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What is the best BM out there? No I am not trying to start a fight LOL

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Ok so this is what I want to do in order of importance.
1. Top balance my batteries.
2. Protect from the batteries going to low and dying. As in turn off at 2.5 v per cell. Or better, 3v per cell.
3. Temp protection. Maybe a warning beep or something just before it gets to hot so I can be warned before they shut down and maybe cool them off?
4. Visual interface that makes sense.

Ok suggestions for this?

Lastly, looking for a good Lifepo battery charger that is adjustable. As in amount of amps in and how high to charge it too as well as I do NOT want a full charge but a 90% charge.

Suggestions? Ideas? Other things a BMS can do?


Ok so now I will get some popcorn and lets the games begin LOL. :)
Thanks guys for all of your help. :)
 
4. Visual interface that makes sense.
Sadly, that rules out everybody (that's i've used or researched) except Victron. And yes, I am a user-interface snob.

1. Top balance my batteries.
This is something that you will need to do yourself. A BMS is not going to disassemble your battery, build it up with all cells in parallel and do the top balancing.
 
This is something that you will need to do yourself. A BMS is not going to disassemble your battery, build it up with all cells in parallel and do the top balancing.
Ok that makes absolutely NO sense whatsoever.
Every BMS I have heard of can, and will top balance batteries.
I think you misunderstood something here. :)
 
I think you misunderstood something here.
Maybe.
But "my" understanding of top balancing involves wiring all the cells in parallel and charging them to their upper limits (3.65v per cell) together.

Charging a battery (with all cells wired in series) is NOT what I consider top balancing. But, if your BMS has enough balancing power to get all the cells to the top, together, then maybe its the equivalent.
 
Maybe.
But "my" understanding of top balancing involves wiring all the cells in parallel and charging them to their upper limits (3.65v per cell) together.

Charging a battery (with all cells wired in series) is NOT what I consider top balancing. But, if your BMS has enough balancing power to get all the cells to the top, together, then maybe its the equivalent.
Yes, paralleling batteries to balance them is an option. However that can take days, weeks or even a month or two if they are very off balanced.
A BMS can top balance when the cells are in series making up a battery though. It is actually one of their jobs.
Top balancing with a BMS is rather simple. You charge the cells of the battery to almost full [or full if you like to live dangerously]. Then just sit and let the BMS do its thing of balancing them.
Some BMS have a 200 ma rating and some have a 2 amp rating. This tells you how fast it can balance out of balanced cells. Of course a 2amp rated one will do this faster.
Watch some of Will's videos on the subject of top balancing for more detailed info on this. :)

And you do not charge battery cells to top balance them. You use the BMS when they are charged to top balance the battery cells. A huge difference. :)
 
There is no "best" BMS. Everyone has different requirements. The amount of peak current you intend to draw is an important consideration you didn't mention.

The OverKill Solar BMS is probably the most popular one from what I have seen, but I don't think it has much balance current. I have one of these in my smaller 100 AH pack and it is doing fine. I am using it to power electronics in my boat and it works very well for this and the Bluetooth App is very handy once you learn how to use it. I have the Iphone version of the App.

The Electrodacus BMS is also popular .... I don't know much about it. I tried to read up on it once, but his concepts didn't fit with the way my mind works.

I have the Chargery BMS for my larger pack for my RV and am very happy with it except SOC tracking. I think you are aware of it since I have seen you post over there. The Chargery does balance at 1.2 A and you can set it to balance in all modes if you want for the initial balancing. It doesn't have a Bluetooth option yet, but if you mount the display, it has all the info you need.

What is your time frame for needing the BMS. Do you already have the cells? You should be able to get the OverKill solar BMS or the Chargery BMS pretty quickly. You can order direct from Chargery or order one from @Craig.

If I were thinking about building another battery right now, I would wait a couple months and see what the new Chargery product looks like if it was a bigger pack. If your current draw is low, I would use the OverKill Solar BMS and balance manually.
 
I think @MisterSandals might be splitting hairs here a bit. The generally used definition of top balancing does mean you wire all the cells in parallel and charge them all to whatever the "top Voltage" wanted is. This can be done with a BMS as well though by using the balancing features of the BMS.

I will not say which BMS is best because I think it depends. I have found the best BMS for my system and it still is a little short of perfect but its "The Best" I have found so far.

I honestly think having a BMS and then a seperate more powerful active balancer might be the best scenario if your cells are not perfectly matched, which I think it is turning out to be the case for many DIY packs. If the cells are perfectly matched then a small amount of passive balancing might be all you need.

If you are not in a hurry to have perfect balance but are in a hurry to use your cells then BMS "top balancing" may be the way to go. In the end how much extra capacity will you get if your cells are relatively close to being balanced but not perfect so what if it takes a few weeks for the BMS to balance as long as the capacity is trending up.
 
And you do not charge battery cells to top balance them. You use the BMS when they are charged to top balance the battery cells. A huge difference. :)
Will has a lot of videos and they have evolved over the years. It is widely accepted to charge the cells in parallel to top balance them, charging them to top balance produces faster results than just hooking them in parallel. It is not the only way, your way will work quite fine as well.
 
Sherylin, I think you have some misunderstandings about the process of initial top balancing. For one, it is not letting the cells sit in parallel for days or weeks (it is the quickest method of balancing) and it does involve charging the cells in parallel. It is faster and more effective than letting the BMS try to do it.

What Mr Sandals is referring to is an "Initial Top Balance" or "Manual Top Balance", what you are referring to is a top balancing BMS (which they all are) and what I refer to as "maintenance balancing" (there may be a better term out there). These are not equivalent techniques, they serve different purposes (the first is to align/balance your cells so they start out balanced, the second is to account for cell differences and try to keep your cells in balance through incremental balancing during each charge cycle).

Some people choose to skip the initial top balance for one reason or another (lack of tools, lack of motivation, or risk of screwing up are three common reasons), in which case, you use your pack as normal with a BMS but at reduced capacity and your BMS willl theoretically bring your pack into balance probably over weeks or months.

The type of balancing Mr. Sandals, is recommending is pretty standard practice here and elsewhere. You can read about it in the Nordkyn or MarineHowTo links in my signature, also if you rewatch Will's video on top balancing, you will also see that this is basically the process Will uses as well.
 
Sherylin, I think you have some misunderstandings about the process of initial top balancing. For one, it is not letting the cells sit in parallel for days or weeks, and it does involve charging the cells in parallel. It is much faster and more effective than letting the BMS try to do it.

What Mr Sandals is referring to is an "Initial Top Balance" or "Manual Top Balance", what you are referring to is a top balancing BMS (which they all are) and what I refer to as "maintenance balancing" (there may be a better term out there). These are not equivalent techniques, they serve different purposes (the first is to align/balance your cells so they start out balanced, the second is to account for cell differences and try to keep your cells in balance through incremental balancing during each charge cycle).

Some people choose to skip the initial top balance for one reason or another (lack of tools, lack of motivation, or risk of screwing up are three common reasons), in which case, you use your pack as normal with a BMS but at reduced capacity and your BMS willl theoretically bring your pack into balance probably over weeks or months.

The type of balancing Mr. Sandals, is recommending is pretty standard practice here and elsewhere. You can read about it in the Nordkyn or MarineHowTo links in my signature, also if you rewatch Will's video on top balancing, you will also see that this is basically the process Will uses as well.
Yes I agree it is standard practice but I have 3 banks in which I just allowed the BMS to top balance just fine . I just want to make it clear that though it is standard practice it is not necessary and both methods should achieve the same results over time.
 
Yes I agree it is standard practice but I have 3 banks in which I just allowed the BMS to top balance just fine . I just want to make it clear that though it is standard practice it is not necessary and both methods should achieve the same results over time.

I did the same ..... Just let my Chargery BMS top balance the cells. They are staying in balance very well so far.

There is always more than one way to accomplish the same thing, but some get hung up that you have to do it a certain way to get results.
 
Actually I do. I've done 8 sets of cells this way with very good results.

I am very interested to hear of your results, it sounds like you're very experienced with this.
And I am interested in how you top balance through only charging while in parallel as well. :)
I just got the first of four packages of my batteries. UPS decided the rest will come later this week instead of all four at the same time.
Not experienced. But I use to make transistor throttles etc for model trains. So I have a tiny amount of electronics know how. But not much to be honest.
 
There is no "best" BMS. Everyone has different requirements. The amount of peak current you intend to draw is an important consideration you didn't mention.

The OverKill Solar BMS is probably the most popular one from what I have seen, but I don't think it has much balance current. I have one of these in my smaller 100 AH pack and it is doing fine. I am using it to power electronics in my boat and it works very well for this and the Bluetooth App is very handy once you learn how to use it. I have the Iphone version of the App.

The Electrodacus BMS is also popular .... I don't know much about it. I tried to read up on it once, but his concepts didn't fit with the way my mind works.

I have the Chargery BMS for my larger pack for my RV and am very happy with it except SOC tracking. I think you are aware of it since I have seen you post over there. The Chargery does balance at 1.2 A and you can set it to balance in all modes if you want for the initial balancing. It doesn't have a Bluetooth option yet, but if you mount the display, it has all the info you need.

What is your time frame for needing the BMS. Do you already have the cells? You should be able to get the OverKill solar BMS or the Chargery BMS pretty quickly. You can order direct from Chargery or order one from @Craig.

If I were thinking about building another battery right now, I would wait a couple months and see what the new Chargery product looks like if it was a bigger pack. If your current draw is low, I would use the OverKill Solar BMS and balance manually.
Peak current at the moment would be 30 amps. However that will change in the future to about 75 amps.

The bluetooth thing sounds interesting.

Yes I almost got the Chargery and even paid for it. But Citibank screwed up the deal and even charged me for the privilege. So no Chargery sadly. But I do like the interface on theirs yes.

The batteries have started to come today. So I was thinking tomorrow would be nice. If impossible LOL. I am hoping that the worse delivery company brings the other three boxes this week.

Thanks a lot for all of this info Bob. :)
 
Will has a lot of videos and they have evolved over the years. It is widely accepted to charge the cells in parallel to top balance them, charging them to top balance produces faster results than just hooking them in parallel. It is not the only way, your way will work quite fine as well.
Yes, I fear I will have to go this route until I get a BMS since Citibank screwed up my payment.
Thanks Craig.
 
Sherylin, I think you have some misunderstandings about the process of initial top balancing. For one, it is not letting the cells sit in parallel for days or weeks (it is the quickest method of balancing) and it does involve charging the cells in parallel. It is faster and more effective than letting the BMS try to do it.

What Mr Sandals is referring to is an "Initial Top Balance" or "Manual Top Balance", what you are referring to is a top balancing BMS (which they all are) and what I refer to as "maintenance balancing" (there may be a better term out there). These are not equivalent techniques, they serve different purposes (the first is to align/balance your cells so they start out balanced, the second is to account for cell differences and try to keep your cells in balance through incremental balancing during each charge cycle).

Some people choose to skip the initial top balance for one reason or another (lack of tools, lack of motivation, or risk of screwing up are three common reasons), in which case, you use your pack as normal with a BMS but at reduced capacity and your BMS willl theoretically bring your pack into balance probably over weeks or months.

The type of balancing Mr. Sandals, is recommending is pretty standard practice here and elsewhere. You can read about it in the Nordkyn or MarineHowTo links in my signature, also if you rewatch Will's video on top balancing, you will also see that this is basically the process Will uses as well.
Hey, that is a great definition. Best one I have seen so far actually. Myself and others fumble like drunks trying to explain it and here you are just putting it out there for all of us. :) :)

Yes I fully understand parallel balancing actually. About one of the few things I do understand here LOL.

Thanks again for the explanation. :)
 
I think @MisterSandals might be splitting hairs here a bit.
I did not intend to split hairs or nitpick about minutia.

My thought on top balancing (which you refer to as “initial top balancing”) is that it is more of a process than a destination. I believe that there are benefits to having all the cells complete a full charge together. This is not accepted by everybody and i am fine with that.

Charging a battery to the top and having the BMS or any balancer bring them to the same top voltage (destination) is what i consider balanced charging.
 
Hey, that is a great definition. Best one I have seen so far actually. Myself and others fumble like drunks trying to explain it and here you are just putting it out there for all of us. :) :)

Yes I fully understand parallel balancing actually. About one of the few things I do understand here LOL.

Thanks again for the explanation. :)

In your situation where you need the BMS soon .... and 75A is the largest draw you expect to see ... I would go with the @OverkillSolar 120A BMS.
You can start parallel balancing the cells you have while you are waiting to get it.
 
Yes I agree it is standard practice but I have 3 banks in which I just allowed the BMS to top balance just fine . I just want to make it clear that though it is standard practice it is not necessary and both methods should achieve the same results over time.
I agree. Standard (arguably best) practice, but not mandatory. I think there are valid reasons not to top balance if you understand the differences.

Hey, that is a great definition. Best one I have seen so far actually. Myself and others fumble like drunks trying to explain it and here you are just putting it out there for all of us. :) :)
The only reason I can define it is because I spent a lot of time fumbling like a drunk and trying to understand it too :) in fact I still am to some degree ;)

It took changing my mindset from trying to understand "how to balance" and "best way to balance" to trying to answer the question "fundamentally what is balancing and what does it accomplish" before things slowly started to click a little more.

Yes I fully understand parallel balancing actually. About one of the few things I do understand here LOL.
Okay, I just want to reinforce, that this:
Yes, paralleling batteries to balance them is an option. However that can take days, weeks or even a month or two if they are very off balanced.
(Which I take to mean leaving the cells sitting in parallel until they are balanced) is not what is generally being referred to when people talk about an initial top balance which involves a power supply and charge being applied, and is the quickest method I am aware of, still may take days with large banks and a low current power supply.

But Citibank screwed up the deal and even charged me for the privilege.
Sounds like the exemplary level of customer service that can be expected from big banks :) its heartwarming how they always put the customer first! ;)
 
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Do you have an android or Iphone? The reason I ask is the apps are different. I found it necessary to calibrate the charge and load current on mine to make the SOC work right.
 
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