12 Volt Lead Acid Battery Replacement

[Nubo]

there is much much space for a large battery if you throw out the plastic battery carrier. it gives you space for a 280x160x200mm battery which may have 72Ah, insteaf of the tiny stock 36Ah battery. wouldnt it be nice to help out the main battery not having to recharge the 12V battery all the time? wipers, vent, lights, sound system... costs a lot of electricity.

It doesn't work that way. Whatever 12V power you use is eventually replaced by the main pack, regardless of how large the 12V battery is. A larger 12V may result in shallower cycles which would be better for the life of the 12V, and of course will give you more reserve time. But it won't reduce the load on the main battery.

 

[hornstudio]

there is much much space for a large battery if you throw out the plastic battery carrier. it gives you space for a 280x160x200mm battery which may have 72Ah, insteaf of the tiny stock 36Ah battery. wouldnt it be nice to help out the main battery not having to recharge the 12V battery all the time? wipers, vent, lights, sound system... costs a lot of electricity.

It doesn't work that way. Whatever 12V power you use is eventually replaced by the main pack, regardless of how large the 12V battery is. A larger 12V may result in shallower cycles which would be better for the life of the 12V, and of course will give you more reserve time. But it won't reduce the load on the main battery.

i think the same. would it extend the LEAFs overall range? it should do, but you would almost double the weight of the 12V battery.

 

[Stanton]

Guys, I think you're missing the point here. Where the 12v battery is concerned, you really want to do 2 things:
1) reduce weight
2) move to a chemistry that will survive "deep cycling", or at least not be destroyed when discharged >50%

The answer to both of these questions is: LiFePO. The main reason no one does this (especially car companies) is:
1) it's very expensive
2) at the very least, the 12v battery needs to have it's own BMS to survive long-term

I've found something I think will work (check my last couple of blog entries on MNL) and will be creating a new thread when I finally get it in my Leaf and try it out (by the end of March).

 

[smkettner]

Here are some Li-Ion 12v:

http://www.lithiumion-batteries.com/products/12-volt-lithium-ion-batteries/

 

[TonyWilliams]

Here are some Li-Ion 12v:

http://www.lithiumion-batteries.com/products/12-volt-lithium-ion-batteries/

There are a bunch of choices out there now:



12V 40AH LITHIUM ION BATTERY
Model/SKU: SB40
Weight: 13.50 lbs
Price: $518.99 $599.99

IN STOCK
Smart Battery™ SB40
12V 40AH Lithium Ion Battery
Nominal Voltage: 12.8V
Amp Hours: 40
400 Cranking amps
Length (inches): 7.75"
Width (inches): 6.5"
Height (inches): 6.87"
Weight: 13.5 lbs.
120 min @ 20A
Max Continuous Discharge 40A
Charge Voltage: 14.6v
Life in Cycles: 3000-5000
Operating Temperatures - 4 F + 158 F
99.1% Efficient
Internal Impenetrableness: 0.9>>

-LiFePo4 technology
- 70% Lighter
- 10 x Longer life
- ZERO Maintenence

-Heavy duty high output terminal posts.

-Dual purpose; Engine Starting and Deep Cycle

-Automatic built in battery protection system.

Perfect for:
MOTORHOMES, TRAVEL TRAILERS, FIFTH WHEELS,
BOATS, YACHTS, SAILING, TROLLING, ELECTRONICS
SOLAR BACK UP POWER AND OTHER DEEP CYCLE APPLICATIONS

 

[planet4ever]

It doesn't work that way. Whatever 12V power you use is eventually replaced by the main pack, regardless of how large the 12V battery is. A larger 12V may result in shallower cycles which would be better for the life of the 12V, and of course will give you more reserve time. But it won't reduce the load on the main battery.

i think the same. would it extend the LEAFs overall range? it should do, but you would almost double the weight of the 12V battery.

Wait a minute. You said you agreed with Nubo, then said just the opposite. I do agree with Nubo. Increasing the capacity of the 12v battery has zero effect on the total amount of electricity used from the main battery to keep it charged, so it has zero effect on range except, as you say, the very small negative effect of adding weight.

Ray

 

[TomT]

No, it would have absolutely no affect on the range. The capacity of any 12v battery is nothing in comparison to the main pack.

i think the same. would it extend the LEAFs overall range? it should do, but you would almost double the weight of the 12V battery.

 

[dcpatters]

Here are some Li-Ion 12v:

http://www.lithiumion-batteries.com/products/12-volt-lithium-ion-batteries/

There are a bunch of choices out there now:


12V 40AH LITHIUM ION BATTERY
Model/SKU: SB40
Weight: 13.50 lbs
Price: $518.99 $599.99

In your opinion, is this a good option for replacing the OEM battery?

 

[TomT]

Nope, no difference in range. Zero. Nada. None.
It simply does not work that way.

i think the same. would it extend the LEAFs overall range? it should do, but you would almost double the weight of the 12V battery.

 

[TonyWilliams]

Here are some Li-Ion 12v:

http://www.lithiumion-batteries.com/products/12-volt-lithium-ion-batteries/

There are a bunch of choices out there now:


12V 40AH LITHIUM ION BATTERY
Model/SKU: SB40
Weight: 13.50 lbs
Price: $518.99 $599.99

In your opinion, is this a good option for replacing the OEM battery?

I don't have any first hand experience with this battery. I do recommend that whatever you chose MUST HAVE A BMS !!!!

If you get this, please report back with your findings.

 

[dcpatters]

I don't have any first hand experience with this battery. I do recommend that whatever you chose MUST HAVE A BMS !!!!

If you get this, please report back with your findings.

I might pull the trigger on this one then. According to their site, BMS is self contained.


Sort of off topic, but found 17" wheels @ 10lbs each. Should make for a nice upgrade.

 

[TickTock]

Bump. My 12V battery is dead. Anyone here have any actual experience to share? Deep Cycle Lead acid, LiPo, what-ever. I really am interested in anything that has been proven to work and fit in the existing bracket. Not guesses - I can Google as well as any . That 40Ah LiPo is interesting but looks too big (physically).

 

[thimel]

My 12v battery was replaced after two years under warranty. I bought a CTEK battery charger and charge it once a week. I hope that will make it last a good long time as it is probably undercharging by the LEAF which caused the early death.

 

[Stanton]

Please see this thread on my LiFePO4 replacement; I've had NO TROUBLE whatsoever after almost a year.

http://www.mynissanleaf.com/viewtopic.php?f=37&t=11999

I also did a blog post on it.

http://stanton.myevblog.com/2012/01/16/getting-the-lead-out/

 

[EVDRIVER]

Three years on my LEAF battery no issues. I think many people abuse their battery by using accessory mode.

 

[LeftieBiker]

Three years on my LEAF battery no issues. I think many people abuse their battery by using accessory mode.

If just using it were "abusing" the car, it wouldn't have an accessory mode. The car needs a larger 12 volt battery.

 

[TickTock]

Please see this thread on my LiFePO4 replacement; I've had NO TROUBLE whatsoever after almost a year.

http://www.mynissanleaf.com/viewtopic.php?f=37&t=11999

I also did a blog post on it.

http://stanton.myevblog.com/2012/01/16/getting-the-lead-out/

Thanks for sharing - very cool. However too pricey for me. Since I needed to replace it today, I ended just replacing with a deep cycle AGM (Optima Yellowtop). Nice fit and being deep cycle should help it cope with the Leaf's tendency to neglect it.

 

[rmay635703]

Just curious has anyone tried to gain an extra 0.5-2kw of power by upgrading the 12v battery to a 14v 7 cell lead acid or similar?

I plan on testing this if I buy a Leaf/Volt by getting a 200ahr+ set of seven 2v lead acid cells, this should keep the DC_DC shut off until the battery is flat (70%dod)

Anyone ever check the voltage the leaf keeps the 12v battery system at when its "idling" and what range the battery operates in if you "for example" have all the 12v accessories on VRS off?

Is anyone willing to put a 15v power supply & ammeter on the leafs 12v system and start the car?

I am mainly looking to see if the leaf will throw a cel and if it will shut off the DC-DC if the leaf thinks the front battery is topped off.

Generally the 12v system on a car is designed to operate from 10.5v - 16v with tolerance to an overload voltage up to 18v (yes I work in an automotive factory) The issue on the leaf is it controls the voltage more tightly and may think something is amiss if volt is outside the normal range of the DC-DC, no way to know without trying though.

Thanx
Ryan

PS

Good Lead acid batteries can have a positive cost/benefit ratio. (coming from a guy who ran an EV 7 years off one pack)

So adding a little power to the 12v system might gain 2-6 miles of range by keeping the 85-95%eff DC-DC shut off.

 

[DaveEV]

Just curious has anyone tried to gain an extra 0.5-2kw of power by upgrading the 12v battery to a 14v 7 cell lead acid or similar?

Doesn't work that way.

The LEAF will charge the 12V battery at around 14.4-14.7V briefly every time the car is turned on.

At some point it decides the battery has had enough and then switches to maintaining voltage at 13.0V.

I have noticed that it will stay in charge mode for longer after using the accessories for a while - for example after I top off the tires using my 12V compressor.

And after topping off the battery with an external 12V charger, it will only briefly stay in charge mode and quickly drop back into 13.0V maintenance mode.

So you might save a tiny bit of energy by manually topping off your 12V battery each time, but either way it's not significant. Even if the battery was fully discharged it's rated at perhaps 60 Ah. 60 Ah * 12V = 720 Ah. So at most you might get a couple miles out of it. If your 12V battery is not dead, the effect is probably negligible.

Would be interesting to put a logging Ammeter/Voltmeter on the 12V battery, though, to confirm!

 

[Stanton]

If just using it were "abusing" the car, it wouldn't have an accessory mode. The car needs a larger 12 volt battery.

Not at all. In fact, I replaced the 40+ AHr (stock) battery with ~20 AHr Lithium battery and have had NO PROBLEMS. Remember, you can't discharge Lead Acid <50%, so you have to "over-size" the battery. In addition, the charging profile of the Leaf (a short time @14.1v and then steady-state 13.0v) works quite well with my LiFePO4 (you don't want to apply >14.5v or so to the cells).