# Charging battery through the OBD Port.



## PJB (Feb 2, 2018)

Can anyone please confirm if you can charge the battery through the OBD port? 
I constantly have problems with my battery going flat if the car is not used for more than two weeks. Have changed the battery but this has made no difference. I do not have a garage and do not want to have trailing leads across my drive for a trickle charger.
I have bought a solar panel charger that connects through the OBD port to allow the battery to be topped up when not in use but this hasn't helped either. The charger is definitely working (have checked with a multi meter) but I am unsure if the OBD port is allowing the charge to get to the battery.
Is the OBD port blocked from allowing this to happen?
My car is a 2018 GTR which I have had from new and has always had this problem, mostly in the winter. Summer not quite as bad.


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## Tin (Aug 15, 2010)

I don't think its possible, as it shuts down after 10mins or so.
Can you not route the wires to the battery terminals up through the gap near the A pillar and then over around the wipers to the battery area.


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## PJB (Feb 2, 2018)

Thanks Tin, thought someone on here would know. Will look into your suggestion. Cheers.


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## SKNAM (Nov 30, 2018)

Don't know about the OBD charging point but if you get a remote control battery isolator that would do the trick. 

Little (ish) box that connects to battery positive terminal. In auto mode it will disconnect battery when voltage drops below a certain point BUT still powers alarm/immobiliser/tracker etc. With remote you can turn it on/off. If you leave car for a while and come back it will either start OK as battery OK charge or you simply click remote and it reconnects battery and turns right on. It's basically a remote relay and they cost less than £50. Worth it for peace of mind always being able to get in and start car after its sat for a while.


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## PJB (Feb 2, 2018)

SKNAM said:


> Don't know about the OBD charging point but if you get a remote control battery isolator that would do the trick.
> 
> Little (ish) box that connects to battery positive terminal. In auto mode it will disconnect battery when voltage drops below a certain point BUT still powers alarm/immobiliser/tracker etc. With remote you can turn it on/off. If you leave car for a while and come back it will either start OK as battery OK charge or you simply click remote and it reconnects battery and turns right on. It's basically a remote relay and they cost less than £50. Worth it for peace of mind always being able to get in and start car after its sat for a while.


Just looked it up on ebay, sounds good. Do you know of anyone who has used it in anger and any down sides?


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## SKNAM (Nov 30, 2018)

I've got one on mine, fitted by previous owner. Works a treat, car has never failed to start. Tracker and alarm etc definitely still work (if I disconnect battery Tracker are on the phone within a minute). Its a Powerlock version from Antigravity batteries).

Downsides, if you are like me and clean the interior with the boot/doors open the battery can turn off after a while, the door window can sometimes stay dropped slightly until you manually restart car etc and manually raise it. The trip computer resets itself. All minor things really, and once used to it its not that much of a pain.


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## PJB (Feb 2, 2018)

SKNAM said:


> I've got one on mine, fitted by previous owner. Works a treat, car has never failed to start. Tracker and alarm etc definitely still work (if I disconnect battery Tracker are on the phone within a minute). Its a Powerlock version from Antigravity batteries).
> 
> Downsides, if you are like me and clean the interior with the boot/doors open the battery can turn off after a while, the door window can sometimes stay dropped slightly until you manually restart car etc and manually raise it. The trip computer resets itself. All minor things really, and once used to it its not that much of a pain.


Thanks SKNAM. 
Looked up their website and sounds good, will investigate further. Quick question do you loose your radio stations, sat nav memory etc when the power goes off. Also I have a Ghost Immobiliser does it effect that?
Do you know of anyone who has gone for the replacement lithium ion battery, very expensive but seems to resolve all the problems of having a car that is not used for longish periods.


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## SKNAM (Nov 30, 2018)

Radio and sat nav locations aren't lost, which is good.

Don't know re. Ghost, as I don't have it fitted. Can't see it being an issue, even when the battery power is "off" the unit still allows some power to be residual within the system e.g. alarm/immobiliser/tracker function normally.

Don't know anyone using a lithium ion battery, that would be a high tech, high cost option for sure. Didn't know it was an option, interesting....


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## PJB (Feb 2, 2018)

They also do a battery tracker that downloads the health of your battery via Bluetooth to an app on your phone. Only £30-£40 so might be useful to know when your battery is getting low.


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## barry P. (May 9, 2010)

That’s the CTEK Battery Sense, useful but the blutooth only works over a couple of metres away so you need to go and stand by the car to check it.


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## barry P. (May 9, 2010)

Not sure how much good the automatic isolator is going to be as when the car is stationary and locked the only drain should be the tracker. If it cuts the battery when the voltage gets low the tracker and alarm will be working off their internal battery which will only last for a relatively short period of time.
You will be able to start your car in two weeks time but it will have been sitting with no alarm or tracker working.


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## adz87kc (Jan 8, 2018)

Are you not better off trying to solve the problem rather than the symptom?


If you're not handy with a multimeter and wiring take it to an automotive electrician, might be a simple fix.


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## PJB (Feb 2, 2018)

barry P. said:


> Not sure how much good the automatic isolator is going to be as when the car is stationary and locked the only drain should be the tracker. If it cuts the battery when the voltage gets low the tracker and alarm will be working off their internal battery which will only last for a relatively short period of time.
> You will be able to start your car in two weeks time but it will have been sitting with no alarm or tracker working.


I can confirm that you are right Barry, spoke to the manufacturer and they have said it's not designed to be disconnected for long periods of time and will allow the back up batteries in the alarm etc to drain down. The system is designed to allow for enough power reserve to be held in the battery for restart following an accidental drain, like say leaving your lights on.


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## PJB (Feb 2, 2018)

adz87kc said:


> Are you not better off trying to solve the problem rather than the symptom?
> 
> 
> If you're not handy with a multimeter and wiring take it to an automotive electrician, might be a simple fix.


Have already looked into this. 
GTR's and many other modern cars suffer from "Parasitic Drain". This is not a problem if you drive the car often but if you don't a trickle charger or similar is the only fix.
Porsche allow for this and have a 12v outlet that stays live when the ignition is off, they will even provide a Porsche trickle charger. Nissan don't.


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## adz87kc (Jan 8, 2018)

PJB said:


> Have already looked into this.
> GTR's and many other modern cars suffer from "Parasitic Drain". This is not a problem if you drive the car often but if you don't a trickle charger or similar is the only fix.
> Porsche allow for this and have a 12v outlet that stays live when the ignition is off, they will even provide a Porsche trickle charger. Nissan don't.


Would it not be the case for all of our Datsun's then given the wiring _should_ be the same?

I can leave mine 3 weeks and it starts fine; original battery too. Longest I've had to leave it it is 25 days and it was fine- albeit that was a one off being sat so long.


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## barry P. (May 9, 2010)

Do you have a tracker on your car? This makes a massive difference to how long the battery lasts before needing to be charged.


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## PJB (Feb 2, 2018)

adz87kc said:


> Would it not be the case for all of our Datsun's then given the wiring _should_ be the same?
> 
> I can leave mine 3 weeks and it starts fine; original battery too. Longest I've had to leave it it is 25 days and it was fine- albeit that was a one off being sat so long.


Understand where you are coming from, they should all be the same. Temperature is a factor, in the summer I don't usually get much of a problem but in the winter when it gets very cold, 2 weeks is the best I get. Replaced the original battery with an Ultima yellow top and made little difference, although it recharges very quickly.


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## PJB (Feb 2, 2018)

barry P. said:


> Do you have a tracker on your car? This makes a massive difference to how long the battery lasts before needing to be charged.


Had the tracker disconnected and made no difference. Do have a Ghost Immobiliser though, which I was told has very little draw.
It's going in for a service at Auto Torque in April so I'll ask them to have a look.


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## Tinyflier (Jun 13, 2012)

Mine sits on drive sometimes for well over 3 weeks. No tracker fitted but does have active Ghost. 

Never fails to start even in the coldest of weather. Battery was renewed about 5 years ago.

David.


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## lordretsudo (Dec 24, 2011)

Mine is garaged at all times when not in use and goes flat in a week. It did it on its original battery and it does it on the replacement one, which has a higher crank rating. It has a tracker but it’s not activated, plus I don’t bother to set the alarm as it’s in a locked, alarmed garage behind a large immovable gate! Weird that some GTRs go flat quickly whilst others don’t...


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## SKNAM (Nov 30, 2018)

If the tracker is still drawing a current (despite not being activated) it will drain the battery. If you get an isolator fitted which has a capacitor built in (and properly working - I don't know the science but it switches been DC and AC if I understand it right) then the capacitor charges when the battery is on and when the battery is off the capacitor provides the tiny amount of current (amps) to power the tracker and other security, which saves their inbuilt batteries. It only has a tiny reserve but its supposed to be enough for several days.


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