Chargery BMS, DCC (Solid State Contactor) thread.

[Steve_S]

Separate Port is supposed to always have the "Charge Port" open unless it is cutoff by the BMS, so that's a simple one.
Seperate Port can also be configured to run from a Common DC-Bus (just clunky) because you have the extra +/- to deal with.

BMS disconnects while charging from an SCC, SCC should immediately jump to standby mode (almost all do, only cheapo's don't). The moment it can send power it will go into charge mode... This is "normal" for a quality SCC. The Solar Panels having to be disconnected from SCC is nonsense UNLESS dealing with cheapo value SCC's. (ie cheap no name brand Chinese / Taiwanese "value" models).

I will answer more "generically" with regards to Common-Port.
When a BMS cuts off for LVD, and it does not go into "Safe Mode" or turns itself off (some do) it should take a sense voltage state reading every few seconds to determine if there is charge voltage available and if so allow charge. With a Relay/Contactor type of system that means closing the relay every few seconds to test for voltage. The FET based BMS' have no relays, they will just open, sense, close if nothing.

This was discussed at Great Lengths previously and boy it even got "warmed up" a bit shall we say. I believe one of the threads even got deleted cause it got nutty.

The real GOTCHA, is there are no "standards" as such and so BMS' vary and there are so many variations and flavours to do all sorts of things. Even things like turning OFF a battery pack and it's BMS as well for a true 100% OFF is not that easy, you'd think it would be ! Almost like a Faceplalm Why the heck didn't you include an OFF Switch on the BMS. Other BMS' can run Heating & Cooling systems and thermal management of the cells and even more.

I hope this answers your Q but I don't think it's the answer you wanted, sorry about that.
To the best of my knowledge, the Chargery will sense the voltage and enable charge. I had two packs in a bank of 4 LVD out, when Genset power came on they took the charge without intervention. I run Common Port.

 

[DerpsyDoodler]

Jumping in "Deep End" with a DCC ????
300A DCC = 89.90 Kilovac/gigavac EVE type relay = 180+/- USD
And you only need one for Common Port.

I have 5 BMS8T's with DCC300's (First issue as well) and No Problems, Inverter has been shutdown, caps drained and started on LFP no issues and it has Monster Caps which really suck it in on startup.

Well you are one person I see raving positive reviews about the chargery product line. There are many more railing with negative reviews. I gave chargery the benefit of the doubt for a long time, but as i read more horror stories and talked to more people, i just cant call the DCC a wise decision. built-in precharge was a 1/2 baked after thought (as with several things). why do i need iso boards and external power boards? why arent they just built-in and included for an appropriate price? i just cant see spending the money on contactors that are iffy at best.

 

[Steve_S]

I worked through many of the issues, suffered glitches along the way, cooked two BMS' and fried a wire harness as well. The original docs made it MUCH worse so I tried to make that better for folks, while also working the problems. Jason did things quickly and sure problems popped up and he worked to fix those too... such is the result of Rapid Dev & deployment.

With all that said, they are not perfect but find me one that is. In the grand scheme, mine (2 versions) are working as expected. I had one BMS8T stressing me out and it turned out to be the QNBBM and my wiring wasn't "just so"... 3 months to figure that out. So technical that is a User Error and often, it is the user / builder making mistakes. I'm an Electronics IT guy, I respect static electricity and what it can do to fine electronics, one good zap and it's toast but how many people even think of it ? or they just toss the electronics around cavalierly onto the worktable etc... See folks doing it all the time on Youtube and I cringe every single time.

As you also know, Jason has been designing & testing a new series of BMS & more, not on "rapid dev" mode so as to not repeat these issues.
And yes I did recommend Chargery & Others but I very rarely do so anymore, I share "my experience" and usually also point out other alternatives. I got sick of being a target for nonsense I have no need of.

 

[Cheap 4-life]

Both of my relays are closed unless the bms stops sending power to them. I’m using all four of the wires from the chargery port so I assume each set of 2 wires is controlled independently. Isn’t it the opposite of what you explain? Isn’t it that charge and discharge is always closed unless the bms stops sending power to the charge or discharge which allows the respective one to open?

Don’t most charge controllers get their power to operate from the battery? When I shutoff battery power to the charge controller it shuts off completely, screen is blank, no standby mode. If I cutoff the solar (instead of the battery) then the controller will go into standby mode. I’m using an outback fm80 which wasn’t cheap. If the bms cuts off charging (in my case solar) then yes the charge controller goes into standby mode, but if I shutoff battery to the controller it just shuts off completely even if thousands of watts from solar was presently going through it.

Ok so your saying that if a chargery common port bms disconnects the battery due to LVD, the bms will search to see if charging/voltage is available by closing the relay? Then if there is charging available the bms will allow the relay to stay closed so charging can happen? The chargecontroller wouldn’t be in standby mode (it would be completely off) because the battery was disconnected from it. So the charge controller would have to turn back on, that takes time. Would the bms give the charge controller enough time to turn back on? the bms couldn’t detect voltage to allow relay to stay closed till after the chargecontroller turns on and starts letting voltage go through itself.

Like if right now I turn off the battery power (the charge controllers power supply) while it’s sending 4000w to the load or batteries, I’d assume that could damage a charge controller. Wouldn’t it be best to turn off the solar and then turn off the battery power supply to the chargecontroller so it’s not charging when it’s cutoff instantly?

I hope this doesn’t get “warmed up”. I really want to understand if I’m not

 

[Cheap 4-life]

Separate Port is supposed to always have the "Charge Port" open unless it is cutoff by the BMS, so that's a simple one.
Seperate Port can also be configured to run from a Common DC-Bus (just clunky) because you have the extra +/- to deal with.

BMS disconnects while charging from an SCC, SCC should immediately jump to standby mode (almost all do, only cheapo's don't). The moment it can send power it will go into charge mode... This is "normal" for a quality SCC. The Solar Panels having to be disconnected from SCC is nonsense UNLESS dealing with cheapo value SCC's. (ie cheap no name brand Chinese / Taiwanese "value" models).

I will answer more "generically" with regards to Common-Port.
When a BMS cuts off for LVD, and it does not go into "Safe Mode" or turns itself off (some do) it should take a sense voltage state reading every few seconds to determine if there is charge voltage available and if so allow charge. With a Relay/Contactor type of system that means closing the relay every few seconds to test for voltage. The FET based BMS' have no relays, they will just open, sense, close if nothing.

This was discussed at Great Lengths previously and boy it even got "warmed up" a bit shall we say. I believe one of the threads even got deleted cause it got nutty.

The real GOTCHA, is there are no "standards" as such and so BMS' vary and there are so many variations and flavours to do all sorts of things. Even things like turning OFF a battery pack and it's BMS as well for a true 100% OFF is not that easy, you'd think it would be ! Almost like a Faceplalm Why the heck didn't you include an OFF Switch on the BMS. Other BMS' can run Heating & Cooling systems and thermal management of the cells and even more.

I hope this answers your Q but I don't think it's the answer you wanted, sorry about that.
To the best of my knowledge, the Chargery will sense the voltage and enable charge. I had two packs in a bank of 4 LVD out, when Genset power came on they took the charge without intervention. I run Common Port.

Your batteries started charging when Genset came on. Yes but unlike a Genset the chargecontroller can’t come on if the bms has disconnected the battery power to it.

 

[Steve_S]

No if your SCC shuts down then it is manual due to SCC being off. Quite correct, I got MIXED UP so my BAD.
Relays are NO Normally Open.

Well using a Tier-1 SCC shutting it off with 4000W incoming should not be a problem, the capacitors would take it diffuse, just like my midnite, BUT that's still not good, kill at combiner or incoming breaker first, ;-) .

Now I picked up a trick or two along the way... Setup your SCC to bulk @ 28.2 (for 24V I forget what you have) and float at 27.9. That is a pleasant conservative good charge rate and float being the CC with adapting amperage, allows the cells to soak it in and level up nicely. I'm using in float by 12-1pm over summer. Now if Batt cuts off the stepped down float will just dissipate and shut off. But it would be highly unlikely to get an HVD this way, if not impossible.

At night when the SCC is in sleep mode, it's using the batt power to keep going. IF an LVD occurs and that batt power is gone, then the SCC will shutoff and require a manual start. I know of no system that does otherwise.

Could it be worked around, most likely by using a small same volt low AH battery connected to a relay, taking the signal from the discharge relay circuit via an opto-coupler, so that when Power is ON backup batt disconnected when Power is OFF backup batt connected. That would keep the SCC alive till sun up. Just a quick thought...

Many people have used the charger relay signals in combo with opto-couplers to do a lot of different things for their systems.

 

[Cheap 4-life]

You said “that’s still not good”. That’s what I’m trying to say about the common port. It will disconnect battery power from the chargecontroller when it’s possibly charging. I agree that’s not good. This is why I use separate port using 2 relays. The chargery cuts off the solar only when there’s a HVD. Then controller isn’t getting turned off while it’s charging.

 

[Cheap 4-life]

my chargecontroller seems to always use the battery power to stay on. If using common port with one relay the charge and discharge are both cutoff for LVD or HVD by the one relay. then the chargecontroller is off and not in standby. My question remains. How can I charge the battery back up if LVD event happens and battery power is cutoff to the chargecontroller due to using common port with a single relay?
And also if HVD event happens how do I discharge the batteries with the inverters if the battery power is cutoff to the inverters due to using common port with one relay

 

[Steve_S]

If you are hitting HVD, then your need to adjust your config to prevent that, IF I push my SCC to dump 29.2V I'll get HVD's one after the other. I fiddled & piddled with settings and tweaks and now I never see an HVD, even if I am pushing 150A Charge.

 

[Cheap 4-life]

If you are hitting HVD, then your need to adjust your config to prevent that, IF I push my SCC to dump 29.2V I'll get HVD's one after the other. I fiddled & piddled with settings and tweaks and now I never see an HVD, even if I am pushing 150A Charge.

I’m not hitting LVD or HVD. My inverters have DOD settings to prevent the battery from getting to LVD. The chargecontroller stops HVD from happening. I’m referring to if LVD or HVD happens unexpectedly.

 

[DerpsyDoodler]

@Steve_S @curiouscarbon @cinergi

thanks for yall’s input. because of it, my plan modified to a time delay release, then with encouragement from cinergi i went back to gigavac’s site and perused more of their options. i ordered 2 - mx12sa contactors. they are bidirectional, support 200a continuous, require less than 2 amps @12v to pick up and use ~1 watt to maintain contact. link below. I no longer need a time delay or any other trickery.

Sensata | Gigavac | Sensata Technologies

www.gigavac.com

 

[cinergi]

@Steve_S @curiouscarbon @cinergi

thanks for yall’s input. because of it, my plan modified to a time delay release, then with encouragement from cinergi i went back to gigavac’s site and perused more of their options. i ordered 2 - mx12sa contactors. they are bidirectional, support 200a continuous, require less than 2 amps @12v to pick up and use ~1 watt to maintain contact. link below. I no longer need a time delay or any other trickery.

Sensata | Gigavac | Sensata Technologies

www.gigavac.com

Wow nice find on that contactor. I missed the columns to the far right in the spec sheet.

 

[Cheap 4-life]

@Steve_S @curiouscarbon @cinergi

thanks for yall’s input. because of it, my plan modified to a time delay release, then with encouragement from cinergi i went back to gigavac’s site and perused more of their options. i ordered 2 - mx12sa contactors. they are bidirectional, support 200a continuous, require less than 2 amps @12v to pick up and use ~1 watt to maintain contact. link below. I no longer need a time delay or any other trickery.

Sensata | Gigavac | Sensata Technologies

www.gigavac.com

What is the max voltage the contractor can pass through? How much does it cost?

 

[DerpsyDoodler]

What is the max voltage the contractor can pass through? How much does it cost?

its rated for 24v nominal. it has an interrupt rating of 1500a @ 28v dc. i would search their site for a contactor suitable for your application. i paid 125 a piece. ups ground was free, but there was a 17% covid surcharge (or something like that)...so yeah :/.

 

[curiouscarbon]

@Steve_S @curiouscarbon @cinergi

thanks for yall’s input. because of it, my plan modified to a time delay release, then with encouragement from cinergi i went back to gigavac’s site and perused more of their options. i ordered 2 - mx12sa contactors. they are bidirectional, support 200a continuous, require less than 2 amps @12v to pick up and use ~1 watt to maintain contact. link below. I no longer need a time delay or any other trickery.

Sensata | Gigavac | Sensata Technologies

www.gigavac.com

Woohoo! Really great specs on that 12V one. Especially the idle power draw! Still more than DCC but really exceptional for solenoid type contactor.

Glad you’re finding components that meet your requirements ?

Am working with/designing in the MX12TA for each BMS/pack (yes, mosfet and contactor combined in series) and MX14CA for main programmable disconnect.

I’m still looking at the DCC but until the terminals are placed a reasonable amount of space apart I will buy gigavac contactors specifically because the terminals are 80mm+ separated center to center. Having <10mm of clearance unconditionally disqualifies the DCC for me ?

As far as I understand, the DCC is like a MOSFET BMS but without cell monitoring and logic, and with much higher ampere rating.

 

[DerpsyDoodler]

As far as I understand, the DCC is like a MOSFET BMS but without cell monitoring and logic, and with much higher ampere rating.

This was one of the final clinchers for me (that and the "always on" precharge). I hear everyone talk about how mosfet BMS are not good because fets fail closed. This is a lot of current to be pushing. I have plenty of other safeguards and it might have been OK, but I'd rather just not dink with questionable stuff. If it was a lab environment, I'd have a blast. This isn't that. This is an RV/home with potentially devastating consequences for getting something wrong.

 

[Steve_S]

I live rural & remote... 2 hours drive to a major city. I can be snowed in for a week in winter because I am OUT There. My life depends on my systems. I have 3 ways to heat, get water, 3 power backups and so on... Mil Training do it in 3s for redundancy. I cannot allow for failures and if there is, there is always a fallback. I even have a "board" from hot-swapping in place with 2 Kilovac Relays and Delay Board setup just in case, it's getting dusty now.

Granted I have 5 Packs with DCC's so even if one or two fail I'm still running... Advantage of having a bank with multiple packs versus just one battery pack.

Fears, even little ones can become limiting & debilitating... even when unfounded.

 

[DerpsyDoodler]

I live rural & remote... 2 hours drive to a major city. I can be snowed in for a week in winter because I am OUT There. My life depends on my systems. I have 3 ways to heat, get water, 3 power backups and so on... Mil Training do it in 3s for redundancy. I cannot allow for failures and if there is, there is always a fallback. I even have a "board" from hot-swapping in place with 2 Kilovac Relays and Delay Board setup just in case, it's getting dusty now.

Granted I have 5 Packs with DCC's so even if one or two fail I'm still running... Advantage of having a bank with multiple packs versus just one battery pack.

Fears, even little ones can become limiting & debilitating... even when unfounded.

and you were also one of the first to jump in. The guinnea pig so to speak. Knowing what you know now, would you still have made the dcc choice or would you have weighed other options more heavily?

 

[curiouscarbon]

really grateful that this product has been developed and is being tested!!

the active thermal management on the DCC gives me hope, but the terminal spacing must change for me to accept it. i can’t be filing down lugs for a safety device. recognizing that trace length is something to be managed… i wish it was made like the JBD BMS handles things.. copper bar on PCB soldered. or something.

active thermal management is one of the features of DCC i really like.

temperature of the mosfet strongly affects behavior of the safety device (mosfet)

if DCC can monitor the mosfet temp and shut off gate before danger zone then i’d feel pretty good about that..

advanced cars these days have Silicon Carbide switches snugged up to big aluminum water/glycol blocks, cooled by refrigerant based compressor heat pumps and that’s pretty darn reliable. don’t let those chips get hot!

 

[Steve_S]

Guinea Pig, yes... spent an obscene amount of cash of relays contactors & even had some made to spec the 500A & 1000A SSRS.
and now I am still using the First Generation of DCC. I have one latest generation DCC en-route to complete my final pack going into my bank, shipped Air Express this morning with other goodies. While you hang on the complainers and those who had issues, yet there are far more folks out there not having any issues and yes they are talking about it on other forums too... IN FACT, that is how I found out about chargery a Couple of years ago, from people using them for recycled EV cells.

The FIRST Generation which is what I posted at the START OF THIS THREAD were updated and changed, lugs are farther apart... Then came the ISO Boards and external adapters which WE here asked for and Jason @ Chargery responded and met the need....

Also to the point, I run DCC-300's and have pulled 250A and pushed 150A through them and they only got warm, not hot and the fans barely came on and that happened when I covered the vent holes (because I wanted to see, what would happen).

BUT a qualifier for that... My Powerhouse is heated to 50F in winter and in summer it never goes above 27C/81F because it is as insulated as my house is with Thermally broken walls with 6" of Foam (5" between studs, 1" between studs & sheathing) and a Cool Roof system for passive venting and a thermal break as well. Not at all typical in most places.