12v Battery

[dhanson865]

I connected my Battery Tender 1.25a charger leads to the 12v battery, ran the wire through the front charging port.

First time I charged (w/o charging main battery), mid-day, full sun, 90f ambient, charger ran for 6 hours before it showed full.

Drove the car yesterday, mostly highway, 76 miles, 90f ambient, A/C set to 75f, radio on.

Battery tender (simultaneously with main battery) has been charging (overnight) now for 12 hours, 70f ambient, showing 80% charged.

Shouldn't the highway use (probably 55 miles) have kept the 12v battery fully charged? Thoughts?

Ed in Ft. Worth, TX

Nope the leaf won't keep the 12v fully charged no matter how long you drive it.

I'd also say that 1.25a charger isn't enough to keep up.

If you don't see cold temps I'd go for a 4.3 amp CTEK https://smile.amazon.com/dp/B006G14FK8

If you see very cold temps on a regular basis (think negative temps) I'd get the Polar version https://smile.amazon.com/dp/B00GODCLYU that is labeled 4.3 amp on the name plate but says 5 amp on the side and has cables that play nicer with the cold.

either one has a desulphation in all modes, and enough logic to handle lead acid and AGM, and its smart enough to restart the cycle if it isn't going to charge to normal voltages.

Even then a full cycle can last up to 13 hours on a 40ah battery though it may finish sooner. It'll likely take half as long as using the battery tender.

 

[dhanson865]

Nope the leaf won't keep the 12v fully charged no matter how long you drive it.

I'd also say that 1.25a charger isn't enough to keep up.

If you don't see cold temps I'd go for a 4.3 amp CTEK https://smile.amazon.com/dp/B006G14FK8

I've got a new favorite 12v charg.er (aka charging device*). https://smile.amazon.com/dp/B004LWVEKS it desulphates at 1.5A but charges at 7.2A and it handles lithium battery packs as well should you get one down the road. Plus there is a 25%/50%/75%/100% charge indicator that will show you how low the battery got between charging sessions.

* It's annoying in a 12v thread to have the word charger link to EVSEs when what I'm actually talking about is something that charges 12v batteries not the EV pack.

 

[LeftieBiker]

I'd also say that 1.25a charger isn't enough to keep up.

Once you understand the problem, and change your behavior a bit to make the car charge the 12 volt battery a bit better, even a 0.75AH battery Tender JR should be able to make up the difference, at least in most cases. Basically you have to treat the car like an ICE with a weak alternator, turning lights and other accessories off before the car, and using the wiper trick (running the wipers on the longest variable intermittent setting) to get a little extra charging in light rain. Just using the maintainer whenever the car is charging may be enough.

 

[jjeff]

Nope the leaf won't keep the 12v fully charged no matter how long you drive it.

I'd also say that 1.25a charger isn't enough to keep up.

If you don't see cold temps I'd go for a 4.3 amp CTEK https://smile.amazon.com/dp/B006G14FK8

I've got a new favorite 12v charg.er. https://smile.amazon.com/dp/B004LWVEKS it desulphates at 1.5A but charges at 7.2A and it handles lithum battery packs as well should you get one down the road. Plus there is a 25%/50%/75%/100% charge indicator that will show you how low the battery got between charging sessions.

Very nice looking charger and at a price not much more than the little one I have, that does much less. I've put in my wishlist and will have to think about it. Wow! over 2000 reviews and almost all good, most things I generally look at are lucky to have a dozen or so reviews....

 

[dhanson865]

I'd also say that 1.25a charger isn't enough to keep up.

Once you understand the problem, and change your behavior a bit to make the car charge the 12 volt battery a bit better, even a 0.75AH battery Tender JR should be able to make up the difference, at least in most cases. Basically you have to treat the car like an ICE with a weak alternator, turning lights and other accessories off before the car, and using the wiper trick (running the wipers on the longest variable intermittent setting) to get a little extra charging in light rain. Just using the maintainer whenever the car is charging may be enough.

That might be true if you drive very little and are very very OCD about plugging in the battery tender the second you get home.

In my usage patterns and I'd wager the average drivers, you need way more amps to be able to just charge it once a month instead of every second of every day.

I can tell you right now that a 3.3 amp CTEK takes overnight in my usage patterns.

I'm thinking a 7.2 amp might charge it fast enough that I can get it back off the car quicker if I want and this one is smart enough to desulphate at 1.5 amp if it doesn't need the charge rate difference so I can leave it on overnight or for a day or two if I want to maintain/desulphate.

I don't think .75A even covers the OBDII and background carwings drain. If it does it isn't by much.

A lot of the older battery tenders aren't designed for AGM and Lithium 12v batteries. I don't know about you but I don't buy regular lead acid batteries anymore. All my cars are AGM right now.

 

[LeftieBiker]

So, er, I'm not a typical Leaf driver, but typical Leaf drivers have AGM batteries? Anyway, I don't plug in the tender every time, and it usually runs only a couple of hours. I don't drive a lot of miles, but that doesn't actually help keep the 12 volt battery charged. Short trips tend to run it down.

 

[dhanson865]

So, er, I'm not a typical Leaf driver, but typical Leaf drivers have AGM batteries? Anyway, I don't plug in the tender every time, and it usually runs only a couple of hours. I don't drive a lot of miles, but that doesn't actually help keep the 12 volt battery charged. Short trips tend to run it down.

OEM battery is old fashioned Lead Acid. Sulphates easier, deep discharge is a very bad thing, heaviest battery type.

The majority of highly rated replacement batteries are AGM (Optima, Exide, etcetera). Slightly lower weight, slightly higher cost, easy to find deep discharge friendly.

There is a new wave of Lithium Ion variants becoming more common (mostly LiFePo but no guarantees, some don't specify and it will vary over time). Way lower weight, way higher cost (for now, but price will drop), deep discharge friendly guaranteed. This is where the 12v battery industry is heading.


The thing is there are a lot of Leafs on the road with aging/dead 12v batteries and there is no reason to buy the older equipment/parts when the newer equipment/parts have advantages. My OEM battery from 2011 that was in my 2012 Leaf died just a few months ago. How many 2013 Leafs are on the edge of needing a new 12v now? How many of those will be replaced with a AGM or Lithium battery in the next year or so? How many more the year after that?

If you don't have a battery tender/charging device you should get one that is lithium friendly so you don't have to replace it again in a few years. A battery charging device might last the rest of your life, no sense tossing working equipment in the trash or just having it clutter up your shed/garage/closet.

 

[Levenkay]

If you don't have a battery tender/charging device you should get one that is lithium friendly so you don't have to replace it again in a few years.

Isn't one of the reasons for replacing the 12V lead-acid battery with a lithium one that the lithium battery *won't* sulphate, and therefore not NEED any "tending"? Why, then, would a tender need to be "lithium-ready" ?

 

[jjeff]

I agree, both my '12 and '13 Leaf are probably going to need a 12v battery in the next year or so, when I replace them they won't be a standard lead acid battery, probably a AGM(yellow top Optima)
https://www.amazon.com/dp/B0013ZGZ9Q/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=2FOFVDA67L13W&coliid=I1EN7GGUV98IE4&psc=1
but maybe lithium. Any future 12v charger I'd purchase would need to not only charge AGM but also Li.

 

[LeftieBiker]

The thing about lithium batteries is that the BMS is the failure point, in most cases. It will manage the battery fine 99% of the time, and then often fail, killing the otherwise perfectly good battery. I'd rather get a 'stone axe' gel or AGM battery for an application like a Leaf, so I'm not worrying about the accessory battery BMS failing, on top of any other worries. When present lithium technology gets replaced with something more reliable in the long (years) term, that will be when I'll look for a 12 volt lithium car battery.

 

[dhanson865]

If you don't have a battery tender/charging device you should get one that is lithium friendly so you don't have to replace it again in a few years.

Isn't one of the reasons for replacing the 12V lead-acid battery with a lithium one that the lithium battery *won't* sulphate, and therefore not NEED any "tending"? Why, then, would a tender need to be "lithium-ready" ?

Good point. Assuming you get the right size Ah lithium and don't have odd usage patterns you won't need the battery to be charged outside the Leaf. In any case you won't have to counter sulfation. Hopefully people wont go buying the largest lithium battery they can fit in the car. Price should prevent that for a while.

But how will you check to see if the Leaf is charging it sufficiently? You could grab your hand held voltage meter if you are the type to have one laying around. Or you could reuse this if you had one that you use on your AGM batteries.

And what about self discharge and vampire loads? If you don't drive the car enough to keep it charged (either ultra short commute or the car sits idle most of time for any number of reasons) then you put it on a device like this. It's fire and forget, it knows how to charge the battery and if it needs charging.

Plug it up every month to top it off and if you see the charge level below 50% (just the 25% light showing) then you know you need to keep a closer eye on it and charge more often or diagnose to see if the car isn't charging properly or the battery is failing.

Silly me I'd rather not have my primary means of transportation surprise me on a cold/hot/rainy day when I'm not in the mood to stand around and troubleshoot. Between Leafspy Pro and a 12v charging device I feel like I can keep an eye on things without having to take it to the dealer for maintenance and without putting batteries in my multimeter. And yes Leafspy will tell me if the charging process is nearing 14v like it should but it can't check the voltage of the 12v while the car is off or when the car is sitting unused.

Give me a good DMM that doesn't run on 9v batteries or that still reads accurately no matter what chemistry 9v I stick in it and I'll use it. I've gotten lazy and used 120v devices like a killawatt meter and a 12v battery charging device to do my readings with. I've got some rechargable 9v batteries now and a that DMM is in the house somewhere. I suppose if my dryer ever acts up again I'll have to find it. But until then I'm happy to let it sit idle.

 

[LeftieBiker]

Good point. Assuming you get the right size Ah lithium and don't have odd usage patterns you won't need the battery to be charged outside the Leaf. In any case you won't have to counter sulfation. Hopefully people wont go buying the largest lithium battery they can fit in the car. Price should prevent that for a while.

But how will you check to see if the Leaf is charging it sufficiently? You could grab your hand held voltage meter if you are the type to have one laying around. Or you could reuse this if you had one that you use on your AGM batteries.

Smaller lithium batteries are notoriously hard to read SOC from with a voltmeter, because they usually stay near the rated voltage until discharged about halfway. I use small 24 volt packs in my electric bicycles, and the linear or even digital voltmeters that work so well with lead-acid packs won't tell you much until the pack gets near 50% SOC. A lithium battery used for 12 volts in a car would probably have a BMS, but even a BMS with lights won't usually tell you the SOC once it falls below about 98%. So how do the people using these batteries know if they are being kept charged reasonably well? I guess they may be sitting at roughly 60% SOC, pretty much like the OEM FLA batteries, and just tolerate that state better...

 

[knightmb]

The thing about lithium batteries is that the BMS is the failure point, in most cases. It will manage the battery fine 99% of the time, and then often fail, killing the otherwise perfectly good battery. I'd rather get a 'stone axe' gel or AGM battery for an application like a Leaf, so I'm not worrying about the accessory battery BMS failing, on top of any other worries. When present lithium technology gets replaced with something more reliable in the long (years) term, that will be when I'll look for a 12 volt lithium car battery.

Just like anything though, BMS can out-last the battery if cheap electronics are not used. The same reason you don't worry about the electronics in your car needing replacement every few years. I've racked up 2 years on my Lithium replacement and have not had a single issue with cold or hot weather so far. I check the battery every few months by removing it from the car and doing a full charge (which takes little time), then full discharge to measure the amp-hours to see if I can detect degradation, but so far it has been solid every time. It is nice not having to clean up spilled acid in the Leaf, they have the discharge ports at the bottom sending acid to the worse possible places on the Leaf, like bolts on the frame, etc. That will just eat up the metal and cause a lot of rust, nasty stuff! :shock:
Trying to get my friends and family to switch out their lead weights as well, Lithium is the way to go for the Leaf, don't need CCA for a solid state EV anyway.

 

[knightmb]

Good point. Assuming you get the right size Ah lithium and don't have odd usage patterns you won't need the battery to be charged outside the Leaf. In any case you won't have to counter sulfation. Hopefully people wont go buying the largest lithium battery they can fit in the car. Price should prevent that for a while.

But how will you check to see if the Leaf is charging it sufficiently? You could grab your hand held voltage meter if you are the type to have one laying around. Or you could reuse this if you had one that you use on your AGM batteries.

Smaller lithium batteries are notoriously hard to read SOC from with a voltmeter, because they usually stay near the rated voltage until discharged about halfway. I use small 24 volt packs in my electric bicycles, and the linear or even digital voltmeters that work so well with lead-acid packs won't tell you much until the pack gets near 50% SOC. A lithium battery used for 12 volts in a car would probably have a BMS, but even a BMS with lights won't usually tell you the SOC once it falls below about 98%. So how do the people using these batteries know if they are being kept charged reasonably well? I guess they may be sitting at roughly 60% SOC, pretty much like the OEM FLA batteries, and just tolerate that state better...

Every test I've done with mine, the battery is always at full charge and doing a full discharge test always matches up with rated capacity. There really is a big difference between the Lead and Lithium, the Leaf loves the Lithium much better. The Lead seems better suited for the ICE and probably should stay that way.
Read some of my old test here: http://nissanleaf.guru/forum/viewtopic.php?f=9&t=6

 

[LeftieBiker]

Every test I've done with mine, the battery is always at full charge and doing a full discharge test always matches up with rated capacity. There really is a big difference between the Lead and Lithium, the Leaf loves the Lithium much better. The Lead seems better suited for the ICE and probably should stay that way.

Was it you who speculated that higher capacity batteries get charged better, because of slower voltage rises? That would argue in favor of both lithium and the much less expensive AGM batteries - any type, really, as long as they have lots of capacity.

 

[BrockWI]

I know I suggested that larger or better batteries, AGM or otherwise did fare better in the Leaf due to its charging setup. At least that seems to be the case.

 

[Stanton]

If you don't have a battery tender/charging device you should get one that is lithium friendly so you don't have to replace it again in a few years.

Isn't one of the reasons for replacing the 12V lead-acid battery with a lithium one that the lithium battery *won't* sulphate, and therefore not NEED any "tending"? Why, then, would a tender need to be "lithium-ready" ?

Ding-Ding-Ding: someone gets it! I realize that a 12v LiFePO4 battery is > 2x the cost of a lead-acid, but it solves multiple problems simultaneously. I don't understand why folks want to mess with a battery tender, let alone running wires through the charge port, etc. If you're concerned enough to go to all that trouble, just get the lead out! I'm going on 3 years with my 12v Lithium battery and have never been stranded (and I use a lot of accessories).

 

[knightmb]

Every test I've done with mine, the battery is always at full charge and doing a full discharge test always matches up with rated capacity. There really is a big difference between the Lead and Lithium, the Leaf loves the Lithium much better. The Lead seems better suited for the ICE and probably should stay that way.

Was it you who speculated that higher capacity batteries get charged better, because of slower voltage rises? That would argue in favor of both lithium and the much less expensive AGM batteries - any type, really, as long as they have lots of capacity.

The AGM might do a lot better, I've only had the ability to test the stock Lead and my Lithium against it. The Lead never seems to fully charge or reach 14.5 volts for some reason. When running the Lithium, I can put a meter right on the battery and always get a 14.2-14.5 voltage reading when the vehicle is on without any accessories running. I think the Lead turns into a low power heater since it never reaches top voltage because that extra power must be going to something...

I think Lithium has the advantage in an EV because it doesn't need to pull a lot of power to crank a motor. It just needs enough power to flip a relay for the big battery. The Lithium never gets too hot because there is not much waste heat to deal with from the motor or AC. In an ICE where the engine is always running +200F, I could see the Lithium not performing as well as a Lead. I think Lead is well suited for ICE because it has many years of research and testing for the environment it works in, just store enough engine to crank the engine, then recharge as quickly as possible for the next time.

The Leaf on the other hand, I could probably start the vehicle a thousand times on a Lithium battery before needing a recharge. The Lithium just needs to be topped off to keep the electronics working after it is turned off.

 

[LeftieBiker]

The Lead never seems to fully charge or reach 14.5 volts for some reason. When running the Lithium, I can put a meter right on the battery and always get a 14.2-14.5 voltage reading when the vehicle is on without any accessories running.

Keep in mind, though, what I wrote earlier: the lithium battery won't show a large voltage drop until it's used a lot of its capacity. It could be at 60% of full charge and still show 14.2 volts.

 

[jjeff]

Nope the leaf won't keep the 12v fully charged no matter how long you drive it.

I'd also say that 1.25a charger isn't enough to keep up.

If you don't see cold temps I'd go for a 4.3 amp CTEK https://smile.amazon.com/dp/B006G14FK8

I've got a new favorite 12v charg.er. https://smile.amazon.com/dp/B004LWVEKS it desulphates at 1.5A but charges at 7.2A and it handles lithum battery packs as well should you get one down the road. Plus there is a 25%/50%/75%/100% charge indicator that will show you how low the battery got between charging sessions.

Very nice looking charger and at a price not much more than the little one I have, that does much less. I've put in my wishlist and will have to think about it. Wow! over 2000 reviews and almost all good, most things I generally look at are lucky to have a dozen or so reviews....

For anyone who lives in the Midwest(MN, WI and maybe other places) Menards(similar to Home Depot or Lowes) has the above 12v charger on sale for the great price of $34.95, regularly the same as Amazon at $59.95. I picked one up(the last one on the shelf as best I could see) and they also had the cheaper version(1.1a regularly $39.95) for $24.99. Great prices IMO, I think it was a sale but it's also possible they are clearancing them out, I don't know. Glad I waited and didn't purchase one at Amazon