Experience with Daly BMS

[ice57]

Sharing some experiences I've had over the last two months with Daly BMS that led me to switch (at considerable cost) to JK BMS.
First, my experience applies only to the 48v16s 300A LiFePO4 model of the Daly BMS, although it could be a predictor of their other models.
The status reporting of the units either via their bluetooth-enabled iOS app or via UART to a Solar Assistant instance was erratic from the start. I had had two BMS in production with two battery banks for about a year, but felt I could never trust what the status reporting was telling me. Especially as one battery bank had substantially better capacity behavior than the other, both banks being built from the same batch of cells.
I was planning the addition of a third bank, purchased a third identical BMS from Daly and noticed when installed that this third BMS behaved even differently (better) than the first two. At my request, Daly sent me a firmware update. I applied it successfully to one of the older BMS, but when I tried to apply it to the second one it failed and 'bricked' the unit. Daly support eventually went dark on me as I had requested help with the bricked unit. The one with the successful firmware update was now even more erratic than before and was reporting known-faulty information on the status of SOC and MOS charge/discharge switches. Eventually that battery bank was unusable with the Daly BMS.
Since then, I've implemented three JK BMS (200A units) for my three battery banks and my off-grid system is working extremely well. The status reporting of the JK's through Solar Assistant match up perfectly with the battery information from my MPP Solar inverters (never the case with the Daly BMS) so I can trust what they report. The JK's have integrated active balancing, necessary with the daily/hourly stress on the battery banks, so the cells stay well balanced and the banks stay relatively even capacity throughout each cycle. Very pleased with the performance of the JK BMS.

 

[sunshine_eggo]

Thanks for sharing.

DALY seems to be unique on this site as a consistently unreliable option.

 

[ice57]

I still have a much smaller system with Daly BMS in my off-grid cabin that's working okay. I recently added the Daly active balancer unit, as I was seeing some cell variations that were concerning with the passive balance only. That battery bank (24v8s) is behaving much better since.

 

[Texas-Mark]

DALY seems to be unique on this site as a consistently unreliable option.

Perhaps because it is more popular than others. And there are issues with other brands reported here. I have 5 Dalys, and they all work fine.

 

[sunshine_eggo]

Perhaps because it is more popular than others. And there are issues with other brands reported here. I have 5 Dalys, and they all work fine.

JBD/Overkill and JK are equally prolific and there are occasional issues, but DALY seems to dominate DOA reports and users with multiple DALY experiencing multiple failures. A recent user with above average skills identified a likely design/manufacturing flaw.

 

[Texas-Mark]

JBD/Overkill and JK are equally prolific

Based on what data? Posts here? How many thousands are in use where people never post about them or even join a forum? Without seeing actual sales numbers of each manufacturer, there is no way to get an accurate failure rate.

 

[sunshine_eggo]

Based on what data? Posts here? How many thousands are in use where people never post about them or even join a forum? Without seeing actual sales numbers of each manufacturer, there is no way to get an accurate failure rate.

I understand you might be defensive thinking I'm attacking your chosen solution, but I'm simply stating what I'm seeing in posting trends.

Given that I'm one of the top post whores, it's probably safe to say that I'm here more than you are, and while this avatar has only been here since October 2021, my other, linked in my signature predates you by a year. My combined post count is over 19K. I'm not speaking to quantity or value, simply presenting evidence of presence. A LOT of posts are about DALY BMS failures. They stand out. Problems with JK and JBD/Overkill are comparatively rare.

This is also a VERY heavily trafficked site, so it's probably a strong statistical representation of the overall population.

What is the probability of a single having 2 of the 4 fail?

 

[Texas-Mark]

I understand you might be defensive thinking I'm attacking your chosen solution, but I'm simply stating what I'm seeing in posting trends.

Not at all. I've just seen brand bashing on many different forums based solely on negative posts of brand X, and not based on any actual data regarding overall sales (compared to others) and actual % failures. I've also seen the negative Daly posts here, and probably half of them or more are due to user error and not actual failures. Look at some of the lifepo4 battery reviews on Amazon. Most of the 1 star reviews (which may be a high percentage) are from people who are clueless as to how a BMS works, and the battery is actually operating normally. Does that mean the battery and/or brand is junk?

 

[ice57]

@Texas-Mark I’m curious what models of Daly BMS you’ve used and/or tested? My experience could be very model-specific. As I mentioned in my second post, the smaller model (24V8S 100A) seems to be working fine.

 

[Texas-Mark]

@Texas-Mark I’m curious what models of Daly BMS you’ve used and/or tested?

Four of them are 4S 100A and one is 4S 60A. I actually have another 60A that I am not currently using, but I did test it just to make sure it worked. All have BT.

 

[ice57]

So then the problems others and I have experienced might be symptomatic of the size (300A / 500A) or the number of cells (16s). In any case, my post was meant to give any future users some sense of the experience with that particular model. IMO Daly could help themselves considerably if they invested in more/better customer support.

 

[Checkthisout]

Not at all. I've just seen brand bashing on many different forums based solely on negative posts of brand X, and not based on any actual data regarding overall sales (compared to others) and actual % failures. I've also seen the negative Daly posts here, and probably half of them or more are due to user error and not actual failures. Look at some of the lifepo4 battery reviews on Amazon. Most of the 1 star reviews (which may be a high percentage) are from people who are clueless as to how a BMS works, and the battery is actually operating normally. Does that mean the battery and/or brand is junk?

Daly brand is junk.

Thought mine worked ok too until the weather got cold. ?

 

[hardtop]

It sounds like the DALY isn't ready to be on the market. My JK BMS arrived DOA so you have a much better experience with JK. I went with JBD last week and pleased so far since its working, although I could only go downhill from the DOA.

One gripe I have of the JBD is it doesn't know my capacity. It will ask for capacity, I tell it, save and the updated value doesn't stick. Clearly it is a bug but I'm going to run some full cycles on the pack since its new as someone suggested. Hopefully it has self learning for the capacity, but I'm not holding my breath lol.

 

[sunshine_eggo]

It sounds like the DALY isn't ready to be on the market. My JK BMS arrived DOA so you have a much better experience with JK. I went with JBD last week and pleased so far since its working, although I could only go downhill from the DOA.

One gripe I have of the JBD is it doesn't know my capacity. It will ask for capacity, I tell it, save and the updated value doesn't stick. Clearly it is a bug but I'm going to run some full cycles on the pack since its new as someone suggested. Hopefully it has self learning for the capacity, but I'm not holding my breath lol.

Cycling JBD is not necessary. Attain the full charge voltage cell value or trigger over voltage protection, and it will sync to 100%.

There is nothing to be gained cycling. The benefit comes from triggering 100% when it's actually at 100%.

 

[Checkthisout]

It sounds like the DALY isn't ready to be on the market. My JK BMS arrived DOA so you have a much better experience with JK. I went with JBD last week and pleased so far since its working, although I could only go downhill from the DOA.

One gripe I have of the JBD is it doesn't know my capacity. It will ask for capacity, I tell it, save and the updated value doesn't stick. Clearly it is a bug but I'm going to run some full cycles on the pack since its new as someone suggested. Hopefully it has self learning for the capacity, but I'm not holding my breath lol.

I'm eating my words.

My Daly was clocking 70 amps charge at night with no charging current applied and the charging mosfet off due to low temp. This made the SOC go to 100% so once the battery temp came back up, it would not reactivate the charging mosfet because SOC was 100%.

Dafuq?

I manually reset SOC to 20% and it started charging. This is after the useless software update they sent me. Support has since gone dark.

Soooo....what's the consensus on the best BMS that allows monitoring with a PC when needed?

 

[sunshine_eggo]

I'm eating my words.

My Daly was clocking 70 amps charge at night with no charging current applied and the charging mosfet off due to low temp. This made the SOC go to 100% so once the battery temp came back up, it would not reactivate the charging mosfet because SOC was 100%.

Dafuq?

I manually reset SOC to 20% and it started charging. This is after the useless software update they sent me. Support has since gone dark.

Soooo....what's the consensus on the best BMS that allows monitoring with a PC when needed?

JBD (overkill) with the JBDTools (overkill) package and a UART to USB adapter.

 

[Checkthisout]

JBD (overkill) with the JBDTools (overkill) package and a UART to USB adapter.

Any chance you verfied operation in cold weather I.E. freezing and how does it do for small amounts of current I.E. less than 2 amps?

Also, Bummer. They are all sold out on 18650's site.

 

[sunshine_eggo]

Any chance you verfied operation in cold weather I.E. freezing and how does it do for small amounts of current I.E. less than 2 amps?

Also, Bummer. They are all sold out on 18650's site.

I did the ice water test, and it cut charging.

Pseudo self-discharge exercise

Battery: 4S 25Ah Topband Navitas 3C cells. 120A JBD BMS UART to USB adapter from Overkillsolar Bluetooth module uses the BMS UART connector, so it was not installed. VRM: Raspberry Pi 3 B+ 1GB (RPi) 256G MicroSD Venus OS 3.11 start, 3.12 end @Louisvdw serial battery driver There were NO LOADS...

diysolarforum.com

VRM logged < 2A down to about 0.2-0.3A before cut off:



Accuracy was relatively consistent with the separate hall effect sensor battery monitor I use with it.

 

[sunshine_eggo]

Any chance you verfied operation in cold weather I.E. freezing and how does it do for small amounts of current I.E. less than 2 amps?

Also, Bummer. They are all sold out on 18650's site.

Got my 14S "backup" BMS for my NMC from here:

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[Checkthisout]

Thank you!