Zimnismoboy34 Posted March 27, 2018 Share Posted March 27, 2018 So over the past few days i've been doing the dirty work, reading through pages and pages of information looking for some facts and of course information to better educate the folk on this forum as well as myself . I do want to mention that if you are considering buying lithium batteries please be careful about what you buy and make an educated decision based on pure information read the fine print. The battery packs ive been assembling use good cells that have a end of life or (EOL) of 80% retention or more after the stated 2000 cycles which in actual fact is more but will write another topic based on that . So what has end of life got to do with it you might be asking , well Lithium battery manufacturing companies are supposed to use the global standard to term end of life 80% retaining capacity at X cycles, which gives us the consumer the benefit of understanding what we are paying for . End of life is an indication of how much life span the battery has after the number of cycles its being used for .Kind of like a life span gauge of a timing belt on a car use 60 000kms and know that you have 40 000km remaining . So inherently on lifepo4 you have most transparent producers using a value of 2000 cycles and 80% . However just picked up on a datasheet that does put some worry in me, and i did mention this before, on another page, conclusively the pylon tech battery does rate their system to 6000 cycles at 80% DOD but they also have termed their end of life at 60% ...... meaning you have used 40% of the batteries life span at 6000 cycles . It also means that your 2kw pack will only retain 1.2kw of energy at 6000 cycles . Sounds like they have been doing a little bending of rules call me wrong but im sure all lifepo4 systems can do 6000 cycles @ 80% with a remaining capacity of 60%???? any one care to comment on this false advertising ? not to mention also that their system is 50AH at 52v is the smallest lithum battery backup on todays market . for reference ive added a link to the site with the data sheet stating the EOL. https://www.sungiftsolar.co.uk/wp-content/uploads/2016/08/Pylon-Datasheet-US-Series.pdf Please note i am not slagging the product its good value for money but im not so sure consumers are making educated decisions, and this is something that needs highlighting . Quote Link to comment Share on other sites More sharing options...
___ Posted March 28, 2018 Share Posted March 28, 2018 7 hours ago, Zimnismoboy34 said: Lithium battery manufacturing companies are supposed to use the global standard to term end of life 80% retaining capacity at X cycles Yup, I've lamented this lack of apples-for-apples conditions before. I wouldn't say this is false advertising, but it is definitely "creative" advertising. In fact, I asked one of the manufacturers to his face about these shenanigans and he denied that using a C10 discharge rate is in any way out of the norm :-) It's not completely true though that the cells are all the same. The higher priced ones (LG Resu, Victron, Daimler, etc) can discharge at 0.5C continuous, so their relatively low 2000 cycles can be explained in terms of their higher discharge rates. Similarly, the higher cycle life of say a Pylontech which can only do C/2 sustained, makes perfect sense in that light. Does it really extend to 6000 cycles? I have my doubts, just like you. 7 hours ago, Zimnismoboy34 said: not to mention also that their system is 50AH at 52v is the smallest lithum battery backup on todays market . Yup, the Pylons are 15s. They are still good value for money, but again, when you take that into account and stack it next to say a FreedomWon... apples for apples... it's not as clear-cut anymore. Quote Link to comment Share on other sites More sharing options...
___ Posted March 28, 2018 Share Posted March 28, 2018 Here is an interesting battery I ran into at the Power and Electricity World exhibition yesterday. This battery is UL rated, which is an American thing which they assure me means it can do better than "25 degrees Celsius or no warranty". Quote Link to comment Share on other sites More sharing options...
Zimnismoboy34 Posted March 28, 2018 Author Share Posted March 28, 2018 thats very interesting indeed but im not sure i understand you, does this mean that it will be able to provide energy at 25 Degrees celcius and if it cant then no warranty ? Quote Link to comment Share on other sites More sharing options...
Zimnismoboy34 Posted March 28, 2018 Author Share Posted March 28, 2018 sorry only reading your response to my post now. i do believe there are cells for an application in each environment, meaning high rated discharge lithium = lipoly and low rated lithium standby energy storage, although in the fields in which each is used the cell structure is changed slightly to suite, it helps provide the purpose required. but to "cleverly" advertise of the customers expense is a bit crude i would say .... will find some more proof on another product i feel isnt adequate and respond in a few days my thoughts and proof there off with to provide consumers once again the best education they can get . Lg chem i should mention arent very good their ability to deliver energy to a high powered inverter for their size isnt great a very big complaint from alot of installers. This limits the size of setup greatly and well maybe a bonus on LG chems side they sell two battery units instead of 1 to power an average house hold ? Quote Link to comment Share on other sites More sharing options...
Zimnismoboy34 Posted March 28, 2018 Author Share Posted March 28, 2018 PS their data sheet has UL tests pending, and has no cycle life or indication of EOL ..... LOL http://discoveraes.com/wp-content/uploads/2017/12/Discover-AES-14-24-2800-Datasheet.pdf Quote Link to comment Share on other sites More sharing options...
SilverNodashi Posted March 30, 2018 Share Posted March 30, 2018 While on the topic of "all those considering Lithium batteries", just keep in mind that Lithium batteries are not the best option if you have big motors on the system. Big motors often draw a lot more energy than rated, which can shoot past the safe discharge rate of Lithium Batteries. Quote Link to comment Share on other sites More sharing options...
___ Posted March 30, 2018 Share Posted March 30, 2018 5 hours ago, SilverNodashi said: safe discharge rate I will echo that advice. I vaguely recall that at least one manufacturer don't even allow off-grid use, precisely because you have no control over the discharge rate. You obviously also have to use a good hybrid inverter than can act on the information and take the difference from the grid. I've actually seen a Pylontech bank drop its discharge current after running at c/2 for an extended time. The internal temperature reached 38 centigrade at which point the BMS dropped the discharge current. If there was no grid to fall back to, there'd be no way to deal with it other than shutting down completely. (The customer actually complained that the inverter is using too much grid power... :-) ). Quote Link to comment Share on other sites More sharing options...
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