I have been running an AMG 15lb battery for about 5-10 years... starts my car amazingly every time... i have gone through about 3 of them due to car sitting forever and no charge to 0 volts... then big charge.. all my fault.. treat it badly, and yes i know all about how to do it right, i just dont... lazy i guess...
anyway... went to Amazion looking for a new replacement, again..... and ran accross this one.

the one im looking at:

About this item

• Product Dimensions: (L) 6.54 inch x (W) 4.96 inch x (H) 6.89 inch, Item Weight: 7.66 Pounds, M6 Terminal: - + ; 700 CCA. Charge temperature:-20℃~+45℃/Discharge temperature -20℃~+60℃ ; Size, cold cranking amps, terminal location, and battery type are vital pieces to getting the right unit. please measure your old battery and compare the dimensions with this battery, if the measurements are the same, positive and negative poles are consistent, CCA is no big difference, and it will fit your vehicle. Terminal： Left : Negative (-), Right: Positive (+).
• BUILT TO LAST : Our 12V 10Ah LiFePO4 Batteries are designed for durability, with 500+ amps, 50,000+ starts, and 2,000 charge cycles. This means our battery will provide exceptional performance for longer periods compared to traditional lead-acid batteries. Simply put, it's 2X more power, 10X more starts.

 

A-h-h-h-h-h-h- NO.

It's a lawnmower battery. Note the posts.
And those CCAs are likely over estimated.

Save your money for a Optima Red Top and a Deltran tender / charger.

 

way way to heavy… 15 lbs or less nothing more is acceptable

 

There was a thread on this.

https://www.corvetteforum.com/forums...for-cheap.html

I haven't mounted one in the car yet, but a similar sized battery has no problem cranking my LS engines.

 

I have a battery disconnect switch because of a .2 amp drain to one of the ignition boxes.

I have run the 13.4 volt motorcycle racing batteries. As a good weather daily driver they kinda have to get replaced every year or so. The 2000 charging cycles goes pretty fast. The post of using two batteries would help

 

Why would anyone need a super lightweight battery, unless it's a track or drag strip Vette?

 

Losing weight is like adding HP, but only if you accelerate in a straight line. For the rest of us, losing weight also benefits braking and handling.

Plus, chasing new tech is a fun hobby by itself. Certain lithium batteries (LiFePo) are ready for aftermarket early adopters.

 

The little motorcycle batteries might look like a real battery but they are not going to be charged completely and properly in a older C3 which will lead to their premature failure. 20 years ago I had a LiFe (Lithium Ferrous battery) Motorcycle battery in my Yamaha and the first went dead in a few months. The second battery still shows voltage but has very little capacity left. As a battery person I like to keep up with the newer technologies but I still use a plain old Flooded Lead Acid like my C3 came with from the factory. The flooded batteries last a long time as I perform regular maintenance on them. I top off the electrolyte when low and clean the battery and it's connections. Then I coat them in Battery grease (NOT Die-Electric grease) to keep out oxidation.

The battery shown on Amazon says it has overcharging protection and under-voltage protection. This all depends on HOW the over charging protection circuit works. There are lots of Lithium Polymer batteries out there and some are pretty good batteries. One indicator that the battery company may be questionable is when they tell you that you can mount the battery in "any position". That has not worked out real well for other sealed batteries, what makes this battery any different?

The requirements for a Corvette battery are pretty tough and they need the extra amp hours just to let the cooling fan run after shutdown. My cooling fans pull 30-35 amps for up to 30 minutes after engine shutdown and that would be an interesting load on that tiny Lithium Polymer battery in a Corvette. That battery would not like the loads put on it by a BB with factory starter let alone EFI and cooling fans. I use a Deep Cycle battery in my C3 and have had years of battery life with a battery that is maintained and charged up occasionally. I have a lot of weight with my BB so a full size battery actually helps me balance the car better.

I use a gear drive starter on my 12.25-1 compression ratio BB and it cranks nicely. The biggest benefit is that it use less power than the factory standard starter does to start the engine. A gear drive starter along with being able to pull timing during cranking makes for a very happy starting system. I was absolutely amazed at the difference between cranking with full timing and cranking with the timing pulled back 20* only while cranking, at ~800 rpm the timing goes back to normal. The newer MSD boxes are able to pull the timing. I use a MSD Digital Retard box to pull the initial timing back up to 20* in 5* increments.

Using Lithium Polymer batteries with my RC airplanes has shown me how they work in different applications. I could take one of my polymer battery pouches and it will start most cars even though it is the size of a pack of cigarettes. Lithium Polymer is a great battery technology but when they catch on fire you are in for real trouble. In my C3 and my shop I keep Halon Fire Extinguishers which are capable of putting out a battery fire. I charge my LiPo batteries while they are inside of a Fire Proof bag to minimize the risk of getting burned

Have you ever seen a Tesla catch on fire? They can't spray water on it to put it out, they have to use a special foam spray for battery fires. Tesla's never Catch on fire do they?? I have and it is time to break out the marshmallows and grab a soft drink while watching an Eco Car burn to the ground! There are tons of Tesla Cars in the Northern Virginia area and the Fire Departments are learning new methods of putting out a Lithium battery fire out without letting it burn up the car.

I wouldn't want a Lithium fire in a Fiberglass Corvette as it would likely be a total loss if a Lithium battery experienced thermal runaway while in your Corvette. I will stay with my 1000 CCA Flooded lead acid battery for a few more years!

 

So as those of you on here that know me know, I work for a large American motor vehicle company that is HUGE on ongoing training.
training on the differences between these modern lightweight and expensive batteries and the Glass Matt maintance free batteries we've been using for years. And the flooded batteries that really are out of date. And seldom used.
As an example of the types of classes I'm required to take.
Big difference in how these lithium battery's deliver power.
let's say for a example. You have a engine that requires a fair few amp's to spin it over.
The lithium battery will deliver one heak of a good kick of power on that first start attempt.
And if the engine fires as it should.
Well, you'll be impressed with your new lithium battery! Wow, it only cost 4 times as much! But it really spins my engine! I'M IMPRESSED!
Now, what if you have my luck?
Vehicle doesn't wish to start on the first start attempt?
Hummm, ???
Now here's the difference.
Your maintance free Glass Matt Battery will loose a little bit of power with each start event. So the 5th event will be slightly less powerful than the first.
However all is not the same with a lithium battery.
It's not likely to get past a third event in comparison.
As the lithium battery will deliver a large amount of it's reserve power when a load is applied. Depleting the lithium battery quickly in a multiple start event situation.
Big difference in how they deliver the stored power.
Me, can't sell me a lithium battery for a starting battery in a motor vehicle.
Starting events in a motor vehicle are a completely different world than running a cell phone.
I'll carry the weight. I might need that one more shot at getting her started, in the rain, in the dark. Far from home.

 

I have since switched to smaller like a 1/3 of a typical group 27 size. Bigger AGM OHV type.

If your fans run that long you need to place the temperature pick up on the radiator not the engine block. Or if you want to cool everything down you need an electric water pump.

My electric fans shut off in a minute or two or not even run at all depending on the ambient temperature

 

Since it seems no one but @4-vettes read to the end of the 7-page lithium battery thread I posted, here's a shorter one, with a specific recommendation.

https://www.corvetteforum.com/forums...-corvette.html

It's still best practice to disconnect your C3 when you aren't using it. Not counting the gasoline, even the window motors will try to burn down your car.

 

Then remove the A/C compressor, bracket and belt. That's got to be a significant weight reduction in the engine bay.

 

Already one step ahead of you.

 

I have spent many years on nothing but battery technology and am intimately familiar with the various types of batteries that are out there and the ones heading for production. I loved the idea of the LiFe battery as it weighed about 3 pounds and would solve my battery needs on my old Yamaha motorcycle. I love the newer LiPo batteries because of their discharge curve. A LiPo will make a long flat discharge curve and then drops rapidly at the bottom of the charge. The AGM battery is like most flooded batteries makes a nice bell shaped curve where the voltage drops pretty quickly initially. The test where you run the headlights for 10 minutes and check the battery voltage would clearly prefer the LiPo batteries who are still high on the bell curve compared to the Flooded Lead Acid would have dropped voltage slightly as the capacity drops and likely been a lower voltage number after the 10 minute test.

LiPo batteries come in 3.7 volt cells so 3 of them makes 11.1 volts and 4 of them is 14.8 volts. The 14.8 can be charged up to 16 volts when charging in a car. Our alternators were simply NOT designed to charge anything but a standard FLA battery and the temperature compensation is not set to help anything but FLA batteries. To charge any type of battery used in a car we will need alternators with the various charging technology allowing you to select the type of battery be charged. This would be the easiest for right now IF the manufacturers see any use in it. If not the aftermarket can make new alternators programmed to give the LiPo or even AGM battery a good solid charge. They need to be charged but NOT blow the pressure relief valve while doing so, this means it will be slower to charge to get them absolutely full. To charge them fast you will need a temperature control system to keep the cells from therm al runaway

A standard FLA battery is made of 6-two volt cells. If one cell dies the battery will probably still start the engine. If you have a 4 cell LiPo and one cell drops out you loose 25% of the useful capacity. The LiPo is a very reliable product and I have not sen as many failures but lots of capacity lost as I continue to test these cells. LiPo cells require their own charging algorithm and it is substantially different than the FLA. LiPo cells have a problem with growing puffy when used multiple times, I am anxious to see what the industry does to eliminate the swelling of the battery packs.

I have been testing the 18650 cells for their capacity and cycling them to verify the capacity. Much to my surprise some of the earlier 18650 batteries have lost serious amounts of capacity when discharged to 100% like they claim they can do. At a shallower discharge stopping at 80% of the capacity they don't seem to have many issues. Why are some different than others? CHINA, they copied the Panasonic 18650's and produce a lot of lower capacity 18650's and they w. When working with a FLA battery the capacity will grow slightly and then they start the downhill trend. The LiPo has the most energy capacity when brand new.

My Cessna 172 had a AGM battery that was light and very expensive. It worked great until the temperatures plummeted and then back to the "slow" cranking speed. I had a plug where I could plug in my car's battery to assist in starting the engine up and that helped the Little AGM battery when it was cold. The AGM battery is really good if you don't drive often. The AGM battery has a very low self-discharge rate which makes charging intervals a bit longer which makes the ideal for a RV. This is where AGM and LiPo batteries have the advantage of the standard FLA battery.

One of the benefits of the FLA battery is that we CAN extend their life by simply doing the required maintenance on the battery. Checking the electrolyte is important on a FLA because as the battery is charged up over and over the electrolyte can boil away or evaporate the water in the mixture. Replacing the water is easy and the best way to get some extra mileage out of the battery. Using face protection and a rubber apron to keep the electrolyte from getting in your eyes or on your clothes. The electrolyte is strong acid and will really damage the eye if you get some in there, I keep a eye wash station in my shop just in case. Cleaning the top of the battery before starting is a good place to start. I use water from my Reverse Osmosis system as it has very few Undissolved solids in the water. I open the cell tops and then find the level indicators for the electrolyte and top off the electrolyte with R/O water very slowly. Only fill it to the level indicators as too much water is not good either. Then charge the battery to 2.5 volts per cell or 15 volts for a 6 cell FLA battery and let the battery get up to and boil the electrolyte to prevent stratification of the electrolyte. This can be done in a car but the alternators rarely charge at 15 volts so I like to isolate the battery and then perform the maintenance.

The future is very bright on the battery front as the researchers keep finding better ways to make a battery. I wish they sold a battery jar that allows the owner to rebuild the battery by simply draining the electrolyte and flushing the old electrolyte off the parts, then removing the plates and replacing with new plates and fresh electrolyte. It would be a much more affordable way to own and use batteries. This would be so much better than throwing the big cases away after you are done with the battery. I still remember driving through central Mexico and seeing old FLA batteries in the creek and river beds actually in the water. This is a terrible thing to let happen, if they had a rebuild-able battery they could still use the battery after a few hours re-newing the battery. Even if there was a shop that rebuilt them it would be better than polluting the drinking water with dead batteries. Lead in the drinking water can adversely affect the locals and in a bad way.

For me and my household, we will continue using FLA and an occasional AGM batteries!

Best regards,
Chris
P.S. The batteries that say are "Maintenance Free" but are still FLA and 90% of them have access holes to get to the electrolyte to inspect it and or replenish it. The LiPo and AGM batteries allow no maintenance. Advantage?

 

No one is talking about LiPo (lithium-ion polymer) batteries, or 18650s, except for you. That is not what the vehicle battery replacements are using.

Here's the curve for a LiFePO4 (LFP) battery. Cell voltage of 3.2 (20% SoC) to 3.32 (80% SoC). 4 cells puts it at 13.0V at 50% SoC. Couple that with a DR44G alternator (default 13.7 output voltage, tunable with a PWM signal), and you're all set.

 

Wrong battey tech... tesla uses the same 18650 lithium ion batteries as a laptop battery. (4.2v fully charged per cell and 3.7v nominal...)

Lifepo4 is completely different chemistry.. 3.65v fully charges and 3.2v nominal per cell.
Also no cobalt and nowhere near as volatile. You can stab them with a screwdriver and they typically still wont catch fire and they wont explode when over charged either like lithium ion.

I do agree the voltage regulator in the car is likely not setup for the lifepo4 battery though. probably ok if the battery never really gets discharged much but when discharged they pull a LOT of amps from the alternator and may over heat it. (again unlikely in this type use use scenario though)

 

Typically lithium battery will actually delivery more constant output current longer without slowing down the starter than any type of acid battery. That being said if that that tiny 8ah battery is really a lifepo4 battery it likely wont deliver 600 cranking amps and if it did see a 600amp load it would be dead in seconds. Most lifepo4 cells are rated at 3c max meaning that battery should be able to deliver like 24amps output. so either the specs are BS or theres some other magic going on. They do make higher C rate cells but they arent all that common and are typically depleted in a very short time with a dramatically shorter lifespan in a high c rate load application. There is likely some other type of super capacitor circuitry or something to to that effect to make it output more amps for a very short time frame like the newer battery jumper boxes sometimes use.

 

 

Well Augie, I certainly can not post up entire classes from my employer. However, my take on it is this.
Yes, they love selling these overpriced lightweight batteries.
We make money selling them.
I personally have seen a VERY high rate of warranty.
Yes, a load like leaving your lights on they handle well.
starting events they DO NOT handle well.
These are 20amp hour batteries.
Not 8. We're not starting scooters here.

 

I cannot comment on any of that, I am only pointing out that lithium batteries do not typically give up the ghost and crank slower on each sequential starting attempt becoming useless in starting like lead acids can The discharge curve is pretty flat and a lot more consistent right up until the bms senses they are depleted and cuts off the voltage to prevent damage to the cells.

Since you brought up scooters yes those are a good example of a High amp load scenerio where they far out perform any lead acid battery in its size class by delivering more current, for longer periods. This is why more and more scooters, golf carts bikes and electric vehicles use them over lead acid tech.

The key is having the correctly sized lithium battery for the application.

BTW that said you and I are in agreement that a lithium battery is not ideal as far as being practical for this particular application in most cases. That is why despite building many lifepo and lipo batteries myself for multiple applications, both high and low load bearing I use a $45 Blem lead acid battery from my local interstate dealer in my corvette. More and more High end gasoline powered vehicles are using lithium starting batteries though because when sized and built correctly and paired with the proper charging system they can work very well. They just arent actually cost effective for this yet.