2 mppt controllers compatibility
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timselectric
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Not a problem. You can connect as many chargers as you want. And of any brands that you want. As long as you don't exceed the charging limit for the batteries.
{{The two controllers sharing one input will fight for control.....when one sweeps the other will be thrown off its MPP causing it to sweep which will cause the other to sweep endlessly.....}}, some one told that 2 mppt will fight for control in one group of batteries, is it? kindly advise
Samsonite801
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Yeah you're right, but I think he meant 'as many charge controllers' on the battery-side, he didn't mean on the PV side. Only one charge controller per PV circuit.
On the battery (charger) side though, you probably will need to use custom 'user' battery charge profile on them so you can match the stage voltages, so they work more together (one doesn't go into float stage too early while other still in absorption stage or something), so you can get maximum watts all through the overall battery bank charging cycle.
timselectric
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They are not sharing any input. Look at the drawing.
Samsonite801
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On a side note, if you use Victron SmartSolar charge controllers (BlueSolar series not sure but maybe also), they actually have a fully supported network sync mode they can operate in which you install it with either a Smart Shunt or a BMV series battery monitor, and on mine, you use the bluetooth to create a network group (within the Victron Connect app), and I add my BMV-712 battery monitor (shunt), into the group, along with my two SmartSolar 250|100 charge controllers, and the algorithm picks a master, and the other one is a slave, and they both read voltage, current, and temperature off of the BMV-712, and they sync their charge stages together. The amps can fluctuate between the two chargers as the 2 solar arrays are pointing different directions on mine, but the charge stages operate in unison (they both stay in Bulk together, then Absorption together, then Float together)...
I really like how it works so far. It is not a requirement to have this kind of syncing setup, as you can still put as many chargers you want of different brands onto a battery bank, but to optimize the max watts, so they charge at best output together, you may have to tweak the user profiles a bit, because they are all reading voltages from their own perspectives and may not all be calibrated the same, so setting the same voltages on all the charge stages may or may not be totally accurate, and may require some offsetting (across all the different charge controllers) in the custom voltages you wind up with.
The Victron sync setup, they all read the same voltage, current, and temperature from a common single point (on the shunt) so it is easier for them to know what the actual voltage is in relation to each other, since the perspective sample point is the same.
Of course I also have a normal battery charger (AC input to DC charger output) on my Magnum inverter, so that one is not in sync with Victron and I had to tweak with the voltages on the user profile a bit to find the best happy points, but I seldom use that method of charging so it is really not all that important that it is in sync, since I would more use that at nighttime anyways when the solar chargers are not active.
I really like how it works so far. It is not a requirement to have this kind of syncing setup, as you can still put as many chargers you want of different brands onto a battery bank, but to optimize the max watts, so they charge at best output together, you may have to tweak the user profiles a bit, because they are all reading voltages from their own perspectives and may not all be calibrated the same, so setting the same voltages on all the charge stages may or may not be totally accurate, and may require some offsetting (across all the different charge controllers) in the custom voltages you wind up with.
The Victron sync setup, they all read the same voltage, current, and temperature from a common single point (on the shunt) so it is easier for them to know what the actual voltage is in relation to each other, since the perspective sample point is the same.
Of course I also have a normal battery charger (AC input to DC charger output) on my Magnum inverter, so that one is not in sync with Victron and I had to tweak with the voltages on the user profile a bit to find the best happy points, but I seldom use that method of charging so it is really not all that important that it is in sync, since I would more use that at nighttime anyways when the solar chargers are not active.
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Each mppt going to the same group batteries positive and negative side, my question is will they affect other mppt?
If I divide two batteries each for one mppt, I am asking that these 2 batteries linked together to the inverter? I am confusingly
clarkpeacock
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Bluesolar does not support this, even when using the Bluetooth smart dongle. However, they will synchronise with a smart battery sense device.
Great feature with Smartsolar controllers though!
timselectric
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No
That's the output side.
Samsonite801
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The PV side of the charge controller and the battery side of the charge controller really don't have much of anything to do with each other except that the load placed on the PV circuit, is correlated to the charge rate being set on the battery charger side (like a fancy variable buck converter).
I like to just think of a charge controller, as a battery charger (knows how to handle different battery types/chemistries and manage charging and maintaining a battery, without overcharging it)... But instead of using an AC input power source to power the battery charger, it uses a PV solar circuit, and it buck (down) converts it to maintain the required power that the battery charger side of it needs.
It can perform MPPT sweeps on the PV solar circuit (pull down voltage by lowering input resistance), which draws up the amps on the PV circuit, finds the maximum power point in watts, sets it there, and can pull best power as required (best mix of amps to volts ratio to get max watts), so it can get the battery charger side of it up to maximum rated amps output, or best amps for whatever stage it's in.
You can have a battery bank of several batteries (connected in parallel), and you can parallel in many battery chargers, it is fine. In this sense, the PV side of it doesn't matter, it is just a power source for its respective charge controller (battery charger).
Once all the battery chargers see that the battery bank is charged, they will all 'relax' their respective PV circuits (by raising the resistance in the PV circuit, in turn lets PV volts go high, and amps drop down to nothing), which will lower the battery charger output amps down to trickle.
Hopefully some of that makes some kind of sense.
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Samsonite801
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Thanks for clarifying, I had wondered if BlueSolar did or didn't work with it...
Yeah originally, I had purchased a couple VE.Direct cables thinking I was going to need them to connect the sync feature on my SmartSolars, but later realized it was as simple as using the internal bluetooth that each of the 3 units have built in and it was so easy to set it up in a sync group. Didn't need the cables anyways.
I do it and many others do it. It is not a problem as long as you set the parameters the same on each controller. You may get one controller shut off before the other but your battery will be very near fully charged.
Warren Dallas
New Member
My trailer came with a Furrion 165W panel and a Furrion 25 amp MPPT. I want to add 6 100W panels in a series/parallel configuration. The 165W panel cannot be used in series or parallel with the other 100W panels without serious power loss. Can I leave the system that came with the trailer in place and hook up the 100W PV's to a separate 100A MPPT and feed the same battery bank of off both MPPT's? My battery bank is 6 Battle Born Lithium 100 amp-hour batteries connected in parallel. The specs of the 100W PV's are:
Voc = 21.5 V, Vmp = 17.1
Isc = 6.4 A, Imp =6.1 A
The plan is to connect 2 panels each in series then connect those 3 groups of series connected panels in parallel. That will give me an array output of Voc = 43V, Isc = 19.2A
Another question: when calculating the power to the MPPT should we use the open circuit/short circuit values or the optimum operating voltage/current?
Thanks in advance.
Voc = 21.5 V, Vmp = 17.1
Isc = 6.4 A, Imp =6.1 A
The plan is to connect 2 panels each in series then connect those 3 groups of series connected panels in parallel. That will give me an array output of Voc = 43V, Isc = 19.2A
Another question: when calculating the power to the MPPT should we use the open circuit/short circuit values or the optimum operating voltage/current?
Thanks in advance.
Vigo
Solar Addict
Yes.
Well, power would mean watts and watts are actually too vague. You need to know the open circuit voltage of your PV string because if you exceed the max input voltage of the mppt you will smoke its internal components. Amps do not matter as much because the MPPT itself controls how many amps flow through it. It is common practice to hook an 'oversize' (in terms of amps..) array to an MPPT, although there are some caveats.
The main concern with amps is fusing between panels when you have 3 paralleled panels or strings of panels. If a panel was to short, it would be 'fed' by the other panels in parallel with it. With 2 panels in parallel, one shorted and one feeding into the short, that is still the same amount of current that would be flowing through that shorted panel as if it was working normally (aka 1 panel/string worth of amps). However, once you get 3 in parallel you could have the possibility of a panel having double the normal current flow through it if it were to short. That is why it is recommended to start fusing between paralleled PV branches when you hit 3.
Warren Dallas
New Member
Thanks Vigo, that is very helpful. The open circuit voltage of the string is 43 volts, the short circuit of the string is 19.2 amps. That is fed into a 100 amp MPPT. The system that came with the trailer is a 165 watt PV feeding a 25 watt MPPT. The 165 watt PV has 23.12 V open circuit voltage, 9.49 A short circuit current. Can I connect the outputs of both MPPT's to the same battery bank? The input of the 100 amp MPPT is selectable. I would choose the 48 V selection to input 43 V.Yes.
Well, power would mean watts and watts are actually too vague. You need to know the open circuit voltage of your PV string because if you exceed the max input voltage of the mppt you will smoke its internal components. Amps do not matter as much because the MPPT itself controls how many amps flow through it. It is common practice to hook an 'oversize' (in terms of amps..) array to an MPPT, although there are some caveats.
The main concern with amps is fusing between panels when you have 3 paralleled panels or strings of panels. If a panel was to short, it would be 'fed' by the other panels in parallel with it. With 2 panels in parallel, one shorted and one feeding into the short, that is still the same amount of current that would be flowing through that shorted panel as if it was working normally (aka 1 panel/string worth of amps). However, once you get 3 in parallel you could have the possibility of a panel having double the normal current flow through it if it were to short. That is why it is recommended to start fusing between paralleled PV branches when you hit 3.
Vigo
Solar Addict
Yes, you can have two different MPPTs charging the same battery/bank.
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