point 6 below]

1. PW2 can be installed in multiphase (mine is 3-phase). PW2 monitors each phase current using Current Transformer (installed by the installer of course).
2. PW2 basically absorbs all your solar power instead of injecting them back to the grid. What is worth to be noted, although you have load on different phases, the PW2 will compensate this so that your electricity meter reads export as 'zero' (since Australian domestic electricity meters don't care on which phase you're consuming). So, in my example, I was using an induction stove top at 1000 Watts on the 'white' phase, and the PW2 injecting back to the grid at 1000 Watts at 'red' phase, resulting net zero export. To mention the obvious, PW2 inverter maxed out at 5kW power.
3. Non-noticeable transfer time when the grid has failed. I've tested this 2 times: at first attempt, the solar panel inverter anti-islanding has to reset (causing the solar power to cut for about a minute). In the second attempt, the solar inverter didn't trip at all (as if nothing happen). I'm definitely impressed on this one. To mention the obvious, only 'red' phase of my home is backed up by PW2. Other phases are not. Now I can officially welcome mad max scenario!
4. During daytime (when the solar panel is active), I've noticed PW2 constantly draws around 100 Watts from the grid, but not at night time. I can't find any info in the internet on the why, yet. My guess, PW2 requires power for its own functionality and ineffeciencies in converting AC to DC and somehow only compensates during daytime? 
5. It is also worth to be noted, unlike the Tesla cars, users can't set the maximum charge level on PW2. My guess, Tesla is now extremely confident that this is no longer required. Maybe combination of newer chemistry and internal software to limit when required during hot days?
6. My particular one consistently under report kWh used and exported to the grid by roughly 15 - 20% (compared to my grid provided meter). However, the solar energy kWh is spot on (compared to my soalr inverter kWh measurement). No idea the why. Anyone experiencing the same issue?

What it doesn't do and I wish Tesla will update this functionality sometimes in the future:

• Change the timing on the 100-Watt constant draw from the grid. I wish this is user configurable. For example, to draw this at night time, or to use solar panel instead. For me who on Time of Use plan, this total of 1kWh on daytime is something I'm not willing to pay the grid for. Call me stingy.
• Ability to charge PW2 from the grid during off-peak via the app. At the moment PW2 only absorbs power from solar panel. Since my solar panel is not enough for my usage, I'd love to have the ability to get cheaper electricity at night to be used by my household during peak time. Quicker ROI anyone?

Now, to how I use the Tesla app:

• Once the installer enter account holder details via the installer page, your PW2 will be immediately visible on the Tesla app (you'll need wi-fi router for PW2 to connect to Internet). I haven't accessed the PW2 directly via the ethernet router (no reply). Will try again next time.
• The visualisation of the app is indeed very useful. For a data hoarder like me, the visualisation has altered my energy usage. For example, now I know my inverter reverse cycle Air Conditioner doesn't have linear energy consumption (I thought it does). It has step changes, i.e. 2.4kW at full power, then 1.5kW, then 900 Watts at lowest power (in cooling mode). When the PW2 is low in charge, I deliberately turn off my air-con to minimise grid usage and happy with slightly higher room temperature (but still comfortable). My guess, sometime in the future, all home appliance will talk to each other (via ethernet router, just like the PW2 at the moment) and have AI (Artificial Intellegence) based on user preference on how and when to consume energy (whether to save energy, or maximum comfort).

So here is my data, just 1 day after it's being installed (grid data not shown for clarity):

The data above is definitely not my average day. I had to travel 120-ish km on that day, so most consumption gone to EV (I'm guessing around 18kWh).

Now my debt has increased significantly again (thanks to PW2 as an expensive toy), so the family now have to be content living from boiled water and salt. At least we have a good-lookin' dead weight on the wall now (wheel added in MS Paint to make me feel less guilty by the dead weight):

[UPDATE 12 Oct 2020 for 2018 annual figure]:

Motor Listrik

Akhirnya, Indonesia akan memproduksi sepeda motor listrik [1]. Sedikit telat, tapi lebih baik telat daripada tidak sama sekali. Menurut saya, tidak ada yang spesial dari sepeda motor listrik ini. Modelnya hanya mencontoh dari motor bebek. Eropa, Amerika, Cina, Jepang, dan banyak negara lainnya sudah memproduksi sepeda motor listrik mereka sendiri, dan modelnya jauh lebih menarik.

Melihat spesifikasinya, produsen motor listrik ini mengunggulkan koneksi ke smartphone Android. Daripada menambah fungsi-fungsi 'nggak-penting' (untuk apa CPU ber-GHz di motor listrik??), produsen motor listrik di Indonesia, bersama dengan pemerintah (PLN), seharusnya juga memproduksi motor listrik untuk kelas 'ekonomi'. Sistem Baterai yang sama juga bisa digunakan untuk elektrifikasi daerah pedalaman yang sulit terjangkau oleh listrik.

Saat ini, banyak daerah pedalaman yang masih menggunakan gen-set untuk mendapatkan listrik. Bahan bakar untuk gen-set di daerah pedalaman, apalagi ratusan pulau di Indonesia Timur, harganya tidak terjangkau (berhubung mahalnya ongkos kirim). Walaupun beberapa daerah mendapat subsidi, anggaran tersebut seharusnya digunakan untuk kepentingan lainnya, seperti membangun infrastruktur daerah.

Stasiun-stasiun pengisian baterai (dari panel surya, atau sumber energi terbarukan lainnya) dibangun di daerah-daerah ini untuk mengisi baterai motor listrik. Bagi yang mampu, bisa memasang panel surya sendiri di rumahnya. Dengan sistem energi terbarukan, tidak perlu lagi bayar ongkos kirim untuk bahan bakar. Sampai di rumah, baterai yang sama bisa digunakan untuk lampu, TV, dan pengisian telpon genggam dan banyak lainnya. Sistem peminjaman juga harus diterapkan, karena tidak mungkin masyarakat membayar harga motor-motor listrik ini.

Baterai untuk motor listrik ini tidak dapat diremehkan. Dengan kapasitas hampir 2kWh, baterai ini bisa digunakan untuk mengoperasikan kulkas kecil beberapa hari. Sulitnya implementasi di lapangan, saat ini, karena tidak adanya standardisasi untuk tegangan rendah. PLN seharusnya mempelopori standardisasi tegangan rendah untuk daerah pedalaman. Dengan adanya standardisasi ini, produsen-produsen lokal bisa mulai memproduksi peralatan rumah tangga yang mampu menggunakan baterai yang sama dengan motor-motor listrik ini. Contoh, motor listrik ekonomi mungkin bisa menggunakan baterai 48-Volt, dan peralatan rumah tangga untuk daerah-daerah pedalaman ini (seperti lampu, kulkas, sampai kompor listrik dengan induksi) bisa menggunakan sistem ini juga.

Kalau saya sendiri saja sudah merakit sepeda listrik sendiri dan diisi ulang oleh panel surya. Masa produsen besar tidak bisa?

Sekali tepok, ratusan nyamuk. Tidak perlu konek-konek-an ke Android.

Sumber:
[1] http://www.jpnn.com/read/2016/05/05/401025/Ini-Keunggulan-Gesits-Motor-Listrik-Buatan-Indonesia-

Secondary Battery System for Camping Trip

So, I've done a few research into 4WD battery system (dual battery system) since I had few colleagues asking me what secondary battery system is best for their 4WD camping-bush-trip. The more I look into this (in Australian market), the more I am impressed of how expensive these battery systems are. By simply looking into REDARC website, one should wonder, why on earth battery management system can cost in the order of thousand of Australian dollars (excluding batteries). There is nothing 'smart' with lead acid batteries! Boy oh boy!!

It is true that you need some charging management system so that your car is protected from over-loading in charging deep-cycle batteries. But, do you really need to spend thousand dollars computerised battery charging system?

"People don't buy for logical reasons. They buy for emotional reasons" rings so true in this 4WD market. Just looking around the car park at my work, people spent literally tens thousands of dollars to upgrade their 4WD (or cars, generally). Nothing wrong with that of course, here is me being hypocritical, willing to spend hundreds of bucks accumulating second-hand batteries to satisfy my emotional needs! Luckily I can't afford those yet.

Anyhoo, for those who want to go camping trip, and simply need pure battery function (no emotion involved), then I got a surprise for you! Please don't buy those off-the-shelf power pack (the like of ArkPak) with batteries from camping shop, they are a RIP-OFF!! If you can tinker a bit, then you can save literally hundreds of dollars!!! (yup, that's right, 3 exclamation marks)

Here is my proposal (no need to tinker your car wiring either):

Component list:

1. Cigarette Lighter 12V plug from Altronics (click here)
2. DC – DC converter (to be set to 13.8 Volt and 5 Amp). Get it here.
3. 12V 100Ah lithium battery
4. Low voltage protection switch
5. 12V cigarette lighter socket

Technical note:

• The setup above is charging the lithium battery one way only, i.e. no current back flow from lithium to your car system.
• Since you plug it to your car's cigarette lighter socket, it ONLY charges when you turn the engine on. Do keep it connected all the time to ensure the battery charged, always.

The whole lot above can give you up to 1000Wh of electricity and cost less than AUD1000. Forget those expensive ArkPak or the like that can cost you more than double of what I proposed above. Well, yes, you do need to tinker a bit, but hey, I'm talking to those who are adventerous right? The electric is so simple: red to positive, black to negative. Come on, it's not rocket surgery (or brain science)!

If you feeling even more adventerous, you can replace the supply (item 1 and 2) with solar panel (minimum 60 Watt) with MPPT module. For the MPPT, I can recommend Genasun. Please, please, please, simply skip crap 'charge controllers' and save yourself troubles.

Happy camping!