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Here you go, https://www.aliexpress.com/item/4001226339012.html?spm=a2g0o.search0302.0.0.2a7a724cOEIDDt&algo_pvid=e070965e-3d1a-4c2d-a72f-5a4d5836ee0d&algo_expid=e070965e-3d1a-4c2d-a72f-5a4d5836ee0d-2&btsid=0bb0622916201835644692234e5437&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_...

Have disabled the heltec for now, turned the BMS balancer on but only above 3.43 and .50mv difference going to leave it for a week or so and see how it goes. When I have time I will refresh all the connections as a next step, would love to do a fresh top balance but it means disassembling the...

Here we go. I've pulled 40a from it for a hour this evening and I'm not seeing the single cell drop. I'll keep monitoring.

Yes

If you search for me you'll see I made an incredibly simple jump start loom with a battery, moment switch, some alligator clips, etc. I made a similar one for soft starting the inverter/pre-charging caps to stop big inverters fooling the BMs into thinking theirs a short.

Didn't get a chance to fiddle with the cables, but as we had 3 over cast days I did get to see the behaviour of the pack in the low end of the cycle. With this in mind, and having to go through the process again of restarting the BMS, pre-charging caps etc, thoughts on the following. Cold...

Yep misread, Cheers

If we look at Nominal voltage x AH then I've got at best 14.18kwh (51.2x277). I've paid $2103 AUD delivered (I'm in Aus) or $1627.68 for you US folks. $148.35 AUD/$114.82USD per kWh at best, which will only go up from there. I was hoping they would perform as close to rating as possible, but...

There might be more too it as the problem continues. Last night under a 2.7kw load I had cell 12 dipping noticeably so went down with the Fluke 325 and checked that cell and confirmed it was genuinly a solid .1 .2 v below the other cells under load 3-3.1v vs 3.2-3.3v in adjacent cells. So either...

I haven't received them yet so not sure if there's a customs bill. A mate of mine just got his 16 cells so I'll ask him. I won't be paying GST as my order was shipping in 2 bundles to different addresses to drop the value below the threshold.

Fair enough, at least you have seen resistance values go down. I'll have a fiddle.

For what setting? Your upper and lower disconnects, balance trigger voltage difference, and recovery times are all personal preference. Take a look at the below and decide how high and low you want to push the cells. Notice how tight the upper and lower knees are. Lots of people treat 3v as...

Agent fees are half that through the place that contacted me - Top Logistics (never heard of them). I'm expecting a few hundred extra in fees, I'm fortunate enough that it's not an issue but who wants to pay more if they don't have to :) Oh well, better get a BMS on the way.

I don't charge that high, I have bulk set to 55.4 or so I think, Used to be higher but backed it off a while back for longevity (hopefully).

Yesterday when I got home, the Bluetooth was now working correctly across all my devices by itself, and the BMS has continued to charge/discharge fine the whole time 0_0 Logs showed no issues at all since the last boot.

For anyone that read my previous posts, I made that little wire wound resistor/moment switch jig and it worked a treat.

Just sure to allow for voltage diff at each end, my 7248 and BMS always show a slight difference between the voltages in the apps and at the terminals.

Cells have been top balancing in parallel for a week now, starting to see the voltage on the supply and pack rising, but we are still in CC mode, I expect it to switch to CV mode very shortly and begin the wind down in current. I am using your basic Ali Nice Power 30v 10a supply and I can say...

Am I understanding it correctly, I must disassemble the case to access the port? I do not have any more external ports visible, the temp probes take up the last slot.

just did a short 2kw discharge also, much more even. Is it possible my observations are just issues with terminal connections 0_0

Got it, so charger goes from main pack positive to -p connect from the BMS. See how I go tomorrow. Many thanks for your help.

I did some testing over the weekend as I had 2 good days of sun. Turns out it's the inverter + battery but not as I assumed. As above, I assumed maybe it was SoC related and in a way it was, but I also discovered a quirk of the inverter. As the battery was getting closer to full (high 80%...

Yeah I don't have a box, my cells are compressed, but sit inside a large metal cabinet with the rest of the gear for easy access. My point was more that I'd done it as I showed in my picture, which is slightly different to how others have done it, mainly because I do not have a master on/off.

No I'm using the full BMS with the additional 2a active balancer function built in.

I have moved cell 14, re-checked the bars/connections and cleaned up anything unusual. I did find this washer, which is odd as I bought new washers for this install so I've either missed it or its degraded like this in 6 weeks. I have made a very conscious effort to centre the washers/balance...

I purchased my own studs and used a basic 1/4" drive screw driver style hand tool to torque them, I did not use a torque wrench as I don't have one that goes that low - all of my tools are automotive based as motorsport is my other hobby. That said, I have a reasonable amount of experience with...

Also, the 2v thing is irrelevant to you because you'll be setting your BMS at 3v or so. They are "dead" flat at 2.5v and nobody wanting any sort of useful life is going anywhere near that depth of discharge. II should add I'm not saying buy them, only that I ended up with them and they work. I...

Yes I know, and to be fair the 2A does 2A at all times in my testing. But I see my biggest imbalances under large loads at the bottom end of the pack capacity and at that time, I want the 5a cranking to keep the lowest cells from trigger a LVD. Design your system how you like and depending on...

I was advised by the seller, this forum, and the seller again when discussing this issue to top balance before commissioning. I can already identify weak cells now with a 2kw draw, the screen shot demonstrates it. As it sits right this second even light loads show bigger deltas. See pic. If...

2a seems enough for me, but my pack was top balanced in parallel for almost 2wks prior to commission. I thought I had balance issue but it turned out to be a bad washer on the balance lead. I redid them all and its been solid for the few weeks since, but given its autumn the pack is going...

No software, I have only just wired it. JK said to use Serial Debug Assistant, but so far I'm unable to get any data out of it, it opens the port but nothing happens. Grafana was also mentioned and I'll take a look at "jblance" though it appears to be for talking to the inverter. I'm wanting to...

I'm not sure but I'm not lifting the black plastic to see under it lol It's glued on so peeling it back will mean it's always gonna look shit. I'll have a look to see what's on the outside. In the end, 2k - 2.5k for a pack this big is cheap as shit and as long as they last at least 2yrs...

OK I don't have one of those handy. So more info, sun is up and the pack started charging, I know it was on the lower side of SoC due to resting voltages prior, instantly seeing cell 9 and 16 doing the HVD again, thought stuff it, went and quickly swapped them with a neighbouring cell so in...

Update for anyone that was interested, in short interposing relay fixed it. Long version. Previous control logic, electronically interlocked contactors as you'd expect had one contactors coil being driven off the aux contactor on the other coil, so one cannot be opened while the other is...

Should it be ASCII or hex though?

My BMS has stopped allowing me to connect via Bluetooth, on 3 separate devices (iOS and Android). Is there a way to reset/reboot without disconnecting from the inverter so I can avoid the pre charging caps process? Can I just remove the balance lead harnesses and reconnect them?

SL being silicon labs? If so I grabbed a driver install package directly from them. I'll try again in a moment.

Each cell is double stacked busbar (basic ones you get with cells from Ali) and "feels" fine. Though I do have an IR gun if needed. I'll keep this mind.

No bingo yet

Seems I need to ship the BMS back to them for review/repair/replacement so I will be without it for a few months I'd have to think. In the meantime I have a Heltec 5a balancer coming, locally, should have that in a week or so. That will keep the pack balanced and I've got the inverter set...

The washers are zinc coated steel. Cells are compressed with ratchet straps on the upper and lower edge areas, wood boards at both ends to ensure no cell damage where straps rest. IKEA chopping boards between cells. Bus bars are tinned copper Xuba tells me.

Forgot to add I checked this and it ascends by ~3.3 on each pin at the connector end as you would expect, so we know voltage is making its way to the connector at least. I only removed one lead at a time so there was practically zero chance of swapping them plus the cables are cable tied in...

Fees were a bit over $330, the bastards lol, treated as 1 shipment for total value but charged twice for handling/logistics because it's actually 2. Tried to cheat the system, got shafted instead lol Oh well, live and learn. Ordered the 150A JK Smart BMS with 2A Active Balancer, was a bit under...

Yes The laptop in the cabinet has been rebooted a number of times and the BMS was only just rebooted today as the Bluetooth was acting up after 65days up time

Putting 65a in it now and still far more even, 0.05-0.07v delta currently, much lower than before. Then 70, then 80a and deltas are the same.

Similar setup to me then, more battery though. I'm 4.5kw PV, MPP7248, ETC 277AH Cells. I also have an old grid connect system with 5kw PV and the ability to pull in another 30a DC from that system into the battery as required.

The setting in the app is 16 as it's a 16s 277ah pack, pack voltage at the time of the screen shot was around 54.4v, float voltage on the DMM. The inverter, just an MPP 7248 also sees pack voltage perfectly when I bypass the BMS and run it direct. It does default to 24 when you "reset" the BMS...

Didn't get a chance to fiddle with the cables, but as we had 3 over cast days I did get to see the behaviour of the pack in the low end of the cycle. With this in mind, and having to go through the process again of restarting the BMS, pre-charging caps etc, thoughts on the following. Cold...

Interesting situation. I've ordered and paid for 16x 277ah Cells from Alibaba - Shenzhen Xuba/Selina Li and Pina Long. During the initial conversation, I specifically asked for Grade A cells, and on the advice of a mate, requested Lishen. Pina confirmed all cells are Grade A. In checking the...

I bought mine from Heltec but have been unable to see anything useful out of it. I'm hoping to use BLE on Pi4 instead.

More info, there's clearly connection issues at play here. Last night I get and find that cell 12 is showing 3v at only 10a load yet was hitting HVD early in the day during peak charging phase (approx 60a). I put the house back on grid so I could switch off the BMS and have a fiddle. I find...

I should add, I've noticed this issue 2 weeks after shipment, so they are currently in transit. I've contacted the supplier, but welcome the any feedback others have on the cells or a similar experience.

Updates. I did not top balance as I would've had to label/mark all the balance leads to ensure they went back in the right spot. I removed each connection, cleaned, used copper grease on the surface of all battery terminals and the stud threads, removed 1 bus bar (it was double stacked) and...

I wouldn't say I paid a premium, but I had some level of "hope" of them being "decent" given what people are seeing here from EVE/Lishen and Wills recent testing showing above rated capacity.

I'm thinking almost certainly on cell 12 so I'll remove those studs and chase the thread to clean it out. This has been such a good learning exercise and it's a real departure from building race cars :D

ENJ Power 123456 LED is always red.

Home Assistant up and running so I will start playing with BLE and the JK soon. I had an interesting "issue" over the weekend though where the BMS noted LVD on a single cell but then 4mins later was fine again (the pack was a good 60% full and that cell was not showing any other issues). This...

All good. As for the flashing, I can't remember if it does that when it's booted, but not discharging/charging or if it does it when it's connected via bluetooth or something, but it's obvious you can do a thing and the light changes i I just can't remember what it is, but it's not a fault...

OK so it's just the 2 harnesses with the balance wires that need to come out before disconnecting a main pos or neg? As I want to reboot the BMS so a main pos or neg will need to be disconnected.

Yes it shows low voltage because it's only seeing 11 of the cells to calculate voltage. I will quadruple check the leads to ensure they are in the right order, but given I am missing 5 random cells, I doubt that's it, it would make sense if all cells after a given point were wrong, but it can...

Time for some cleanup!

Oh and in your case were you missing a number of cells? or Just 1 or 2 from having swapped wires?

- Unplug both harnesses - Disconnect main neg To repower, last time I had both harnesses plugged in first, then made last main neg connection to the pack. I will also move Cell 14 location to see if the low voltage follows it. I am still assuming the pack turned off last night because cell...

I also see the Heltec has some pads that can be wired for a switch, meaning I could put a relay on it and only have it turn on when pack is above X volts which is another option is it's a higher amp balancer. What do people consider acceptable cell delta's in larger capacity packs like this?

I've got a PDF version for the 7248 if that helps?

Not sure about Forex rate, standard USD to AUD is worse now. Was 77.x now 76.x *Shrug* Paid, move on with life :)

Can you snap a pic? I never work with resistors so I'm picturing the little thin wire ones from high school, I can't see how I'd neatly permanently wire that in, but I know there'll be something more suitable.

I'll have to check to be sure, I can remove it but it was a recommendation on here and given the the need for a washer between the bus bar and the balance lead (due to holes size on the buss bar) it seemed like a good idea. BUT given the Fluke tells me that cell is actually low it's not just a...

Not without building myself a box, which honestly I CBF doing as time is precious here.

The issue with the app is remote access from anywhere. I can put a phone/tablet in the cabinet and leave the app running and then remotely access the phone from a PC, but anytime you close/disconnect that session you have to re-authenticate on the phone end from what I've seen, unless you know...

No, my order has always beem remove main pos/neg (BMS powers down). Then do any work I'm doing and reconnect pos and neg when done. I was only removing one lead at a time, I didn't remove the connector. Are you suggesting a loose cell wire had touched another cell and that's enough to kill it...

Thanks for the info. I'm thinking adding a smart shunt might be the best step forward IF it will integrate with HA, I'll have a search for what works on that front. That way I can run HA, get my automation and have accurate SoC data to do the automation want. Also means avoiding needing a...

So the question remains, has anyone used ETC cells?

Hmm. Well it's a possibility I guess. Usually if something touches something it shouldn't there's generally a clear visual indication lol

So the plot thickens, as well as hitting HVD first (which it's no longer doing with lower charge voltage) it's also showing signs of dropping first/sagging furthest. Wondering if this cell had capacity issues and assuming the next step is swap two cells and be sure the problem follows that...

Establishing remote connectivity requires actions taken on the phone side though doesn't it? It always did from my testing. Which is finea static display PC or something. My BMS is in a locked metal cabinet away from my house. My plan was either have a phone in the cabinet and remote connect to...

Much better

I'll keep that in mind. The supplier has finally replied so we'll see if I can wrangle another one for testing. I will make a point of making sure I remove the balance lead loom completely in future, just in case that's happened here.

I had an attachment showing how it's wired currently, but I've added some detail showing what I currently do. I think you're missing some of what I'm saying. See the diagram and then read the below. Whether I am start the BMS or Pre-charging caps to get he inverter going I currently connect...

The lot, customs, GST, agent fees. $330 total for both shipments.

I have a really hard time following what you are saying sorry. The power supply, with a boost converter, has never needed to be more than about 59v because my pack never goes above 54v. These are 2 separate issues, with 2 separate setups to solve them. I am not trying to do one thing to...

As above is what I do with mine. I made a loom with a 9v in series, a moment switch and 2 alligator clamps, I just clamp it on the main bat neg and the output side of the BMS, hit the button and remove. Similarly, if the inverter is being cold started I have a resistor wired up the same way...

Awesome, thanks will take a look.

This is my issue, I do not have an on/off switch (other than the battery to inverter breaker). As the BMS sees an inverter starting as a short, currently I connect a DC power supply to the battery main positive and the BMS output lead/inverter connection point and feed it a few volts above pack...

I'll watch the clip thanks, The heltec 5a stand alone is not configurable from what I can see, but it does bugger all until the cell voltages are decent as I've put a clamp meter on the leads before so it's quite conservative. The BMS balancing is configurable but I was advised not to run them...

Assume it's this? https://github.com/jblance/mpp-solar I still have an issue seeing any data from the JK RS485 cable so I'll watch the video and see what they are doing there.

150A version 6 or so BMS is giving me a bit of grief on my 48v 16s 280ah pack. The unit has failed in the 2 or so years I've had it and 4 cell wires just stopped reading completely, and it was sent back for repairs (painful). Since then it has mostly been "ok" but increasingly I am seeing 1...

Well she seems confident I'll give her thekat even if the "previous batch" stuff seems very convenient. Hopefully these attach properly.

I've realised the BMS starting battery setup is wrong, should all be on the neg side. Also, the resistor setup should all ideally be on the inverter side of the breaker with DPST moment switch across the breaker and a resistor in series with one of the terminals, I'll see what access I can get...

I upgraded those after reading the same which is how I got it up to about 6a, ran double leads to test also, I think it was just the supply. Anyway, it balanced eventually.

I have a JK BMS (2a active balancer model) and I would like to be able to monitor the BMS remotely, I can see no way of configuring alarms and having them emailed/pushed? While I wait for an answer from JK, I was going to leave a phone in my solar cabinet to run the app and remote in to it, but...

Connector is standard. The product is listed as carbon conductive grease, sold from an electronics store. Given I have continuity and voltage at each pin without any issue, I am confident there's not a conductivity issue. I will check the order of the leads but I'm not going to spend another...

7 days off grid so far, on-grid system continues to just bulk export everything other than when I need to run one of the pumps to to fill a tank as it's down the other end of the property and not connected to the house sub-board. Did some basic tidy up in the cabinet, have since added a power...

I have the JK BMS (2a active balancer model) and I would like to be able to monitor the BMS remotely, I can see no way of configuring alarms and having them emailed/pushed? While I wait for an answer from JK, I was going to leave a phone in my solar cabinet to run the app and remote in to it...

Team viewer requires input on the phone end to work and the instant you close that session you need to re-authenticate next time. So I'd effectively have to connect a session on a machine and leave it running 24/7 so I could then remote access that machine to see the BMS when I wanted to so my...

OK so the pack is in and working but the BMS doesn't want to play. It wants a charger connected to the pack after it's all wired in and I don't have a 60v charger - Full pack voltage 57.6. I've quadruple checked the wiring is as so and tried bridging between the pack main neg and the -p...

Quick update, chatted with my elec engineering mate, he believes it's a control circuit issue due to timing of the coils movement. I'm collecting an interposing relay this afternoon and will drive the coils from that and we'll see how we go.

Can do, thoughts on the arc suppressors in this this example? Is my understanding about flow/resistance correct?

Quick update, chatted with my elec engineering mate, he believes it's a control circuit issue due to timing of the coils movement. I'm collecting an interposing relay this afternoon and will drive the coils from that and we'll see how we go.

Now have the pack running "through" the inverter - bridged pack main neg to -p so the inverter could see the battery and push some charge in, which worked, I then removed that bridge and the whole thing is still running/charging etc so it's going via the BMS now but I cannot see it in the software.