How's your 12v battery health?

RegGuheert said:

Would you mind opening one or more of the cells and trying to get a photograph of what is going on down in there?

Click to expand...

Well, I decided to take a look at mine to see what is in there. Here it is:



The voltage of the battery when this was taken was 12.35V. Looking at the picture, I have a new theory: I don't see any buildup of lead sulfate. But what I do see is a near short directly in the center of the photograph. If these plates can easily short around the edges of the insulators, I wonder what the resistance of that short would be. If it is on the order of 10 ohms, then it could discharge the cell in about the time seen by Nubo. If there were such a short in each of Nubo's cells, then I guess the entire battery could be discharged overnight.

Can such a short exist in a deep-cycle lead-acid battery? I know you can get a dead short, since it seems we have had some failed cells around, but what about one with a few ohms of resistance. I suppose it is possible since there is paste on the grids. Unfortunately, I do not know the resistivity or the thickness of the paste. Anyone out there know?

There are tons of LiFePo4 options. This 20ah one weighs about a pound:

http://www.all-battery.com/Tenergy12.8V20AhLiFePO4RechargeableBattery-31943.aspx" onclick="window.open(this.href);return false;

RegGuheert said:

RegGuheert said:

Would you mind opening one or more of the cells and trying to get a photograph of what is going on down in there?

Click to expand...

Well, I decided to take a look at mine to see what is in there. Here it is:



The voltage of the battery when this was taken was 12.35V. Looking at the picture, I have a new theory: I don't see any buildup of lead sulfate. But what I do see is a near short directly in the center of the photograph. If these plates can easily short around the edges of the insulators, I wonder what the resistance of that short would be. If it is on the order of 10 ohms, then it could discharge the cell in about the time seen by Nubo. If there were such a short in each of Nubo's cells, then I guess the entire battery could be discharged overnight.

Can such a short exist in a deep-cycle lead-acid battery? I know you can get a dead short, since it seems we have had some failed cells around, but what about one with a few ohms of resistance. I suppose it is possible since there is paste on the grids. Unfortunately, I do not know the resistivity or the thickness of the paste. Anyone out there know?

Click to expand...

i have to admit to not looking at plates closely before but is it me or do those plates just seem to be just a bit too distorted? yours look worse than Nubo's but could be just the picture angle/camera, etc...

DaveinOlyWA said:

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.

Click to expand...

Thank you for doing that. I really like this blog entry, well done.

TonyWilliams said:

There are tons of LiFePo4 options. This 20ah one weighs about a pound:

http://www.all-battery.com/Tenergy12.8V20AhLiFePO4RechargeableBattery-31943.aspx" onclick="window.open(this.href);return false;

Click to expand...

Nice find! I really think that LiFePO is the way to go, especially when considering some of the more expensive replacement options. The price will be comparable with AGM. As RegGuheert and others have said, any lead-acid chemistry just won't be very happy in this environment, not until Nissan has tweaked the charging protocol.

By contrast, AGM batteries in that type of application are lasting 18 months to two years. The additional lifetime of 2.5 to 3x will help offset the higher cost of the Li-ion solution, Kessen says.

Click to expand...

Click to open

DaveinOlyWA said:

i have to admit to not looking at plates closely before but is it me or do those plates just seem to be just a bit too distorted? yours look worse than Nubo's but could be just the picture angle/camera, etc...

Click to expand...

There is some distortion on the right side of my photograph caused by the refraction of the light as it passes through the meniscus around the depth gauge. As mentioned earlier, the electrolyte level in our LEAF's 12V battery is a bit above the full line.

That said, I agree with you: If you focus on the center of my picture the plates in our LEAF look worse than those in Nubo's. I wonder which LEAF is older. Perhaps Nubo can update his profile to correct the delivery date and add in his serial number. For reference, our LEAF was built in June 2011.

BTW, I hadn't seen Nubo's photograph yet when I commented that I thought it could be a short. It took me a while to compose my post due to Internet issues. Looking at his photograph, I don't see any obvious failure modes.

drees said:

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.

Click to expand...

Thanks Drees, The BatteryMinder (with desulfation pulsing) is exactly what I was looking for! The technical details on their website is quite extensive.

I have ordered the Battery Minder Model 2012 (12V, 2Amp) Charger/Maintainer/Desulfator.
https://batteryminders.com/details.php?prod=2012
Free shipping and you can choose between a Digital Voltmeter or a Battery Conditioner Indicator to be included free with your order. This should be very helpful with extending the life on all the lead acid batteries in my other cars too

Here s their explanation on sulfation and how their product works:
http://batteryminders.com/battery-sulfation.php

I also like their phrase "As with our own bodies, prevention beats rehab, every time."

RegGuheert said:

DaveinOlyWA said:

i
That said, I agree with you: If you focus on the center of my picture the plates in our LEAF look worse than those in Nubo's. I wonder which LEAF is older. Perhaps Nubo can update his profile to correct the delivery date and add in his serial number. For reference, our LEAF was built in June 2011.

Click to expand...

Click to expand...

I never put my serial# into my profile because I didn't want to specify my exact VIN, and the profile wouldn't allow something like "16xxx". So anyway it's in the 16000's.

Purchased in Dec 2011, the car had just recently been delivered to the dealership. Iirc, manufacture was Oct 2011.

Well, after some further investigating with Trojan, the terminal configuration on their 22-AGM looks to be the reverse of what's needed. You could flip the battery around but there isn't much play in the cables and they might not reach. This is based on a photograph they took today. Contradicts any online picture I'd found so who knows... I imagine terminal locations aren't that critical for its intended market. Editing original post....

Nubo said:

Well, after some further investigating with Trojan, the terminal configuration on their 22-AGM looks to be the reverse of what's needed. You could flip the battery around but there isn't much play in the cables and they might not reach. This is based on a photograph they took today. Contradicts any online picture I'd found so who knows... I imagine terminal locations aren't that critical for its intended market. Editing original post....

Click to expand...

When you talk about Trojan batteries please remember there are 3 kinds of liars in this world.
1) Everyday Liars.
2) G. D. Liars
3) Battery Salesman

http://www.evalbum.com/3175" onclick="window.open(this.href);return false;

http://www.evalbum.com/2058" onclick="window.open(this.href);return false;

http://www.evalbum.com/1414" onclick="window.open(this.href);return false;

RegGuheert said:

Looking at the picture, I have a new theory: I don't see any buildup of lead sulfate. But what I do see is a near short directly in the center of the photograph.

Click to expand...

I dont think I have ever seen build up on the top of a cell.. that short will simply reduce the capacity of that particular cell, it could even reverse polarity if you discharged the battery low enough so it is bad news.. fix it!

So what I did was finally install the AGM deep-cycle battery that I'd purchased back in May.

http://www.solar-electric.com/pvx-1240.html" onclick="window.open(this.href);return false;

The problem I had back then was I couldn't quite get it to fit. The positive terminal "block" on the LEAF doesn't give a lot of leeway and this battery unfortunately comes in "left hand positive" terminal orientation.

Now that my OEM battery was running weak, I took another look. The sticking point was the cable from the DC-DC converter. It's routed around the plethora of other positive leads, to the front of the "block" where it connects inside its own little plastic cage. By disconnecting that cable and routing it to the *outside* of the other cables, enough slack was freed up. Just enough. The terminal block ends up canted a bit, but it's functional and there's still plenty of clearance between the post and the hood when closed (verified by taking an iPhone movie inside while closing the hood ).

Other than that, I did have to add a bit of material to the hold-down to gain purchase on the rigid portions of the battery top. Worked out well enough. For a more professional-looking installation you'd still need to extend the charging cable, or replace it with something a bit longer so that the terminal block could be better aligned with the battery case.

Anyway, this is a truly purpose-built deep-cycle battery and has decent amp-hour capacity for its size. Not sure why I obsessed so much over a stupid 12V battery but now at least it's in the car. It was still holding good voltage (12.35) after sitting on the garage floor for 7 months. I charged it with an AGM cycle and it was back up to 12.85 volts.

Couldn't quite bring myself to pull the trigger on a Lithium replacement. How weird is that? :lol:

that looks pretty small, what is the size of the stock battery in inches (LxWxH)?

Is there any sort of consensus that it is better to leave the car unplugged when not charging for awhile? Even unplugged the car's systems keep running or one wouldn't be able to talk to it via Carwings.

I often charge in the middle of the day for an hour and a half or so to use my solar directly and it appears that charging a bit every day ought to keep the 12V battery topped off. Correct?

dgpcolorado said:

Is there any sort of consensus that it is better to leave the car unplugged when not charging for awhile? Even unplugged the car's systems keep running or one wouldn't be able to talk to it via Carwings.

I often charge in the middle of the day for an hour and a half or so to use my solar directly and it appears that charging a bit every day ought to keep the 12V battery topped off. Correct?

Click to expand...

If the car isn't plugged in, the LEAF turns on the DC-DC converter every 5 days to keep the 12v battery up. I consider the fact that it doesn't when plugged in to be a bug. Ingineer says it's best to disconnect the 12v if leaving the car for a long period. I wouldn't do that unless I were planning to leave it for more than a month.

Nubo said:

So what I did was finally install the AGM deep-cycle battery that I'd purchased back in May.

http://www.solar-electric.com/pvx-1240.html" onclick="window.open(this.href);return false;

Click to expand...

Thanks for the detailed update, Nubo! The solar extenders are good AGM batteries. They also have a very low resistance, so I would guess some of the concerns about jump-starting other cars would be reduced (though I would still want to have the car running while doing that).

Please let us know how things work for you!

davewill said:

dgpcolorado said:

Is there any sort of consensus that it is better to leave the car unplugged when not charging for awhile? Even unplugged the car's systems keep running or one wouldn't be able to talk to it via Carwings.

I often charge in the middle of the day for an hour and a half or so to use my solar directly and it appears that charging a bit every day ought to keep the 12V battery topped off. Correct?

Click to expand...

If the car isn't plugged in, the LEAF turns on the DC-DC converter every 5 days to keep the 12v battery up. I consider the fact that it doesn't when plugged in to be a bug. Ingineer says it's best to disconnect the 12v if leaving the car for a long period. I wouldn't do that unless I were planning to leave it for more than a month.

Click to expand...

and that is the recommended procedure

and that is the part that is not working. The battery when new is able to make that 5 day stretch or if the weather is good. but now we are having people doing exactly that and still getting failures.

case in point (why this thread was started) one guy, leaves LEAF over long holiday weekend. SOC charged to 50% unplugged. comes back 4 days latter and 12 volt battery is dead.

** he did park it outside so forget the solar. it is the PNW, but the period in question was relatively sunny which brings us to

** it was cold. lows in mid 20's and parked outside probably contributed to the 12 volt battery dying. now, in Summer; warmer temps, bit more Sun (we are pretty far North so we have a lot of daylight) etc.

but that is a lot of "ifs" and "buts" that we need to rely on.

what it boils down to is it appears the Nissan charging scheme is letting the 12 volt battery run down too far. over time, the voltage gets lower and lower and eventually cant go 5 days between charges.

either way, any one trying the Li? a change in chemistry means that the Li may have issues with the charging cycle. obviously dont want it to overcharge. anyone have any insight as to whether a simple chemistry swap might do the trick?

dhanson865 said:

that looks pretty small, what is the size of the stock battery in inches (LxWxH)?

Click to expand...

They're fairly comparable in width and height. The 420T is shorter in length, at 7.7" vs stock at just over 9", iirc.

However, if you shine a flashlight from behind the OEM case you see just how much of that interior volume is reserved for free liquid electrolyte. In contrast, by using concentrated electrolyte in thin absorbent mats only where it's needed, there is more room for Lead and Lead Oxide. The AGM design allows the battery to have smaller physical dimensions but still have more capacity.

could also be that the 12V batteries are defective, I think many of these are practically dead already.. I would disconnect the 12V battery and put it on trickle for anything over a week.

DaveinOlyWA said:

what it boils down to is it appears the Nissan charging scheme is letting the 12 volt battery run down too far. over time, the voltage gets lower and lower and eventually cant go 5 days between charges.

Click to expand...

Depth of discharge is a big factor in longevity for a lead-acid battery. Deep-cycle batteries fare better in this regard and can tolerate more cycles at the deeper discharges. Car starter batteries are usually optimized more towards producing a maximum burst of energy all at once ("Cold Cranking Amps") as opposed to deep-discharge survivability. Deep-cycle batteries sacrifice maximum output by having fewer, thicker plates meant to accommodate deeper cycles.



I've seen it said that the OEM battery is a deep-discharge type but I'm not sure of that. In any case, a higher amp-hour capacity will result in shallower cycling, which helps too. Since the LEAF has absolutely no need for "cold cranking amps", a pure deep-cycle type seems appropriate for the application.

http://bestbatteries.co.nz/categories/deep-cycle-batteries-nz/what-are-deep-cycle-batteries.html" onclick="window.open(this.href);return false;

After I read this thread, I decided I'd better take my Leaf's 12 volt battery's readings... pretty crummy; 11.78 V. I live in a poor reception area and I know Carwings has to try several times to connect from the few times I used it when I first got the car. I haven't used Carwings since the first month of owning my Leaf, so I called Nissan and asked if I could shut it off since all it does (for me) is drain the 12 V battery a lot, and since I only drive anywhere once or twice a week, not a whole lotta recharging going on. To my amazement, I was transferred to someone who gave me two options: shut down the downloading portion, or turn off the whole thing. (He explained what the effect of each would be quite well.) I chose the latter option for myself. It may very likely be that very few of you will want to do this, but I thought I'd let you know that for once Nissan was obliging when I made a request. Hopefully this will slow my 12 V degradation a good bit.