Now is hard to get vpn for inphone or android phone. sometime work some time don't. now ...mostly don't work. i am chinese, living in us. lazy at school, now regret with poor english.
NEW CHARGERY MANUAL NOW ONLINE - THX JASON AND @STEVE_S
- Thread starter ghostwriter66
- Start date
I got a question regarding spec 4.0, page 40:
"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. "
Why does this practice affect the BMS negatively? Why will it result in damage?
I use the BMS to disconnect charging sources. It works very well. For example, the charging source is set for 14.0V. The Chargery cell OV is 3.48V (13.92V if all cells are equal). Charging is completed in the shortest amount of time. If the charging source voltage is set lower so that cell OV never trips then as the SOC approaches 100% current drops down to a trickle. Charging becomes very, very slow.
"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. "
Why does this practice affect the BMS negatively? Why will it result in damage?
I use the BMS to disconnect charging sources. It works very well. For example, the charging source is set for 14.0V. The Chargery cell OV is 3.48V (13.92V if all cells are equal). Charging is completed in the shortest amount of time. If the charging source voltage is set lower so that cell OV never trips then as the SOC approaches 100% current drops down to a trickle. Charging becomes very, very slow.
I will let steve answer but I think for him it is a meter of using the BMS as a fail safe because if it were to fail and your charger keeps charging damage can occur. If the charger fails with BMS as back up you wont be able to overcharge. I do not think there is anything wrong with your set up especially if you are going to keep a good eye on it. My BMS tells my Midnite classic to shut down all the time.
I think if the BMS failed it would fail for both due to electro/mechanical Issues. I am confident that if it sees any cell too high it will send the correct signal. But how that signal gets interpreted by the relay or whatever it is signaling could be a problem.
Please this is a really only a theoretical problem. I'm also confident that it will work as it is supposed to always.
Bob B
Emperor Of Solar
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- Sep 21, 2019
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I'll be interested in what @Steve_S has to say .... I plan to use the Chargery BMS to disconnect load and charging routinely .... It won't be the sole method for protection .... I also am not going to be switching high current relay coils .... I don't see how doing this will damage the BMS.
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
When the BMS reaches CUTOFF point it cycles the relay(s) on/off constantly. This is no good for the relays, especially the electro-mech ones. SSR's couldn't care. Depending on the topology, this can interrupt output as well, think of common port in series where either charge / discharge relay can disconnect the power in/out of the pack. Separate port config is a different, as charge comes in on one side, discharge goes out on the other side.
Also consider that if the BMS is set to stop charging cells @ 3.65V (default value) which is 100% for LFP and we are trying to maintain it at 90% of max capacity which is 3.285V then charging by DEVICE should end at THAT Voltage and not 3.65. By default the Chargery BMS will perform LVD @ 2.5V per cell which is Bottom or Zero Remaining.
CHARGE Cut-offs from SCC & Inverter/Charger or AC to DC Charger should be as follows IF holding to the 90% of Max rule:
- (13.14 for 12V) / (26.28 for 24V) & (52.56V for 48V)
For LVD @ 5% from bottom is 2.625V (2.50 is absolute bottom)
- (10.5V for 12V), (21.0V for 24V) & (42.0V for 48V)
I cannot put enough emphasis on Calibrating your devices and Voltage Matching or Compensating for voltage differences. Lead Acid is simple because it can handle variations and be a bit more generic and TBH a 0.5V difference in charging discharging FLA makes no difference to the batteries, but LFP like all other Lithium Ion based cells precision is far more important as the voltage curve is very different for SOC. A Half Volt difference can be a problem - 0.5V over 3.65 Volts (Max Charge per cell) is 4.15 and OVERCHARGE for LFP resulting in ballooning and eventual failure. YES 1/2 Volt Can & Will cause damage and the more often it occurs the more damage till total failure. Every connection, terminal, device (shunt / relay) etc all add resistance & some voltage drop and cumulatively it adds up and fast.
The Chargery BMS is designed in such way as to maximize flexibility for configuration relative to your particular application. This is fairly obvious as people are configuring them with SSR's in Common & Separate Port and some even with Hybrid methods. Of course this can become complicated quickly as well... If you only have ONE BMS and using it's relay signals to accomplish certain things that's easy enough, but have 3 or 4 BMS' in a bank and you now have that many more signals from the BMS to deal with so then you need an "Arbitrator" in between to take the signals and then to take action according to programmed settings. BMS 1 says it's full and stop charging but BMS 3 & 4 still need charging from SCC, "who wins" ? Do you have one charge source like an SCC or do you also have a Genset that can be started via Inverter/Charger to charge ? Even the Chargery AC-DC Chargers with intelligent control from the BMS is designed for a SINGLE PACK controlled by hat one BMS... would you buy 4 chargers for 4 Packs in one bank ?
The flexibility lends itself to being used in many ways and various topologies in design. Common & Separate port and hybrid variants of them including split bus or dual or even triple bus which depends on overall system sizing and number of BMS'.
An Arbitrator can be any number of devices but I feel that some smart programming of a Raspberry Pi or Arduino / Single Board computer (there are quite a few) can accomplish it IF someone was inclined to do so. I have yet to see anyone produce something like that but it would be mighty specific per installation so there would have to be a fair bit of underlying code to make it "publicly palatable" for general use. I would NOT expect Chargery to come up with something for that, they are not a software development house and this is beyond their scope I think.
Hope that helps, if not, you'll have to specifically aim at Jason who is here now.
I am just a Chargery BMS user - maybe an advanced one but still just a regular Joe User.
Also consider that if the BMS is set to stop charging cells @ 3.65V (default value) which is 100% for LFP and we are trying to maintain it at 90% of max capacity which is 3.285V then charging by DEVICE should end at THAT Voltage and not 3.65. By default the Chargery BMS will perform LVD @ 2.5V per cell which is Bottom or Zero Remaining.
CHARGE Cut-offs from SCC & Inverter/Charger or AC to DC Charger should be as follows IF holding to the 90% of Max rule:
- (13.14 for 12V) / (26.28 for 24V) & (52.56V for 48V)
For LVD @ 5% from bottom is 2.625V (2.50 is absolute bottom)
- (10.5V for 12V), (21.0V for 24V) & (42.0V for 48V)
I cannot put enough emphasis on Calibrating your devices and Voltage Matching or Compensating for voltage differences. Lead Acid is simple because it can handle variations and be a bit more generic and TBH a 0.5V difference in charging discharging FLA makes no difference to the batteries, but LFP like all other Lithium Ion based cells precision is far more important as the voltage curve is very different for SOC. A Half Volt difference can be a problem - 0.5V over 3.65 Volts (Max Charge per cell) is 4.15 and OVERCHARGE for LFP resulting in ballooning and eventual failure. YES 1/2 Volt Can & Will cause damage and the more often it occurs the more damage till total failure. Every connection, terminal, device (shunt / relay) etc all add resistance & some voltage drop and cumulatively it adds up and fast.
The Chargery BMS is designed in such way as to maximize flexibility for configuration relative to your particular application. This is fairly obvious as people are configuring them with SSR's in Common & Separate Port and some even with Hybrid methods. Of course this can become complicated quickly as well... If you only have ONE BMS and using it's relay signals to accomplish certain things that's easy enough, but have 3 or 4 BMS' in a bank and you now have that many more signals from the BMS to deal with so then you need an "Arbitrator" in between to take the signals and then to take action according to programmed settings. BMS 1 says it's full and stop charging but BMS 3 & 4 still need charging from SCC, "who wins" ? Do you have one charge source like an SCC or do you also have a Genset that can be started via Inverter/Charger to charge ? Even the Chargery AC-DC Chargers with intelligent control from the BMS is designed for a SINGLE PACK controlled by hat one BMS... would you buy 4 chargers for 4 Packs in one bank ?
The flexibility lends itself to being used in many ways and various topologies in design. Common & Separate port and hybrid variants of them including split bus or dual or even triple bus which depends on overall system sizing and number of BMS'.
An Arbitrator can be any number of devices but I feel that some smart programming of a Raspberry Pi or Arduino / Single Board computer (there are quite a few) can accomplish it IF someone was inclined to do so. I have yet to see anyone produce something like that but it would be mighty specific per installation so there would have to be a fair bit of underlying code to make it "publicly palatable" for general use. I would NOT expect Chargery to come up with something for that, they are not a software development house and this is beyond their scope I think.
Hope that helps, if not, you'll have to specifically aim at Jason who is here now.
I am just a Chargery BMS user - maybe an advanced one but still just a regular Joe User.
I am setting mine up right now and it is a pain in the butt. The current calibration is a joke. It should require a resistance value instead.
The DC contactor doesn't seem like continuous duty rated. I ran 65A thru 100A contactor and its at 121 degrees F.
The SOC meter setting should be labeled showing as a coulumb variable disconnect. I don't know what they were thinking by omitting that from setup menu.
Still working on a video right now, but I am not thrilled.
The DC contactor doesn't seem like continuous duty rated. I ran 65A thru 100A contactor and its at 121 degrees F.
The SOC meter setting should be labeled showing as a coulumb variable disconnect. I don't know what they were thinking by omitting that from setup menu.
Still working on a video right now, but I am not thrilled.
Thanks Steve for providing reasons not use the BMS for primary over voltage disconnect. You provided two reasons:
1. The relay will cycle on/off. The relay off-to-on again time period is dependent on the voltage hysteresis, which is programmable in setup. If you lower the voltage level where the relay engages again then cycling will be minimal. You don't need huge relays to disconnect charging sources. I use small relays that can cycle thousands of times with no degradation. You just need to choose the right spot to disable the charger.
2. Default OV is set at 3.65V. That's doesn't matter. We can program that to 3.48V (13.92V) and adjust charger to 14.0V. Everything is safe! BTW, if 3.65V is 100% SOC, then 3.285V is not 90% of max capacity. Voltage in not linear above the knee. It will not scale.
It is so much easier to program the BMS for primary disconnect than to adjust the charger(s).
I'm not sure you realize when setting charger max voltage below the BMS disconnect voltage then charging current becomes extremely small. You may have a 50A or 30A charger, but it turns into a trickle charger. Charging current will drop below an amp as the charger voltage limit is approached.
1. The relay will cycle on/off. The relay off-to-on again time period is dependent on the voltage hysteresis, which is programmable in setup. If you lower the voltage level where the relay engages again then cycling will be minimal. You don't need huge relays to disconnect charging sources. I use small relays that can cycle thousands of times with no degradation. You just need to choose the right spot to disable the charger.
2. Default OV is set at 3.65V. That's doesn't matter. We can program that to 3.48V (13.92V) and adjust charger to 14.0V. Everything is safe! BTW, if 3.65V is 100% SOC, then 3.285V is not 90% of max capacity. Voltage in not linear above the knee. It will not scale.
It is so much easier to program the BMS for primary disconnect than to adjust the charger(s).
I'm not sure you realize when setting charger max voltage below the BMS disconnect voltage then charging current becomes extremely small. You may have a 50A or 30A charger, but it turns into a trickle charger. Charging current will drop below an amp as the charger voltage limit is approached.
Hello all - I am new here. Been watching Will on YouTube since the beginning. I just got some of the LG Chem Lithium NMC cells (32) and planned on building out 2 16S 8kw batteries. I went with 16S to match my existing 16S LG Chem packs that come preconfigured as 16S 2.5kwh 67.2v units and I have 15 of them. The issue is inverters DO NOT LIKE voltages over 61v really. I have now decided to adjust my configuration to 14S (58.8v) which makes every 48v inverter happy. I will have to send back my 2 Daly 200a BMS boards that just arrived from China due to them being 16S but also because they came with separate ports and not the one port which was what I wanted. I then came across Will's video showing the Chargery unit. Although he was NOT PLEASED with the configuration of the Chargery - I can see the potential of the unit once the kinks are ironed out. I am wondering if the Chargery gives users the option of using 14s, 16s etc all in the same unit. Also Will complained about the heat buildup of the relay - has there been a solution to that issue or is it a issue of concern at all?
Thanks for any feedback and I look forward to responses.
Adnubian from YouTube
Thanks for any feedback and I look forward to responses.
Adnubian from YouTube
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
Chargery supports 14S and such (with the BMS16 but it's not designed for ALL chemistries.
Check out the BMS16 Manual. http://chargery.com/doc/Chargery_BMS16T_specification_V4.0.pdf
Other threads have covered the many variants of relays etc...
I will review the manual, thank you for that reference link. My LG Chem cells are Lithium NMC and have been rock solid for over 2 years without BMS of any sort. I check cell voltages manually by pulling the plastic covers from the packs. I really have been thinking of a easy solution of paralleling all of the 15 packs and running them off of 1 BMS but that is for another day. The proprietary sense ports on the LG packs are not going to make it easy due to one being on the front (8 cells) and 1 being on the back. To make a current sharing cable system would be a EXTENSIVE task. Breaking the batteries down to cells and then paralleling them 15p would probably be a much easier way but would remove that near little pack that they come in. I am drifting from the topic lol. I would imagine the chemistry should be supported. 3v flat 4.2v full.
You can make the chargery work. This is exactly why I like it.
I am quite excited to see what she can do. Is there a wifi option available for remote monitoring of the system?
LOL that is a loaded question. Yes there is but it will require additional equipment. I can not say as of now that it is an easy process. What I'm gonna need to do is start making my own videos.
I posted a request for purchasing the Chargery as a new thread. Can you review it and advise? I am sure that other users probably might be a bit confused as well. Thanks!
@Chargery and @Steve_S ... I think I see an error in the manual on page 6, in the drawing below, for the charge and discharge control lines. On my unit, the wires (starting from the side closest to the Ext Power Input port) go black, red, black, red. Not red, black, red, black as shown in the drawing. I also verified this with a voltmeter on the pins on the BMS, seeing the 2nd and 4th pins from the top of this drawing as the ones that toggle between 12V and 0V. Would be good to correct in next revision of the manual.
itsmattmp
New Member
I'd be curious to know your opinion on the updated Chargery. I think they've addressed a lot of your concerns. It comes pre-calibrated from chargerystore.com, and the DCC solid state relays seem to work well. For situations that need high C rate discharge and charge this setup seems ideal.
tim0shel
Solar Enthusiast
- Joined
- Jan 27, 2020
- Messages
- 462
I dont think the new ones have been released yet.