great video testing LFP vs AGM vs FLA

[mkaye]

Don't Waste Your Money On Batteries - The Shocking Truth I Discovered When Testing RV Batteries

 

[grizzzman]

Doesn't work.

 

[Delmar]

 

[Sabre36]

That is a good video and while there are some issues, such as not cycling the LA batteries to break them in, and that the batteries are rated at 77F and at a 20 hour rate to 10.5V, none of this will change much in the results of the testing. While they took some of the LA batteries to 9V the actual industry cut off (BCI) is 10.5V not 9V. While there is little capacity beyond 10.5V taking them to 9V will give a slight bump and be misleading.

The point that many LA batteries do not actually meet their rating is something we've known for years as we are physically set up to test LA batteries at the 20 hour rate for SoH. A large percentage don't even meet their rating when properly broken in and brand new. Also, with LA batteries, unless you have enough time to fully absorb them your actual usable capacity is really only 30-40% +/- of the Ah rating.

Those of us who have been dealing with LFP for any period of time (I've been working with LFP 2008 and been using them on my own vessel now for about 11 years,) there is no calculation you can make, unless being purposely misleading, where lead acid beats LFP on life time cost. The other part that is not realistic with the LA batteries is that the lab cycle-life ratings are basically a fairy-tale ratings in the real world. Real world is not how these batteries are treated in the real world.

Also what is lacking in this test is what happens to LA with PSoC use. For example the "AGM 3" is a very poor performer when PSoC use is taken into account and in just 30 PSoC cycles to 11.7V has these batteries losing anywhere between 27% to 30% of the tested new capacity. (See Practical Sailor May and August 2015 "Fighting Sulfation in AGM Batteries"...

Again, excellent video and testing and it is good to see folks using actual science when discussing batteries.

 

[Delmar]

Would have been interesting comparison to get two different FLA batteries. The one tested appears to be the cheapest Costco Interstate that receives poor reviews. Would have been an interesting comparison against a typical FLA Trojan or equivalent.

Purchasing LFP for a 48V system is expensive. Don't want to go broke saving money. Additionally four BB in series may not give me the required 130+A needed for my golf cart to accelerate or climb hills.

 

[Aaron_85]

there is no calculation you can make, unless being purposely misleading, where lead acid beats LFP on life time cost.

I can think of one instance where a lead acid bank could still beat out a LFP on life time cost: low cycle standby backup power systems.
Think somewhere like a remote communications site, that has grid connection 99% of the time powering the equipment and keeping the bank at float, that is absolutely critical for it to keep running for say 12 hours until either the grid is restored, or a generator is able to be shipped in. it will do practically no cycling for its entire life, sitting there fat dumb and happy until it is needed.
The cycle-life cost that lfp wins every time kind of vanishes if your only going to ever need 50 cycles out of it, and don't even need the 500 that LA gives, let alone the 3000+ that LFP offers.

Another where it may come close, is someone with an RV/Camper that sits in their yard on a DC:DC charger and or solar system, and only gets wheeled out and used one weekend a month. Weight is not an issue, and the owners will probably die well before they wear out their batteries.

I do agree that the scenarios where LFP don't win out are few and far between.

 

[mkaye]

thanks for fixing the link
i agree, not perfect, but the best comparison i have seen
i was trying to describe exactly what he saw with LA in another RV forum and couldn't do it justice i.e. doing the simple math with Ah and up-front cost