Chargery BMS News / Update (July-27-2020)

[Bob B]

In a strictly solar charge installation, I can see where the BMS should only be the 2nd safety for the batteries .... but shore power charge solutions for RV lithium installations are mostly just power supplies. I have yet to find one that is configurable in a way that makes sense .... so, I plan to use my BMS to turn the shore power charger on and off.
I haven't done enough research yet to know if the same holds true for the DC-DC chargers used to charge from the vehicle, but I suspect the same is true there.

I am open to other options.

 

[Cal]

Getting back to Chargery...

I like the BMS, but it has several deficiencies. The statement in their manual that their BMS must not be used as a primary disconnect gives me heartburn. Is Chargery saying they have no confidence in their design or components they use? Will it fail at any time and leave you high and dry?

One of their competitors, ElectroDacus appears to have no problems saying they are the primary disconnect.

I would like to get that verbiage out of the manual.

 

[Bob B]

Getting back to Chargery...

I like the BMS, but it has several deficiencies. The statement in their manual that their BMS must not be used as a primary disconnect gives me heartburn. Is Chargery saying they have no confidence in their design or components they use? Will it fail at any time and leave you high and dry?

One of their competitors, ElectroDacus appears to have no problems saying they are the primary disconnect.

I would like to get that verbiage out of the manual.

Strictly a guess ... but I suspect @Steve_S inserted that language. Maybe he will check in an let us know if that is the case or not. It is also possible that it is also a legal CYA which isn't a very comforting thought.

Chargery does have the ability to control a 120V Charger via communications ... and I saw some verbage in the manual for it that was something like .... This power supply should be under observation the entire time it is used and should not be used unattended .... that's not an exact quote, but is kinda what I took away from it. That didn't leave me with a warm fuzzy feeling.

Chargery is also now making a dual input power supply that has the BMS built into it .... That's a real interesting device that I gotta research further.

So far I am liking my Chargery and the protection disconnects have tested just fine.

 

[Steve_S]

Getting back to Chargery...

I like the BMS, but it has several deficiencies. The statement in their manual that their BMS must not be used as a primary disconnect gives me heartburn. Is Chargery saying they have no confidence in their design or components they use? Will it fail at any time and leave you high and dry?

One of their competitors, ElectroDacus appears to have no problems saying they are the primary disconnect.

I would like to get that verbiage out of the manual.

OK, please point out the page & direct quote of that. Also which version of Manual you are looking at.

The manual more or less says that the BMS is the Guard on Duty and that the Solar Charge Controller and/or Inverter/Charger should control when disconnects occur and not the BMS as the BMS is the Failsafe - last stop to safety. The BMS monitors & manages the cells within and protects the pack which is it's specific job. There are different types of BMS as you point out with Electro-Dacus but then look at TinyBMS or 123SmartBMS and they do things differently as well with different capabilities.

 

[Cal]

“the BMS is the Failsafe - last stop to safety” is BS.

The BMS is the the only stop to safety. The charge controller has no idea what’s going on with individual cells. The CC provides no guaranteed safety.

In addition, it’s a poor choice to set the max charging voltage below the BMS over voltage set point. The charging source turns into a trickle charger as battery voltage approaches the charging voltage setting. It can take hours and hours for the battery to complete its charge. This is not the case when the charging voltage setting is greater than BMS OV disconnect. In my case BMS OV is at 3.48 Vpc and charging source at 14.4V (3.60Vpc).

 

[apctjb]

Who do you want to have control? Someone who’s clueless or someone who has all the facts

Lets not talk politics....

 

[Cal]

Lets not talk politics....

I had a feeling that would come up. Let’s make the right choice!

 

[Steve_S]

NEW Manuals posted See this thread:

Chargery BMS now with Low Temp Cutoff

Why is there Wh and Ah input on the latest firmware update? Cannot one be calculated from the other? I think the user instructions should spell out clearly each configuration parameters' function. Am I the only who feels this is missing from the user manual? Or perhaps this is included in...

diysolarforum.com

 

[apctjb]

NEW Manuals posted See this thread:

Good work!!!

 

[Seawalker]

I have just ordered one of these for my 16s Lifepo4 bank that will be connected to a AC coupled inverter for battery storage. a) i wasnt aware that it didn't come with the relay despite choosing the 300amp option on checkout, I presume now this is for the shunt value. b) how can this be used with a single relay to manage charge and discharge, is that even possible seeing as my Ac coupled inverter only has one terminal for battery without a separate charge port.

The models 100, 300, 600 have specific firmware in each. The setting for max over discharge is 100, 300, 600 based on your specific model. I made a costly mistake by not checking this attribute.

 

[Cal]

@Chargery I find the paragraph “Don’t make the BMS do the work it shouldn’t do” quite disturbing. If you believe your BMS is not up to the task of controlling primary disconnects then I can no longer support Chargery as a good product. Why do you say the BMS may fail?

 

[Steve_S]

Nowhere in the manual does it say it "may fail". Those are Your Words.

Don't make the BMS do the work it shouldn't do.
The BMS of course will cut off for High / Low Volt etc but this is not it's job, those are "safety" features to protect you batteries and are more or less the "fail safe mechanism", as such they should not be doing that work as a matter of normal operations. This is really the task of the Solar Charge Controller and Inverter/Charger to manage on an ongoing basis. Continually using the BMS to do this function can actually affect the BMS negatively and may even result in damage, it is not what they are designed to do.

A Charge Controller (Solar or Otherwise) should be capable of regulating & cutting off charge when the battery system is full and that should be determined by the programming within and the reading it senses on the wires. Just like an Inverter should read Low Voltage and cutoff BEFORE the BMS forces it to protect the batteries. SOME BMS' will trip and cutoff, then require a manual reset to allow charging again... SCC's & Inverter/Chargers look at the DC Voltage at the terminals to determine the state of the battery bank as a whole, they do not peak into the cells... They don't to it with Lead Acid do they.

The Chargery is NOT a BMS that interacts directly with an Inverter or Solar Controller directly to control ON/OFF. If you want that, then look at purely Victron with Victron Batteries and more but you might not like that either.

Sorry, but your aim here is what ?

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[Cal]

Nowhere in the manual does it say it "may fail". Those are Your Words.
Sorry, but your aim here is what ?

“....affects the BMS negatively and may result in damage” can be interpreted as failing.

My aim here? I thought I was quite clear: have @Chargery explain their position.

Will any damage occur if BMS is used as primary disconnect?

Why is it not the job of the BMS to detect harmful conditions to the battery AND provide signals that will rectify this condition?

Steve doesn’t believe your BMS is capable of being the primary disconnect. Is he correct?

Edit

Can you be more exact, what work shouldn’t the BMS do?

 

[BiduleOhm]

Took my votes back as I don't want be part of the argument.

But still want an answer from Chargery about if the reliability is affected by the BMS disconnecting more than a few times.

 

[KohalaJim]

Continually using the BMS to do this function can actually affect the BMS negatively and may even result in damage, it is not what they are designed to do.

Since the questions from @Cal are now asked in Chargery specific context, they're worthy of discussion here.

To @Steve_S, the cited verbiage above ventures into the subjective design attributes of BMS's in general, and the word "they" is what I'd push back on... if you're word-smithing this content, I'd suggest making that read "Chargery BMS" specific vs. BMS's in general. That discussion should be in another thread...

 

[Bob B]

I think that @Steve_S ... and the manual are generally following Will's recommendations for the function of a BMS.

I, however, respectfully disagree that in all cases, the primary arbitrator should be the charger or inverter. In the case of RV shore power charger, I haven't been able to find a single on that I am happy with the way it's internal algorithms control charging. Victron has some inverter / Chargers that will accomplish this, but they are out of my price range and will not fit where I want to install my equipment.

I am using a less expensive inverter .... but it has a power switch that I can put a relay in series with to shut it off. I want to trust the Chargery BMS to shut down the inverter and other low current DC loads in my RV .... I can choose exactly where the cutoff point will be. Will actually made a video using one of the SSR BMS's to do this.

I have begun to systematically test the Chargery to control these things and so far it is working as expected. The "best practice" philosophy that is generally recommended just doesn't fit my situation.

As a side note ... Chargery does have a power supply that can communicate and be controlled by the Chargery BMS. I have looked at that power supply as a possible alternative for my RV power, but can't really find anyone else who is using it.
Chargery also makes an "all-in-One" dual input power supply that has the BMS built into it. That device looks very interesting as a possibility for an RV shore power charger and DC-DC converter combined. I am assuming that the BMS functions built into that charger are the same as the stand-alone BMS but just built into the package.

 

[Steve_S]

The Chargery could be used to send the disconnect relay signal to an Inverter, depending on inverter this can be done in different ways. My own Samlex EVO has the capability built-in, others may need to have a relay used to switch the inverter on/off, Will has a video doing that, using a different BMS. Will doing so harm the BMS ? no, why would / should it ?

What if you have multiple Chargery BMS in a bank and one Inverter to control ?
You could use a 4 Channel OptoCoupler to receive the relay signals and then act to switch the inverter off by relay, or input depending.

The only limitation is the BMS cannot output more than 12V/3A total for the relay signals.

 

[Cal]

Why use scare tactics to steer users to a method which is in of itself wrong.

The inverter or charger can’t make any intelligent decisions what’s going on with individual cell. Only the BMS has that information. Is that so hard to understand?

 

[Bob B]

The Chargery could be used to send the disconnect relay signal to an Inverter, depending on inverter this can be done in different ways. My own Samlex EVO has the capability built-in, others may need to have a relay used to switch the inverter on/off, Will has a video doing that, using a different BMS. Will doing so harm the BMS ? no, why would / should it ?

What if you have multiple Chargery BMS in a bank and one Inverter to control ?
You could use a 4 Channel OptoCoupler to receive the relay signals and then act to switch the inverter off by relay, or input depending.

The only limitation is the BMS cannot output more than 12V/3A total for the relay signals.

@Steve_S The Samlex was one I looked at seriously .... but found that the remote control of it was to be able to disable charge OR inverter. The input could not do both independently.
Have you found a way to independently control the charger and inverter in the EVO?

 

[Bob B]

Why use scare tactics to steer users to a method which is in of itself wrong.

The inverter or charger can’t make any intelligent decisions what’s going on with individual cell. Only the BMS has that information. Is that so hard to understand?

Exactly .... every other device controls things at the pack level while the BMS protects the cells individually. The BMS is in a better position to be the primary control with the inverter and charger shutdowns being secondary.