Another Top Balance Screwup

toms

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Exactly, so the folks who are quoting their experience with expensive factory direct cells, or with batched/matched cells as typicaly, are either being intentionally obtuse, or just downright malicious.

There is more than one way to top balance, and for those skilled/experienced its a non issue. These other methods are good, but they probably require an extensive writeup for the masses.

Curious comment. I have been helping people install off-grid DIY Lifepo4 packs for a decade now, and haven’t come across any problems with individually charging cells before assembling, or using power resistors to drain high cells when a pack is series assembled for the first time.

The last few packs i have assembled from used mismatched cells i have used an active balancer in combination with a BMS until the cells are matched.

You say these methods require extensive write up or training, yet the so called simple method of connecting your entire pack in parallel with no failsafe in the event of a charger malfunction is apparently fine?

Look at where all the problems are occurring before you decide which advice is malicious.
 

ArthurEld

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Look at where all the problems are occurring before you decide which advice is malicious.
I agree. It seems to me that the number of cells destroyed by people making mistakes parallel top balancing is high. The amount of effort to parallel top balance is high. Parallel top balancing is also expensive because it requires extra equipment that isn't used later.

By the way, Nordkyn, MarineHowTo and Overkill say top balancing is important but they don't say parallel top balancing is important.
Balancing with an active balancer is cheaper than parallel top balancing and takes much less effort. It is safer because the BMS will stop the charging if any cell goes above the voltage limit.

I realize people spent a lot of time developing parallel top balancing methods and they work well. But active balancing gets the job done easier, cheaper and safer. And the active balancer continues to be a useful tool unlike some of the parallel top balancing equipment.

Progress is happening. I choose to move with it.
 
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Just John

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I agree. It seems to me that the number of cells destroyed by people making mistakes parallel top balancing is high. The amount of effort to parallel top balance is high. Parallel top balancing is also expensive because it requires extra equipment that isn't used later.

By the way, Nordkyn, MarineHowTo and Overkill say top balancing is important but they don't say parallel top balancing is important.

I certainly agree that there are a lot of problems when people attempt to parallel top balance. I also agree that top balancing by individual cells can work just as well, but I have 3 Riden supplies to test that with. It does require equipment that you probably have no need for later. I haven't cycled enough yet to see how long the top balance will last. I also don't have an active balancer to test (yet)
 

cinergi

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Curious comment. I have been helping people install off-grid DIY Lifepo4 packs for a decade now, and haven’t come across any problems with individually charging cells before assembling, or using power resistors to drain high cells when a pack is series assembled for the first time.

The last few packs i have assembled from used mismatched cells i have used an active balancer in combination with a BMS until the cells are matched.

You say these methods require extensive write up or training, yet the so called simple method of connecting your entire pack in parallel with no failsafe in the event of a charger malfunction is apparently fine?

Look at where all the problems are occurring before you decide which advice is malicious.

You misunderstand. First, you wrote (bold mine):

I can’t comment for all manufacturers, but the ones i have spoken to don’t fully discharge as part of their process, they discharge to stated capacity and then apply storage charge. The cells are effectively top balanced as they leave the factory.

Luthj is saying that the cells are not arriving top balanced. I don't see him saying that parallel balancing is required (individual is fine), nor do I see him saying that resistors or balancers aren't a sufficient way to bring a pack into balance.

He also said that the extensive writeup is for the masses. You are not the masses -- you have a lot of experience. The newbies coming to the forum are the ones screwing up their cells.

All - no one said you must parallel top balance. The only statement being made here is that these are not balanced at the factory; you will have to perform balancing (whatever method) when you assemble the pack.
 

ArthurEld

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You misunderstand. First, you wrote (bold mine):



Luthj is saying that the cells are not arriving top balanced. I don't see him saying that parallel balancing is required (individual is fine), nor do I see him saying that resistors or balancers aren't a sufficient way to bring a pack into balance.

He also said that the extensive writeup is for the masses. You are not the masses -- you have a lot of experience. The newbies coming to the forum are the ones screwing up their cells.

All - no one said you must parallel top balance. The only statement being made here is that these are not balanced at the factory; you will have to perform balancing (whatever method) when you assemble the pack.
Somebody parallel top balanced
1616336035888.png
 

toms

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Now we are getting somewhere, all we need to do is address the issue of charging a cell without a cell level voltage monitoring capable of disconnecting the charger, and the issue of continuing to charge a full cell.

Then we will have progressed back to how cells were top balanced a decade ago :)

it’s disappointing to be accused of being malicious for recommending that cell level monitoring is used at all times, and that it is unwise to hold a charge on a full cell.

Yet that is exactly what has happened!

edit: where you quoted me was in response to a claim the cells leave the factory bottom balanced, if you took the time to read my full response i said this wasn’t true for at least two manufacturers (where the cells leave the factory top balanced) - but you need to check with your own manufacturer.
 
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Zwy

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I cannot add an overlay to the video any longer. That was an option a few years back, not anymore. I will add a note to the description. I could add a "card" but it would be hard to see.
You should attach the positive lead on one end of the pack and negative on the other end of the pack. That long of a pack and there has to be some resistance in the connections. :cool:
 

Lt.Dan

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You should attach the positive lead on one end of the pack and negative on the other end of the pack. That long of a pack and there has to be some resistance in the connections. :cool:
I think Will debunked that in another video. I remember him talking about it, but don't remember which video.
 

Fil-Am Gabe

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I had him pull the cells down to 3.6V right away.

They went pretty flat once put in a fixture. Still a noticeably bulged though.

View attachment 38876

I had him do a test discharge/charge cycle outside just in case. I will report back with the capacity test results. I am curious what kind of degradation the cells experienced. Anyone wanna take bets?

View attachment 38877

What kind of rig/case are you using for the battery?
 

hour

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What starting charge current are these power supplies (the ones with knobs and a screen) people commonly charge with putting out? I seem to recall reading plenty of posts stating 10 amps.

Seems safer (and more logical if you don't already own a power supply) to just buy a hobby balance charger. iCharger X6 with a dumb 24v power supply just completed a top balance on my second pack, both times nailing my target voltage and holding it until current dropped to what I specified. And I can do periodic balance charging on my packs, also up to 30 amps. Great for 4s packs, and the X8 can do 8s @ 40a.
 

DerpsyDoodler

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What starting charge current are these power supplies (the ones with knobs and a screen) people commonly charge with putting out? I seem to recall reading plenty of posts stating 10 amps.

Seems safer (and more logical if you don't already own a power supply) to just buy a hobby balance charger. iCharger X6 with a dumb 24v power supply just completed a top balance on my second pack, both times nailing my target voltage and holding it until current dropped to what I specified. And I can do periodic balance charging on my packs, also up to 30 amps. Great for 4s packs, and the X8 can do 8s @ 40a.
Got a link?
 

Luthj

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Now we are getting somewhere, all we need to do is address the issue of charging a cell without a cell level voltage monitoring capable of disconnecting the charger, and the issue of continuing to charge a full cell.

Then we will have progressed back to how cells were top balanced a decade ago :)

it’s disappointing to be accused of being malicious for recommending that cell level monitoring is used at all times, and that it is unwise to hold a charge on a full cell.

Yet that is exactly what has happened!

edit: where you quoted me was in response to a claim the cells leave the factory bottom balanced, if you took the time to read my full response i said this wasn’t true for at least two manufacturers (where the cells leave the factory top balanced) - but you need to check with your own manufacturer.

I suggest you stop strawmanning my arguments. I wasn't calling you out in particular either. At no point have I made this a measuring match about qualifications, but if you think thats a path to truth or fact... Well, you are wrong. The fact that you prefer to put words in my mouth says volumes as well. But go ahead, move the goal posts again...

I have at length, and numerous times, specifically stated my issues with your positions. The fact that you simply refuse to acknowledge the issues is not my concern. I could drop a dozen quotes from you to the effect that "top balance isn't necessary". Are you willing to retract those statements now? We are also still waiting with baited breath for your replies to our requests for source material.

As I have stated before, if you have the best method (as you have implied many times). Do a freaking detailed writeup. Preaching about the benefits of your approach, when it isn't even accessible to those having issues, is pure ego. If you want to drop into every thread and help the struggling newbs, do that. But posting just enough to assuage your ego does nothing to help these users. The amount of time you have spent telling us we are wrong for "reasons" could have created several excellent writeups.
 

ArthurEld

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People keep screwing up the parallel top balancing. Even with great instructions that have been developed for over 10 years.

The active balancer is pretty much fool proof as long as the BMS is set up right. I don't think anybody will balloon their cells using an active balancer to top balance. I'm not writing up anything but I will say it is easy to figure out. I didn't have instructions.
 

Just John

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What starting charge current are these power supplies (the ones with knobs and a screen) people commonly charge with putting out? I seem to recall reading plenty of posts stating 10 amps.

Seems safer (and more logical if you don't already own a power supply) to just buy a hobby balance charger. iCharger X6 with a dumb 24v power supply just completed a top balance on my second pack, both times nailing my target voltage and holding it until current dropped to what I specified. And I can do periodic balance charging on my packs, also up to 30 amps. Great for 4s packs, and the X8 can do 8s @ 40a.
So, people have problems putting cells in parallel and setting 3.65 volts and you think they won't have any problems with the icharger x6? I must be missing something.
 

Gazoo

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So, people have problems putting cells in parallel and setting 3.65 volts and you think they won't have any problems with the icharger x6? I must be missing something.
Or doing the rest of their build? I parallel top balanced mine and it was a great way for me to become familiar with the cells and my Riden power supply. Granted the Riden wasn't cheap but I have found other uses for it.
 

hour

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So, people have problems putting cells in parallel and setting 3.65 volts and you think they won't have any problems with the icharger x6? I must be missing something.
Well.. you can't adjust it during charging. And it audibly complains every step you go above 3.60v on the lifepo4 profile. Plus chimes and graphs and stuff 😁 It's not a bad thing to have around after top balancing either.

Got a link?
At timestamp, 4:40


and RC sites for purchase, lot of other videos about it too including that guy's channel. Pretty sure he's used it for initial charging of cells in parallel in a somewhat recent video too.
 

Just John

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People keep screwing up the parallel top balancing. Even with great instructions that have been developed for over 10 years.

The active balancer is pretty much fool proof as long as the BMS is set up right. I don't think anybody will balloon their cells using an active balancer to top balance. I'm not writing up anything but I will say it is easy to figure out. I didn't have instructions.

I think judging by the number of people having problems top balancing, and having problems with their BMS, a Battleborn or Lion might be a better choice.

But even though Costco still has the Lion batteries at 2 for $1300, they want to save money.
 

ArthurEld

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I parallel top balanced mine and it was a great way for me to become familiar with the cells and my Riden power supply. Granted the Riden wasn't cheap but I have found other uses for it.
I enjoyed learning about cells by individual charging and parallel top balancing. And I didn't balloon any cells.
I enjoy balancing cells connected serial using the active balancer too.
 

ArthurEld

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I think judging by the number of people having problems top balancing, and having problems with their BMS, a Battleborn or Lion might be a better choice.

But even though Costco still has the Lion batteries at 2 for $1300, they want to save money.
So that's it DIY stops here.
 

Just John

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So that's it DIY stops here.
Not for me, and I hope not for you.

Sometimes you just have to accept the fact that Murphy is an optimist.

I am just not seeing hooking up a programmable buck converter as being more foolproof.
 
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