12v battery problem

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shuma89

Active member
Joined
Nov 15, 2021
Messages
36
Hello averyone.
My nissan leaf 2011 year. Every morning is discharged 12 v battery. Whan i disconect 12v battery on evening and connect on morning it starts good, if night it will be conected it is discharged for morning.
Whare i can search problem?
 
goldbrick said:
How old is the battery? It may be worn out and must be replaced.

It is 1 years old.
I tried second battery, it do same.
I think that somewhare some relays stole voltage.
If i stay on charging the car and disconect 12v battery it charges normaly the HV battery, if 12 v battery is conected, charging proces is stopped.
 
You could try pulling one fuse at a time to try to isolate which circuit the phantom drain is on. Same with the relays.

Do you have an OBD2 dongle installed? Might be that...
 
Keep in mind that after you resolve the battery drain, your existing battery may well be weak. Most automotive batteries do not fare well after being drawn down repeatedly. So once you fix the drain problem I'd recommend you get the battery load-tested to determine its health.
 
LeftieBiker said:
In the meantime, connect a 2 amp or greater 12 volt battery maintainer every night while charging, as a stopgap measure.

Whan i am charging the car HV battery, it is charging the 12v battery also.

If the car stands 10-12 hours it will not starts without charging the 12 v battery or bridge from other car 12v.

i tested curent from the 12 v battery, it spends 1.8A from 12v battery even the car is locked.

Can the Dc to DC converter may cause this problem? I have read in google thet it could the problem from the dc-dc converter or the motor inverter or onboard charger in the back of the car in laguage


My car is 2011 nissan leaf gen1.
 
The 12V battery is being charged while the traction battery is actually charging, but not while still plugged in after charging is complete. The 1.8 amperes discharge current while the car is locked is high. The discharge current will be higher with the car plugged in and not charging than with the car unplugged, but the 12V battery should handle that overnight if the battery is OK. You need to find (and eliminate) the excessive discharge current. In the meantime, an external 12V charger would keep the 12V battery from being discharged (as LeftieBiker recommended).
 
GerryAZ said:
The 12V battery is being charged while the traction battery is actually charging, but not while still plugged in after charging is complete. The 1.8 amperes discharge current while the car is locked is high.

Yes, typically it's about 60 ma (.06 amps).
GerryAZ said:
The discharge current will be higher with the car plugged in and not charging than with the car unplugged, but the 12V battery should handle that overnight if the battery is OK. You need to find (and eliminate) the excessive discharge current. In the meantime, an external 12V charger would keep the 12V battery from being discharged (as LeftieBiker recommended).

Assuming 1/2 capacity for a 60 Ahr, i.e. 30 Ahr, to provide adequate start-up current;

Time= 30 Ahr/ 1.8 amps ~= 17 hrs. For a marginal 12V battery, 1.8 amps is an excessive drain for that time period.
 
I meant a battery in good condition will handle the normal discharge current (30 to 60 milliamperes) while parked. The source of the 1.8 ampere discharge current must be found and eliminated unless an external charger is used whenever the car is parked.
 
shuma89 said:
i tested curent from the 12 v battery, it spends 1.8A from 12v battery even the car is locked.

Well, that is quite high, about 30 times more than normal dark-current. One thing to be careful, you need to measure after the car has been sitting for a while. It takes some time before it goes into low-power mode. That being said, 1.8A does fit with your symptoms.

Fortunately, the high drain may also make it easy to find. Start pulling fuses one at a time while observing the current draw. Hopefully you'll find which circuit is involved and can troubleshoot from there.
 
This video has some good ideas on how to find the battery drain source:

https://www.youtube.com/watch?v=B__DqK90IIc&feature=youtu.be
 
Nubo said:
shuma89 said:
i tested curent from the 12 v battery, it spends 1.8A from 12v battery even the car is locked.

Well, that is quite high, about 30 times more than normal dark-current. One thing to be careful, you need to measure after the car has been sitting for a while. It takes some time before it goes into low-power mode. That being said, 1.8A does fit with your symptoms.

Fortunately, the high drain may also make it easy to find. Start pulling fuses one at a time while observing the current draw. Hopefully you'll find which circuit is involved and can troubleshoot from there.
Very good post and in particular your first paragraph, second paragraph is also good but as you said, just measuring draw shortly after doing something with the car can lead to misassumptions as you said.
 
hello averyone.
i foumd problem, it was light from lagguage door. it was everytime on, because of door problem.

but i have already other problem with 12v battery.
if I leave the charger pluged in and HV battery charge fully it drains the 12v battery :(
whare i can search problem? i think that 220v charger is guilty.
 
Use a battery maintainer on the 12 volt battery when you charge the car. The 12 volt battery gets drained after charging finishes if the car remains plugged in. You may need a new 12 volt battery if the one you have has gotten damaged by being discharged too much.
 
LeftieBiker said:
Use a battery maintainer on the 12 volt battery when you charge the car. The 12 volt battery gets drained after charging finishes if the car remains plugged in. You may need a new 12 volt battery if the one you have has gotten damaged by being discharged too much.

when i have measure voltage on 12v battery, it is 12.5v and when charging HV battery, it was 13.2v. in my mind it is charging 12v battery when HV battery charger is on.
in my mind the 12 volt battery gets drained after charging finishes if the car remains plugged in, is this normal fact?
 
That is correct, as I wrote above. Leaving the car plugged in while it is not charging will, over many hours, drain the 12 volt battery. It is a design flaw. The other problem is that while the car does add charge to the 12 volt battery while the car is charging, it doesn't add a lot of amperage.
 
LeftieBiker said:
That is correct, as I wrote above. Leaving the car plugged in while it is not charging will, over many hours, drain the 12 volt battery. It is a design flaw. The other problem is that while the car does add charge to the 12 volt battery while the car is charging, it doesn't add a lot of amperage.

Thank you for answers.
Whan HV fulls and stops charging process it drains 12v battery 1.8 A
i think thet 1.8a is very high. May be it is problem from my home charger? (Not onboard charger)
Whan i turned off 220v this drain become 0.14a. But the charging handle was pluged in the car.
 
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