ksoul2084
Posts: 149
Joined: Thu May 16, 2019 10:48 am

Re: Has anyone replaced their 12V battery with lithium?

Sat Mar 06, 2021 6:09 pm

MassDeduction wrote:
FLKiaEV wrote:How long is the stock 12v likely to last? It's commonly said that 3-5 years is typical for 12v batteries in cars, but the #1 stressor is being used as a starter battery in an ICE car. Perhaps it'll last even longer in an e-car?


The main killer of lead acid batteries is draining them below 50% capacity. Of course, in an ICE car cold weather starts are one common way of doing just that.

My understanding is that in EV's the main killer of the 12v is vampire drain on the battery while the car sits unused for an extended period of time, since they don't get charged unless the car is "started" with the main battery-pack engaged.

notfred
Posts: 520
Joined: Thu May 07, 2015 2:28 pm

Re: Has anyone replaced their 12V battery with lithium?

Sat Mar 06, 2021 6:33 pm

It seems to last 3-5 years, perhaps because of the way it is charged via the DC/DC converter from the main battery versus a gasoline engine alternator. I know one of the early firmware changes was to how the 12V was being charged.

One of the nasty things is that you get no warning of it being about to die. On a gasoline car it would start to crank slowly. On an EV suddenly one time it will not be enough to engage the main battery relay and you go from everything being fine to stranded with no prior indication.

IanL
Posts: 173
Joined: Tue Feb 18, 2020 12:57 pm
Location: Jersey, English Channel Islands

Re: Has anyone replaced their 12V battery with lithium?

Sun Mar 07, 2021 4:12 am

I have an inexpensive electronic battery tester. It gives a readout of battery SOH and recommends when the battery should be replaced. It would be a good idea to use it (say) once a month, to forestall sudden death.

FLKiaEV
Posts: 79
Joined: Tue Apr 14, 2020 6:03 am

Re: Has anyone replaced their 12V battery with lithium?

Sun Mar 07, 2021 9:32 am

Well, I think the reason Kia used that 45AH battery is because it was readily available and so they didn't have to have a specially made one (which would increase cost slightly). Just my guess. But you're right: A typical lead-acid battery for an ICE vehicle gets used up so quickly because of the high demands put on it to turn over the engine, which you can imagine would not be easy especially in high compression engine situations. Plus, I imagine that the high temperature under the hood of an ICE vehicle doesn't do it much good.

Neither of those things are really a factor for an EV because the regular demands on it are low and the temperature under the hood is a fraction of what it is on an ICE vehicle. I'm always amazed at not only how relatively cool it is under my hood but also how CLEAN it is (since the bottom of the engine compartment is closed instead of open to the road, etc).

As for how long the battery that came with it lasts, mine died very shortly after I got the car, less than a week! Luckily I had already ordered the lithium replacement and had it on standby. In general I would think even a lead acid battery would last longer with an EV than with a an ICE vehicle for the reasons mentioned above. Not sure if the stock battery is a deep cycle battery, like the lithium replacement or not though. It's good that the price of these things are starting to come down. Supposedly they have a lifespan of about 10x what a lead acid battery has. That would mean 30 to 50 years, which I doubt, but I still imagine it will be in good shape at 5 or 6 years. I test it (them) every month or so with a multimeter just to make sure it's holding a good charge, etc.
Russell
Kissimmee, Florida USA

"Even 93 miles of range is 3 times farther than the average person drives in a day."

FLKiaEV
Posts: 79
Joined: Tue Apr 14, 2020 6:03 am

Re: Has anyone replaced their 12V battery with lithium?

Sun Mar 07, 2021 9:55 am

Lithium batteries also do much better at holding a charge when not being used for extended periods of time. Lead acid is not good at this. But you're right that it's good to test them regularly. Lithium holds its charge while being used really well until the very end and then it just dies suddenly. If you have lithium battery-powered tools you've probably noticed that it can be down to only one bar of charge and still be going strong and then suddenly: Nothing. On the other hand, other types of batteries will gradually give less and less power until they die letting you know that they need to be charged or replaced.

IanL, I have a multimeter and I use it about once a month to test the 12V battery combo, but it doesn't give the SOC. Which battery tester do you use? (I do also have SoulEVSpy and the dongle but haven't used it yet and that is supposed to give a ton of info about the traction battery but not sure if it gives info about the 12V).
Russell
Kissimmee, Florida USA

"Even 93 miles of range is 3 times farther than the average person drives in a day."

IanL
Posts: 173
Joined: Tue Feb 18, 2020 12:57 pm
Location: Jersey, English Channel Islands

Re: Has anyone replaced their 12V battery with lithium?

Mon Mar 08, 2021 9:11 am

Mine is a Topdon ArtiBattery 101, It is appropriate for lead/acid batteries, but makes no claim as regards Lithium. I only suggested it for people who are still using lead/acid, and want some assurance about its condition.

SoulEV Spy only tells you the voltage of the aux. battery. I guess no other parameters are measured by the car.

FLKiaEV
Posts: 79
Joined: Tue Apr 14, 2020 6:03 am

Re: Has anyone replaced their 12V battery with lithium?

Mon Mar 08, 2021 10:14 am

Thanks! I'll check into it and see if there are any others that can give the SOC of lithium batteries.

As for the other parameters being measured, this reminds me of something that always annoyed me about car manufacturers: Dummy warning lights that don't even come on until you ALREADY have a fatal or near fatal condition for some part of your car. Like, there apparently are ways to determine if a lead acid battery is getting close to dying (even before we notice, on ICE vehicles, that engaging the starter seemed a bit slower this morning, etc) by reading voltage of the system before, during and after turning over the engine (or putting some other high load on the system). But instead we get a light that comes on WHEN your battery or alternator are pretty much already dead. I thought it would be nice if the vehicle was constantly monitoring everything electrical in the system to see how voltages and amps change over time under the same conditions to give us a "state of health" from green to yellow to orange to red, etc.

Anyway, rant complete. Glad that I (hopefully!) don't have to worry about dummy lights too much anymore.
Russell
Kissimmee, Florida USA

"Even 93 miles of range is 3 times farther than the average person drives in a day."

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