diy solar

diy solar

Multiple charge controllers on a single battery 'fight' each other.

I experienced MPPT charge controller fighting each other the first time I connected two EPEVER 2210 AN to the same battery bank. I started them separately with the circuit breakers to the battery and then added the PV circuit breakers. They started out sharing the load, but in the first five minutes the controllers started doing strange things like one would charge and then the other and they finally both shut completely down. I separated them to separate battery banks and restarted them and they have worked fine since, but now winter is coming and I need to add controllers so I can use my other panel arrays to keep the system up on those short cloudy days... I have also had issues with "glitches" in EPEVER controllers causing them to not charge properly so the battery never achieved a full charge. Shut down and restart always corrects the issue... I am considering replacing the entire controller string with Victron Energy MPPT's and using a Cerbo GX as the communication hub. My hope is that they will not fight when two charge controllers are connected to the same battery bank through circuit breakers then to buss bars? I have found a Great deal on four BlueSolar 100/20-48v units. They will all interconnect on the Cerbo GX so I should have good monitoring capability? Please jump in and offer advice.
 
They can fight for sure. Depends on the models and array size on each one. My OutBack models had this issue. It was impossible to match the voltage settings between the units. One MPPT would go from adsorb to float mode, but the other MPPT would have not hit it's absorb voltage yet, and stay in adsorb mode and keep the battery voltage high, boiling the FLA batteries for many hours.

Deep in the Outback Mate setting, there is a option to sync the float of all the CC. Once this is enabled, once one CC goes into float, they all do.
 
SolarMuppet said:
Some modern ones can have data links between them so they can communicate and work together rather than risk fighting and falling out with each other. It’s never a pretty sight seeing a controller in sulk mode after losing a fight while the sun is out and the batteries are still hungry and wanting to be fed.
Click to expand...
lol! error code: sulk mode :cautious:?

this topic of battling battery chargers is of interest to me since deciding to not go the gigantic devices route to start.

victron bluesolar MPPT have a “ve.direct” data port which is effectively a UART serial data plug that can easily be attached to arduino type microcontroller

by default they just report ASCII stats on power every few seconds.

but they also speak HEX! and if an arduino sends a properly formed HEX data message to the MPPT, it’s possible to adjust both the 1) Charge Current and 2) Charge Voltage parameters in close to real time.

by “simply” using a handful of these small 100V rated 20A output SCC in parallel, with a custom arduino central brain with firmware to optimize/coordinate behavior of SCC. have already tested reading data from ve.direct port to arduino for ASCII data. HEX is required for modifying the charge parameters.

this is a relatively new area for me, deciding what each one should do given immediate conditions.

food for thought perhaps
 
GEBIII said:
I experienced MPPT charge controller fighting each other the first time I connected two EPEVER 2210 AN to the same battery bank. I started them separately with the circuit breakers to the battery and then added the PV circuit breakers. They started out sharing the load, but in the first five minutes the controllers started doing strange things like one would charge and then the other and they finally both shut completely down. I separated them to separate battery banks and restarted them and they have worked fine since, but now winter is coming and I need to add controllers so I can use my other panel arrays to keep the system up on those short cloudy days... I have also had issues with "glitches" in EPEVER controllers causing them to not charge properly so the battery never achieved a full charge. Shut down and restart always corrects the issue... I am considering replacing the entire controller string with Victron Energy MPPT's and using a Cerbo GX as the communication hub. My hope is that they will not fight when two charge controllers are connected to the same battery bank through circuit breakers then to buss bars? I have found a Great deal on four BlueSolar 100/20-48v units. They will all interconnect on the Cerbo GX so I should have good monitoring capability? Please jump in and offer advice.
Click to expand...
after reading issues with EPEVER SCC, such as the one you described, i too look for new alternative

victron high amp SCC so expensive

but as you say BlueSolar 100/20-48 is maybe more affordable than the high amp ones.

i found a decent deal on that same one you mentioned, the BlueSolar 100/20-48, and took the plunge and now have a handful of them to build with.

at first will just configure them to all same charge parameters and i assume that will work perfectly fine. all connected to same battery bank, in parallel to same bank.

but importantly the BlueSolar can talk to Arduino so MPPT can be control by computer program

one “Feature Add” that i wish to experiment with is directly telling the SCC to reduce charge ampere current when battery cell is cold. NOT just chop off charging but reduce according to user provided look up table between temperature of cell material and allowed charge rate. of course also to insulate cells and consider heater in addition. engineering solar system is fun :)
 
Interesting. Another option for me is to use natural shade to extend the total available charging time. My off grid system is at a cabin in the woods and the clearing in front of it offers numerous options for spacing solar panel arrays to take advantage of doing just that. I have mapped the clearing well over the past two years and have made use of the "best" locations for this ground based solar panel array system.
 
Porch said:
They can fight for sure. Depends on the models and array size on each one. My OutBack models had this issue. It was impossible to match the voltage settings between the units. One MPPT would go from adsorb to float mode, but the other MPPT would have not hit it's absorb voltage yet, and stay in adsorb mode and keep the battery voltage high, boiling the FLA batteries for many hours.

Deep in the Outback Mate setting, there is a option to sync the float of all the CC. Once this is enabled, once one CC goes into float, they all do.
Click to expand...
thanks for sharing?

good example of communication between charging devices enabling greatly optimized system performance!
 
curiouscarbon said:
after reading issues with EPEVER SCC, such as the one you described, i too look for new alternative

victron high amp SCC so expensive

but as you say BlueSolar 100/20-48 is maybe more affordable than the high amp ones.

i found a decent deal on that same one you mentioned, the BlueSolar 100/20-48, and took the plunge and now have a handful of them to build with.

at first will just configure them to all same charge parameters and i assume that will work perfectly fine. all connected to same battery bank, in parallel to same bank.

but importantly the BlueSolar can talk to Arduino so MPPT can be control by computer program

one “Feature Add” that i wish to experiment with is directly telling the SCC to reduce charge ampere current when battery cell is cold. NOT just chop off charging but reduce according to user provided look up table between temperature of cell material and allowed charge rate. of course also to insulate cells and consider heater in addition. engineering solar system is fun :)
Click to expand...
Please keep us in the loop on how this goes. It sounds like something others of us could use?
 
GEBIII said:
I experienced MPPT charge controller fighting each other the first time I connected two EPEVER 2210 AN to the same battery bank. I started them separately with the circuit breakers to the battery and then added the PV circuit breakers. They started out sharing the load, but in the first five minutes the controllers started doing strange things like one would charge and then the other and they finally both shut completely down. I separated them to separate battery banks and restarted them and they have worked fine since, but now winter is coming and I need to add controllers so I can use my other panel arrays to keep the system up on those short cloudy days... I have also had issues with "glitches" in EPEVER controllers causing them to not charge properly so the battery never achieved a full charge. Shut down and restart always corrects the issue... I am considering replacing the entire controller string with Victron Energy MPPT's and using a Cerbo GX as the communication hub. My hope is that they will not fight when two charge controllers are connected to the same battery bank through circuit breakers then to buss bars? I have found a Great deal on four BlueSolar 100/20-48v units. They will all interconnect on the Cerbo GX so I should have good monitoring capability? Please jump in and offer advice.
Click to expand...
That is strange. Have you asked EPever about this? It sounds like there is something NQR (Not Quite Right) with the control logic of the EPever. From the description above, you might not even be able to use the EPever Tracer with an inverter charger.

I have never used the Tracer controllers, but I have noticed several reports on the forum of strange behavior.... and it seems like the reports all contain "Shut down and restart always corrects the issue..." Perhaps it is wise to go to a different controller
 
FilterGuy said:
That is strange. Have you asked EPever about this? It sounds like there is something NQR (Not Quite Right) with the control logic of the EPever. From the description above, you might not even be able to use the EPever Tracer with an inverter charger.

I have never used the Tracer controllers, but I have noticed several reports on the forum of strange behavior.... and it seems like the reports all contain "Shut down and restart always corrects the issue..." Perhaps it is wise to go to a different controller
Click to expand...
I agree with the NQR. Epever does not give me very good support online. The tech usually just gives me a one liner about some other peripheral he thinks I need with no explanation of how to implement it... I have just ordered some Victron controllers that will hopefully solve the problem...
 
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