Lightweight lithium battery

[Steve W]

Wanted to share what is the current the market on lightweight lithium batteries for our cars. For years I've been using a Deka ETX14 AGM battery, which is an 11lb 12Ah battery, rated at 220CCA, and has never had a problem cranking and starting the motor in my 3.2 or GT3. Great battery and little attention or worry ever needed if on a battery maintainer when the car sits. In looking for a lighter replacement in lithium, I recently got this Houny YTX20L-BS, which is a true 20 Ah LiFePO4 battery with 480CCA, and internal BMS to protect from over discharge and over charge, and weight just under 6 lbs. Cost: $105 on Amazon. I specifically searched for something in the 20 Ah capacity range, as it gives more reserve than the Deka, of which for a lead battery, actual usable Ah is half of its rated capacity if you want to be able to start your motor. In other words on a 12 Ah AGM battery, if it drops below half capacity or 6 Ah, it may not be able to crank the starter, vs this lithium will still start the motor at 85% discharge. So this 6lb 20Ah battery would equal to a 40 Ah 30lb lead battery



In the 3.2 it cranks over the motor so much more rapidly and easily, and engine starts more immediately, you don't even need to compare with another battery to tell the difference. To verify its capacity, I used a lithium balance charger to bring the battery to full charge at 14.4v, then did a discharge down to 8.0v, which measured at 21.7 Ah. I brought the battery back up to about 10.5v, and started measuring the charge to bring it back up to 14.4v. Measured total capacity shows 20.7 Ah, meeting and exceeding its rated capacity.



When comparing batteries, don't be fooled by listings using a PbEq equivalent for Ah capacities, which means true capacity is 1/3 of that. Battery weight is a good indicator. For example if the battery weights 3 lbs, the max capacity for LiFePO4 is 8-10 Ah, and usually 7-8.

[silverlock]

(Right after I picked up a 40Ah Antigravity…)

Steve - super useful. What terminal adapters, if any, did you pick up for the Houny?

[Steve W]

I got the posts so long ago I don't remember, but searching online for 'M6 brass battery posts' the Antigravity adapters look the most similar:

https://www.amazon.com/Antigravity-Batteries-AG-TA-1-Automotive-Terminal/dp/B00DUHOCYU

[Ironman88]

Hopefully you'll do ok over time with this battery.

If one were to explore the Rennlist 9Y0 Cayenne forum and do a search on the LiFePO4 Lithium battery - you would come up with quite an extensive litany of issues and woes associated with it.

This battery came as standard equipment from Porsche on the 2019 - 2023 Cayennes. If the charge level of the battery drops to a certain level, the BMS disables it - preventing it from being charged, or even brought back to life. Porsche regards these batteries in this state as being DOA / junk and replaces them. Replacement cost is quite high from Porsche - approximately $2k.

Most 9Y0 owners who had experienced this problem are very frustrated with the battery. An aftermarket conversion has been made commercially available - some owners use that kit to convert over to an AGM battery.

For me, I would never opt to go with one of these batteries.

[Steve W]

That must explain why there are so many used and rebuilt Porsche lithium batteries and rebuild services listed on Ebay. That issue must be unique to the Porsche BMS if it locks you out if it drops below a certain level. The BMS systems in aftermarket lithium batteries don't do that. If anything, if it drops below a certain level, it will disconnect to protect the cells, but will reconnect upon recharge (most), or by pressing a reset button. You want that cell protection because if just one cell gets completely discharge, it cannot be recovered.

I only discharged this battery down to 8 volts in a test but the description states:

【Automatic BMS and Maintenance-free】 : The built-in Battery Management System (BMS) protects your battery from Over Charge and Discharge, Over Current, and Short Circuiting. The BMS disconnects the battery when abnormal conditions are detected, and it can be reactivated without the need for a higher voltage input. Lithium motorcycle battery will not overheat or catch on fire, even if punctured, making it a safe choice.

This battery comes with a two year warranty, and I'd think if it bricked itself on just one accidental discharge, they would have to deal with a lot of returns.

[Ironman88]

Originally Posted by Steve W

That must explain why there are so many used and rebuilt Porsche lithium batteries and rebuild services listed on Ebay. That issue must be unique to the Porsche BMS if it locks you out if it drops below a certain level. The BMS systems in aftermarket lithium batteries don't do that. If anything, if it drops below a certain level, it will disconnect to protect the cells, but will reconnect upon recharge (most), or by pressing a reset button. You want that cell protection because if just one cell gets completely discharge, it cannot be recovered.

Yes - regarding the eBay comments.

The Porsche OEM LiFePO4 lithium battery was sourced by Porsche from a supplier in South Korea. Given all of the problems and inconvenience that battery caused (Porsche as well as their customers), the new Cayennes no longer come with them.

(I had a 2019 Cayenne that had that battery; suffered the failure; and subsequently was replaced - under the emissions warranty by Porsche. Others were not so fortunate and had to pay out of pocket for the replacement battery, programming of the vehicle and installation - about $2,200 or so.) My 2024 Cayenne came from the factory with an AGM battery.

[stownsen914]

Thanks for sharing. I've got my eye on a Noco NLP30 when my current racecar battery dies. It's a high compression 944 engine that needs some oomph to start. Currently has an AGM 700 CCA battery, I'm hoping the NLP30 will be enough for it. 5 lbs, 30 Ah, supposedly 700 cranking amps, a little over $150.

[Steve W]

Looking at the Nico NPL30 I'm sure it would start your motor, but the specs show it's only a 7.8 Ah battery. If weight is the prime consideration, it will do the job, but not the best $:Ah ratio.

https://no.co/nlp30

But if looking for more Ah capacity, the TPE batteries look attractive. Their Group 26 is 30Ah, 8.8 lbs, and $228 Or the Group 47 is 11 lbs and probably 40 Ah. Nice is they have a warning disconnect if the battery drops below 30% that can be reactivated by pressing a button, and that they already have brass battery posts built in.

https://a.co/d/gm4RLrf

[Duc Hunter]

This is the battery I am running in my Rat Rod. I wanted full capacity fo feed my electric A/C. Only had it a short time, but all is well. Car cranks great, A/C seems much appier, and it sure is light. Fits like a glove too. I chose Group 31 as I wanted the terminals closer to the fuel tank, to make hoping up the battery terminals easier, jumping it easier, and hooking up my battery tender easier.

LifiePo Battery - Group 31

[stownsen914]

True, I stand correct on the Ah rating. For my application (racecar), I'm most interested in the ability to start the car. Power requirements once the engine is running are pretty light.

I wonder though how they rate it at 700 CA if it's only 8 Ah. I wonder if it's BS.

[Synchro Joe]

Curious what sort of warranty and support is offered on this battery? Seller on Amazon is in China and what I saw warranty wise was 2 years I think? For $115 it's a cheap solution, but the disposal & warranty would be my concern. I had to return an electric razor for repair/replacement and it required the special hazardous material shipping labels, etc. What a business. https://www.youtube.com/watch?v=DXEbmNhUH80

[Steve W]

There's probably more smoke and mirrors involved in that CCA #. The current output capability of a battery cell is determined by its C discharge rate (how much it can dump out the power, like HP output of a motor). Lower quality cells have a low C discharge rate like in the range of 2-10 and are used in less expensive 'deep cycle', backup, trolling motor type batteries. Such a battery if it were an 8Ah battery, with a 10C discharge rate would only discharge at 80A max. You wouldn't find RC hobbyists using such batteries in their toys. Higher performance batteries such as you'd find with A123 cells, or in high performance LG and Samsung cells such as used by Porsche in their battery packs, or in high end cordless tools such as Dewalt or Milwaukee, are capable of a 30C discharge rate. So the same 8Ah battery would be capable of a discharge of 8x30=240A continuous.

However CCA is the measurement of how many amps a 12v lead battery can deliver for 30sec at 0°F while maintaining 7.2v, which for a lead battery is understandable, but for a lithium, how they come up with that number is more of a mystery, the 7.8Ah lithium battery would have to have cells that can discharge at 90C (rare and unlikely) to deliver 700A (7.8*90). Maybe they the cells used have a 45C continuous discharge rate, but might deliver a transient 90C discharge for 2 seconds?

[Steve W]

Originally Posted by Synchro Joe

Curious what sort of warranty and support is offered on this battery? Seller on Amazon is in China and what I saw warranty wise was 2 years I think? For $115 it's a cheap solution, but the disposal & warranty would be my concern. I had to return an electric razor for repair/replacement and it required the special hazardous material shipping labels, etc. What a business. https://www.youtube.com/watch?v=DXEbmNhUH80

Well, I've got my fingers crossed. If properly maintained, I expect the battery to last at least 10 years, and don't expect to ever use the warranty. But if it only lasts a few years, not a big loss and no different than if I had another AGM battery. With time I only expect the tech and features to improve in the future. I've got a couple of Dewalt lithium battery packs at least that old and still going strong. And they've been used and abused but the internal BMS keep the cells balance and their power tools protect them by shutting down connection when the battery pack level drops too low. Back in 2012 I built a lithium battery with A123 cells, when there were no lithium batteries for cars, (so what is that 14 years ago?) and it's still active in the car and with just as much power and Ah capacity as it did back then.

Who is street legal and under 850kgs/1,875lbs?

[TastyReuben]

Originally Posted by stownsen914

Thanks for sharing. I've got my eye on a Noco NLP30 when my current racecar battery dies. It's a high compression 944 engine that needs some oomph to start. Currently has an AGM 700 CCA battery, I'm hoping the NLP30 will be enough for it. 5 lbs, 30 Ah, supposedly 700 cranking amps, a little over $150.

This is what I have had in my ‘83 since November. For ~120$ it came with a smart charger on Black Friday. Have had 0 problems with it.

[stownsen914]

Originally Posted by Steve W

There's probably more smoke and mirrors involved in that CCA #.

This is what I am wondering. Technically Noco and some of the other small battery manufacturers use Cranking Amps to rate their batteries. I'm no expert, but it looks like the main difference between CCA and CA is just the temp at which the test is done. If this is the test Noco did, then theoretically the Noco NLP30 is good for 700A per the below:

"Measures the current a battery can deliver at 32°F (0°C) for 30 seconds while maintaining a voltage of at least 7.2 volts." [Google AI search on CA definition]

I'll probably just get one when the time comes and find out for myself.