Another Top Balance Screwup

sshibly

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Dec 8, 2020
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Top balancing with these Pico Amp modules is like watching paint dry. If my cells are that outta whack, I would connect an external charger and soup em up.

But if the keep going out of balance, What could be the root cause other than different absolute cell capacity?
 

DerpsyDoodler

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Top balancing with these Pico Amp modules is like watching paint dry. If my cells are that outta whack, I would connect an external charger and soup em up.

But if the keep going out of balance, What could be the root cause other than different absolute cell capacity?
are the terminals clean? Are the bus bars the same size/length? If top balanced then even with differing capacity they should stay top balanced. That is the whole purpose.
 

ArthurEld

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Top balancing with these Pico Amp modules is like watching paint dry. If my cells are that outta whack, I would connect an external charger and soup em up.

But if the keep going out of balance, What could be the root cause other than different absolute cell capacity?
What is your upper charge limit? They aren't going to stay balanced above 3.4V
 

cinergi

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That’s how chargery started out, as well. I don’t understand all the hate directed toward the chargery BMS on this forum, especially when its mfg/seller has been so willing to interact with the people here (though due to the experience I think he is less inclined to do this much anymore). I mean...configuration of the EPEVER MPPT SCC is no less complex than I imagine the chargery to be, yet the epever SCC gets raving reviews and the chargery gets dumped on.

What is the deal?

Sorry if this is off-topic, but I’m strongly considering the chargery, and if no one can tell me why (with supporting evidence and not just subjective opinion and conjecture) it’s a bad option, then what the hell?

After reviewing many threads in this forum related to the chargery, it’s like people want to dump on the guy and his product when he’s been extremely willing to work on and resolve problems/complaints (which he has succeeded in doing, as far as I can tell). It’s like a gang that wants to keep the chargery squeezed out of main stream. Based on what I’ve read, the chargery BMS seems to get unreasonable hate and discord. There were problems early, but they seem to be resolved. I know others who are successfully using the BMS and have no complaints. For the price and capabilities, it seems like a slam dunk home run touchdown with a 2 point conversion in overtime after tying the game with 2 free throws and a grand slam.

So....what the fork?

For me, this is why:
The only problem that is (in theory) resolved is the rapidly changing voltage and current values.
I've brought these problems up (including in PMs) and Jason ignored me. I had invested in TWO Chargery & DCC and ditched them.
It's completely crazy that I purchased 2 at the same time and have one BMS that's off by ~30mv and another by ~90mv (even when externally powered) and the only solution is to pay so much money in shipping to have it factory calibrated that it's cheaper to buy a new one. Why aren't they factory calibrated in the first place?!?! Give me a break. My Orion is dead-on accurate with my DMM. Not to mention all the DCC BS. Ugh, I'm fired up just writing about it again.

When the BMS is off by that much, it makes proper top balancing impossible (circling back to the topic thread lol)
 

sshibly

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What is your upper charge limit? They aren't going to stay balanced above 3.4V
No limited yet but tested at different charge level, 14v would be my pick.

Can you pls explain why above 3.4 the cells will not stay balanced.
 

Will Prowse

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For me, this is why:
The only problem that is (in theory) resolved is the rapidly changing voltage and current values.
I've brought these problems up (including in PMs) and Jason ignored me. I had invested in TWO Chargery & DCC and ditched them.
It's completely crazy that I purchased 2 at the same time and have one BMS that's off by ~30mv and another by ~90mv (even when externally powered) and the only solution is to pay so much money in shipping to have it factory calibrated that it's cheaper to buy a new one. Why aren't they factory calibrated in the first place?!?! Give me a break. My Orion is dead-on accurate with my DMM. Not to mention all the DCC BS. Ugh, I'm fired up just writing about it again.

When the BMS is off by that much, it makes proper top balancing impossible (circling back to the topic thread lol)
Man that is awful. I have never been a fan of the chargery, and a lot of forum members were mad at me about having that position. I do not understand why so many people support that BMS.

The DCC seems completely defective. I hope your victron caps are ok. What a bummer.

The voltage inaccuracy of the chargery seems awful. And those connections and bolt size on the contactor are horrible! They are way too close, and good points about the fets supporting those bars. Awful design.

Many forum members seem to love high current balancing BMS, which the chargery is. I think it is pointless, and the balance current of the Orion is sufficient for even the largest packs around. People get mad at me for saying that and argue that they are using mismatched cells, but I am not sold on their arguments at all. We would need long term data to see if there is any real benefit. I would just set the absorption to 90% and leave them out of balance if one of the cells is constantly spiking in voltage. Or throw the cells in the trash haha!

Anyways, it is good to know your experience with chargery. I would be just as pissed as you are. I never liked that BMS.
 

Will Prowse

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Toward the end of my original chargery video, I listed off multiple problems. First problems start with the current calibration at 9:44. That thing pissed me off:
 

ArthurEld

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No limited yet but tested at different charge level, 14v would be my pick.

Can you pls explain why above 3.4 the cells will not stay balanced.
3.4V is where the upper knee starts. So you can't expect to charge higher than that.
Since you have 4 cells, 3.4 X 4 = 13.6V

See if you still have the problem if you change your charge limit to 13.6V

If that doesn't work then you probably have a bad connection like DerpsyDoodler said.
 

Bob B

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@DerpsyDoodler .... The software updates Chargery introduced were very effective on all but the BMS16T which even after the updates and using external power has some cell voltage inaccuracies.
I have a BMS8T that I am very happy with after the updates .... For what I want to do, the BMS8T perfectly fits. I'm not switching the battery power as most people are, I'm remotely controlling the charge and load devices with low power relays and SSR's. I am going to have redundancy in all the protections, but just think it is better to control devices in such a way that only a low current device is required for the switching.
So .... I don't have any experience with the DCC's .... some are having good success with them and some not. The issues people are having with them are with the built in pre-charge ..... other than that I haven't heard anything but good reports on them .... it would be possible to use a separate pre-charge strategy like one would use if they just had a high powered SSR to mitigate that issue.

They are supposed to be introducing their new line pretty soon and it will be interesting to see what they come out with. They seem to be taking more time testing this new one than they did with the DCC when they introduced it.

I have the JBD Overkill solar BMS in my 100 AH pack that is only going to be used for providing power to my boat electronics at a low current draw .... but when you get into applications that require control of higher power loads, it just seems counter intuitive to me to be switching that power with a BMS when it isn't necessary. People are using larger and larger SSR type BMS and I just don't see the necessity for it in most cases. Some have multiple packs in parallel and design in that situation becomes a little more complex .... but I'm not dealing with that situation.
 

DerpsyDoodler

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@DerpsyDoodler .... The software updates Chargery introduced were very effective on all but the BMS16T which even after the updates and using external power has some cell voltage inaccuracies.
I have a BMS8T that I am very happy with after the updates .... For what I want to do, the BMS8T perfectly fits. I'm not switching the battery power as most people are, I'm remotely controlling the charge and load devices with low power relays and SSR's. I am going to have redundancy in all the protections, but just think it is better to control devices in such a way that only a low current device is required for the switching.
So .... I don't have any experience with the DCC's .... some are having good success with them and some not. The issues people are having with them are with the built in pre-charge ..... other than that I haven't heard anything but good reports on them .... it would be possible to use a separate pre-charge strategy like one would use if they just had a high powered SSR to mitigate that issue.

They are supposed to be introducing their new line pretty soon and it will be interesting to see what they come out with. They seem to be taking more time testing this new one than they did with the DCC when they introduced it.

I have the JBD Overkill solar BMS in my 100 AH pack that is only going to be used for providing power to my boat electronics at a low current draw .... but when you get into applications that require control of higher power loads, it just seems counter intuitive to me to be switching that power with a BMS when it isn't necessary. People are using larger and larger SSR type BMS and I just don't see the necessity for it in most cases. Some have multiple packs in parallel and design in that situation becomes a little more complex .... but I'm not dealing with that situation.
I appreciate your input but I’m not going to flip flop on this. What makes it a further issue for me is shipping from China and that since Jason prefers direct orders through the chargery site, now, trade assurance is kind of up in smoke. It may work well, but what I was going to order (with the DCc) I think would have been a disappointment and a hazard. Combine it all and it didn’t amount to the same worthwhile risk as ordering batteries from forum-reviewed suppliers off alibaba.
 

D. Abineri

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On this topic, When top balancing is it OK to use the charger in an 'all-in-one' inverter with a bms to charge the battery the first time?
 
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On this topic, When top balancing is it OK to use the charger in an 'all-in-one' inverter with a bms to charge the battery the first time?
Yes and no.
The all-in-one charger will charge at "battery" voltage.
So you can do the first part of the top balance at "battery" voltage but you need to top off the individual cells at "cell" voltage.
This link will explain https://diysolarforum.com/resources...ls-using-a-low-cost-benchtop-power-supply.65/
If you have any questions after you read that doco I'm glad to answer.
 
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