Active 12v to interior.

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Markokk888

Member
Joined
Mar 21, 2018
Messages
24
Hello, i want to run small computer inside a nissan leaf it needs 12v and i want to leave it overnight running but the problem is when the leaf is off the 12v socket is also off. What is the best way to get 12v lines from the battery to the interior and from where ? Can i just tap in to active 12v lines somewhere inside the interior ? What is the best options here ? The power will not always be used so no need to worry about draining the 12v small battery.
 
Best response is don't, unless your hook your LEAF to a battery maintainer.

But if you must, check the fuse panel on the left side of the dashboard for an unswitched 12v fuse and plug in an "Add-aCircuit" fuse tap there for your source of 12v. But remember with out a battery maintainer, you are probably looking at a dead 12v battery in the morning.
 
Well it's not for 24/7 use and the leaf have a solar panel so i probably will be fine. What will run 24/7 are a small cameras for security reasons but they will not consume much and they will run of a 5v i will add a separate battery for them. Btw dose a leaf charges the 12v battery from the main pack when the car is on ?
 
Thank you for the answers. :)
One more question is it possible to replace the nissan leaf original small 12v battery with a bigger capacity one from the petrol or diesel car ?
or the car will somehow struggle with the regular car battery ?
 
Markokk888 said:
Thank you for the answers. :)
One more question is it possible to replace the nissan leaf original small 12v battery with a bigger capacity one from the petrol or diesel car ?
or the car will somehow struggle with the regular car battery ?

You can use a larger 12-volt battery, if you want to find a way to mount it. The car will periodically charge the 12-volt battery from the main battery when it is parked, but the original 12-volt battery may be too small to support your continuous load between charges. The solar panel just provides enough in bright sun to overcome the residual load of various modules in the car--it will not keep the battery charged with accessories on.

I replaced the Nissan original 12-volt battery in my 2011 (when it failed) with an AGM (sealed) deep cycle battery that fit the original tray. The deep cycle was much better for the discharge/charge cycles of the LEAF. When the original battery in my 2015 failed, I also replaced it with a Yellow-top Optima AGM deep cycle battery (group size 51R fits in the tray and has terminals in proper locations).
 
Well i'm driving a lot and i want to run many accessories some of them even when i'm not in a car. so just looking for some alternatives.
Sometimes when i'm on a trip i need to do some office stuff so sometimes i need a scanner, printer, pc.. etc.. sometimes it's better to do work on a side of the road than just sit all day in the office.. sounds crazy.. but this way i get more free time with a people i love family stuff.. and etc... :D so in the end i need a lot of power :D
 
This will likely end in tears as they say, but here is one BIG tip: Do NOT use the Accessory mode to run accessories. If you are in the car, always use Ready mode (yellow-green car icon lit, car ready to drive) to keep the DC-DC converter running the accessories. You will still likely have to use a battery maintainer, and I strongly suggest you install a larger deep cycle or at least "marine" type battery. No make that definitely a deep cycle battery, preferably AGM type.
 
Well thanks for the advices but is there any big reasons to worry that much ? what can possible happen is i drain the 12v battery dead and that's it.
 
Markokk888 said:
Well thanks for the advices but is there any big reasons to worry that much ? what can possible happen is i drain the 12v battery dead and that's it.

That's it if you don't mind replacing 12 volt batteries like wiper blades. Oh, and when the 12 volt battery fails it can take the brake assist with it, and/or strand you on the road.
 
LeftieBiker said:
Markokk888 said:
Well thanks for the advices but is there any big reasons to worry that much ? what can possible happen is i drain the 12v battery dead and that's it.

That's it if you don't mind replacing 12 volt batteries like wiper blades. Oh, and when the 12 volt battery fails it can take the brake assist with it, and/or strand you on the road.

Well i'm not stupid and i will not stress a small battery that is meant running basic systems that much. I just needed basic overall so i can make my own opinion on things. I understand what you are saying no need to joke like this. its nothing to do with a brakes.. Even if there is a some critical systems that needs power from a 12v battery it will get it from the dc/dc converter in any case. What do you will say next that the car will turn into dinosaur after you remove the battery lol :D sesh..
 
I understand what you are saying no need to joke like this. its nothing to do with a brakes.. Even if there is a some critical systems that needs power from a 12v battery it will get it from the dc/dc converter in any case. What do you will say next that the car will turn into dinosaur after you remove the battery lol :D sesh..

You are expecting safe, logical engineering from Nissan. Guess again. The brakes can indeed fail with the car on if the 12 volt battery dies. It SHOULDN'T happen, but it does. You also expect the car to keep a larger 12 volt battery fully charged, and it may indeed do that. Or not - we'll have to see. The 2013 Leafs don't do that at all well, while the 2015 cars do.
 
Yeah it will stop working if someone will drink my brake fluid :D still doesn't make any sense what you are trying to say. Maybe ABS or a brake assist can stop working properly which i don't think but still in any situation you will still have your foot. 12v battery doesn't make your brake pedal to drop dead. Btw my leaf does not have a brake assist it would be a nice feature to add. Your brakes will work even if you will half strip your car and remove any batteries from it. As long as the brake lines ar fine. It will work.
 
12v battery doesn't make your brake pedal to drop dead. Btw my leaf does not have a brake assist it would be a nice feature to add. Your brakes will work even if you will half strip your car and remove any batteries from it. As long as the brake lines ar fine. It will work.

I understand that you think you are on solid ground, here. What you say does make sense for any typical hydraulic brake system. The Leaf, however, is not typical. Maybe some kind soul will give you some links to brakes failing in the Leaf - foot to the floor failing, albeit with a little braking at the floor.

Here you go: http://www.mynissanleaf.com/viewtopic.php?t=18283
 
Markokk888 said:
Yeah it will stop working if someone will drink my brake fluid :D still doesn't make any sense what you are trying to say. Maybe ABS or a brake assist can stop working properly which i don't think but still in any situation you will still have your foot. 12v battery doesn't make your brake pedal to drop dead. Btw my leaf does not have a brake assist it would be a nice feature to add. Your brakes will work even if you will half strip your car and remove any batteries from it. As long as the brake lines ar fine. It will work.
Starting with the MY2013 LEAFs, Nissan switched to a mechanical accumulator to assist with braking force. (And, yes, ALL LEAFs have some method to assist with the braking force needed to stop the car since doing that with just your foot with four disc brakes is quite difficult.) But in the MY2011s and 2012, there was a 12-V ultracapacitor to assist with braking force. If that ultracapacitor was not fully charged to nearly 12V, the vehicle would COMPLETELY lose the brake pedal and it would move all the way to the floor with little effort. Low voltage could be caused by a low battery or you could have a fully-charged battery, but the capacitor was discharged for service.

The latter case happened to me. I took my LEAF in for a service bulletin to reprogram the braking computer. They completed the service in about an hour but the would not return the vehicle to me because they said it had no brakes. I asked what they meant by "no brakes" and they said there was no pedal. The guy sat in the car pushed the pedal all the way to the floor with ease. They gave me a loaner car for the weekend and the ultracapacitor had recharged by Monday and all was well.

Since that time I have been diligent to keep the 12-V battery fully charged.

I believe the MY2013-2017 LEAFs cannot have the problem mine had due to the ultracapacitor, but I suspect they can still have the same issue due to a low battery voltage since it appears to result in communications issues with the braking computer over the CAN bus.
 
My 2011 had and my 2015 has braking available with no power assist. On both cars, the pedal goes NEARLY to the floor and it takes a LOT of pedal pressure to stop the car (or keep it from moving on a slope). The LEAF, like most modern cars, has numerous computers that communicate over the CAN Bus network. The DC-DC converter will generally keep the 12-volt system at appropriate float voltage with the car in READY mode (green car symbol with arrows on dash), but a discharged or defective 12-volt battery can cause many issues (and DTC error codes) when trying to start the car. The communication errors can cause malfunction of the ABS system, brake power assist, etc. and prevent the car from going into READY mode. It will require a booster battery to get the car started and into READY mode if the 12-volt battery is discharged enough to cause CAN Bus communication errors.

I use my car as a portable office once in a while (powering stuff from the 12-volt system), but I always keep it in READY mode so the DC-DC converter and the HVAC systems remain active. The DC-DC converter should easily handle your 12-volt power needs as long as the car is in READY mode.
 
Like most modern vehicles, 12V is cut from everywhere further in the line.
You need to tap closer to the 12V battery. With a fuse (don't burn your car down :lol: )
Leaf's battery can give you 10-15Ah of energy safely with ignition off and car is not charging.
So one amp for one night (dashcam takes that much).
 
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