How's your 12v battery health?

[Nubo]

took my 11.67V battery out of the car to charge on a dedicated battery charger to see if it would perk it up. Did finally get to 100% SOC but by this morning had dropped back down to 11.9V so not a whole lot of lasting benefit. Definitely time for a replacement. Overkill always being appropriate, I am looking at this fellow:


http://www.trojanbatteryre.com/PDF/datasheets/22AGM_TrojanRE_Data_Sheets.pdf" onclick="window.open(this.href);return false;

50AH rating, deep cycle AGM. Definitely a far more capable battery that will tolerate periods of discharge. Terminals look to be in the right place though I'll have to come up with some kind of SAE post adapters.

EDIT: I wasn't totally certain of this battery since the photograph and the diagram on the datasheet disagreed. So I sent a query to their tech support, who forwarded me an actual photograph -- which shows yet a THIRD terminal configuration. Sorry to say, the + and - are reversed and likely would not be a drop-in fit for the LEAF. They are going to update the .pdf

 

[DaveinOlyWA]

looks like anything below 70% is not good and we are all there

 

[dhanson865]

Does the Leaf use pencil post batteries like a Prius or the fatter posts like the avg north american car

I'm curious to know is what voltage is low enough to not be able to power up the car.

On my Prius is was around 9.x to 10v on the MFD when I could barely power on. If it was 10.5 or higher on the MFD it'd power up reliably.

Keep in mind the MFD voltage displayed is lower than the direct measurment with load which is lower than the direct measurment without load.

The numbers in this table are for a brand new Optima battery 100% charged on a smart charger outside the car then placed back in the Prius

At Battery  vs  MFD (2005 Prius)

12.52            N.A.   out of box charge level
12.94            N.A.   after 18 hours on charger
12.72            ??.?   connected to car (SKS load)
??.??            12.5   accessory mode (SKS + display and such)
12.45            12.25  IG-ON (SKS plus a ton of other systems)
12.59            N.A.   car off after first round of testing
??.??            11.9   IG-ON plus headlights on

I hope that helps on comparing raw battery numbers even if it is a different battery brand (It's AGM so it's not traditional lead acid) and a different car.

 

[Nubo]

Does the Leaf use pencil post batteries like a Prius or the fatter posts like the avg north american car?

American-market LEAF uses SAE posts ("avg north american")

 

[RegGuheert]

Most automotive chargers simply charge at a temperature-compensated voltage around 14.5V since they have no idea how much current is going into the battery or is being used elsewhere. But clearly the LEAF is different in what it is doing. It may use more standard deep-cycle battery-charging algorithms, as you are indicating, since it possibly has access to the battery charging current, but if this is what Nissan has done, then that was an unwise decision. Why? Because it is critical to get lead-acid batteries back to a 100% SOC quickly without overcharging. Those normal algorithms work because there is charge continuously available (or often, as in PV applications). But in the LEAF, charging is available only occasionally, at best.

Just one comment on my previous comment: It's likely that the flooded deep-cycle battery in the LEAF cannot handle the high currents that would be associated with going straight to 14.5V on a mostly-discharged battery. As a result Nissan was probably forced to go with a non-standard algorithm. Still, what they are using does not seem to be working out.

took my 11.67V battery out of the car to charge on a dedicated battery charger to see if it would perk it up. Did finally get to 100% SOC but by this morning had dropped back down to 11.9V so not a whole lot of lasting benefit. Definitely time for a replacement.

So you saw a resting voltage of 12.7V after you took it off the charger and let it sit for 30 minutes or so? If so, then I agree it is dead.

Overkill always being appropriate, I am looking at this fellow:


http://www.trojanbatteryre.com/PDF/datasheets/22AGM_TrojanRE_Data_Sheets.pdf" onclick="window.open(this.href);return false;

50AH rating, deep cycle AGM. Definitely a far more capable battery that will tolerate periods of discharge.

I'm not sure I would call an AGM battery "overkill." "Differentkill" may be more like it. Here are some important differences to consider:

Benefits of AGM batteries:
- As you state, AGM batteries can handled sitting at lower SOCs better than flooded batteries.
- The electrolyte in a flooded battery will freeze at an increasingly higher temperature as the SOC drops. I believe the freezing point at 0% SOC is around 15F. This means that it's possible that the LEAF battery could suffer a "sudden death" up in the northern U.S. if it is not maintained close to full by the car. The freezing point of the electrolyte in an AGM battery stays very low, even at low SOCs.
- AGM batteries can handle much higher charge and discharge currents than flooded batteries. I'm not sure this is a benefit for the LEAF unless the charging algorithm could be changed to better suit the AGMs.

Benefits of flooded batteries:
- AGM batteries are sealed (with one-way valves to prevent overpressure). As a result, there is no way to replace water lost during overcharge. This makes AGMs *very* sensitive to overcharge. Flooded batteries, OTOH, can be topped of with distiller water, if needed. (BTW, did you check that in your current battery? The LEAF has a LOT of electrolyte above the plates when new, but since you are having issues, perhaps it is low.)

It is this last item that would worry me in the LEAF. As I noted the other day, our LEAF was charging the battery at 12.7V while climate control was running. That voltage would be fine for an AGM UNLESS it was fully charged. In that case, the battery would be rapidly releasing hydrogen and oxygen gasses, never to recover them. This would lead to very early battery death if it happened frequently enough. So, I guess the question comes down to whether or not the LEAF keeps track of the battery state of charge (or charge current draw) well enough to prevent frequent overcharging. It might, but it might not.

In the end, I would say it's worth a shot, given that the original battery did not last two years. Just be aware that it is possible that an AGM will die even faster!

 

[RegGuheert]

I'm curious to know is what voltage is low enough to not be able to power up the car.

On my Prius is was around 9.x to 10v on the MFD when I could barely power on. If it was 10.5 or higher on the MFD it'd power up reliably.

There is a report on this forum that one LEAF started seriously malfunctioning with a battery voltage around 10.5V and it worked fine after the battery was replaced with a new one. The implication is that at least one of the three CAN busses became unreliable at the lower voltage and so did the car, as a result.

As such, I do not believe I would drive our LEAF with a very low 12V battery, even if it would start.

Edit: Added link.

 

[surfingslovak]

I'm not sure I would call an AGM battery "overkill." "Differentkill" may be more like it.

Speaking of overkill, have a look at this: LiFePO, 60Ah, 8 to 14.4V. About $200 in bulk. I shouldn't say this, but I happened to see one of the very first LEAFs ever made recently. Guess what, it had a dead or near-dead 12V battery.

 

[RegGuheert]

Speaking of overkill, have a look at this: LiFePO, 60Ah, 8 to 14.4V.

Cool! Thanks!

About $200 in bulk. I shouldn't say this, but I happened to see one of the very first LEAFs ever made recently. Guess what, it had a dead or near-dead 12V battery.

Why shouldn't you say it? Was it a test vehicle or something?

In any case, it's not clear to me if this is an issue only with the early-build LEAFs or if they are simply are the ones hitting it first. Time will tell.

Edit at 8:45AM: I just went out and checked the battery in our LEAF. The electrolyte is still slightly above the "Full" line. (BTW, the best way to see the level is to shine light from a flashlight into the back of the battery and view the level from the front. Be sure to check all six cells.) We last drove the LEAF two days ago (for about 1.5 hours) and it has been plugged in for slightly over a day and a half. It would have charge for about four hour yesterday morning and it has sat, plugged in for the 26 hours since then. The voltage now is only 12.24V. IMO, this is too low. If the charging system were functioning effectively and the loads had been designed to be very low draw, I would expect to see about 12.6V right now.

Edit at 9:00AM: Battery is up to 12.38V now. I guess I didn't let it sit long enough before I took the previous measurement for all the sustems to turn off. That is still not quite as high as I would like, but it is more in line with what I expect from previous measurements on this vehicle.

 

[Herm]

Nubo, a 50Ah battery is not overkill, perhaps underkill.. see if a 100Ah will fit, an AGM with no starting loads should last 12 years easy.

What are the dimensions of the battery tray?

 

[DaveinOlyWA]

I'm not sure I would call an AGM battery "overkill." "Differentkill" may be more like it.

Speaking of overkill, have a look at this: LiFePO, 60Ah, 8 to 14.4V. About $200 in bulk. I shouldn't say this, but I happened to see one of the very first LEAFs ever made recently. Guess what, it had a dead or near-dead 12V battery.

http://daveinolywa.blogspot.com/2013/01/12-volt-battery-management-houston-weve.html" onclick="window.open(this.href);return false;

blogging this and possible solutions. SS; you have hit on what I was thinking about. the charging algorithm for the 12 volt system is set to lead acid but was thinking like you that if I put in a 14 volt Li battery system, it would be like charging in "long life" mode so would not have to worry about overcharging.

question I have is the algorithm still going to work since its partially based on the voltage curve?

or would it just be easier to petition Nissan to change the charging parameters to every day? I am guessing the poor conditions of our batteries now is due to a 5 day stretch being too much but unlike most here, Mine has never sat more than 3 days and that was only one time this past August. other than that, there is only a handful of times it went more than 24 hours without being driven.

after all, I camp in my LEAF!

 

[DaveinOlyWA]

Nubo, a 50Ah battery is not overkill, perhaps underkill.. see if a 100Ah will fit, an AGM with no starting loads should last 12 years easy.

What are the dimensions of the battery tray?

not with the algorithm Nissan is using. a bigger Lead acid battery in this case will only delay the problem. might give you another year.

only real solution is to drive it every day or fix the algorithm

 

[dgpcolorado]

I have an old style needle VOM and it is very inaccurate; I basically use it for continuity checks and the like. I presume that most of you have modern digital Volt meters; do they need to be calibrated periodically? Are you sure they are accurate? Does anyone have a model that they would recommend?

 

[DaveinOlyWA]

I have an old style needle VOM and it is very inaccurate; I basically use it for continuity checks and the like. I presume that most of you have modern digital Volt meters; do they need to be calibrated periodically? Are you sure they are accurate? Does anyone have a model that they would recommend?

i have the $20 version from Sears. generally as long as the battery is good, they are fairly accurate. they base their reading by creating a parallel series against a precision resistor so pretty accurate. (parallel circuits have same voltage thru out...)

now what does "fairly accurate" mean. well, mine has resolution to 1/100th of a volt and I am ok with it being with .05 or so. true precision is much better (and much more expensive) than that.

besides, your old style VOM is pretty accurate as well. it just needs to be calibrated more often but I dont think its all that necessary with voltage measurements. just zero it first.

 

[ebill3]

I have an old style needle VOM and it is very inaccurate; I basically use it for continuity checks and the like. I presume that most of you have modern digital Volt meters; do they need to be calibrated periodically? Are you sure they are accurate? Does anyone have a model that they would recommend?

I have a very high precision 10 VDC standard, a few El-Cheapo Harbor Freight digital multimeters, and a couple of Flukes. At 10 volts, the El-Cheapos read the same as the Flukes.

Check Harbor Freight - their meter often sells for less than five bucks, and it is just fine for most home and garage applications.

Now, if you want to spend about $100 and have 54 minutes of spare time, go here: http://www.eevblog.com/2010/07/11/e...probe-bk-precision-ideal-uei-uni-t-part-1of2/

Bill

 

[Nubo]

took my 11.67V battery out of the car to charge on a dedicated battery charger to see if it would perk it up. Did finally get to 100% SOC but by this morning had dropped back down to 11.9V so not a whole lot of lasting benefit. Definitely time for a replacement.

So you saw a resting voltage of 12.7V after you took it off the charger and let it sit for 30 minutes or so? If so, then I agree it is dead.

12.8V a few minutes after charging. 12.3V a couple of hours later, 11.9V the next morning, out of the car, no load. Compare this to a battery I've had sitting idle in the garage for about 9 months, which measures 12.38V. Unfortunately this one won't fit in the LEAF

Overkill always being appropriate, I am looking at this fellow:


http://www.trojanbatteryre.com/PDF/datasheets/22AGM_TrojanRE_Data_Sheets.pdf" onclick="window.open(this.href);return false;

50AH rating, deep cycle AGM. Definitely a far more capable battery that will tolerate periods of discharge.

I'm not sure I would call an AGM battery "overkill." "Differentkill" may be more like it. Here are some important differences to consider:

Benefits of AGM batteries:
- As you state, AGM batteries can handled sitting at lower SOCs better than flooded batteries.
- The electrolyte in a flooded battery will freeze at an increasingly higher temperature as the SOC drops. I believe the freezing point at 0% SOC is around 15F. This means that it's possible that the LEAF battery could suffer a "sudden death" up in the northern U.S. if it is not maintained close to full by the car. The freezing point of the electrolyte in an AGM battery stays very low, even at low SOCs.
- AGM batteries can handle much higher charge and discharge currents than flooded batteries. I'm not sure this is a benefit for the LEAF unless the charging algorithm could be changed to better suit the AGMs.

Benefits of flooded batteries:
- AGM batteries are sealed (with one-way valves to prevent overpressure). As a result, there is no way to replace water lost during overcharge. This makes AGMs *very* sensitive to overcharge. Flooded batteries, OTOH, can be topped of with distiller water, if needed. (BTW, did you check that in your current battery? The LEAF has a LOT of electrolyte above the plates when new, but since you are having issues, perhaps it is low.)

The level when new was right at the "full" line, where it has remained. It's still at the "full" mark and I have never added water. I don't think overcharging was this battery's problem. It's either undercharging or the car allowing large SOC cycles. Since we already know that sitting plugged-in the car will refuse to charge the battery, I imagine that's part of it.

It is this last item that would worry me in the LEAF. As I noted the other day, our LEAF was charging the battery at 12.7V while climate control was running. That voltage would be fine for an AGM UNLESS it was fully charged. In that case, the battery would be rapidly releasing hydrogen and oxygen gasses, never to recover them. This would lead to very early battery death if it happened frequently enough. So, I guess the question comes down to whether or not the LEAF keeps track of the battery state of charge (or charge current draw) well enough to prevent frequent overcharging. It might, but it might not.

In the end, I would say it's worth a shot, given that the original battery did not last two years. Just be aware that it is possible that an AGM will die even faster!

 

[Nubo]

Nubo, a 50Ah battery is not overkill, perhaps underkill.. see if a 100Ah will fit, an AGM with no starting loads should last 12 years easy.

What are the dimensions of the battery tray?

Well, I'd guess the OEM battery to be about 30AH or less. I was looking for something of comparable dimensions with serious deep-cycle capability. I personally hate flooded batteries so wanted AGM. The terminals also have to be in the proper orientation. The ornate battery connections in the LEAF don't give you a whole lot of maneuvering room.

Here's a nice lightweight option (as far as Pb goes) which I'm also considering. Just not sure of its cycling capabilty.

http://www.tnrbattery.com/etx30l-deka-replacement-braille-b3121-advanced-lightweight-agm-battery/" onclick="window.open(this.href);return false;

 

[DaveEV]

Probably not a bad idea to pick up a battery tender to let it top off the battery once a month or so. Although the battery minder claims to be able to desulfate batteries, don't know if that really works or not.

 

[RegGuheert]

12.8V a few minutes after charging. 12.3V a couple of hours later, 11.9V the next morning, out of the car, no load. Compare this to a battery I've had sitting idle in the garage for about 9 months, which measures 12.38V. Unfortunately this one won't fit in the LEAF

That's not good!

The level when new was right at the "full" line, where it has remained. It's still at the "full" mark and I have never added water. I don't think overcharging was this battery's problem. It's either undercharging or the car allowing large SOC cycles. Since we already know that sitting plugged-in the car will refuse to charge the battery, I imagine that's part of it.

Agreed the issue seems to be the LEAF just seems to keep the 12V battery in an undercharge condition. I suspect your battery is full of lead sulfate. Would you mind opening one or more of the cells and trying to get a photograph of what is going on down in there?

Edit: Spelling.

 

[DaveinOlyWA]

Wow! Nubo. your battery has nothing left. if fully charged and no load. it should sit a week at 12.7 volts or so...

 

[Nubo]

12.8V a few minutes after charging. 12.3V a couple of hours later, 11.9V the next morning, out of the car, no load. Compare this to a battery I've had sitting idle in the garage for about 9 months, which measures 12.38V. Unfortunately this one won't fit in the LEAF

That's not good!

The level when new was right at the "full" line, where it has remained. It's still at the "full" mark and I have never added water. I don't think overcharging was this battery's problem. It's either undercharging or the car allowing large SOC cycles. Since we already know that sitting plugged-in the car will refuse to charge the battery, I imagine that's part of it.

Agreed the issue seems to be the LEAF just seems to keep the 12V battery in an undercharge condition. I suspect your battery is full of lead sulfate. Would you mind opening one or more of the cells and trying to get a photograph of what is going on down in there?

Edit: Spelling.

Here's a shot.