Sterling Power testing Lithium against lead acid batteries

[jkidd]

Here is a video testing Lithium against lead acid and the cost. Interesting results and a little shocking if your being mean to your batteries.

https://www.youtube.com/watch?v=jR34QF3xcCc

[T.R. Bauer]

Interesting - thanks for sharing. I have lead acid batteries that are over 10 years old and going strong still. I'm sure the new technology is better, no question in my mind, but my wallet wouldn't like it.

[thataway]

Thank you Jody. Sterling Power is a very good company. My battery to battery charger is a Sterling. Sterling and Pro Mariner Pro Nautical line is the same as Sterling (which is based in the UK), so there is some connection there.

He didn't do Carbon Foam (unless they are the same as "lead crystal", which I don't think is the case, even thought they perform similarly. )

The issue is that when you discharge any lead acid battery at more than 50 % (about 12.2 volts) it shortens the life span. If I see a battery which is 10.5 volts I will usually tell that person that the battery has had some significant damage. The usual lead acid battery is considered discharged for all practical purposes at about 11.8 volts, so he was severely damaging the batteries. He is correct that many people do this-and occasionally we see a C Dory do this. This is why I monitor my batteries, with a Victron shunt monitor (I have used Link and others thru the years).

The Li Fe PO4 battery is entirely different. A LIFe battery voltage fully charged is 3.6 volts floating at 3.4+. The standard lead acid battery charges to 2,3 volts per cell.

Thus for the LiFePO4 battery: four time 3.6 volts equals: 14.4 fully charged and resting at 13.6 volts.

For any lead acid (including AGM) there will be Six cells x 2.3 volts and the max charge floating voltage will be about 13.8 and resting will be 12. 6 Volts to about 12.8 for AGM. For the lead acid batteries, I try and not take them below 12.2 volt resting. which is 50% discharge.

The discharge curve on the Li Fe PO4 battery keeps the voltage above 12.8 volts until it is 80% discharged and at 90% discharged it is still at about 12 volts. By the 10.8 voltage which was the end point for the study the battery was 95% discharged.



Now, if you never discharge to more than 80% or 70% or even 60%, and keep the batteries free from sulfating, avoid extremes of weather, avoid excessive vibrations and G Forces you can get good Flooded lead acid batteries which will last for more than 10 years. I had a pair of FLA group 31, I used to start an 8.3 L Cummins 350 HP diesel. Those were 10 years old, when I sold the RV, and I just switched them out as a precaution for the new owner...But they were only used for starting, never went below 12.4 at steady state and were charged immediately backup.

Where the LI battery shines. Light weight, high capacity refill--you can charge at C1 (that is put 100 amps into a 100 amp battery I don't, but charge at about C .5 rate.(80 amps into a 200 amp bank. There is a lot of usable current in a small and light package. It will allow 100 % draw for a short time--that would be 200 amps for start up of an AC unit for example...They begin to pay when you are cycling the batteries every day, and need a good amount of power. We use our 200 amp. hour usable bank to power two chest freezers/refers, an induction or two Burners for meals, and a microwave oven on the 25. They will charge back up using about 30 amps per hour from the Outboard--charging profile especially for the li battery form the Sterling Battery to battery charger. With the 80 amp charger on the inverter, we can charge a depleted bank in just a little over 2 1/2 hours. Lead acid would take well over twice that for half the power. The best use is if you do this every day for 10 years...that is what the LiFePo4 is made for.