diy solar

diy solar

16S, 272Ah Lishen + TinyBMS - Build Thread

Well, interesting data points. Mine (so far) settle to 3.55 to 3.53 in 24 to 72 hours. I use my Riden set at 3.65 and let it turn off when .1 amps or lower is drawn, my Fluke says that is 3.652. So far I haven't had a cell settle to under 3.5 volts even after 3-4 days.
I forgot to add, yes. I think they are top balanced, worth trying a capacity test of the full bank.
Thanks for sharing your experience! I'll be surprised if all of these cells stay above 3.50 over the next couple days, but I am generally pleased that they all seem to be leveling out around that point. Considering the condition of the cells I received, it wouldn't have surprised me to see one or two not holding a charge.

I think I will probably series connect them and get the BMS connected for a capacity test. I can always put them back in parallel and re-top balance if needed.
 
update
Thanks for sharing your experience! I'll be surprised if all of these cells stay above 3.50 over the next couple days, but I am generally pleased that they all seem to be leveling out around that point. Considering the condition of the cells I received, it wouldn't have surprised me to see one or two not holding a charge.

I think I will probably series connect them and get the BMS connected for a capacity test. I can always put them back in parallel and re-top balance if needed.
Update?
 
Step 2 – Series Connect: With the initial top balance out of the way, it's on to step 2. The first part of this process is going to be to address the threading issues and install grub screws (I've been using the supplied bolts to this point). I'm using a M6x1.0 bottom tap to chase the existing threads and in most cases, complete the threading to the bottom of the hole. In the first picture below, you'll see just how incomplete some of the holes are. In that example, I could only get the grub screw in about 3mm. With re-threading, I'm able to all the screws in at least 6 mm.

I'm not using any cutting oil, so the threading is a bit 'crunchy' at times. I'm about half way through the threading at this point, and haven't botched any of the holes yet. Fingers crossed my luck continues.

One new issue that has come to light now that i'm installing grub screws is that several of the holes are not tapped straight (ie, not vertical). The positive terminal in the pic on the right is one of the worst examples I've found so far. I haven't tried to measure it, but it looks to be at least 5 degrees off vertical. I'm worried that this is going to seriously compromise the quality the bus-bar/terminal contact. I'm wondering if I should include a copper crush washer under the flange bolts to even out the compression force. Other thoughts/ideas on this?

Once i'm done with the re-threading and grub screw installation, I'll series connect the pack and wire up the BMS and inverter for an initial capacity test.

Edit: In case anyone's interested, I'm using 20 mm M6x1.0 grub screws. I've seen that others have been recommending 25mm, but that seems to be a bit longer than I need. After re-threading, I've got about 13 mm of screw to work with. 3.2 mm for my 1/8" bus-bars leaves 10 mm for a flange nut and washer.


IMG_7547.JPGIMG_7545.JPGIMG_7549.JPG
 
Last edited:
Step 2 – Series Connect: With the initial top balance out of the way, it's on to step 2. The first part of this process is going to be to address the threading issues and install grub screws (I've been using the supplied bolts to this point). I'm using a M6x1.0 bottom tap to chase the existing threads and in most cases, complete the threading to the bottom of the hole. In the first picture below, you'll see just how incomplete some of the holes are. In that example, I could only get the grub screw in about 3mm. With re-threading, I'm able to all the screws in at least 6 mm.

I'm not using any cutting oil, so the threading is a bit 'crunchy' at times. I'm about half way through the threading at this point, and haven't botched any of the holes yet. Fingers crossed my luck continues.

One new issue that has come to light now that i'm installing grub screws is that several of the holes are not tapped straight (ie, not vertical). The positive terminal in the pic on the right is one of the worst examples I've found so far. I haven't tried to measure it, but it looks to be at least 5 degrees off vertical. I'm worried that this is going to seriously compromise the quality the bus-bar/terminal contact. I'm wondering if I should include a copper crush washer under the flange bolts to even out the compression force. Other thoughts/ideas on this?

Once i'm done with the re-threading and grub screw installation, I'll series connect the pack and wire up the BMS and inverter for an initial capacity test.

Edit: In case anyone's interested, I'm using 20 mm M6x1.0 grub screws. I've seen that others have been recommending 25mm, but that seems to be a bit longer than I need. After re-threading, I've got about 13 mm of screw to work with. 3.2 mm for my 1/8" bus-bars leaves 10 mm for a flange nut and washer.


View attachment 34395View attachment 34397View attachment 34398
Just a tip I seen Will do...use all thread cut to make posts instead. Finger tighten down, then use nuts to tighten cables down. Much safer. Just a thought. Anyway, u won't know how much threads u need for bolts till u add cables & connectors. With all thread lugs u can make them as long as u want & cut them down after everything is tightened down & pretty...?
 
What happened to your complaints with Amy (et al) on the status of the batteries you received?
What was their answer?
 
What happened to your complaints with Amy (et al) on the status of the batteries you received?
What was their answer?
I am curious about this as well. Did you decide not to pursue refund/replacement? Did Basen deny it?

@BabylonFive these cells were purchased from Shenzhen Basen
 
Just a tip I seen Will do...use all thread cut to make posts instead. Finger tighten down, then use nuts to tighten cables down. Much safer. Just a thought. Anyway, u won't know how much threads u need for bolts till u add cables & connectors. With all thread lugs u can make them as long as u want & cut them down after everything is tightened down & pretty...?
I’m not sure why all-thread would be better than the grub-screws (aka set screws) that I’m using. Could you please clarify?
 
I am curious about this as well. Did you decide not to pursue refund/replacement? Did Basen deny it?

@BabylonFive these cells were purchased from Shenzhen Basen
On the 15th, Sheila from Basen requested a video of all the cells showing the issues. I sent them the video on the 18th, along with a note requesting that they send me new Grade A cells ASAP. Her last reply (on the 18th) was:

“We have got the video, and I will also report to the company and give you a satisfactory solution asap.”

If I don’t get a response tomorrow, I’ll request a refund or replacement. Depending how they respond, I may end up filing a claim with Alibaba.

I’ll keep everyone posted.
 
Series Connect Update: I managed to get all the cells re-threaded and grub-screws installed without any major issues. I then connected up the cells in series using the provided bus bars. I decided not to put the cells in the final configuration with larger bus bars at this point for two reasons: 1) I'm not 100% confident in my top balance, 2) I don't plan to go over 30A for the next phase of testing. Pack voltage was around 56v, which seems to add up. With everything connected up and nuts secured down, I'm on to the fun part (BMS connection).
 
Last edited:
Step 3 - BMS Connection: As previously noted, I went with a TinyBMS for this build. The main drivers for my BMS decision were 1) flexibility (tons of analog and digital pins to play with), 2) quality (this thing is really pretty...), 3) fit for purpose (I'm using all external relays for LVP, HVP, and LTP, so I wasn't concerned at all about current ratings), and 4) excellent documentation.

First step (after reading the manual) was to get the wiring harness sorted and installed, starting with the balance leads. For this temporary setup, I just added a second nut to all my negative terminals and sandwiched the tinned leads between the two nuts. I'm going to have to replace a lot of the leads, so didn't want to waste my time with connectors. The 300mm leads provided with the BMS just barely made it to the oposite corners of my 2 x 8 configuration.

Next, I soldered on the B+ and B- leads. I went with 22awg wire for these, as no current (beyond what's needed to power the BMS) will be passing through them. From there, I connected up B+ and B- leads to the battery terminals and it fired right up. I then installed the balance lead connectors, external current sensor, and USB cable. After a quick driver update, the BMS connected to the Battery Insider application automatically and all my cell voltages popped up. I was quite please that there were no issues here, considering I'm running the application Windows running on Parallels on a Macbook Pro.

Next, tinkered with the settings on the BMS to get it set up for my 'testing configuration'. For this initial setup, I'm using the BMS in single-port mode with the switch set to the AIHO1 pin. It took me a bit of testing to figure out exactly how these pins function. I'm probably going to get the terminology wrong here, but I believe these relays are controlled as 'low side' switches, in that they can take 48v power from anywhere in the system, and the switch connects or disconnects that supply to ground. For my setup, I'm using a 5A Relay with 48V input (Crydom EH10F5) wired in series with the inverter switch. I'm pulling the 48v 'signal' directly from the switch itself, so i only need one 'low side' wire running back to the BMS. I've tested it out, and it seems to be working fine (ie, it turns the inverter off if there's a fault detected.

Here's a few pics (so you know I'm not just making this all up...):
IMG_7551.JPG IMG_7563.JPG
IMG_7562.JPG Screen Capture (windows).PNG
 
VERY IMPORTANT QUESTION: Does anyone with a Growatt inverter know how to get the horrible beeping to stop? Every time I hit a key it beeps. I watched Will's video where he shuts off the alarm (Video, ~3:22, "under option 15...disable it, hit enter, and it's gone"), and that just doesn't work for mine. I've set program 15 to "bOF" and it still beeps every time I hit a button. Also set program 17 to "AOF" and that didn't help. Can't find anything else in the documentation to suggest another way to get the beeping to stop.

PLEASE HELP OR I MAY HAVE TO ABANDON THIS WHOLE PROJECT!
 
VERY IMPORTANT QUESTION: Does anyone with a Growatt inverter know how to get the horrible beeping to stop? Every time I hit a key it beeps. I watched Will's video where he shuts off the alarm (Video, ~3:22, "under option 15...disable it, hit enter, and it's gone"), and that just doesn't work for mine. I've set program 15 to "bOF" and it still beeps every time I hit a button. Also set program 17 to "AOF" and that didn't help. Can't find anything else in the documentation to suggest another way to get the beeping to stop.

PLEASE HELP OR I MAY HAVE TO ABANDON THIS WHOLE PROJECT!
I think the advantage of a Growatt is supposed to be tech support that isn't based in China (I could be wrong). I would try contacting them, and let us know, I am sure others will be looking for this answer.
 
I’m not sure why all-thread would be better than the grub-screws (aka set screws) that I’m using. Could you please clarify?
How are u securing anything wit a "set screw"? All-thread lugs you can make as long as u want & trim later.. ?. Post a pic of this, please.
 
Last edited:
I’m not sure why all-thread would be better than the grub-screws (aka set screws) that I’m using. Could you please clarify?
Nm, I seen ur pics. Not like set screws I've seen lol. Those are a lot longer & more like the cut all-thread lugs I was talking about. Hopefully those allow room enough for everything. Looking great tho! Keep up the great job! ?
I’m not sure why all-thread would be better than the grub-screws (aka set screws) that I’m using. Could you please clarify?
 
Update on Condition of Cells: I finally heard back from Sheila at Basen regarding a 'resolution' to the cell condition issues. I've pasted her full response below. Bottom line, they want to give me a full refund for 4 cells, and a 50% refund for 2 cells. Definitely not the resolution I was hoping for, but better than a kick in the teeth I suppose...

"Hello, Jon, thanks for waiting.

The video has reported to the company, they also checked with the workers of the warehouse. Then they found that is caused by our new workers in the warehouse, they disarrange the goods, sorry for the inconvenience. So here is our solution:

1. About the goods without QR code, we checked it, there are 4pcs batteries. So we will give back the full payment of these batteries.
2. About the goods that QR code is not clear, and there are 2pcs batteries. We will give back a half of the battery price.
3. The rest of the battery, you can check their voltage and resistance, they are in goods performance.

Some battery withuot QR code or not clear one, it is use for domestic battery pack. Both of them are brand new battery, no used.

Any other question, please let me know.

Thanks,
Sheila"


What do you guys think? Fair deal? Or should I push back on this?
 
Update on Condition of Cells: I finally heard back from Sheila at Basen regarding a 'resolution' to the cell condition issues. I've pasted her full response below. Bottom line, they want to give me a full refund for 4 cells, and a 50% refund for 2 cells. Definitely not the resolution I was hoping for, but better than a kick in the teeth I suppose...

"Hello, Jon, thanks for waiting.

The video has reported to the company, they also checked with the workers of the warehouse. Then they found that is caused by our new workers in the warehouse, they disarrange the goods, sorry for the inconvenience. So here is our solution:

1. About the goods without QR code, we checked it, there are 4pcs batteries. So we will give back the full payment of these batteries.
2. About the goods that QR code is not clear, and there are 2pcs batteries. We will give back a half of the battery price.
3. The rest of the battery, you can check their voltage and resistance, they are in goods performance.

Some battery withuot QR code or not clear one, it is use for domestic battery pack. Both of them are brand new battery, no used.

Any other question, please let me know.

Thanks,
Sheila"


What do you guys think? Fair deal? Or should I push back on this?
Refund for 5 batteries? If the batteries check out as good, then I say good deal. My opinion.
 
Update on Condition of Cells: I finally heard back from Sheila at Basen regarding a 'resolution' to the cell condition issues. I've pasted her full response below. Bottom line, they want to give me a full refund for 4 cells, and a 50% refund for 2 cells. Definitely not the resolution I was hoping for, but better than a kick in the teeth I suppose...

"Hello, Jon, thanks for waiting.

The video has reported to the company, they also checked with the workers of the warehouse. Then they found that is caused by our new workers in the warehouse, they disarrange the goods, sorry for the inconvenience. So here is our solution:

1. About the goods without QR code, we checked it, there are 4pcs batteries. So we will give back the full payment of these batteries.
2. About the goods that QR code is not clear, and there are 2pcs batteries. We will give back a half of the battery price.
3. The rest of the battery, you can check their voltage and resistance, they are in goods performance.

Some battery withuot QR code or not clear one, it is use for domestic battery pack. Both of them are brand new battery, no used.

Any other question, please let me know.

Thanks,
Sheila"


What do you guys think? Fair deal? Or should I push back on this?
Curious if you are willing to share - does the refund include a portion of the shipping cost or just the cells? Was there ever an option discussed to have them send replacement cells?
 
Update on Condition of Cells: I finally heard back from Sheila at Basen regarding a 'resolution' to the cell condition issues. I've pasted her full response below. Bottom line, they want to give me a full refund for 4 cells, and a 50% refund for 2 cells. Definitely not the resolution I was hoping for, but better than a kick in the teeth I suppose...

"Hello, Jon, thanks for waiting.

The video has reported to the company, they also checked with the workers of the warehouse. Then they found that is caused by our new workers in the warehouse, they disarrange the goods, sorry for the inconvenience. So here is our solution:

1. About the goods without QR code, we checked it, there are 4pcs batteries. So we will give back the full payment of these batteries.
2. About the goods that QR code is not clear, and there are 2pcs batteries. We will give back a half of the battery price.
3. The rest of the battery, you can check their voltage and resistance, they are in goods performance.

Some battery withuot QR code or not clear one, it is use for domestic battery pack. Both of them are brand new battery, no used.

Any other question, please let me know.

Thanks,
Sheila"


What do you guys think? Fair deal? Or should I push back on this?
Honestly, better than I expected. You should also ask for a discount on 4 replacement cells.
 
I ended up accepting the offer, as I've not found any reason to believe that these are bad cells (more on that to follow). I don't think they're going to reimburse anything of the shipping cost. Still, if these do all end up being good cells, nice to have a few hundred bucks back in my pocket...

Thanks for the feedback on this.
 
Step 4 - Capacity Testing: With the BMS installed and generally working as expected, I'm moving on to a capacity test of the bank. I don't have any way to test individual cells in an efficient manner, so a full bank test will have to suffice. I've wired up one of my Growatt inverters along with a 1500 watt space heater. I'm using 4awg wire from the inverter to the battery and i've included a 50A fuse on the positive side. With the heater on high power, it was pulling about 29amps (~0.1C) from the batteries. I checked all connection points and wires and nothing was getting hot, so I proceeded with the test.

Unfortunately, as soon as I got the system up and running, I noticed that the current measurements coming from the BMS were wildly variable (it's using an external hall effect sensor). At my 30amp draw, it was swinging back and forth between about 20 amps to 40 amps, almost in a sine wave pattern. I once again checked all connections and settings and couldn't figure out what was going on. I sent the guys at Energus an email and decided to go ahead with the test and just use the current numbers coming from the Growatt as the basis for my test. Let me know if you have any thoughts on what might be going on here.

The heater ran for 9 hrs and 25 min before the first cell hit 2.50 and the BMS shut things down. A few of the cells were still up around 2.7 at this point, but they were all dropping fast. According to all the calculations I performed, the system (inverter + heater) was pulling just over 1500 watts from the bank during the test. 9.4 hrs * 1500 watts = 14.1 kWh. I've been using a 'nominal' value of 14.3 kWh (51.2v * 280 Ah) as my basis, so i'm fairly pleased with this result. Yes, it's a rough approximation based on how I measured current, but I'm satisfied...

Screen grab of the voltage readings at 1% SOC pasted below. I'd be interested on thoughts on whether or not this looks like a typical level of imbalance for a top balanced bank at a very low SOC. I charged the batteries back up over night at 20 amps and I'm very please to report that they all stayed extremely well balanced back up to 80%. Not sure if that's a sign of a good top balance, or if the BMS is able to manage any imbalance (I think it balances at 150 mA).

IMG_7561.JPG Screen Shot 2021-01-25 at 9.29.27 PM.png
 
Back
Top