Cheap 4kwh LiFePO4 batteries from Battery Hookup

HMR said:

Jason: thanks for this very timely posting. I have just finished with 14 hours of charging my first cycle on my BYD battery and my anxiety level if high trying to figure out what I did wrong. I charged my one BYD test battery at 10 amps with a cutoff voltage of 3.55 per cell. It went overnight and I found it stopped out in the morning. The thing that caused my anxiety to go high is that the shunt only recorded 1.15 KwH and 40 Ah accumulation in the battery. I then reduced the amps to only 5 amps and increased the cutoff voltage on my balancing charge controller to 3.6 v per cell. It got there in 30 min more with final reading of 1.18 KwH and 44.5 Ah. Thats only 26% of the expected capacity of 4.5 KwH and 160 Ah. So I freaked out wondering what went wrong. The current settled voltage is 26.76 or 3.34 per cell.
What was your capacity for your batteries? If you could put it in terms of a single BYD expected battery capacity of 4.5 KwH that would be helpful.
I am planning to let the battery rest for a day or two and then discharge it again down to about 2.8 v per cell and recharge for my second cycle. Any suggestions and ideas?

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The only way to know how much kWh the battery has is to use it and just let it cycle down to where ever you want it to be.

I run my entire house with everything going normal, no saving nothing for 6+ hours a day 5 days a week. Starting today at 52.2V and ending at 51.0V. The "SOC", went from 89% to 85% in today's 6 hours of usage.

Relax, they are very high quality, designed for utility grade or public transit use. BYD doesn't fool around. One of my packs is dated 2012. Think about that.

Why spend all this effort "testing", they work, just use them.

I keep my batteries in the 95% to 20% cozy comfy range:

Click the link in my signature.

jasonhc73 said:

The only way to know how much kWh the battery has is to use it and just let it cycle down to where ever you want it to be.

I run my entire house with everything going normal, no saving nothing for 6+ hours a day 5 days a week. Starting today at 52.2V and ending at 51.0V. The "SOC", went from 89% to 85% in today's 6 hours of usage.

Relax, they are very high quality, designed for utility grade or public transit use. BYD doesn't fool around. One of my packs is dated 2012. Think about that.

Why spend all this effort "testing", they work, just use them.

I keep my batteries in the 95% to 20% cozy comfy range:
View attachment 5035
Click the link in my signature.

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OK. thanks for the reassurance. As a complete newbie I am using the step by step process and testing what I think I know as a way to learn. My knowledge has expanded greatly since I got these batteries from learning how to attach terminals to the undersized posts, to decoding the balance harness process so I can measure cell voltages, to attaching cell voltage meters, realizing that charge controllers actually need power supplies to run them, etc, etc. So because of my lack of knowledge I have to take things step by step because at the end of the day I want to really understand what I have done. But I also appreciate your point of view, as a knowledgeable person to just use them. I will do as you suggest and just discharge it using a 1500 w space heater. So if that can be powered for about an hour, then the shunt meter reading is correct. If it goes longer, then I cant trust the shunt meter and need to learn another way to monitor capacity of my battery. One way or the other, I need to see these things at the 80% capacity level Battery Hookup claimed to be a happy camper.

HMR said:

OK. thanks for the reassurance. As a complete newbie I am using the step by step process and testing what I think I know as a way to learn. My knowledge has expanded greatly since I got these batteries from learning how to attach terminals to the undersized posts, to decoding the balance harness process so I can measure cell voltages, to attaching cell voltage meters, realizing that charge controllers actually need power supplies to run them, etc, etc. So because of my lack of knowledge I have to take things step by step because at the end of the day I want to really understand what I have done. But I also appreciate your point of view, as a knowledgeable person to just use them. I will do as you suggest and just discharge it using a 1500 w space heater. So if that can be powered for about an hour, then the shunt meter reading is correct. If it goes longer, then I cant trust the shunt meter and need to learn another way to monitor capacity of my battery. One way or the other, I need to see these things at the 80% capacity level Battery Hookup claimed to be a happy camper.

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I still don't know exactly what my kWh is. But I do know the "880 ah @ 48V" will power my entire house for more than 24 solid hours. I am still waiting on parts to get here for a few real live kWh meters, "just to know" also.

One with a big name on it is Renogy,
https://www.amazon.com/dp/B07RP5B5P7/ref=cm_sw_em_r_mt_dp_U_jlshEbW5VZ325

And then there are these "no-brand" ones:
or
Or this one is pretty neat looking (Will Prose has one like this in his videos)

Just remember to be safe. Take it slow when connecting everything. Always respect the e-.

edit-
Nevermind on those "kWh meters" I just saw the one you have installed.

OK, on my BMS, you just type in how much AH the battery has.
Today as I start my battery discharge cycle I did just that. Now I know exactly where the Voltage is when I started and a AH number where I started.

I am at 52.4V about 15 minutes after starting. I set the AH to exactly 800.
I expect today to be a fairly low load day, most of the afternoon I will be gone. The heater goes to ECO mode, only the refrigerator, freezer, water cooler, and laptop will be regular power users.

The Current load is 4.1A per pack, so 16.4 Amps draw on the entire battery bank. The total load is only about 850 watts.
Last night when I switched over to charging, The BMS was showing 739.288 AH.

So in about 8 hours, I'll be able to guess a "kWh".
---------------------------------------------------------------------
8 hours later.

The AH shows 771.549, V shows 51.0.

What else do you need to make a kWh conversion?

8 hours use and 28.451 AH used. 3.55 kWh?

The SOC on the BMS shows 88%. What's a good accurate, kWh measurer?

Delete for inaccurate report.

nicpaige said:

Well I finally removed the cover on my second BYD 24v from battery hookup. Right away I noticed the rear cell looked different. Not so much the cell but the bus. I sent them an email yesterday. My 60 days to return will be on the 19th of this month. The cell also has 0v. I tried calling them and their answering machine is full so I cant leave a message.

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I sent in a few emails Nov 19th to them with pictures, concerns of the condition of the battery, no response, BEWARE Your pictures show normal busbar, it is expansion-contraction, they are all good, all the batteries have that rough solder connection. As for your DOA send it back, call paypal or your credit card company. paypal will notify them if no response you get your money.

I have to retract my previous statement that the cell was dead. It was operator error.

nicpaige said:

I have to retract my previous statement that the cell was dead. It was operator error.

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It gets you excited though, doesn't it?

Success! After 2 charge discharge cycles producing only 1.2 Kwh discharge capacity, my third charge discharge cycle was more successful. I successfully discharged 3 kwh from my test BYD battery. I was despairing and thought I had a dud. But no more. David Poz reported in a video that his 8 BYD batteries were able to discharge 19 KwH which equates to 2.35 Kwh per battery. So mine finally did 3 KwH per battey. This is well on the way to the minimm expected 4 Kwh capacity. Anyone else able to report on capacity of their BYD batteries?

HMR said:

Success! After 2 charge discharge cycles producing only 1.2 Kwh discharge capacity, my third charge discharge cycle was more successful. I successfully discharged 3 kwh from my test BYD battery. I was despairing and thought I had a dud. But no more. David Poz reported in a video that his 8 BYD batteries were able to discharge 19 KwH which equates to 2.35 Kwh per battery. So mine finally did 3 KwH per battey. This is well on the way to the minimm expected 4 Kwh capacity. Anyone else able to report on capacity of their BYD batteries?

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Do to being far over built and utilizing only 5% of the ability.

I typically only use 50 ah of my packs.

48V setup, and artificial limiting of the low and top SOC/DOC has created somewhat of an extreme system.

I am using my batteries for a solid 8 hours, with no charging and watching the AH go from 800 to usually 750~755 range. I then charge at only 16 amps, 0.25 amp per cell. My house usually uses 20 to 25 kWh per day. So I am guessing the 8ish kWh is what the 50 ish AH is. I am 16S4P with the BYD packs.

jasonhc73 said:

Do to being far over built and utilizing only 5% of the ability.

I typically only use 50 ah of my packs.

48V setup, and artificial limiting of the low and top SOC/DOC has created somewhat of an extreme system.

I am using my batteries for a solid 8 hours, with no charging and watching the AH go from 800 to usually 750~755 range. I then charge at only 16 amps, 0.25 amp per cell. My house usually uses 20 to 25 kWh per day. So I am guessing the 8ish kWh is what the 50 ish AH is. I am 16S4P with the BYD packs.

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Thanks, Jason for reporting your numbers. Please help me understand better because your numbers confuse me. At 16S4P, you must have 2 24 V BYD batteries in series and 4 in parallel for a total of 8 batteries with 800 AH total capacity at 48 V. So if your batteries draw down to 750 Ah that means you have consumed 50 AH x 48 V = 2, 400 WH . If your house uses say, 20 KwH per day as you state in your message, then 20,000 WH divided by 48 V is 466 Ah consumed, not the 50 AH you report. So you should be drawing down to 334 AH not just down to 750 AH. Where have I got my math wrong?

HMR said:

Thanks, Jason for reporting your numbers. Please help me understand better because your numbers confuse me. At 16S4P, you must have 2 24 V BYD batteries in series and 4 in parallel for a total of 8 batteries with 800 AH total capacity at 48 V. So if your batteries draw down to 750 Ah that means you have consumed 50 AH x 48 V = 2, 400 WH . If your house uses say, 20 KwH per day as you state in your message, then 20,000 WH divided by 48 V is 466 Ah consumed, not the 50 AH you report. So you should be drawing down to 334 AH not just down to 750 AH. Where have I got my math wrong?

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Your math is correct. I have only done one longevity test, normal daily use is ~50ah.

The 24 hour test was to see how long I could go. Normal operation is 6 to 8 hours, 5 days a week. During discharge I have no connection to any charging, for now. I have 2kWp of solar panels sitting in my backyard about to be connected.

I also have 6.2kWp of grid tied, but still I cannot connect to the batteries directly.

jasonhc73 said:

Your math is correct. I have only done one longevity test, normal daily use is ~50ah.

The 24 hour test was to see how long I could go. Normal operation is 6 to 8 hours, 5 days a week. During discharge I have no connection to any charging, for now. I have 2kWp of solar panels sitting in my backyard about to be connected.

I also have 6.2kWp of grid tied, but still I cannot connect to the batteries directly.

View attachment 5466 View attachment 5467 View attachment 5468

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OK. That's a relief. I am so new to this that I am always afraid to make a mistake both in my math and in my application. Please keep me informed of your progress.
Has anyone else reached the point to where they can report actual charge/discharge capacity of their BYD batteries?

HMR said:

OK. That's a relief. I am so new to this that I am always afraid to make a mistake both in my math and in my application. Please keep me informed of your progress.
Has anyone else reached the point to where they can report actual charge/discharge capacity of their BYD batteries?

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I think all I need is a gizmo that shows kWh.

I'm just not concerned about it enough to care anymore.

I know I have more than 4x the "time capacity" than I need. I also know that I have ~ 115% of the "load capacity" I can create. I turned on everything in my entire house and only used 87% of the system, my normal load sitting idle is about 16%. With the heater going, it is about 23%.

jasonhc73 said:

I think all I need is a gizmo that shows kWh.

I'm just not concerned about it enough to care anymore.

I know I have more than 4x the "time capacity" than I need. I also know that I have ~ 115% of the "load capacity" I can create. I turned on everything in my entire house and only used 87% of the system, my normal load sitting idle is about 16%. With the heater going, it is about 23%.

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Yeah, I understand. BTW, I really liked your video of your system. Its really impressive. When I get further, I would like to get more information from you about the various components you used. I am in the process of finishing my battery power center in an insulated pump house. Just cleaning it up and painting now to provide a good environment.

I wonder that other people have not started reporting on actual useage data yet. I would like to get a bit of corroboration that my discharge experience is in line with that of other BYD owners.

thanks for putting up those videos.. very useful for me

I am gradually beginning to understand my BYD batteries. A big thank you to all the diysolarforum members for all the information you have provided me and in particular to Jasonhc73 for his practical input and solid understanding. I especially find his recent post at: https://diysolarforum.com/threads/lifepo4-voltage-chart.3156/ extremely valuable.

After 3 discharge/charge cycles of my first battery I was able to discharge 2.94 KwH/ 116 Ah and charge back up 3.19 KwH/ 120 Ah using a shunt meter as my measuring device and the ToolkitRC balancing charger charging at 5 amp for 33 hours. After 24 hours rest, this first BYD battery settled at 26.59 v with cells ranging between 3.31 – 3.33 and a delta of 21 mV. During charging the cells sat between 3.31 and 3.33 for the majority of the time. Getting to 3.31 was quick and getting to 3.38 – 3.55 when battery was full was also quick. I am seeing a gradual increase in capacity especially on the 3rd discharge/charge cycle.

I performed my first charge cycle of my second battery. Starting data: 24.14 V; 2.95 – 3.09 cell V; delta V = 14 mV. This time I charged at 10 amp. The battery was full 10 hours later. Ending data: 27.6 V; 2.64 Kwh/ 99 Ah; 3.39 – 3.56 cell V right after charging; delta V = 170 mV. After a few hours I expect the cell voltage and delta to drop.

My experience clearly shows: (1) repeated cycling of the BYD batteries increases storage capacity up to some as yet unknown steady state level. I will continue to cycle until I observe no more increase in capacity at which point I will report the final capacity of my BYD batteries. (2) The limiting factor at each charge cycle is how rapidly or slowly the cells reach their voltage maximum. My charger is set for a maximum cell voltage of 3.55 V and begins to diminish the amps from about 3.5 V upwards. This behavior is constant through all cycles. The variable is the number of Ah the cells can soak up before they top off at 3.5 v. So far those Ah numbers have been increasing at each cycle. BatteryHookUp reported achieving 4 - 4.5 KwH capacity in their sales literature so this is my goal. If I cant reach that, how much capacity should I be satisfied with so I feel that I got my money's worth?

HMR said:

I am gradually beginning to understand my BYD batteries......how much capacity should I be satisfied with so I feel that I got my money's worth?

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These batteries cost 3/64th of new lifepo4 batteries. Every time I use them I remember that, and am instantly satisfied with the 80%(of new) usability that they have.

Each one of these BYD is the equivalent of 4 battleborns.

jasonhc73 said:

These batteries cost 3/64th of new lifepo4 batteries. Every time I use them I remember that, and am instantly satisfied with the 80%(of new) usability that they have.

Each one of these BYD is the equivalent of 4 battleborns.

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Of course, you are correct. Even at only 3 KwH capacity these are a good deal. Maybe I can still get closer to 4 KwH. We'll see.

No_Grid_No_Problem said:

Hey guys... I'm new to this forum but reading voraciously about solar and wind power. I'm very interested in buying a few of these to make a move in this direction. I'm not a die hard environmentally motivated "solar at any cost" person... but I'm more motivated by self-sufficiency and if I can help the environment in the process... then fantastic!

I'm hoping that Will or someone on this forum will post some videos on how to take a home partially off grid in piecemeal sections. My goal is to gradually take circuits off my 200 amp panel into another hybrid panel that can be fed primarily from a battery system and switch over to grid power only during the winter when I can't generate the power needed for those circuits.

My goal is to only do 110V circuits leaving the furnace, AC, dryer, and other 220V heavy energy hogs on the grid perpetually until my system can be expanded enough to fully take the house off grid. I have about 2.5 kW of solar mounted and ready to go once I have batteries installed. I only have one 1000W inverter and a 60amp mppt right now. Pretty early in my process but eager to expand as I save up.

That's my dream... to eventually tell the utility company to take hike. I need some additional technical knowledge to take the first storage steps. I live in OH where it gets pretty cold, but due to how my home is built, I'm going to have to build an outdoor insulated battery shed to house my batteries and inverters.

Any pointers or suggestions?

Will - can you do any videos on taking circuits off grid and using a switch system? You had one previously on a MOES Dual Power Controller 50A 5500 Watt Automatic Transfer Switch but I'm not sure if I can utilize multiples of this to serve my needs... and if so how to wire through a sub-panel.

Thanks in advance!

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I'll be posting videos of my off-grid build. I have 8 of these batteries along with all the Schneider equipment:
XW6848 Pro
Conext PDP (Power Distribution Panel) + Conduit Box
Conext MPPT 60-150
Conext SCP (Controller)
Conext Battery Monitor
Conext Wireless Gateway

I went all-in with Schneider as the system is expandable, they allow for field servicing of their equipment, they have a web portal that I can use to monitor my system using the Conext Gateway (I travel a lot for work,) and I can go to one source for tech support.

I'm in the process of getting it all setup, configured and monitoring. I think I'm going to go with a 16S BMS since I need 48V for my system. I just need to get the wiring connectors in - slow boat from China!

My channel is JC/DC In The AZ. We haven't posted much yet, but we will be going over the construction of our 1200 SQF steel building, our Solar install, rain water catchment and hopefully soon - the ICF house build.