2x Chargery 16T's, 1x DCC ?

Tomco

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Hi all,
First time poster, and I've got to say how happy I'am to have come across this group, the knowledge here is unmatched anywhere on the www!!
Anyway, apologies if this has already been covered, i did some searching and could find anything, and apologies for the crude drawing, however i think it covers what im asking.
The build is 32x 3.2 cells, i have the option of 2 cells in parallel and 16 of those pairs in series, or, 16 cells in series with two of those stings paralleled (this is preferred by me), BMS is a Chargery 16T with a 600A DCC.
Question is can i run two 16T's on the two strings, have each 16T drive an interposing relay (R1 & R2) contacts of which will series up to drive the 600A DCC (power through the contacts to the DCC 'coil' can come from either 16T#1 or #2). Each string will have its own shunt which parallel together downstream at the DCC.
I'am aware that i lose any sort of redundancy doing it this way, but is it possible while maintaining adequate protection on both strings ?2x 16t.jpg
 

Steve_S

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Simply put, NOPE.
The DCC is controlled by the BMS, a secondary BMS could not control it.
Each BMS uses the Shunt to read the voltas coming in/out and uses it for some of the calculations.
Each pack needs its own Rottweiler guarding it. BMS, & DCC (the ON/OFF switch) and do not forget to fuse each pack.

Hope it helps
Steve
 

Bob B

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Hmmm .... I'm not seeing why this won't work .... but I am not working with multiple packs in a system like Steve is.

With your redundancy comment, it seems that you understand that a problem with either pack will kill the entire output.
 

Tomco

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Hmmm .... I'm not seeing why this won't work .... but I am not working with multiple packs in a system like Steve is.

With your redundancy comment, it seems that you understand that a problem with either pack will kill the entire output.
Yes, that i accept (re redundancy). Looking at the specs of the Chargery's there is no communications between the DCC (contactor) and the control board, it appears to be a 12v out for contactor on, or 12v off for contactor off, nothing more
 

Bob B

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Yes, it is a 12VDC output ... but there are separate outputs for charge and load. The DCC can be either common port or separate port, but must be ordered for which one you want to utilize.
In either case, you would need a separate pair of series relays for charge and load.
 

Tomco

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Simply put, NOPE.
The DCC is controlled by the BMS, a secondary BMS could not control it.
Each BMS uses the Shunt to read the voltas coming in/out and uses it for some of the calculations.
Each pack needs its own Rottweiler guarding it. BMS, & DCC (the ON/OFF switch) and do not forget to fuse each pack.

Hope it helps
Steve
Does the BMS have 'communication' to the DCC or is it just a '12v on = DCC on / 12v off = DCC off' ?
If it does have some sort of monitoiring comms between the BMS and the DCC then what i want to do will not work, however i cant see anywhere in the specs that shows the DCC as anything else other than a standalone 12vdc contactor (albeit with fan and overtemp controls, but these are local to the DCC and not driven externally).
Is there something im missing here as to why this wont work? Cheers for the reply too (y)
 

Tomco

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Yes, it is a 12VDC output ... but there are separate outputs for charge and load. The DCC can be either common port or separate port, but must be ordered for which one you want to utilize.
In either case, you would need a separate pair of series relays for charge and load.
ive gone the common port option
 

Tomco

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How do you plan to drive the

The input to the DCC still uses both the charge and the load signals from the Chargery. The DCC and the cable to the DCC is what is different.

I am tagging @Chargery and maybe he can add some clarification for you.
it all depends on what the four cores actually do between the DCC/BMS, but ultimately all i have to do is interrupt the 12vdc to the DCC via interposing relays being driven from either BMS, and as per my (napkin) drawing above the DCC will be driven by either of the 2 BMS's via the interposing relay contacts which will be in series.
Hopefully the chargery tag you've added will be able to explain 'why not' if it cant be done.
 

Bob B

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it all depends on what the four cores actually do between the DCC/BMS, but ultimately all i have to do is interrupt the 12vdc to the DCC via interposing relays being driven from either BMS, and as per my (napkin) drawing above the DCC will be driven by either of the 2 BMS's via the interposing relay contacts which will be in series.
Hopefully the chargery tag you've added will be able to explain 'why not' if it cant be done.
The Chargery unit itself has independent charge and load outputs ..... It is separate port by design if you want to think of it that way ..... how do you plan to drive the relay coil of the relays attached directly to the Chargery?
The DCC can be configured for common port, but the DCC still requires both inputs to work correctly.
 

Tomco

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The Chargery unit itself has independent charge and load outputs ..... It is separate port by design if you want to think of it that way ..... how do you plan to drive the relay coil of the relays attached directly to the Chargery?
The DCC can be configured for common port, but the DCC still requires both inputs to work correctly.
in that case i would have to use 2x single pole 12v interposing relays for each BMS, and drive one relay from the 'charge output' and the other relay from the 'load output' (possibly), series up the two bms charge relay contacts (on the interposing relays) and series up the two bms load relay contacts (on the interposing relays).
It really all hinges on what the BMS outputs from its 4 port connector when being used as a common type BMS. Once i get it ill throw some scenarios at it and see how it switches when set up as common type.
 
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Bob B

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The Chargery BMS itself ALWAYS has independent charge and load outputs .... there is no configuration changes for that.
 

Bob B

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For example ... If you get a cell low voltage ... the load relay output voltage drops to 0 and the charge stays on. If you get a cell high voltage ... the charge output drops voltage but the load output stays on.
 

Tomco

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For example ... If you get a cell low voltage ... the load relay output voltage drops to 0 and the charge stays on. If you get a cell high voltage ... the charge output drops voltage but the load output stays on.
From the Chargery user manual, when using the Common Port example (on the left), only one DCC is required using a 4 core connector between DCC and BMS. So both scenarios you describe will switch the one DCC contactor, just have to work out what the pin outs are doing for each scenario you describe.
Without actually checking (as i dont have possession of the unit as yet) as a guess, i would say that both reds (from the BMS) on the 4 pin connector have 12vdc on them when everything is happy, loss of 12v on either will drop out the DCC..... so if that is the case then two relays required for each BMS.

dcc connections.jpg
 
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Bob B

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What makes in common port is the cable for the DCC and the DCC itself. That doesn't change the fact that the BMS itself has independent outputs.
Still wondering how you are going to control R1 and R2 in your diagram.
 

Tomco

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What makes in common port is the cable for the DCC and the DCC itself. That doesn't change the fact that the BMS itself has independent outputs.
Still wondering how you are going to control R1 and R2 in your diagram.
if on the 4 pin connector (between the BMS and the DCC) the first two red and black are 'charger healthy' 12v feed then that will drive 12vdc interposing relay 1A and if the second pair are 'load healthy' 12v feed then that will drive 12vdc interposing relay 1B.......... same for the second BMS. The actual DCC can be driven by any 12vdc source, its the switching of the interposing relays to reflect what the BMS's are doing thats the important bit, once i have that sorted i can drive whatever i want. My understanding is that these BMS's dont have to be used with the Chargery DCC contactor units.
 

Bob B

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I'm sure you can accomplish it with relay logic .... just wanted to make sure you understood that the Chargery BMS has independent charge and load outputs. If you get a fine tuned diagram I'd like to see how your are doing it.
 

Steve_S

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BMS*T outputs 12V/1.5A max per relay circuit (Charge/Discharge). The original implementation used two N.O. electro-mechanical relays which got hot and used between 4-10W. There is a Delay Relay board to use with these to provide for Pre-Charge to deal with start surges from inverter/motors. This series of BMS was intended for the light EV & E-Bike segment. We sort of nudged into this arena, you might say.
 

Capt Bill

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Hi all,
First time poster, and I've got to say how happy I'am to have come across this group, the knowledge here is unmatched anywhere on the www!!
Anyway, apologies if this has already been covered, i did some searching and could find anything, and apologies for the crude drawing, however i think it covers what im asking.
The build is 32x 3.2 cells, i have the option of 2 cells in parallel and 16 of those pairs in series, or, 16 cells in series with two of those stings paralleled (this is preferred by me), BMS is a Chargery 16T with a 600A DCC.
Question is can i run two 16T's on the two strings, have each 16T drive an interposing relay (R1 & R2) contacts of which will series up to drive the 600A DCC (power through the contacts to the DCC 'coil' can come from either 16T#1 or #2). Each string will have its own shunt which parallel together downstream at the DCC.
I'am aware that i lose any sort of redundancy doing it this way, but is it possible while maintaining adequate protection on both strings ?View attachment 29696
Interersting to read the replies. I think you could use two lower amp rated dc-dc SSR, one connected to each Chargery BMS16T, to pass current through both of them as a set to the DDC contactor to keep it closed battery circuit until relased. You would need a power source that matches the DCC contactor (going through the SSRs to energize it to close circuit) . If the the DDC has two inputs to hold it close (two ports, would be more dependable than a single port set up), you could use four SSRs, two each for the charge sides, two other for discharge sides. If you have one single port on DDC Contactor, you could still use this with an ideaI got from Steve S / copy of attached; ... and for an inexpensive relay option to test Steve's relay idea (Not sure how dependable/ and you battery set is an important investment to PROTECT ... here's a $7 option on Amazon I think would work, but would only recommend for testing idea (as in unsure of long term dependability) !!! ... My two cents while remembering that saying: When There Is a Will, There Is a Way ! :+) Bill
 

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