[shrowell]

Per KA, one of the features of the 530 update is:

The end of the ‘trickle charger’ - The current functionality of the vehicle requires you to use a trickle charger to keep the 12v battery maintained during longer periods of vehicle disuse. The new software will allow the HV battery to maintain the 12v battery charge until the HV battery is drained to around 10% SOC at which point it will start to protect itself only. In all but extreme circumstances, a trickle charger will no longer be needed.

I had the 530 update performed by Pat's Garage last week. I have had the car sitting for a few days without my trickle charger attached (but with a fully charged HV). Today, I was curious to see what the state of charge was on my 12V battery. I found that, according to my trickle charger that has "percentage charged" display, the 12V battery was at 50-60%. Does anyone know if that is the target for the new algorithm?

I am going away for a couple of weeks, so either I risk it and let the car take care of itself for those days or I leave the TC connected.

Thoughts? Anyone proved the self-maintenance is working well? Can leaving the TC on with this software behavior cause an issue?

Simon

 

[Ira]

Good questions Simon. But we need to know if you have a new 12V battery or the original, which is 4+ years old. If the latter is the case, the battery is near the end of its life and might be having trouble maintaining its SOC.

 

[shrowell]

Thanks Ira - I have no records to indicate that the previous owners changed the battery (although I did get a battery depletion warning a few months back, so you could have a point). I have fully charged the battery with my TC and will check to see what it's like tomorrow around noon. If I see much of a discharge I will leave the TC connected while I'm away for the next couple of weeks.

Still very interested to hear the groups perspective on the 12v battery auto-maintenance and whether TCs can/should still be used.

Simon

 

[Harleyguy]

The real test if the software makes a difference is checked my the MA draw before and after the upgrade . I haven't had the time to compare the before and after I will try and make a post this week .

 

[Ira]

Thanks Ira - I have no records to indicate that the previous owners changed the battery (although I did get a battery depletion warning a few months back, so you could have a point). I have fully charged the battery with my TC and will check to see what it's like tomorrow around noon. If I see much of a discharge I will leave the TC connected while I'm away for the next couple of weeks.

Still very interested to hear the groups perspective on the 12v battery auto-maintenance and whether TCs can/should still be used.

Simon

Take a look at this exemplar SOC chart. It doesn't take much of a voltage drop to cause your TC report a lower-than-expected SOC.

 

[shrowell]

That is an interesting chart and suggests to me that my battery may be borderline as it gets into the yellow sector very easily. That being said, I checked the battery this morning after 24 hours of letting the car look after itself. The initial reported charge by the TC was 27% (!) but this rose quickly to 75% after 15 minutes. So I suspect I have a dodgy battery and the 530 software update isn't helping (I will get the battery changed in the near future).

That leaves my key question, though - I assume I won't be doing any damage if I leave the trickle charger running while I'm away.

 

[Ira]

That leaves my key question, though - I assume I won't be doing any damage if I leave the trickle charger running while I'm away.

I'd like to know the answer to that as well. Although I already have a new 12V battery (and will have BL530 this week), it seems like using my TC would be cheap insurance for an upcoming trip. But without knowing what that might do to the HV battery's own trickle charging system, I won't take the chance until we can get an definitive answer from KA or one of our trusted experts.

 

[shrowell]

I left my TC connected for two weeks while travelling (despite having 530 installed) and all was well (100% charged). I disconnected the TC and left it disconnected for 5 days (with one 20 minute drive during those 5 days) and upon connecting the TC, it said initially that I had 35% charged battery and then:

- After 5 minutes - 53% charged
- After 15 minutes - 56% charged

I am not suggesting that my TC is accurate and the official standard (!), but it does suggest that the 530 update is not maintaining the 12V battery at 100% - maybe it just keeps it at some lower percentage (as in Ira's chart).

Any other thoughts? Right now, I cannot trust 530 to be doing what Karma states it should be doing and my car will be dead without the TC.

I will post this note on the Karma forum as well (though I don't find it as helpful as the 'Buzz!).

Simon

 

[shrowell]

Update from Karma Automotive:

With Baseline 530 software installed in your vehicle, the High Voltage Battery Energy Control Module (BECM) ‘wakes up’ every 60 minutes to complete a diagnostic check.

During this scheduled Diagnostic Check, the BECM checks the 12v Battery voltage.
If the 12v Battery is less than < 11.5 volt, - the vehicle will initiate a 20 minute 12v Maintenance Charge Cycle. Note: High Voltage Battery, using the DC/DC converter charges the 12v Battery.

I’m unfamiliar with your Trickle Charger, so I can’t comment on its capabilities, or strategy in determining 12v State of Health.

Our Baseline 530 12v Battery Maintenance strategy is based on a <11.5 volt threshold.
A degraded 12v Battery can see its SOC drop below 11.5 volts well with an hour time frame, and the 12v Maintenance Charge cycle included with BL530 is limited to 20 minutes of charging during each cycle.

If you suspect that your 12v battery regularly has a reduced SOC (State of Charge), I would advise having your 12v battery tested using a Midtronics battery tester to determine if replacement is necessary.

I replied:

I have a Schumacher SP3 TC and by all accounts the % SOC displayed is not very accurate - you are right; I need to check with a Midtronics unit or similar, primarily because most SOC charts I have seen for a 12v battery indicate a 10-20% SOC at 11.5v (and some say discharged).

On the other hand, I could just leave the car to sort itself out - assuming the car is functioning properly and the battery is okay, how long would my Karma take to deplete the 12v battery to the point that it would try to charge itself? Do you think the 12v battery could get to the point where it cannot be recharged?

I'm up for the experiment if you think it might be of interest (or I can fully trust 530 )

 

[Ira]

I left my TC connected for two weeks while travelling (despite having 530 installed) and all was well (100% charged). I disconnected the TC and left it disconnected for 5 days (with one 20 minute drive during those 5 days) and upon connecting the TC, it said initially that I had 35% charged battery and then:

- After 5 minutes - 53% charged
- After 15 minutes - 56% charged

I am not suggesting that my TC is accurate and the official standard (!), but it does suggest that the 530 update is not maintaining the 12V battery at 100% - maybe it just keeps it at some lower percentage (as in Ira's chart).

Any other thoughts? Right now, I cannot trust 530 to be doing what Karma states it should be doing and my car will be dead without the TC.

I will post this note on the Karma forum as well (though I don't find it as helpful as the 'Buzz!).

Simon

I've been away for two weeks as well and left the Karma plugged into the HV wall charger but did not connect my 12V TC. Upon coming home, battery voltage was over 13V and the car started and drove properly. But keep in mind Pat's Garage installed a new 12V battery prior to my trip. Under that scenario, 530 did it's job. (With 520 and an aging 12V battery I always used the TC when traveling.)

 

[shrowell]

An update:

I have BL530 installed and left my Karma unplugged (both HV charger and TC) and unused for two weeks while traveling (the HV battery was fully charged before I left). Upon returning, the 12V battery was fully charged (my trickle charger (for what it's worth) indicated 90% charge). It looks like BL530 is doing its job nicely and my TC is now gathering dust.

Simon

 

[fiskerjim]

I've been away for two weeks as well and left the Karma plugged into the HV wall charger but did not connect my 12V TC. Upon coming home, battery voltage was over 13V and the car started and drove properly. But keep in mind Pat's Garage installed a new 12V battery prior to my trip. Under that scenario, 530 did it's job. (With 520 and an aging 12V battery I always used the TC when traveling.)

Ira, I was under the impression that we should occasionally leave the HV charger connected to the Karma for an extended time for "battery cell rebalancing". However, it is my understanding that charging and holding batteries at 100% for extended periods of time is not good for the batteries long term. When I leave the Karma for extended periods (1-2 months), I have traditionally
left it with a 50-60% charge and connected the trickle charger. I have currently left it for 1-2 weeks with a 50-60% charge and the 530-535 update without issue. My 12v battery is an original. Looking to see the management answer for the 1-2 month period of Karma downtime with the new updates.

 

[Fabulist]

An update:

I have BL530 installed and left my Karma unplugged (both HV charger and TC) and unused for two weeks while traveling (the HV battery was fully charged before I left). Upon returning, the 12V battery was fully charged (my trickle charger (for what it's worth) indicated 90% charge). It looks like BL530 is doing its job nicely and my TC is now gathering dust.

Simon

Did he HV battery charge go down at all? I have left my car idle for up to 30 days at a time without any adverse effects on the 12V battery. I think a lot of it depends on the condition of the 12V battery. Better safe than sorry, I guess.

 

[shrowell]

Did he HV battery charge go down at all? I have left my car idle for up to 30 days at a time without any adverse effects on the 12V battery. I think a lot of it depends on the condition of the 12V battery. Better safe than sorry, I guess.

The car was still registering full charge (50 miles), so there was no appreciable depletion of the HV battery.

The important thing to note is that before BL530, the 12V battery was being discharged significantly after being left unused for the same period of time. So it looks like we can trust the new battery tending capabilities of BL530 (I certainly do now)!

Simon

 

[Ira]

Ira, I was under the impression that we should occasionally leave the HV charger connected to the Karma for an extended time for "battery cell rebalancing". However, it is my understanding that charging and holding batteries at 100% for extended periods of time is not good for the batteries long term. When I leave the Karma for extended periods (1-2 months), I have traditionally
left it with a 50-60% charge and connected the trickle charger. I have currently left it for 1-2 weeks with a 50-60% charge and the 530-535 update without issue. My 12v battery is an original. Looking to see the management answer for the 1-2 month period of Karma downtime with the new updates.

Experts differ about maintaining 100% SOC over long periods of time. Some say it's necessary to keep cells balanced and avoid the necessity for trickle charging (post-530); while others say it may shorten HV battery life. So I, too, would be interested in KA's official position on this issue.

Looking at posts on other EV forums (such as Tesla's), the consensus is to leave the car plugged in during a typical vacation (a few days or weeks) and let the Battery Management System manage the charging. But I haven't seen any advice on other EV forums about longer-term periods like 1-2 months.

You might give your CSP a call to see what they have to say.

While you're at it, consider making an appointment to get your original 12V battery replaced. It is at or near the end of its service life. When it decides to go, it can happen suddenly and leave you stranded.

 

[Fabulist]

Experts differ about maintaining 100% SOC over long periods of time. Some say it's necessary to keep cells balanced and avoid the necessity for trickle charging (post-530); while others say it may shorten HV battery life. So I, too, would be interested in KA's official position on this issue.

Looking at posts on other EV forums (such as Tesla's), the consensus is to leave the car plugged in during a typical vacation (a few days or weeks) and let the Battery Management System manage the charging. But I haven't seen any advice on other EV forums about longer-term periods like 1-2 months.

You might give your CSP a call to see what they have to say.

While you're at it, consider making an appointment to get your original 12V battery replaced. It is at or near the end of its service life. When it decides to go, it can happen suddenly and leave you stranded.

The other option that I have used, when shipping my car for example, is to disconnect the 12V battery by unplugging the the 12V Ground connector (The same one we use to do a hard reset) and leaving it off for the duration of storage or shipping. You need to be careful in that situation to not fully close the hood, or to leave a window open to be able to get back into the car when you come back to it because the electrical door locks will not work any more with the battery disconnected.

 

[Stefan]

Isn't it time to say, that all the "12V charging during absense"-Problems are limited to garages or other facilities without daylight?
In normal daylight conditions, the solar should keep the 12V battery happy.

 

[Harleyguy]

Isn't it time to say, that all the "12V charging during absense"-Problems are limited to garages or other facilities without daylight?
In normal daylight conditions, the solar should keep the 12V battery happy.

100% correct

 

[Fabulist]

Isn't it time to say, that all the "12V charging during absense"-Problems are limited to garages or other facilities without daylight?
In normal daylight conditions, the solar should keep the 12V battery happy.

100% correct

By definition, storage means putting the car indoors. The potential damage from direct sunlight to the paint and interior would, IMHO, negate any advantage offered by the solar charging. I would rather store the car covered and hook up a trickle charger that expose the car to sunlight long term. Obviously, YMMV.

 

[Stefan]

Sure, of you store the Karma for extended periods, you are right.
But who mentioned 'storage'?