Running wire from the 12V battery to back of car

[MarkBC]

I finally got round to installing this Curt wiring system and it doesn't work. I installed it exactly as instructions stated. Great, I bought it last year so I'm sure the return is now expired, and I'm out $100, and I need it next weekend. Now what do I do? Does anyone have suggestions for a simpler version?

Nevermind, I connected the cable to the negative instead of positive battery terminal. Let this be a lesson to all.

 

[macnut]

.... The positive terminal is perfectly fine to connect too. But the negative terminal on the battery should not be used.

On my recently acquired 2012 SL (originally a Seattle car) a red wire has been connected to the +ve terminal and a black wire to the -ve. The red wire is spliced to a blue wire coming out of what I assume is the harness for the lights. Similarly the black wire is pigtailed to some ground wires near the headlights.

I assume this was done to implement DRLs when the car was imported into Canada two years ago. Not sure if that has to pass an inspection or if import dealers just keep it simple and no-one checks.

The factory 12V battery was replaced with a black-cased Nissan one just before I picked up the car as it was the only thing that didn't pass their checklist. I can tell the car was kept outside so the solar panel would have had a good chance to keep the battery maintained. But either its week output or something else caused the factory battery to not last even 4 years.
Maybe that DRL wiring possibly?

Keeping an eye on the new battery. Resting voltage of 12.51V last time I measured.
Presently considering how best to hardwire for a CTEK Multi US 3300 battery maintainer connection at the charge port.
I assume that using a battery tender with a cigarette lighter plug into the 12V accessory port wouldn't be a good idea as the power switch would need to be in the ACC position for the duration?

Appreciate any guidance.

 

[QueenBee]

.... The positive terminal is perfectly fine to connect too. But the negative terminal on the battery should not be used.

On my recently acquired 2012 SL (originally a Seattle car) a red wire has been connected to the +ve terminal and a black wire to the -ve. The red wire is spliced to a blue wire coming out of what I assume is the harness for the lights. Similarly the black wire is pigtailed to some ground wires near the headlights.

I assume this was done to implement DRLs when the car was imported into Canada two years ago. Not sure if that has to pass an inspection or if import dealers just keep it simple and no-one checks.

The factory 12V battery was replaced with a black-cased Nissan one just before I picked up the car as it was the only thing that didn't pass their checklist. I can tell the car was kept outside so the solar panel would have had a good chance to keep the battery maintained. But either its week output or something else caused the factory battery to not last even 4 years.
Maybe that DRL wiring possibly?

Keeping an eye on the new battery. Resting voltage of 12.51V last time I measured.
Presently considering how best to hardwire for a CTEK Multi US 3300 battery maintainer connection at the charge port.
I assume that using a battery tender with a cigarette lighter plug into the 12V accessory port wouldn't be a good idea as the power switch would need to be in the ACC position for the duration?

Appreciate any guidance.

Not uncommon for batteries to only last 4 years. Could be as simple as being drained to nothing many times or the result of the LEAF not fully charging it.

Correct the cig lighter is switched so not a good place for it. I'd wire up a plug and fuse to the positive terminal of the battery and the negative to a bolt somewhere.

I'd move the negative for the DRL while I was wiring up true battery charger as well just to make things better.

 

[powersurge]

You CAN connect the pigtail wires (with wire ring connections) to positive and negative terminals of the battery.

Normally, people recommend connecting the negative "jumper cable" wire to an other part of the car because this is to protect against an electrical spark at the battery and possible explosion.

When you connect the 2 pigtails to the battery, they are bolted down to the terminal, and there is no possibility of a spark. So it is ok to used both pigtail connectors at the battery terminals.

 

[macnut]

I think it's about avoiding any chance of impacting the process of the 12V battery getting charged by the inverter, not the risk of a spark.

A connection to the negative terminal may affect the sensor that monitors the charge level of the 12V battery.

 

[QueenBee]

You CAN connect the pigtail wires (with wire ring connections) to positive and negative terminals of the battery.

Normally, people recommend connecting the negative "jumper cable" wire to an other part of the car because this is to protect against an electrical spark at the battery and possible explosion.

When you connect the 2 pigtails to the battery, they are bolted down to the terminal, and there is no possibility of a spark. So it is ok to used both pigtail connectors at the battery terminals.

As macnut pointed out this is incorrect advice and it's about the LEAFs sensors which monitor the power going into and out of the battery. There is no reason to connect anything to the negative terminal of a LEAF 12 volt battery.

 

[ElectricEddy]

You CAN connect the pigtail wires (with wire ring connections) to positive and negative terminals of the battery.

Normally, people recommend connecting the negative "jumper cable" wire to an other part of the car because this is to protect against an electrical spark at the battery and possible explosion.

When you connect the 2 pigtails to the battery, they are bolted down to the terminal, and there is no possibility of a spark. So it is ok to used both pigtail connectors at the battery terminals.

As macnut pointed out this is incorrect advice and it's about the LEAFs sensors which monitor the power going into and out of the battery. There is no reason to connect anything to the negative terminal of a LEAF 12 volt battery.

Just got back from a free BBQ local Nissan dealership and I happened to notice a 2016 SL ( with the 30 KWH) in a service bay still in the protective wrapping.
They were charging the 12V battery and the leads were attached to the battery posts.
This is the way I have topped mine off since week 1 (except once) with no problems. (As advised by the certified tech).
The one time I decided to attach the negative to the ground strap on the PDM and the positive to the battery as indicated by others on this forum, the gfci tripped on my 5-20 receptacle that supplied the charger, and the third blue light came on with its 1 sec intervals indicating a drop in the 12V level and was being charged by the DC/DC converter. http://www.mynissanleaf.com/viewtopic.php?f=30&t=11082#p388540.
The Motomaster CT-1025 manual says to " connect negative(black) clamp to the vehicle chassis or engine block, away from the battery" however I use the negative terminal on the battery just as the service depot does. It is an older inductive type with diodes
I was not charging the traction battery at that time.

 

[QueenBee]

You CAN connect the pigtail wires (with wire ring connections) to positive and negative terminals of the battery.

Normally, people recommend connecting the negative "jumper cable" wire to an other part of the car because this is to protect against an electrical spark at the battery and possible explosion.

When you connect the 2 pigtails to the battery, they are bolted down to the terminal, and there is no possibility of a spark. So it is ok to used both pigtail connectors at the battery terminals.

As macnut pointed out this is incorrect advice and it's about the LEAFs sensors which monitor the power going into and out of the battery. There is no reason to connect anything to the negative terminal of a LEAF 12 volt battery.

Just got back from a free BBQ local Nissan dealership and I happened to notice a 2016 SL ( with the 30 KWH) in a service bay still in the protective wrapping.
They were charging the 12V battery and the leads were attached to the battery posts.
This is the way I have topped mine off since week 1 (except once) with no problems. (As advised by the certified tech).
The one time I decided to attach the negative to the ground strap on the PDM and the positive to the battery as indicated by others on this forum, the gfci tripped on my 5-20 receptacle that supplied the charger, and the third blue light came on with its 1 sec intervals indicating a drop in the 12V level and was being charged by the DC/DC converter. http://www.mynissanleaf.com/viewtopic.php?f=30&t=11082#p388540.
The Motomaster CT-1025 manual says to " connect negative(black) clamp to the vehicle chassis or engine block, away from the battery" however I use the negative terminal on the battery just as the service depot does. It is an older inductive type with diodes
I was not charging the traction battery at that time.

Just because you saw someone else do it incorrectly doesn't mean it's correct and that you should do it that way too...

It was certainly just a coincidence because electrically the negative post and the body are connected so if one trips your GFCI the other is going to.

 

[powersurge]

I think you folks are overwhelmed by all of this technology crap, with "sensors", "monitors", and "CPUs". I don't know how much car mechanics you folks know, but I can tell you that I have been servicing and repairing my cars for 40 years.

The issue I addressed is that if the 12V battery gets low over time, "I" have been using a battery tender and solar charging panel connected directly to the battery. I have ALWAYS used directly bolted on pigtails to my battery, including the Leaf, and it is fine.

I couldn't care less about the car's charging system or "sensors" because I control that the battery is properly charged.

People, get off my case with the arguments.... You don't agree...... Don't do it.... and rest your typing fingers from telling me that I am wrong... I am not asking for opinions.......

 

[sirfunk]

I think you folks are overwhelmed by all of this technology crap, with "sensors", "monitors", and "CPUs". I don't know how much car mechanics you folks know, but I can tell you that I have been servicing and repairing my cars for 40 years.

Not claiming to know that this is case with the leaf, however, Other car companies (e.g. BMW) have modified the way their batteries are charged in the past 10 years or so. Instead of just having the the alternator charge at whatever the VR is set to, they will adjust charging voltage/amperage to (the standard lead acid battery to) account for battery age/degradation. This is done by isolating the Charge circuit from the rest of the car's 12v circuits.

What occurs if you charge the battery while connected to this charge circuit (i.e. connected to both battery terminals) is that the charge circuit gets the wrong impression of the state of the battery, as what it would measure from the battery with the charger is different from what it would measure with the battery alone. This would mean that whatever the charge circuit thinks is optimum for the actual battery readings would not be performed, rather the readings with the charger attached would be used. This separate charge circuit is the reason that batteries need to be "registered" in BMWs, minis, etc.

The idea is that if the charge circuit gets the wrong idea about the battery it may end up not charging it at too high or low a wattage and reduce the life of the battery. Is connecting your trick charger directly to the battery going to be an ACTUAL problem in most circumstances -- probably not. But this is likely the source of confusion in regard to connecting directly to the battery or not.

 

[powersurge]

The charging rate changes CONSTANTLY while the car is being driven-- (Headlights on, turn signals, a/c on, a/c compressor on/ off, etc.). The voltage regulator in the charging system adjusts how much to charge the battery constantly.

When you trickle charge, you can't "fool" any sensors, because the trickle charging happens while the car is "off". While the car is off, you can charge, discharge or do anything to your battery you want.

Let's not overthink this technology crap. I've read a post where someone was afraid they would get less battery range if they were charging their phone in the cigarette lighter!!

 

[macnut]

Can't put the tech. differences between an EV and an ICE aside - the Leaf's DC to DC converter outputs a very stable voltage to the auxiliary battery so there is no traditional voltage regulator.
The challenge for the Nissan engineers was how to control/program the timing of that charging process so as to not overcharge nor undercharge that little battery.
We know that Nissan have always hung fuses and thing etc. off the +ve terminals of their batteries but now the Leaf has components off the -ve terminal too.
So it makes sense to not add anything else to the mix when there is an alternative.
(Not talking about hooking up a battery tender when the car is off. It's permanent attachments to the negative terminal at issue.)

 

[sirfunk]

Can't put the tech. differences between an EV and an ICE aside - the Leaf's DC to DC converter outputs a very stable voltage to the auxiliary battery so there is no traditional voltage regulator.
The challenge for the Nissan engineers was how to control/program the timing of that charging process so as to not overcharge nor undercharge that little battery.
We know that Nissan have always hung fuses and thing etc. off the +ve terminals of their batteries but now the Leaf has components off the -ve terminal too.
So it makes sense to not add anything else to the mix when there is an alternative.
(Not talking about hooking up a battery tender when the car is off. It's permanent attachments to the negative terminal at issue.)

The battery state monitoring takes place while the car is off and the battery is not being charged by the alternator (or inverter in the case of the leaf), so if the tender is hooked up directly to the battery terminals, then those readings would be off. Don't have docs on the leaf but here's details on BMW's IBS monitor. Intelligent Battery Monitor - http://www.bimmerscan.com/bmw-intelligent-battery-sensor-ibs/

Again is it a big problem if you connect directly to the battery terminals? Probably not, but since there's another way to put the trickle charger on the 12v charge circuit instead of directly on the terminals that won't affect the fancy battery monitor, why not do it that way instead?