January 12, 20206 yr @Gerlach Will you please inform me when this setup of yours is working 100% with BMS and battery balancers. I would also like to know final costing. If this is costing you around R25k for a 120AH lifepo battery it will be worth my time to invest in this. 2 pylontech US3000 will be around R40k and is 150AH.
January 12, 20206 yr I noticed on the site you gave the link to that they have a kit with the batteries BMS battery balancer and some other goodies for R21k. My only concern it states that these cells have a 2000 cycle life. That is 5,5 years. I am wondering if these cells are re purposed car batteries? Well for R42k you can have over 200Ah or 12kw backup where with the pylontech you only have about 7kw. I will be ordering the kit soon. I dont need to play around with settings and software and all the other things.
January 12, 20206 yr 2 hours ago, Krokkedil said: My only concern it states that these cells have a 2000 cycle life. That is 5,5 years. I am wondering if these cells are re purposed car batteries? The testing is not always done the same. If you test at 90% DoD and 1C discharge currents, the battery will be EOL (defined as having irreversibly lost 20% of its capacity) after 2000 cycles. If you test at C/2 (as Pylontech does) or C/10 (as BlueNova does), and define your EOL as 40%-lost (As Pylontech does), you get significantly better numbers. I therefore tend to think the real life is going to be somewhere in the middle, probably around 5000.
January 12, 20206 yr Author 22 hours ago, JJS said: How is your battery coming along @Gerlach ? Groete! @jjs I'm still bussy waiting for my BMS. SaPO is taking there time to send it from JHB to CPT. Waiting patiently for it. Hope to have it in this 2 weeks.
January 12, 20206 yr Author 5 hours ago, Krokkedil said: @Gerlach Will you please inform me when this setup of yours is working 100% with BMS and battery balancers. I would also like to know final costing. If this is costing you around R25k for a 120AH lifepo battery it will be worth my time to invest in this. 2 pylontech US3000 will be around R40k and is 150AH. @Krokkedil you can actually speak to Bain, the person that is importing the cells. His got some buyers that using in there inverters and camping stuff and a farmer that's using it on his farm.
January 12, 20206 yr 1 hour ago, plonkster said: The testing is not always done the same. If you test at 90% DoD and 1C discharge currents What worries me about these cells, is that they have really low recommended charge and discharge current to achieve the 2000 cycles Pylontech recommends C/2 for charging and discharging, these cells recommend you charge them at 0.2C, that to me is a bit low? That is like good AGM territory, however you will at least enjoy the higher charging efficiency of LFP which is nice. I guess therein lies my question, at what point does the lower charging and discharging current of cheap LFP cells not just make you buy good LA batteries?
January 12, 20206 yr Hi All, My cells can, with no problem handle the 0.5c and 1c charge. They are guaranteed to last 2000 cycles if not overstepping the 1c charge and discharge. The 2000 cycles are at 100% dod means that you will have 80% capacity remaining there after. That means after another 2000 cycles you will have another 20% capacity drop. Taking that into consideration i can claim that the cells can do 6000 cycles at 100% dod and have 50% capacity remaining. If looking at the data sheets and the tests performed, one will most likely get over 3.2k cycles out of the cells before they have a 20% capacity drop if they are not abused. I test every single cells voltage upon arrival to make sure there are no damaged cells as this is an clear indication that the cells have been damaged by whatever means. I do not sell cells that will give me a bad reputation. Feel free to look at the reviews on my facebook page as well https://www.facebook.com/Lithium-Batteries-South-Africa-104002904362166 Kind Regards, Bain Viljoen
January 12, 20206 yr I also have a client that is running his bore hole pump on 2 x 24v packs and his house of 4 x 24v packs.
January 12, 20206 yr 7 hours ago, Bain Viljoen said: They are guaranteed to last 2000 cycles if not overstepping the 1c charge and discharge. The victron batteries I'm used to are tested in the same manner and advertised as having 2000 cycles. The very same cells (Winston) are used by bluenova, tested at a lower rate, and advertised as having 7000 cycles.
January 13, 20206 yr 8 hours ago, plonkster said: The victron batteries I'm used to are tested in the same manner and advertised as having 2000 cycles. The very same cells (Winston) are used by bluenova, tested at a lower rate, and advertised as having 7000 cycles. If i'm not mistaken the Winston cells that bluenova uses are LiFeYPO4. These do last longer. Extremely expensive as well.
January 13, 20206 yr 1 hour ago, Bain Viljoen said: If i'm not mistaken the Winston cells that bluenova uses are LiFeYPO4. These do last longer. Extremely expensive as well. True. I'm just making a point about how widely the advertised cycles can vary, to the extent that one manufacturer can advertise a number over 3 times bigger than the other, using the same cells 🙂 Of course it makes apples-for-apples comparisons very hard to the consumer, which is something I have often lamented.
January 13, 20206 yr 17 hours ago, Bain Viljoen said: My cells can, with no problem handle the 0.5c and 1c charge. I have no problem believing they can, but the spec sheet is very clear that it recommends 0.2C So my thinking here is: If you keep to that the and the discharge recommendations you would achieve your 2000 cycles with no problem. Charging at 0.5C would maybe shave off 400 cycles? I really don't know, but you will probably hit that 80% of initial capacity faster if you charge at 0.5C, how much faster? I honestly don't know, I am quite tempted to buy 4 and test them, it could be interesting, my boss is also looking for a small battery for his caravan, a 12.8V pack of this would do that job perfectly.
January 13, 20206 yr 3 minutes ago, PJJ said: I have no problem believing they can, but the spec sheet is very clear that it recommends 0.2C So my thinking here is: If you keep to that the and the discharge recommendations you would achieve your 2000 cycles with no problem. Charging at 0.5C would maybe shave off 400 cycles? I really don't know, but you will probably hit that 80% of initial capacity faster if you charge at 0.5C, how much faster? That is the recommended charge yes, But they are guaranteed to last at least 2000 cycles to the 80 percent capacity degradation meaning that you will get 2000 cycles if you do not surpass the Max parameters. It is for this reason that I can give a guarantee on my built packs.They are sealed up and i know they have the necessary protection. The Built in BMS for these units allow a C of 0.66 on these cells. If a customer were to report a degradation in capacity not consistent with the guarantee i would replace it. Hope this helps and gives some sort of assurity.
January 13, 20206 yr 20 minutes ago, Bain Viljoen said: That is the recommended charge yes, But they are guaranteed to last at least 2000 cycles to the 80 percent capacity degradation meaning that you will get 2000 cycles if you do not surpass the Max parameters. See I think this is where we see it differently (I might be completely wrong and I am willing to accept that, no problem) To you keeping below the max current values allowed = 2000 cycles To me keeping below the recommended current allowed values = 2000 cycles To me, going above the max current values is the type of thing that dramatically reduces the life or even damage the battery outright, and the recommended values are the ones used to achieve a certain cycle life number, sometimes in LFP spec sheets they will have cycle life graphs at different charge and discharge rates, perhaps you could ask the manufacturer to provide this to you? Then you would know for sure, otherwise you might be staring down the barrel of a tsunami of warranty claims if the cells only manage 1000 cycles at 0.5C charging current.
January 13, 20206 yr All the best Bain for your venture with these LiFePO4 batteries ! I am interested in getting some cells from you and for a BMS this unit from AliExpress with bluetooth module. https://www.aliexpress.com/item/4000425316662.html?spm=a2g0o.productlist.0.0.679f305eqLa8vP&algo_pvid=20b3aad5-0dd6-4979-af68-93e2ef19e523&algo_expid=20b3aad5-0dd6-4979-af68-93e2ef19e523-18&btsid=13a4281f-b72b-4a12-9a8f-f49fd0ddc7be&ws_ab_test=searchweb0_0%2Csearchweb201602_8%2Csearchweb201603_55&aff_request_id=141ae981c7b3450e82968bdf95e1bc07-1578901127032-03937-l5hk5UVw&aff_platform=link-c-tool&cpt=1578901127032&sk=l5hk5UVw&aff_trace_key=141ae981c7b3450e82968bdf95e1bc07-1578901127032-03937-l5hk5UVw&terminal_id=7ba9d86aa42e42478f72cdbbd6e8dfa0 Last year I successfully purchased some 7S and 14S (Daly brand) BMSs from AliExpress for LiIon cells. These work fine but it would be great to be able to see the voltage of each cell which is what the bluetooth module and smartphone app allows you to do. What warranty do you offer on your cells ? Obviously you are at risk from clients unaware of the detrimental effects of subjecting the cells to over and under voltage conditions caused by over and under discharging respectively.
January 13, 20206 yr 3 minutes ago, GreenMan said: All the best Bain for your venture with these LiFePO4 batteries ! I am interested in getting some cells from you and for a BMS this unit from AliExpress with bluetooth module. https://www.aliexpress.com/item/4000425316662.html?spm=a2g0o.productlist.0.0.679f305eqLa8vP&algo_pvid=20b3aad5-0dd6-4979-af68-93e2ef19e523&algo_expid=20b3aad5-0dd6-4979-af68-93e2ef19e523-18&btsid=13a4281f-b72b-4a12-9a8f-f49fd0ddc7be&ws_ab_test=searchweb0_0%2Csearchweb201602_8%2Csearchweb201603_55&aff_request_id=141ae981c7b3450e82968bdf95e1bc07-1578901127032-03937-l5hk5UVw&aff_platform=link-c-tool&cpt=1578901127032&sk=l5hk5UVw&aff_trace_key=141ae981c7b3450e82968bdf95e1bc07-1578901127032-03937-l5hk5UVw&terminal_id=7ba9d86aa42e42478f72cdbbd6e8dfa0 Last year I successfully purchased some 7S and 14S (Daly brand) BMSs from AliExpress for LiIon cells. These work fine but it would be great to be able to see the voltage of each cell which is what the bluetooth module and smartphone app allows you to do. What warranty do you offer on your cells ? Obviously you are at risk from clients unaware of the detrimental effects of subjecting the cells to over and under voltage conditions caused by over and under discharging respectively. Unfortunately i cannot offer a warranty on the cells as for the exact same reason you just mentioned. I do have confidence in these cells on the other hand and that is why i offer a warranty on the built units. However, I test every single cell before they are sent to customers because if there is a cell with low voltage it is a clear indication that it is potentially faulty. I charge these cells up then and let them sit for a month and then discharge them to see if they are fine. Hope this helps.
January 13, 20206 yr 25 minutes ago, PJJ said: See I think this is where we see it differently (I might be completely wrong and I am willing to accept that, no problem) To you keeping below the max current values allowed = 2000 cycles To me keeping below the recommended current allowed values = 2000 cycles To me, going above the max current values is the type of thing that dramatically reduces the life or even damage the battery outright, and the recommended values are the ones used to achieve a certain cycle life number, sometimes in LFP spec sheets they will have cycle life graphs at different charge and discharge rates, perhaps you could ask the manufacturer to provide this to you? Then you would know for sure, otherwise you might be staring down the barrel of a tsunami of warranty claims if the cells only manage 1000 cycles at 0.5C charging current. The tests were most probably not done on the max rates. That is why if looking at the graphs on my site you will see that they surpass 2700 cycles on the tests done This would support the 2000 cycle claim. They do not have any other documentation regarding tests other that this and a UN38.3 certification test document.
January 13, 20206 yr Thanks Bian for the email and all the info. I cant wait to order these Yesterday with the storm our area was hit with a blackout again. The old batteries(narada 200ah) we have dropped from 52v to 46v in about 2 hours with about 500w load. I then switched off a lot of the stuff and reduced the load to about 200w and by 1AM the batteries were at 42v I switched everything off. This is way lower than what I am comfortable with. Power was still off at 6am, solar started to charge but with it being cloudy we will struggle to get them full. Kids say power came on at 10 now eskom is charging. I need to upgrade urgently
January 13, 20206 yr 16 minutes ago, Krokkedil said: Thanks Bian for the email and all the info. I cant wait to order these Yesterday with the storm our area was hit with a blackout again. The old batteries(narada 200ah) we have dropped from 52v to 46v in about 2 hours with about 500w load. I then switched off a lot of the stuff and reduced the load to about 200w and by 1AM the batteries were at 42v I switched everything off. This is way lower than what I am comfortable with. Power was still off at 6am, solar started to charge but with it being cloudy we will struggle to get them full. Kids say power came on at 10 now eskom is charging. I need to upgrade urgently I also have my cells powering my house, like clockwork, every 2 weeks we are without power for half an day up 2 days. I have 2x hybrid inverters and they can handle 8kw. I do however switch my geyser of when this happens because if it is to be of for 2 days i can't be taking chances. I can with ease run my kettle, all the normal lights and fans in the house, the toaster, dishwasher and a stove plate all at once, without the cells heating up. If i go over 8kw the inverters go of after 10s if i don't reduce the load below 8kw It's also a treat during load shedding. During load shedding i don't switch anything off I run 2x 48v batteries. Edited January 13, 20206 yr by Bain Viljoen
January 14, 20206 yr I'd be interested to hear from the experts how well this battery https://lithiumbatteriessa.co.za/collections/solar-ups-lifepo4-batteries/products/48v-120ah-6-1kwh-lifepo4-solar-and-ups-battery will work with a Victron ESS system. At the price of one Pylontech US3000 its very tempting.
January 14, 20206 yr 4 minutes ago, deapsquatter said: I'd be interested to hear from the experts how well this battery https://lithiumbatteriessa.co.za/collections/solar-ups-lifepo4-batteries/products/48v-120ah-6-1kwh-lifepo4-solar-and-ups-battery will work with a Victron ESS system. At the price of one Pylontech US3000 its very tempting. I do not know that inverter, that being said, if the charge, cut off and float voltage can be set under some sort of user configurable battery on the inverter then you are sorted.
January 14, 20206 yr 2 minutes ago, Bain Viljoen said: I do not know that inverter, that being said, if the charge, cut off and float voltage can be set under some sort of user configurable battery on the inverter then you are sorted. Thanks - yes that can be set. I guess I'm pondering going from a Pylontech with a Victron supported BMS to something like this without a compatible BMS. Pros and Cons basically.
January 14, 20206 yr 1 minute ago, Bain Viljoen said: What is the advantage of this bms if i may ask? I don't know - I'm waiting for someone with intimate working details like @plonkster to chime in I guess 😀
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