How to Parallel Balancing. (YEP 99% of us is doing it wrong)(PART#1)

[electric]

and there are some excellent OEM companies like DELIGREEN that not only manufacturer but also sell ...

I don't know for sure, but I doubt it very much. OEM cell makers don't have resources to sell retail, it's not their core business.
I just looked at Deligreen Web site and I see a mix of CALB, Winston and "blue" cells. A real cell OEM would never sell someone else's cells, that would be ridiculous. This makes me believe it's a VAR, not OEM. To be clear when I refer to OEM/VAR I only mean cell manufacturing, as anyone can make batteries, but only a few companies are crazy enough to make cells.
"blue" cells are another story, they came to market recently and completely took over, but from what I can tell there are maybe 1-2 real quality OEMs and the rest are either VARs or crappy copycats. I can't speak much due to my NDAs from work.

 

[FilterGuy]

I agree with all the above -- The only correction I would say is that Battleborn does NOT make a solid battery product -- THEY package a solid battery product. Like everyone else - they do not make anything here -- their cells and BMS comes from China - they just package it in the states and slap a sticker on it ...

and there are some excellent OEM companies like DELIGREEN that not only manufacturer but also sell ...

Does Deligreen make cells? On their web site I see CALB and Winston. Are these Delegreen sub-brands?

You are correct that battle born (and many of their competitors) do not manufacture the cells.

This is what they DO do:
1) Source the parts from reliable manufacturers (They have the resources to research and test that a DIYr does not have)
2) The engineering to match up all the components. (Us DIYrs do that too, but we don't have the influence to get customized components)
3) Package it into a complete product.
4) Put a warranty on the product
5) Offer customer service for both pre-sale and post-sale issues
6) Charge for all of the above.

For a lot of people that arn't able or interested in digging in, this is great. For others, the premium for their service is too high and that is fine too.

 

[ghostwriter66]

Double posted ..

 

[ghostwriter66]

Does Deligreen make cells? On their web site I see CALB and Winston. Are these Delegreen sub-brands?

You are correct that battle born (and many of their competitors) do not manufacture the cells.

This is what they DO do:
1) Source the parts from reliable manufacturers (They have the resources to research and test that a DIYr does not have)
2) The engineering to match up all the components. (Us DIYrs do that too, but we don't have the influence to get customized components)
3) Package it into a complete product.
4) Put a warranty on the product
5) Offer customer service for both pre-sale and post-sale issues
6) Charge for all of the above.

For a lot of people that arn't able or interested in digging in, this is great. For others, the premium for their service is too high and that is fine too.

YES Deligreen does make batteries .. they have a large R&D, warehousing, and manufacturing facility outside of Hunan China. Not sure why they have other products from other vendors also on their webpage - perhaps they are sister companies -- but ALL we purchase from them are the BLUE ALUMINUM batteries and then we ourselves package them for our internal needs ...

Look - to be clear - I have nothing against Battleborn -- and for the last several years everywhere I looked there were Battleborn batteries -- but now with tarriffs at rock bottom and shipping cheaper and a MASS amount of Chinese companies now offering the same grade of battery and BMS as one could get with Battleborn - its OK for people to decide that they want to get twice the battery for half the price if they do it themselves. The Battleborn discussion has turned into a FORD vs CHEVY, COKE vs PEPSI .. You have to get the one that best for you ...

 

[electric]

YES Deligreen does make batteries .. they have a large R&D, warehousing, and manufacturing facility outside of Hunan China. Not sure why they have other products from other vendors also on their webpage - perhaps they are sister companies -- but ALL we purchase from them are the BLUE ALUMINUM batteries and then we ourselves package them for our internal needs ...

Look - to be clear - I have nothing against Battleborn -- and for the last several years everywhere I looked there were Battleborn batteries -- but now with tarriffs at rock bottom and shipping cheaper and a MASS amount of Chinese companies now offering the same grade of battery and BMS as one could get with Battleborn - its OK for people to decide that they want to get twice the battery for half the price if they do it themselves. The Battleborn discussion has turned into a FORD vs CHEVY, COKE vs PEPSI .. You have to get the one that best for you ...

You interchange the terms cells and batteries, but the difference is the key to this subject, which makes it difficult to talk about it if people don't use correct terms.

I am now 99% certain Deligreen does not make cells. They sell cells of different OEMs and make their own batteries. You buy cells from them, but they are not made by them. As far as cells go, Deligreen is a VAR, probably a good one as you can vouch for them. Their site claims a warehouse in Europe, so I wonder if US is or isn't an important market for them.

There are many important differences between Battleborn batteries and other re-branded Chinese batteries. BMS quality is one of several factors. Other factors are where employees are located and how much they are paid for their skills, how strong US based customer service is, who is financing the business and how much profit the owners are demanding. All the items @FilterGuy listed cost money, and they cost more if business is heavier on US side than on China side, especially engineering and support.

I work for a company that does everything @FilterGuy listed in the US, only cells come from China, from the best source we can find and we always look for the best ones. This also costs money. This makes our product expensive, but we have a wait-list of customers who are willing to pay a premium for highest quality product.

On the other side you have importers where 100% of product is done in China and only a couple of guys are in US selling them. Support is limited, engineering is non-existent, but profit is high because sales guys are full of BS and business is financed by a bank or a loan shark. All these 10 years warranties are pure BS, but people believe them.
Battleborn is somewhere in the middle of this equation, that's why they are popular, but competition is coming and the market will be red hot soon enough.

As for DIY forum like this one, of course many people would make their own batteries, they just need a source of good cells and a decent BMS.

 

[SolarRat]

I love this forum. It's like hanging out with Robert Heinlein in a disco bar.

I'm not sure if that's a good thing or a bad thing...

"he was among the first to emphasize scientific accuracy in his fiction, and was thus a pioneer of the subgenre of hard science fiction. "

 

[SolarRat]

To make all this even more confusing, for my usage of small Li-ions I find bottom balancing makes much more sense. They get drained all the way down most times, and I only charge to about 90-95% (~4.1v). I parallel the cells and then put a very slow draw on them until they settle at about 3.2v. I don't put a BMS on those packs, but use balance cables for monitoring (and sometimes use a balance charger).

My theory is I don't care if the charge terminates with the cells ranging between 4.05 and 4.15v, because there's not much capacity up there, and after the first few seconds or minutes of draw they all drop to nearer equal. What I do care about is the bottom end. I use a cell monitor to trigger an alarm when any one cell reaches 3.2v, which gives me enough time to get home or land (electric bikes, scooters, skateboards, R/C airplanes). If I top balance, i usually have one or two cells that hit 3.2 long before the rest, but with bottom balancing they are all near equal.

I think many people with smaller insufficiently sized batteries, who often hear the inverter low voltage alarm, would be better off bottom balancing and don't even realize it. Because the inverter senses voltage of the whole battery and not on a cell level, one cell might be very very low (but still above the BMS's trigger point) before the alarm goes off.

 

[ghostwriter66]

To make all this even more confusing, for my usage of small Li-ions I find bottom balancing makes much more sense. They get drained all the way down most times, and I only charge to about 90-95% (~4.1v). I parallel the cells and then put a very slow draw on them until they settle at about 3.2v. I don't put a BMS on those packs, but use balance cables for monitoring (and sometimes use a balance charger).

My theory is I don't care if the charge terminates with the cells ranging between 4.05 and 4.15v, because there's not much capacity up there, and after the first few seconds or minutes of draw they all drop to nearer equal. What I do care about is the bottom end. I use a cell monitor to trigger an alarm when any one cell reaches 3.2v, which gives me enough time to get home or land (electric bikes, scooters, skateboards, R/C airplanes). If I top balance, i usually have one or two cells that hit 3.2 long before the rest, but with bottom balancing they are all near equal.

I think many people with smaller insufficiently sized batteries, who often hear the inverter low voltage alarm, would be better off bottom balancing and don't even realize it. Because the inverter senses voltage of the whole battery and not on a cell level, one cell might be very very low (but still above the BMS's trigger point) before the alarm goes off.

100% agree. So we divide our systems here into two groups - CRITICAL and STORAGE.

We BOTTOM balance our CRITICAL systems. Those include our huge electric pump motors that have huge (4) 4000aH 48V batteries to kick in if the AC goes off ... any battery that starts a generator, all of our electric carts, all of our communication gear, any electric boat thrusters, all of our safety gear, all of our UPS batteries, all of our onboard radar and radio equipment. Because like you said - IF we have to use any of these - then getting every drop of energy out of these is critical.

We TOP balance all of our STORAGE batteries -- these are the ones that's on our work trailers, RV's, Powerwalls, portable charging stations, and any battery that we are going to store and let stand for an extended amount of time. These are typically used daily and 99% of the time are never ran down to 0% but are 100% of the time brought up to 100% SOC typically daily ((So what I call our 100% SOC is really about 90% of what the manufacturer states - but its 100% for us and our monitors))

 

[Solarfun4jim]

100% agree. So we divide our systems here into two groups - CRITICAL and STORAGE.

We BOTTOM balance our CRITICAL systems. Those include our huge electric pump motors that have huge (4) 4000aH 48V batteries to kick in if the AC goes off ... any battery that starts a generator, all of our electric carts, all of our communication gear, any electric boat thrusters, all of our safety gear, all of our UPS batteries, all of our onboard radar and radio equipment. Because like you said - IF we have to use any of these - then getting every drop of energy out of these is critical.

We TOP balance all of our STORAGE batteries -- these are the ones that's on our work trailers, RV's, Powerwalls, portable charging stations, and any battery that we are going to store and let stand for an extended amount of time. These are typically used daily and 99% of the time are never ran down to 0% but are 100% of the time brought up to 100% SOC typically daily ((So what I call our 100% SOC is really about 90% of what the manufacturer states - but its 100% for us and our monitors))

I especially like the thinking on this, in relation to RV's where having a few days autonomous capacity, means that the bank might rarely be drained below say 65% soc and then 'topped up'. It is more likely to be parked up in the Sun topping batteries towards full while the occupants enjoy outdoor activities and few loads running for a large part of the time. This would dictate that the majority of the working operations/cycles would be done in the upper quadrant of the available capacity range.

 

[murphylawe]

I am going to have mental indigestion for a week after reading this thread...

 

[Steve_S]

What if you have a BMS which is capable of balancing cells During Charging / Discharging and while in Storage (no amps being drawn) States ?

Example BMS is the Chargery which does so if enabled. It isn't a big active balancer, being only 1.2A but seemingly capable for most use cases I would think. Seems to me, if you need more powerful balancing than that, there are likely some issues with the cells.

Interesting how no one person commented on this. WHAT IF you have a BMS which can balance while "Charging / Discharging or at Rest (storage)".
Enable them all or only during charge or discharge what effect would that have.

 

[John Frum]

Thanks,
Great post. I can see where active charging them while hooked up in parallel would get them balanced much quicker. If they are 'just' hooked together, as they get closer to the same voltage the current will asymptotically approach zero....and therefore they would only asymptotically approach balanced.

Question: If we get them close, hook them in parallel and then start using them, won't it achieve the same thing as they are charged and discharged?

I wonder why nobody addressed this.

 

[SolarRat]

I wonder why nobody addressed this.

Because not many people put a 3.6v battery to "use".

 

[FilterGuy]

I wonder why nobody addressed this.

Actually, after I posted I realized it was a dumb question. Hooking in parallel is only for balancing. You would not be using them hooked up that way.

 

[John Frum]

Actually, after I posted I realized it was a dumb question. Hooking in parallel is only for balancing. You would not be using them hooked up that way.

But even the flow between paralleled cells is asymptotic.

 

[cass3825]

Interesting how no one person commented on this. WHAT IF you have a BMS which can balance while "Charging / Discharging or at Rest (storage)".
Enable them all or only during charge or discharge what effect would that have.

I have all three balance modes enabled, trying to give the Chargery BMS a fighting chance to keep my pack balanced. Pretty sure I have a weak cell but have yet to locate it. Just ordered/received a 5A active balancer to be wired in parallel with the Chargery, so will likely disable some or all passive modes.

 

[electric]

Interesting how no one person commented on this. WHAT IF you have a BMS which can balance while "Charging / Discharging or at Rest (storage)".
Enable them all or only during charge or discharge what effect would that have.

Can't speak for everyone, but I personally don't comment on "WHAT IF" posts describing something that is not a real thing or something that never happens in practical applications. Life is too short to engage in useless pondering.
Yea, I know you can come back with "but what about this BMS that exists and claims to do stuff".
It took me a few years to learn that none of these claims are real, so I'm not wasting my time trying to prove anything to anyone who is not ready to understand it. It takes time for these things to really sink in and you gotta build a few batteries before you really see it.

 

[ghostwriter66]

But I personally don't comment on "WHAT IF" posts

Yet you just did ... LOL

 

[electric]

one cell might be very very low (but still above the BMS's trigger point)

how is it very very low, but still above BMS trigger point? Isn't this a contradiction?

 

[ghostwriter66]

Interesting how no one person commented on this. WHAT IF you have a BMS which can balance while "Charging / Discharging or at Rest (storage)".
Enable them all or only during charge or discharge what effect would that have.

So for work -- BMS's are used 99.99% of the time to do nothing but to provide Low Voltage Cutoff - High Voltage Cut off - and Temperature (Hi/Lo) protection .. cell balancing is done once when the battery comes into the shop and literally never touched again ... and actually the only reason we do cell balancing is to determine from the onset if we have a bad battery at all ...

BUT with that said - I still like to play around with the BMS's and get everything out of them I can -- we had one battery system that kept getting a little out of whack and it had an active BMS on it .. I kept thinking that i was missing something -- it was charging and discharging fine --and we had the BMS set to read full at 90% of SOC .. BUT cell#2 just never seemed to balance .... Finally I thought the BMS was just bad so I contacted the manufacture and told him the issue and to see if he would swap it out -- he asked me what was my HVC set to and i told him -- and he said we were missing the active balance kicking in by something like 0.09V .. So I raised the SOC to 95% for that one particular BMS and battery -- and BAM - BMS Leveling kicked in - and to this day all 4 cells are fine ...

But with that said - that is exactly why we are playing with the Chargery 16T right now -- it seems to be able to accept any specs or parameters you give it ... we will see ..would be interesting to see Will test one ... but so far - I'm pretty impressed ...