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I had read somewhere about making sure the low voltage system stays charged, and just wondering how that is done.
 

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I had read somewhere about making sure the low voltage system stays charged, and just wondering how that is done.
There are a lot of threads on this topic, for example this one.

I would suggest paying particular attention to posts by our resident experts such as Harleyguy, Lormax, and AVG8MPG.
 

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If you leave the car in the sun it will maintain the 12 volt system yes the solar panel works just the interface doesn't .If you plan on leaving the car in a garage for any length of time lets say a month I suggest buying a trickle charger and hooking it up to the fuse panel located under the hood . Also buy a charger that is capable of turning it self off and on as needed .
 

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Discussion Starter · #4 ·
Thanks! Yeah, since the car is going to be sitting in the garage all winter, we'll put it on a battery tender.
 

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lormax, there is no way to start the car with plugging it in to the regular charger inlet? doesn't that on board charger have an aux output that feeds the 12v and trickle charge it?
 

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lormax, there is no way to start the car with plugging it in to the regular charger inlet? doesn't that on board charger have an aux output that feeds the 12v and trickle charge it?
No, if the 12 volt battery is dead, plugging the charger into the car won't do anything since all of the control modules are powered by the 12 volt battery.

When the charger is plugged in, if the HV battery is ACTIVELY charging (SOC <100%) the HV aux contactors will close and allow the APM to recharge the 12 volt battery (if needed).

Once the HV battery reaches 100% and stops charging, the HV aux contactors will open and the APM will no longer charge the battery
 

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thanks for the details, so from what i see "jump charging" (12v battery in parallel or cig socket cable) is possible as it will turn on the control modules that will enable the OBC communicate with the j1772 charger and will allow both charging the HV and the 12v. am i getting that right?
 

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thanks for the details, so from what i see "jump charging" (12v battery in parallel or cig socket cable) is possible as it will turn on the control modules that will enable the OBC communicate with the j1772 charger and will allow both charging the HV and the 12v. am i getting that right?
Correct, jump starting the 12v system on the karma is the same as any other car. You could use the cigarette lighter thats in the front center console as that is a direct connection to the the battery (hardwired).

The one in the rear console is controlled by the vehicle control module and is only active in ACC or ON, so you wouldn't be able to jump start it that way.
 

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thanks for the details, so from what i see "jump charging" (12v battery in parallel or cig socket cable) is possible as it will turn on the control modules that will enable the OBC communicate with the j1772 charger and will allow both charging the HV and the 12v. am i getting that right?
Correct, jump starting the 12v system on the karma is the same as any other car. You could use the cigarette lighter thats in the front center console as that is a direct connection to the the battery (hardwired).

The one in the rear console is controlled by the vehicle control module and is only active in ACC or ON, so you wouldn't be able to jump start it that way.
To clarify, when you say jump start, are you talking about just energizing the computers and other electronics or are you talking about that plus starting up the ICE? I would not have thought that you can draw enough current through the lighter socket to start an engine.

Also, this would also mean that you can connect a trickle charger through this socket if you are storing the car for a long period of time, correct?
 

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Jump starting means to energize the computers and close the contactors. Starting up the ICE would be done after the car is turned on to System Ready.

Yes, you can trickle charge through that socket.
 

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Personal I always shy away from using the aux outlet in the car to trickle charge the 12 volt battery on any car . I wouldn't risk a fuse blowing while you are away leaving the car for an extended amount of time .I feel there is safer and better places to hard wire a trickle charger in. The APM is one the easiest I find is the fuse panel under the hood the 8mm stud
 

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Personal I always shy away from using the aux outlet in the car to trickle charge the 12 volt battery on any car . I wouldn't risk a fuse blowing while you are away leaving the car for an extended amount of time .I feel there is safer and better places to hard wire a trickle charger in. The APM is one the easiest I find is the fuse panel under the hood the 8mm stud
I prefer that method as well (under the hood), was just answering the question though :)
Thank you both. I drive my car every day, so this not a concern at the moment, but good to know if I go on a long trip.
 

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I like the idea of just turning the car on for 20-30 minutes every 2 weeks if it is sitting for an extended period of time. The ICE kicks in and charges the 12 volt battery. No electrical chargers sitting around.
 

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I like the idea of just turning the car on for 20-30 minutes every 2 weeks if it is sitting for an extended period of time. The ICE kicks in and charges the 12 volt battery. No electrical chargers sitting around.
Karma's ICE does not have an alternator. The 12V battery is charged from the HV Battery. Turning he car on every couple of weeks is probably a good idea, but the ICE does not need to come on to achieve the desired result.
 

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The actual module is called the APM on its located on the drivers side close to the firewall and has the red cover on it protecting the positive terminal .
 

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Karma's ICE does not have an alternator. The 12V battery is charged from the HV Battery. Turning he car on every couple of weeks is probably a good idea, but the ICE does not need to come on to achieve the desired result.
Txs Fab. That seems consistent with the idea of having the HV battery at 50% levels when left for extended periods.
 

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Just reading about Battery Tenders versus Trickle Chargers. It is suggested that there is more of a fire risk with the latter as a Tender will turn off when it reads the battery being fully charged. Does the Karma continue to draw enough current from the 12 volt battery to negate the risk of over charging with the trickle charger and therefore cause an overheating situation? The Battery Tender that was recommended was the CTEK MUS 4.3.
 

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I bough this one as suggested and here - and here is a link to pictures how I hard-wired the charging pigtail under the hood so I can just pop the hood and plug the charger into the socket rather than using the clamps. easy as pie.

here is a link to the pictures in another thread

http://www.fiskerbuzz.com/forums/13-fisker-karma/8346-trickle-charge-3.html#post192418
 
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