Daly 8s 24V 200A LiFePo4 Smart BMS

ATXist

New Member
Joined
Apr 23, 2021
Messages
13
Hey All,

I'm new to all of this, and about to order the Daly 8s 200A Smart BMS (specifically the 200AcomUART485CANFan model listed on this page, it's an extra ~$20 for all of the connection features, so I figured why not?). After reading through the discussions Here: Daly smart BMS, my head is spinning a bit, and I'm hoping some kind soul can provide some clarity on a couple of things:

1) People are commenting on how easy it is to order a BMS for the wrong battery chemistry. As far as I can tell this would be the correct type for a 8s, 24v, 280ah, LiFePo4 DIY battery build, is that correct?

2) There seem to be mixed reports as to whether or not the BMS' settings can be adjusted by the user, and I see people recommending that you send a message to Daly with your preferred settings (temp cutoff, low voltage cutoff, etc) to ensure they get set correctly for your batteries chemistry. Any update on whether this is still necessary?
If so, I'd assume something like:
Cell high v cutoff: 3.7v
Cell low v cutoff: 2.5v
Total high v cutoff: 29.6v
Total low v cutoff: 20v
Low temp cutoff: 1 Celsius

Any other considerations I may be missing? Sorry for the newbie post. I feel like I've been cramming for my electrical engineering degree over these last couple of weeks. It's all fascinating, but definitely intimidating.

Thanks for your help!
 

lonertic

Solar Enthusiast
Joined
Apr 23, 2021
Messages
41
I ended up going for the jikong 200A BMS instead. Similar price to the Daly (actually cheaper), but you can program all of those specific parameters yourself. Also the Daly's balancing current is only 30mA... U do the math on a 280Ah cell... How many months will that take to balance a mismatched cell at 0.03A without another active balancer... I've only run my JK BMS for a few months tho so i can't comment on how reliable it is relative to a Daly. Was there a particular feature that's only on the Daly and not on the jk? I can't remember anymore 😞
 

ATXist

New Member
Joined
Apr 23, 2021
Messages
13
I ended up going for the jikong 200A BMS instead. Similar price to the Daly (actually cheaper), but you can program all of those specific parameters yourself. Also the Daly's balancing current is only 30mA... U do the math on a 280Ah cell... How many months will that take to balance a mismatched cell at 0.03A without another active balancer... I've only run my JK BMS for a few months tho so i can't comment on how reliable it is relative to a Daly. Was there a particular feature that's only on the Daly and not on the jk? I can't remember anymore 😞
That's interesting, I hadn't looked at or considered the balancing current. I'll take a look at the Jikong, I hadn't seen anyone mention it before. The Daly seems to be the most commonly mentioned on this forum/elsewhere, making me think it'll have the most resources and tutorials available, which I'll most certainly be needing. I don't believe I need any features outside of the basics protections, and the ability to monitor levels.

Were there any other features that pointed to in the direction of the Jikong instead of others? Any features you wish you have now?
 

lonertic

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Joined
Apr 23, 2021
Messages
41
That's interesting, I hadn't looked at or considered the balancing current. I'll take a look at the Jikong, I hadn't seen anyone mention it before. The Daly seems to be the most commonly mentioned on this forum/elsewhere, making me think it'll have the most resources and tutorials available, which I'll most certainly be needing. I don't believe I need any features outside of the basics protections, and the ability to monitor levels.

Were there any other features that pointed to in the direction of the Jikong instead of others? Any features you wish you have now?
There's a YT video from Will which basically says active balancers are useless and that you don't need a high balancing current... but he casually caveated that remark with "if your cells are new" or something... I don't know where people are sourcing their cells from but I'd imagine not many DIY'ers are buying retail cells, and even then, the retailer/resellers themselves are often questionable.. I can understand the context of his comment especially if we're talking smaller capacity cells like 18650's, but I'm not sure that still scales up to larger capacity like 50Ah+ cells.. let's face it, almost all the LFP cells we buy are made in china, and they're cheap on aliexpress/ebay etc because they probably didn't meet QA.. so I have to assume there are some manufacturing inconsistencies with them... I received a batch of brand new cells (and yes they're new, I found out how easy the plastic outer skin can get micro scratches or dirt stuck on them so if they've ever left the box it's very easy to tell), and out of my bank of 16, there is already 1 cell in there that is consistently hitting upper and lower voltage limits before any other cell.. (aka it's got a different internal resistance value to other cells). As a result, my jikong is constantly working at 2A balancing current to offset that cell.

My simple solution to my problem is to simply replace that cell (i DO have spares), but it implies if that was not an option, and that I'd like to get access to the capacity available in the remaining 15 cells in my bank, then I would have to rely on a high current balancing function. So if I started with a Daly with 30mA, this would be about the time I'm contemplating whether it's cheaper to replace the BMS, or cheaper to replace the cell (which was also $200/cell + shipping)... u can see how that could become a very expensive mistake very quickly. especially if more than 1 cell is mismatched.

So my only "regret" now with the JK bms is that it doesnt come with >2A balancing. I commented in another thread asking if it's possible to run a separate active balancer with the BMS since I've not done that before.. but if that works and that's your plan from the get-go, then the Daly would meet your needs. but even then - considering the cost, i probably would've still gone with the JK... because that allows up to 24S connection whereas the one you linked is 8S.... sure, your requirement might be 24V now, but why not buy something that has future expansion capability? eg: if u ever changed to a 48V inverter and decided to rearranging the wiring on your cells, you can get more use out of the BMS you already own, that'd be my thinking anyway.
 

Just John

Photon Sorcerer
Joined
Aug 15, 2020
Messages
2,688
That's interesting, I hadn't looked at or considered the balancing current. I'll take a look at the Jikong, I hadn't seen anyone mention it before. The Daly seems to be the most commonly mentioned on this forum/elsewhere, making me think it'll have the most resources and tutorials available, which I'll most certainly be needing. I don't believe I need any features outside of the basics protections, and the ability to monitor levels.

Were there any other features that pointed to in the direction of the Jikong instead of others? Any features you wish you have now?
Daly is the most commonly complained about here, thus the most talked about. My 12v says right on the nameplate, lifepo4, yet it is set up and expects li-ion, so state of charge and cycle count don't work (because I won't charge my cells to 3.7v to trigger the cycle count).
That said, the actual BMS functions work fine, high voltage disconnect, low voltage disconnect, low temperature disconnect all work without a problem.
 

wild01

Solar Addict
Joined
Feb 18, 2021
Messages
226
There's a YT video from Will which basically says active balancers are useless and that you don't need a high balancing current... but he casually caveated that remark with "if your cells are new" or something... I don't know where people are sourcing their cells from but I'd imagine not many DIY'ers are buying retail cells, and even then, the retailer/resellers themselves are often questionable.. I can understand the context of his comment especially if we're talking smaller capacity cells like 18650's, but I'm not sure that still scales up to larger capacity like 50Ah+ cells.. let's face it, almost all the LFP cells we buy are made in china, and they're cheap on aliexpress/ebay etc because they probably didn't meet QA.. so I have to assume there are some manufacturing inconsistencies with them... I received a batch of brand new cells (and yes they're new, I found out how easy the plastic outer skin can get micro scratches or dirt stuck on them so if they've ever left the box it's very easy to tell), and out of my bank of 16, there is already 1 cell in there that is consistently hitting upper and lower voltage limits before any other cell.. (aka it's got a different internal resistance value to other cells). As a result, my jikong is constantly working at 2A balancing current to offset that cell.

My simple solution to my problem is to simply replace that cell (i DO have spares), but it implies if that was not an option, and that I'd like to get access to the capacity available in the remaining 15 cells in my bank, then I would have to rely on a high current balancing function. So if I started with a Daly with 30mA, this would be about the time I'm contemplating whether it's cheaper to replace the BMS, or cheaper to replace the cell (which was also $200/cell + shipping)... u can see how that could become a very expensive mistake very quickly. especially if more than 1 cell is mismatched.

So my only "regret" now with the JK bms is that it doesnt come with >2A balancing. I commented in another thread asking if it's possible to run a separate active balancer with the BMS since I've not done that before.. but if that works and that's your plan from the get-go, then the Daly would meet your needs. but even then - considering the cost, i probably would've still gone with the JK... because that allows up to 24S connection whereas the one you linked is 8S.... sure, your requirement might be 24V now, but why not buy something that has future expansion capability? eg: if u ever changed to a 48V inverter and decided to rearranging the wiring on your cells, you can get more use out of the BMS you already own, that'd be my thinking anyway.
i've got 2 cells from the 16 I got from mike caro that do that. they meet the 200ah specs but they seem to be slightly lower capacity than the other 14. I've been dealing with them with a 5a capacitor balance board, but I've thought about wiring a couple 5or6ah 32650 cells in parallel with the 2 low cells to balance out the pack that way.
 

lonertic

Solar Enthusiast
Joined
Apr 23, 2021
Messages
41
i've got 2 cells from the 16 I got from mike caro that do that. they meet the 200ah specs but they seem to be slightly lower capacity than the other 14. I've been dealing with them with a 5a capacitor balance board, but I've thought about wiring a couple 5or6ah 32650 cells in parallel with the 2 low cells to balance out the pack that way.
Yup I had another question out in another thread somewhere asking whether it's possible to run a separate active balancer on top of the JKBMS's built-in balancer and whether it'd cause problems... and it seems like the prevailing answer is it'll be fine (even the JKBMS seller said the same thing and recommended an external balancer they sell).... so that might be my next step...

Because I run the pack full cycle on a daily basis (sometimes more than 1 cycle per day), they never really keep up with balancing. so my 200Ah are now down to effectively around 180Ah as soon as one of the cells are over or under... so with something like a 10A balancer on top I should be getting my 10% capacity back.
 

robbymax

robbymax
Joined
Oct 26, 2020
Messages
31
Location
south lincs UK
hi i bought a dali smart bms nice looking kit, BUT it was reluctant to connect to my iphone, and when it did would drop out, it was a problem i got over by replacing it with JBD i like the software, you can set everything, and if you want to fit a seperate balancer you can switch the balance part off i like the idea of that there is no conflict
 

BobF

New Member
Joined
May 3, 2020
Messages
4
Hello all. I am always interested in discussions about this BMS vs that BMS and the balancing functions, etc. Years ago, when I first added solar to my boat (full time liveaboard and totally off grid ) I read as much as was available at the time. I decided that if there was any balancing to be done, I would do it manually and not depend on a component which could take my entire costly Lithium bank down. To do so, I would treat it as a system, and not something that automatically took care of itself for all functions. I have 800ahr wired at 24V using 400ahr cells. I have done NO BALANCING for 3 years now, and all cells are within .025ma and 0.055ma on average. Everyone once and a while I have seen 0.150ma, but when testing the cells right at the terminals, that reading proves to be false. For my system I use a very reasonably priced unit called the Chargery BMS-16. It is the original model and it monitors individual cell volts, has high and low cutouts you can set yourself, and also monitors pack voltage and temperature, etc. I use external relays for the High V events and Low V events, as a "hail Mary" backup in case the upstream devices fail to do their job. They have extremely low "hold" current, so they don't drain the system. I use a Victron 5000 to monitor the low volt discharge turnoff, set to a bit higher than the Chargery setting. When charging by an external grid source, like a generator or shore power, the Vic takes care of the High volt charge turnoff. Of course you have to program the Victron to do that via a laptop to get the precise setting you want. My Victron 250/70 and 150/85 SSCs are set to the charge volts I want before a low float voltage. The Chargery has a colored display, albeit a bit small, but it works. I have seen complaints about the Chargery, but they are not justified in my opinion. I think no one took the time to read the comprehensive instructions. I am not claiming I got it all right the first time... But after 3 years the whole system works flawlessly. I also have a BMV 700 for daily glances at the bridge so I can monitor voltages, etc. when underway. Now, as to balancing, I did bottom balancing of all cells when they arrived. They are GBS 400amp lithium iron phosphate cells, and there are 16 of them. They are right from the factory, and class AAA in my opinion. They were close in voltage, and come with a sheet showing at what voltage they were sent. I used a Power Lab 8 to do the balancing. You can find info on the web concerning how to use them. I took my time to do this to make sure all cells were the same before pack charging. Yes, it is tedious, but how can you argue 3 years without the need to balance the cells, and no costly item to mess up the batteries? Watch Andy on This Old Garage and see what he discovered using Active Balancing. At some point, it was actually Unbalancing the cells! I run my system between a low of 20% discharge to around 90% charged. However, in my 800ahr system, records from the BMV show over the years that my deepest discharge was 415Ah, so I have never gone very low. There were a few times when the volts have gone too high, but that didn't last but a minute or two. Sometimes, when the watermaker is running, I might be pulling 120amps at 24v. However, when the sun is full, I might be showing only 60 to 80 amps discharge. My daily consumption is 7.18 kwhr. So why did I bottom balance? Well, mainly because I have not lived on land for 40 years, and for that time I have sailed to many countries. Living on board (not always the same boat) in the days before lithium, yachties always have undercharged Lead Acid batteries. They are impossible to fully charge given that chemistry. So, I went for the method that equalizes the Capacity of the batteries, and not necessarily the voltages. However, they just seem to self balance over time and I think I am better off with bottom balancing. Opinions vary, but it sure works well for me for my kind of lifestyle and needs. For example, up to this date, I have run the generator only 20 hours since Jan1 this year! This is thru storms, cloudy days, and so on. I live in the Philippines and yes it is tropical but not every day is there wall to wall sun. Thus, I put on lots of panels to obviate shading, with separate controllers for the arrays consisting of 6 x 360 watt and 4 x 450 watt panels. Panels are wired in series for a total of 3,900w, and combined into three 400vdc miniature circuit breakers. So, I can fine tune what is going into the controllers if I need to. Breakers interrupt both positive and negative wires going into the controllers. This is what works for me. I would be interested to see if others have gone to bottom balancing instead, and NOT using any balancers. Cheers
 

lonertic

Solar Enthusiast
Joined
Apr 23, 2021
Messages
41
This is what works for me. I would be interested to see if others have gone to bottom balancing instead, and NOT using any balancers. Cheers
There's a few things I'd like to pick with your post..
all cells are within .025ma and 0.055ma on average
What does that even mean? ma is a measure of current.. not capacity or voltage, that isn't really a measure of health of cells? Health is usually measured as either internal resistance, or variances in voltage between cells, or mAh total capacity... what do you mean they're within 0.025ma?

Also, what's your charge/discharge cycles like? In my example, I do a full cycle 0% SoC to 100% each day.. sometimes more than once. I'm also charging at up to 3C (as I can feed in from grid as well as solar).. all of these things makes a difference and you can't just make a blanket statement like "mine's been working fine for 3 years without it". Rapid charge/discharge, as well as depth of charge/discharge makes a huge difference, high current balancers are there to alleviate the imbalances when the cells themselves can't physically keep up because they're already performing at the higher end of their design. In your example you have 3.9kW panels, your cells (24V & 800Ah) equate to almost 20kWh, you are therefore charging at 0.2C at the best of conditions, if these are LFP cells, you're charging at about 6% of what they're capable of, so of course you won't need any balancers! Your cells are bored, they have barely any work to do.

But say if you were charging at 3C, say if that same 3.9kW solar system is now charging/dischaging a 1.3kWh worth of cells (basically look at your cells now and imagine each are ~15 times smaller), I reckon it'll only take days, if not hours, before you start seeing some serious imbalance going on, leave that unattended and without any further protection mechanism you'll probably have completely dead cells within the month.
 

BobF

New Member
Joined
May 3, 2020
Messages
4
There's a few things I'd like to pick with your post..

What does that even mean? ma is a measure of current.. not capacity or voltage, that isn't really a measure of health of cells? Health is usually measured as either internal resistance, or variances in voltage between cells, or mAh total capacity... what do you mean they're within 0.025ma?

Also, what's your charge/discharge cycles like? In my example, I do a full cycle 0% SoC to 100% each day.. sometimes more than once. I'm also charging at up to 3C (as I can feed in from grid as well as solar).. all of these things makes a difference and you can't just make a blanket statement like "mine's been working fine for 3 years without it". Rapid charge/discharge, as well as depth of charge/discharge makes a huge difference, high current balancers are there to alleviate the imbalances when the cells themselves can't physically keep up because they're already performing at the higher end of their design. In your example you have 3.9kW panels, your cells (24V & 800Ah) equate to almost 20kWh, you are therefore charging at 0.2C at the best of conditions, if these are LFP cells, you're charging at about 6% of what they're capable of, so of course you won't need any balancers! Your cells are bored, they have barely any work to do.

But say if you were charging at 3C, say if that same 3.9kW solar system is now charging/dischaging a 1.3kWh worth of cells (basically look at your cells now and imagine each are ~15 times smaller), I reckon it'll only take days, if not hours, before you start seeing some serious imbalance going on, leave that unattended and without any further protection mechanism you'll probably have completely dead cells within the month.
There's a few things I'd like to pick with your post..

What does that even mean? ma is a measure of current.. not capacity or voltage, that isn't really a measure of health of cells? Health is usually measured as either internal resistance, or variances in voltage between cells, or mAh total capacity... what do you mean they're within 0.025ma?

Also, what's your charge/discharge cycles like? In my example, I do a full cycle 0% SoC to 100% each day.. sometimes more than once. I'm also charging at up to 3C (as I can feed in from grid as well as solar).. all of these things makes a difference and you can't just make a blanket statement like "mine's been working fine for 3 years without it". Rapid charge/discharge, as well as depth of charge/discharge makes a huge difference, high current balancers are there to alleviate the imbalances when the cells themselves can't physically keep up because they're already performing at the higher end of their design. In your example you have 3.9kW panels, your cells (24V & 800Ah) equate to almost 20kWh, you are therefore charging at 0.2C at the best of conditions, if these are LFP cells, you're charging at about 6% of what they're capable of, so of course you won't need any balancers! Your cells are bored, they have barely any work to do.

But say if you were charging at 3C, say if that same 3.9kW solar system is now charging/dischaging a 1.3kWh worth of cells (basically look at your cells now and imagine each are ~15 times smaller), I reckon it'll only take days, if not hours, before you start seeing some serious imbalance going on, leave that unattended and without any further protection mechanism you'll probably have completely dead cells within the month.
Hi. First of all, I am sorry for the typo. Of course it should have been Mv instead of Ma. My daily discharge is roughly 7.4 kilowatt hours. At times, when I run a high draw item like a watermaker, for example. It draws well over 100amps @24V from the battery bank, and normally run for 1.5 to max of 2 hours each time. The aircon, 18k BTU will draw the same when running, and latter drop off to amount 1,000 watts consumption. I never run both at the same time. In the event there is sun, the actual draw down from the batteries ranges between 60 to 85 amps from the batteries because the panels are helping. The lowest the system has ever been drawn down is 417ahr out of the 800ahr bank. The highest charge rate, if I have to run the generator is 135 amps @ 24v. Interestingly, I have never seen even 2,000 watts coming in from the panels. Even after 2 days of discharge (no sun, no gen), I might see 1,800 watts of charge. Some of that I can contribute to shading as the boat swings on the mooring. If every day consisted of full sun, I clearly have too many panels for my needs. However, days are rarely 100% free of clouds, so one never gets full use of panels. At my latitude of roughly 14deg north, I can calculate that I am running on average about 60% of the potential. This is based upon several years of operation. So sure, it has been working fine for me. I don't believe I ever said it would work for you, or anyone else. I have no idea if these cells will work for 5 more years or 5 more weeks, but so far it all looks good for the future at MY charge/discharge rate. I hope this discussion helps others when they are making decisions as to which way to go: bottom or top balancing. And if what ever they choose to do, and whether or not using any kind of balancing is needed. Certainly in my 3 years, and the way I have implemented the solar system, keeping with 50mv between all cells, it works for me. Thanks for your input.
 

lonertic

Solar Enthusiast
Joined
Apr 23, 2021
Messages
41
Hi. First of all, I am sorry for the typo. Of course it should have been Mv instead of Ma. My daily discharge is roughly 7.4 kilowatt hours. At times, when I run a high draw item like a watermaker, for example. It draws well over 100amps @24V from the battery bank, and normally run for 1.5 to max of 2 hours each time. The aircon, 18k BTU will draw the same when running, and latter drop off to amount 1,000 watts consumption. I never run both at the same time. In the event there is sun, the actual draw down from the batteries ranges between 60 to 85 amps from the batteries because the panels are helping. The lowest the system has ever been drawn down is 417ahr out of the 800ahr bank. The highest charge rate, if I have to run the generator is 135 amps @ 24v. Interestingly, I have never seen even 2,000 watts coming in from the panels. Even after 2 days of discharge (no sun, no gen), I might see 1,800 watts of charge. Some of that I can contribute to shading as the boat swings on the mooring. If every day consisted of full sun, I clearly have too many panels for my needs. However, days are rarely 100% free of clouds, so one never gets full use of panels. At my latitude of roughly 14deg north, I can calculate that I am running on average about 60% of the potential. This is based upon several years of operation. So sure, it has been working fine for me. I don't believe I ever said it would work for you, or anyone else. I have no idea if these cells will work for 5 more years or 5 more weeks, but so far it all looks good for the future at MY charge/discharge rate. I hope this discussion helps others when they are making decisions as to which way to go: bottom or top balancing. And if what ever they choose to do, and whether or not using any kind of balancing is needed. Certainly in my 3 years, and the way I have implemented the solar system, keeping with 50mv between all cells, it works for me. Thanks for your input.
fair enough, you have a good sized system I believe, your batteries outsize your solar by a huge margin, and your solar outsizes your usage by a fair margin. Hence with that in mind, as I said your system is barely under any stress, so you should see plenty of life left in it.

The danger with not having balancers is like in most domestic applications where you can't really outsize your usage and there's not much you can do about it, for example my system was meant to be an overkill, and it generally is in spring/autumn when there's minimal HVAC use but still plenty of sunny days. But I get absolutely smashed in cold winter nights or hot summer days, actually worse in winter when there's very little solar help too, at least in summer, the heat comes hand-in-hand with blazing sun.. And so in those winter nights, if the rapid charge/discharge happens a few hours in a row without adequate balancing to save the cell's butt, permanent damage can be done very quickly. Unfortunately you really only find out these things after at least a full year or two of ownership, because if someone installed their system in Autum, they could have a solid 10 months of absolutely no issues at all before one day it suddenly becomes a problem unannounced.

I have over 50 cells (but only 48 in use, the rest are spares), and I've already had to swap out 4 cells because of reading advice from other people about "not needing balancers"... that worked ok for a little while so I thought it was all good too, but when the solar/usage pattern changed and the batteries got put under a lot more stress, it suddenly became not OK overnight... Considering these cells were $200+/ea at the time, it was a very expensive lesson to learn, so, you're right, just because it works for some people doesnt mean it'll work for others, and thats why I want to make it very clear for anyone else on these forums, don't make the same mistake I did, just because some other people can run their banks without balancers, that does NOT automatically mean others can automatically do it too. The reality is, these BMS's and balancers cost a lot of money and there's a reason they continue to have a market.... (a $300 BMS with top of the range balancer is nothing compared to 4x dead cells at $200 a pop!)..So whilst it's tempting to trim the fat and not buy any unnecessary stuff, unless you have a crazy large oversized system, please don't try it.
 
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