D-Method on really stubborn cars or the A-Method :)

I have been trying these battery disconnect methods for weeks trying to get more than 29Ah out of my stubborn Australian PHEV.

BAZINGA ! Today I finally got it !!!

It is a modification of the D-Method with precise instruction how to get it right.
As this is the first time I am aware that it has now worked on an Australian PHEV I would like to celebrate by naming it the A-Method

First off I strongly suggest NOT to deep discharge the Auxiliary 12V as described in the D-Method !

1 - Find an old 12V car battery
SWMBO does not allow me to keep old car batteries (like I used to) so I went off to the local tip and found an old car battery that is not totally sulphated. You need a voltmeter, any little $10 job will do, which I consider an essential tool for any house hold and vehicle owner, especially a (PH)EV.
Find a battery that still shows at least 11.5V. I grabbed one that still had 12.2V.

2 - Discharge the old car battery to 8.5V
I used two 50W halogen down lights wired parallel to discharge it down to about 8.5V, measured while the load(lights) where connected.
Two old car head lights will also do. Just for the sake of copying my exact procedure use anything that has a load of abut 100W to discharge the battery, but not the car itself to get this 8.5V under load.
When you now disconnect the battery's voltage will go up again , mine went above 10.5V.

3 - Disconnect the AUX battery and plug in charger

4 - Connect your discharged old car battery with jumper leads to the positive jumpstart terminal in the large fuse box located in the front and negative to a nearby metallic surface and hold until your charger actually switches on.
This step is not that straight forward as it sounds and requires sub categories:

4a - make sure the jumper leads have a very good contact to the old battery. I pressed the clamps on the connector side firmly together and twisted them back and forth around the battery poles several times, so they scrape away any oxidation. Even if the poles look fairly clean you should do this.

4b - Connect as last the positive jumpstart clamp to the + pole in the fuse box and wait for your charger to switch on (of course you can leave the positive always connected and hold the negative against a solid metallic surface), just don't disconnect the jumper leads from the old battery.
Most likely either the voltage is too high and your charger goes on normally or it is to low and charge does not commence but if you followed my 8.5V discharge procedure you should be very close to the critical sweet spot.
It is very important to listen to the relay clicks, which sound like four first then a pause and then the last one which sounds to me like two at the same time.
If it sounds like that don't even bother looking at the watch dog.
You need to find the battery condition that delays the last relay click(s).

4c - If all relays click normally switch off the charger from the mains and wait at least 10 seconds, you should hear a thump like all the relays switch off at once.
Keep trying 4b, you are now further depleting the battery every time to get to that perfect sweet spot.
... and then it suddenly happens:
The relays go an slower, first four still fairly normally but the last one or two take a much longer time, so do not disconnect the jumper lead until the charger has switched on. In my case this seemed be over 10 seconds and then it barely seemed to click, charger light went on and after that quickly lifted the jumpstart clamp

5 - Somewhat excited about this new reaction of the relays and the charger still went on, I opened the watch dog and waited, oh no still 29Ah and stared a while at it thinking what else should I do.
Then a minute later, like magic, the 29Ah jumped to 40Ah right in front of my eyes.

So this really is a magic reset
However couple of charging hours later it dropped to 38Ah.


...well it was not quite like I wrote above because actually the second case under 4b happened to me:
The battery was discharged too much at first and the relays did not go on at all so it could not start the charge.
In reality I had discharged it down to 8.2V while the 100W load was connected.

4d - So I connected the 12V Auxiliary and started the normal charge with the old car battery connected to the jumpstart terminals.
Using the volt meter I measured on the jumps start terminals 14.1V but on the battery poles it showed 13.2V
That is how I discovered how important it is to twist the clamps on the old battery to get the best contact and it went up to 13.6V.
I disconnected the jumpstart lead on the positive jumpstart connector in the fuse box only, shut down charge and disconnected AUX battery and repeated 4c a couple of times until the delayed relay switching happened and the charger still went on.
If you missed the sweet spot just give it a couple of minutes with a 12V Auxiliary activated charge again.

This is probably the most complicated looking method on the net but if other methods didn't work for you:
DO AT YOUR OWN RISK !!

Never drive to 0km EV range, always leave a safe margin and test in a SAFE AREA with no traffic how it behaves when the drive battery gets near empty and check the Dog cell voltages !!!

Super :ugeek:

Let us know how behave your PHEV .. it was 29Ah before reset ... so check that it does not get over discharged when used "hard" in EV mode.

I'm also checking the SOC changes while at rest, for get an idea of real SOH .. I'm losing over 2Ah if I make multiple trips in EV mode without charge and with some rest time over 2h

elm70 said:

Super :ugeek:

Let us know how behave your PHEV .. it was 29Ah before reset ... so check that it does not get over discharged when used "hard" in EV mode.

I'm also checking the SOC changes while at rest, for get an idea of real SOH .. I'm losing over 2Ah if I make multiple trips in EV mode without charge and with some rest time over 2h

Click to expand...

Thanks

Yes I immediately started recording the results and they are now in :ugeek:
Yes the first image is from the ugly past:

After charging a while I saw this, what I would consider a realistic capacity for a near 5 year old battery:

Now look closely at the recorded time top right, it is a whole hour later but SoC has hardly changed.
This looks like a trickle charge to me and it is not over charging over the 4.1V:

This is my DIY slow charger in action that normally charges at 5.3A:

Lets have a look under the hood (of my meter box) so we can measure how many Amps it is actually charging with:

Over-Charge is never an issue

Over-Discharge is what is your risk now.

I see that immediately after charge you get SOC of 35Ah (in my case it is different, I get even more then 100% or more then 38Ah)
So .. I would not assume this is always the case ... sometime the charging process is paused and SOC updated ... so end SOC is variable ...

If you will leave the car charged without using for over 2h .. the SOC will be bounce to around 100% or almost 38Ah ... and from this SOC you have the risk to over-discharge the battery when using EV

Anyhow .. keep an eye on battery voltage via the DOG when using your car for a long EV trip ... if it goes too much down (below 3.5v without load, or after a slow down) .. I would suggest to click on charge button.

MadTechNutter said:

Lets have a look under the hood (of my meter box) so we can measure how many Amps it is actually charging with:

Click to expand...

So .. 1h trickle - charging ... that's strange ... never notice on my PHEV .. I have a monitor on power level from the 220v .. so I should be able to spot it in case.

Trickle charge Lithium battery is not a good thing ... maybe you should use the stock 10A charger, not a 6A charger ...

A miserly 1.18A trickle charge !

This is factual evidence that after this reset method, for me at least, that the battery does not get overcharged.
Keep in mind that I am using a slow charger that I have designed to match the output of my solar panels.
It is likely that the charge process would have terminated around the 95% mark but I had to go to town.
In the past it has terminated before once at 97% when it was doing this trickle charge which is likely a conditioning/balancing process.

So I got in the car started up and a whopping 55km EV range showed on the meter.
I drove my 16 km somewhat hilly round trip and came back with 36km left.
Before I would be lucky to have 22km left.

I noticed in the up hill legs that the guesso-meter does not drop so much as before and when I am coasting B0 down, it gained again.
Before it would only gain when I used regen.

I am not charging tonight so I can see how it performs tomorrow when it gets near empty.

elm70 said:

Trickle charge Lithium battery is not a good thing ... maybe you should use the stock 10A charger, not a 6A charger ...

Click to expand...

Every device with Li-Ion that I have serviced and own has a trickle charge in the end.
This is based on the physics behind charging a Li-Ion battery and the only way to provide a 100% charge.

Up until 4.1V you have a constant current charge, when it reaches 4.1V it becomes a constant voltage charge. The current doesn't suddenly stop but slowly ebbs off until the internal battery voltage and supply voltage on it's terminals have equalised and the current becomes zero.

Battery management may terminate earlier than zero but it never suddenly stops when the voltages on the terminals reach 4.1V. Typically a battery might have another 10% energy to absorb, while at the same time balancing is easier to perform.

I am so glad I don't have to mess around with pirated software.
It almost looks like fate that the data cable was lost in the post and I succeeded with this the next day.
...and I have now $20 to buy some really good beer and celebrate my 'new' car :mrgreen:

MadTechNutter said:

elm70 said:

Trickle charge Lithium battery is not a good thing ... maybe you should use the stock 10A charger, not a 6A charger ...

Click to expand...

Every device with Li-Ion that I have serviced and own has a trickle charge in the end.
This is based on the physics behind charging a Li-Ion battery and the only way to provide a 100% charge.

Up until 4.1V you have a constant current charge, when it reaches 4.1V it becomes a constant voltage charge. The current doesn't suddenly stop but slowly ebbs off until the internal battery voltage and supply voltage on it's terminals have equalised and the current becomes zero.

Battery management may terminate earlier than zero but it never suddenly stops when the voltages on the terminals reach 4.1V. Typically a battery might have another 10% energy to absorb, while at the same time balancing is easier to perform.

Click to expand...

Ok ... I guess is just a terminology "issue"

Trickle charge , which as far as I know it is used for NiMh, NiCd and LeadAcid , is a way to keep fully charged a battery, and this trickly charging is a never ending process

In case of Lithium battery, the charging process has two phase : Constant Current + Constant Voltage ... the second phase you define as trickle charge, but in my view it is a "wrong" terminology


PS: My PHEV does not spend hours in the "second charging phase" ... I can see the reduced power from the 220v source, but this is never longer then 45min .. possibly is also function of how high is the internal resistance of the battery .. so .. possibly my battery is in better shape, since it was also coming from a higher SOH before the reset ...

MadTechNutter said:

A miserly 1.18A trickle charge !

This is factual evidence that after this reset method, for me at least, that the battery does not get overcharged.
Keep in mind that I am using a slow charger that I have designed to match the output of my solar panels.
It is likely that the charge process would have terminated around the 95% mark but I had to go to town.
In the past it has terminated before once at 97% when it was doing this trickle charge which is likely a conditioning/balancing process.

So I got in the car started up and a whopping 55km EV range showed on the meter.
I drove my 16 km somewhat hilly round trip and came back with 36km left.
Before I would be lucky to have 22km left.

I noticed in the up hill legs that the guesso-meter does not drop so much as before and when I am coasting B0 down, it gained again.
Before it would only gain when I used regen.

I am not charging tonight so I can see how it performs tomorrow when it gets near empty.

Click to expand...

I would suggest to check in advance the SOC and voltage after 2h rest from your trip ...

You might get surprise about SOC, and as well, if the voltage per cell is below 3.78v ... I would suggest to don't leave overnight the car in such low voltage ... better to charge a bit the car .. I often set a 1h / 30min charging timer for avoid to leave too low the voltage in my PHEV ... as well .. for me it is not ideal either to left the car fully charged for long time too. My WifI switch is very busy every day for set up ad hoc the charging time/timers :ugeek:

The D-Method has worked for me too! I partly started going along the "A" method using an old car battery, but that only had 6.5v and I wasn't able to get a charge into it. So, decided to revert to the D-Method!

Firstly, I thought I had messed this up. Here's what I did:

1) Main drive battery down to 24.4 Ah
2) Switched auxiliary on (two presses of start button without brake pressed).
3) Put on headlights, main beam, fog lights, fan on full, both seat heaters and 12v charging of phone and iPad.
4) Activated the Dog. BMU showing 11.1v and started dropping. Went in the house for about 15 mins.
5) Returned to the car and the front windscreen wipers moving eerily across the glass with the moaning of a dying battery! Dog shows 6v on the BMU.
6) Disconnected the 12v battery, plugged in the charging cable and reconnected the 12v battery. Nothing, other than the attempt to wipe the windows! The relays didn't even try and trigger.

At this point, I am thinking I have drained the 12v battery too much and hoping my emergency charger still works! However, I notice from the Dog that the BMU has rebounded to 6.3v. So, I reckon to disconnect the 12v battery and leave it 15 mins to see it recovers enough to trigger the charging cycle.

7) Came back 15 mins later, reconnect the 12v and a bit more life, loads of dings from the car console but the charger still not activating. At this point, realise that the car is still switched on and it is throwing loads of errors about EV system failure, brake failure, etc, etc. I hit the power and the car switches off.
8) Disconnect the 12v battery, plug in the charger, reconnect the 12v and remove just before the charger clicks on.
9) The charger activates, I wait 10 seconds and reconnect the 12v. Dog is still showing old capacity (32Ah).

Hmm, so at this point I wonder what SoC the 12v is at. So, I disconnect the charger, jump in the car and start it up. Starts fine. Look at the Dog and it is showing 13.7v for the BMU - the drive battery is clearly now charging the 12v battery.

So, I switch off and start the procedure again but this time, stay in the car.

10) Switch on auxiliary, put on headlights, main beam, etc and activate the Dog. This time, the BMU voltage drops quite quickly from 11v.
11) At about 8v - 9v (can't remember now!) errors start coming on the dash. When the 'EV system error' appears, I switch everything off (fan, lights, seat heaters, etc) and switch the car off. I reckon this is the crucial one - my guess is that this EV message is saying: BMU wiped. . . .
12) Disconnected 12v, plug in charger, reconnect 12v and remove just before the click. Waited 10 seconds and connected 12v.
13) Checked the Dog, still showing old capacity (32Ah). Bugger.
14) Disconnected 12v, plug in charger, reconnect 12v and removed when the charger clicks on this time. Waited 10 seconds, connected 12v. NOTE: I didn't notice any noticeable slowing down of the clicks from the relay and the charger activating.
15) Checked the Dog . . . . capacity now showing as 105.3% and 40Ah!!!!

I left the car charging. Coming back about an hour later I checked the Dog again and the SoC had risen from the initial 24.4 Ah to 29.5 Ah. But, the Dog then updated itself to a 38 Ah / 100% capacity and gave me the 'Battery capacity change detected! New Capacity: +38Ah(+6Ah)'. On the dash, there was still a warning showing an EV error.

Interestingly, when the charger switched off the Dog showed a charge level of 95% and 36.1Ah. I unplugged and switched the car on fully and there was no EV error message. Now, looking at Battery Condition and tapping into the latest (100%) card, it shows the battery age as 60 days old, rather than the 1,858 days that it was. The total Ah value had also reset from 123,444Ah to 0!

I then went out for a drive to celebrate (10km) and used 7.5Ah (with 1Ah regen). I then put it back on charge overnight but with a 1 hour delay before charging started. I had the charger in a mechanical timer that switched off at 6am this morning.

Looking at the Dog this morning, the new capacity dropped 0.1Ah to 37.9Ah, but SoC this time is 99.7% / 37.9 Ah.

I find this interesting in that the overnight charge got to 99.7% SoC versus the 95% from the first charge. In both cases, cell voltage was showing 4.1v. This bit confuses me, I got to admit! What I am thinking is that this second overnight charge kept reaching capacity, switching off, the cells are settling down and the SoC drops and the charger triggers again, gradually reaching the 99.7% SoC. Of course, the long term charge values will be more telling.

Finally, I did try the Lindqvist method several times with no joy. I am thinking here that the important bit is for the voltage being supplied to the BMU is dropping, rather than being removed, so that the EV error triggers. Many of the reports I have seen highlight this EV error on the dash, so I think it is whatever is triggering that error is the key, irrespective of the process being used.

Anyway, going out for a 120 mile drive today, so will see what happens!

mellwaters100 said:

The D-Method has worked for me too! I partly started going along the "A" method using an old car battery, but that only had 6.5v and I wasn't able to get a charge into it. So, decided to revert to the D-Method!

Click to expand...

You could have just done step 4d from the A-Method, I reckon 2-3 minutes would have brought it up to 8.5V and saved you the mess of discharging the Auxiliary.

Anyhow great you got it working

I really can't recommend draining the Aux battery to that extent.

Yes it happens if you leave your lights on by accident etc, but it could reduce your Aux battery life.

So instead you can buy 12 volt power supplies for LED lights.

From another post I see you need more than 5 amps, so 10 amp units cost about £13, UK stock, not from China!

Some have a dimmer, but I suspect that alters the current, not the volts.

So you also need an adjustable 10 amp DC to DC Down Converter, about £7.

Both units have screw terminals, so no soldering!!

They mention fan cooling for 10 amps, but that's for continuous, we're only briefly kicking the relays.

Now you can easily find the "sweet spot".

Michael

elm70 said:

Ok ... I guess is just a terminology "issue"

Trickle charge , which as far as I know it is used for NiMh, NiCd and LeadAcid , is a way to keep fully charged a battery, and this trickly charging is a never ending process

In case of Lithium battery, the charging process has two phase : Constant Current + Constant Voltage ... the second phase you define as trickle charge, but in my view it is a "wrong" terminology


PS: My PHEV does not spend hours in the "second charging phase" ... I can see the reduced power from the 220v source, but this is never longer then 45min .. possibly is also function of how high is the internal resistance of the battery .. so .. possibly my battery is in better shape, since it was also coming from a higher SOH before the reset ...

Click to expand...

Yes terminology issue.
Any charge for me less than 0.1C is a trickle charge, no matter how long, but yes secondary works for me too.

I think the extended secondary stage comes from the fact that the BMU software 'thinks' that the battery is only 94% charged and stays on longer in an attempt to reach 100% but a separate hardware regulator prohibits that the voltage can exceed 4.1V.
No doubt when the fake SoH after this reset drops and gets closer the the real SoH value, maybe around 34Ah this secondary phase will get shorter.
It won't take hours either as I assume when the charge drops below 1A it will be terminated. That could have been in the next 10 minutes but I had to leave for my destination.
Next time when I have time and can be awake to monitor a full charge I will know more.

Age or true state of the battery would indeed play a role here. My 29Ah was a lot lower than yours if I remember correctly.

michael8554 said:

I really can't recommend draining the Aux battery to that extent.

Yes it happens if you leave your lights on by accident etc, but it could reduce your Aux battery life.

So instead you can buy 12 volt power supplies for LED lights.

From another post I see you need more than 5 amps, so 10 amp units cost about £13, UK stock, not from China!

Some have a dimmer, but I suspect that alters the current, not the volts.

So you also need an adjustable 10 amp DC to DC Down Converter, about £7.

Both units have screw terminals, so no soldering!!

They mention fan cooling for 10 amps, but that's for continuous, we're only briefly kicking the relays.

Now you can easily find the "sweet spot".

Michael

Click to expand...

Careful with those regulated/dimmer 12V LED supplies.
AFAIK they could be PWM controlled, duty rate 12V on/off switching. This works far more efficient for lighting.
Normally the voltage control of the 12V is fairly minimal, doubt they go down to 8.5V.

There are proper DC step down converters for 10A and more but they should also have a display of voltage at least.
Not all will survive the sudden 14V external on their output.
A 10A diode on the output for reverse protection would help but the voltage will not be so stable any more because of their voltage drop is dependant on the current.

In fact you could just try a whole bunch of these diodes(they are very cheap) in forward direction as voltage drop in series to the Auxilary Battery and use that instead of any external power supply source.

At 5 amp they would drop around 1V each, 10 A a little bit higher but not massively like using resistors. I mentioned elsewhere that resistors didn't work for me as the voltage drop varies far too much under different loads while the system powers up.
So diodes should behave more stable, like a deep discharged voltage battery that will also drop it's voltage somewhat with load but NOT like ohms law with resistors.

3-4 in series might work. Maybe a Schottky diode in between for a smaller drop to get a better resolution.
Think of the Schottky like half a standard diode.
So trying out combinations of all these diodes until you get the relay response under 4c of the A-Method.

Diodes must be 10A or higher and if you are holding them in your hand they could get quite hot very quickly. Use at least 1.5mm^2 wires for the battery to terminal inline connection.
A terminal strip should be OK to screw them in series.

ALL AT YOUR OWN RISK

There you go:
The Diode Dropper for the ADD-method :mrgreen:




Took me less than 5 minutes. Never mind the fuse holder, I just took that wire from another project.
You should be able to get all those bits for less than 10 bucks at the local Jaycar store, or whatever your electronic parts store is called.
Red goes to the car terminal, black to the AUX battery negative.
I didn't have a 10A Schottky but you see how they are wired just add or replace one of the normal ones.
You might only need three diodes, just try combinations.
If you can only get 5A Schottkys use two in parallel.

You might not even have to bother about immediately disconnecting the battery when the charger starts.
The way this works is that the charger voltage will be higher than the battery, well strictly speaking lower potential as the ground terminal will be too low for the diodes to conduct towards the battery pole. You could say electrically disconnecting themselves.