Can I use 2 mppt SCC from different manufacturer & diff. specs?

[NotToFast]

I'm setting my "new to me" RV up slowly with Solar. To move it along faster I have (2) 220watt panels going on the 2 biggest open areas of the roof. The room left on the roof will handle another (2) 100 watt panels when the money bank fills back up. But when I do that, can I use a smaller cheaper MPPT SCC to add to the system, or do I need to match my Epever Tracer 4215BN? This is a many months long build. Money is tight!

Pros? Cons?

Thanks, Rick

 

[sunshine_eggo]

I'm setting my "new to me" RV up slowly with Solar. To move it along faster I have (2) 220watt panels going on the 2 biggest open areas of the roof. The room left on the roof will handle another (2) 100 watt panels when the money bank fills back up. But when I do that, can I use a smaller cheaper MPPT SCC to add to the system, or do I need to match my Epever Tracer 4215BN? This is a many months long build. Money is tight!

Yes. Just make sure it's an actual MPPT. Many cheap PWM are labeled as "MPPT".

 

[NotToFast]

I was wondering about that, I see many "MPPT" little square controler for under $50. Thats what I paid for my PWM 3 years ago. I didn't think prices had come down that far!!

 

[yodamota]

currently doing just this. I would suggest using two of the same makes. Mostly because they use the same terminology. Having two different manufactures means learning two different manuals. Trying to get them to work together seems to be a bit of trial and error.

 

[sunshine_eggo]

currently doing just this. I would suggest using two of the same makes. Mostly because they use the same terminology. Having two different manufactures means learning two different manuals.

IMHO, this is not even a consideration. Basically, the "terminology" deviation is the use of the words, "bulk," "absorption," and "boost" to mean the same voltage.

Trying to get them to work together seems to be a bit of trial and error.

No trial and error whatsoever. Simply program each charger, regardless of type, for the correct battery voltage. They will "work together" fine.

Charging from multiple sources

One can have as many independent charging sources running concurrently as they like provided they are programmed properly for the voltage of one's battery bank. Examples (some or all at once, even multiples of a single type, different brands, etc.): Solar PV via MPPT Solar PV via PWM AC-DC...

diysolarforum.com

 

[yodamota]

IMHO, this is not even a consideration. Basically, the "terminology" deviation is the use of the words, "bulk," "absorption," and "boost" to mean the same voltage.



No trial and error whatsoever. Simply program each charger, regardless of type, for the correct battery voltage. They will "work together" fine.

Charging from multiple sources

One can have as many independent charging sources running concurrently as they like provided they are programmed properly for the voltage of one's battery bank. Examples (some or all at once, even multiples of a single type, different brands, etc.): Solar PV via MPPT Solar PV via PWM AC-DC...

diysolarforum.com

Well the morningstar terminology is different than the outback power. The morningstar does not have an end absorb amps setting, while the outback power one does. So now the morning star will keep the batteries absorbing for the pre determined time. While the outback power will stop at 7 amps. So I basically have no end absorb amp setting.

The trial and error part has been learning how each interact. They are doing great. Some of the settings are conflicting. The morning star will happily sit there with its voltage above its absorption setting ready to react. While the outback seems to standby saying "charged"

I have reprogramed the morningstar several times trying to get it to work smoothly with the outback. The outback's setting can be changed from the screen on the charge controller while the mornginstar requires a windows computer, to even talk to it.

These might be minor details, however they add up.

 

[sunshine_eggo]

Well the morningstar terminology is different than the outback power. The morningstar does not have an end absorb amps setting, while the outback power one does. So now the morning star will keep the batteries absorbing for the pre determined time. While the outback power will stop at 7 amps. So I basically have no end absorb amp setting.

That's not a terminology issue. That's a features issue. The FM60/80 offers something the morningstar doesn't. You can choose to not set an end amps on the FM.

The trial and error part has been learning how each interact. They are doing great. Some of the settings are conflicting. The morning star will happily sit there with its voltage above its absorption setting ready to react. While the outback seems to standby saying "charged".

You'd see the same thing on two identical Outbacks. One would be floating and the other would say "charged." I know this because my neighbor has 2X FM80, and I helped him program them.

This is the nature of multiple chargers on a battery. Did you read the link I provided?

I have reprogramed the morningstar several times trying to get it to work smoothly with the outback. The outback's setting can be changed from the screen on the charge controller while the mornginstar requires a windows computer, to even talk to it.

These might be minor details, however they add up.

What does "work smoothly" mean to you?

 

[yodamota]

That's not a terminology issue. That's a features issue. The FM60/80 offers something the morningstar doesn't. You can choose to not set an end amps on the FM.



You'd see the same thing on two identical Outbacks. One would be floating and the other would say "charged." I know this because my neighbor has 2X FM80, and I helped him program them.

This is the nature of multiple chargers on a battery. Did you read the link I provided?



What does "work smoothly" mean to you?

thank you for clearing up that it is a feature issue.

I have looked at that thread in the past. Its what told me two different makes would work together. The morningstar was being sold by our neighbor for half what it would cost new. Thanks to that thread I saved having to buy a brand new charge controller. I haven't read it recently.

I am not quite sure what I mean by work smoothly. I seemed to have worked out the kinks. I think smoothly to me means one charge controller controls the other one, or what I also mean is one charge controller is an accessory. Sort of like a master/slave setup. I am not sure if this exist. As it seems right now I have two independent masters trying to achieve one goal.

 

[Texas-Mark]

I have a Renogy and HQST each fed with 800W of panels. They work fine together. Actually their settings pages are almost identical. The only issue I can see is if you set them to different settings. Then one or the other will stop charging before the other. But that would mean you have one of them set wrong to begin with.

 

[sunshine_eggo]

thank you for clearing up that it is a feature issue.

I have looked at that thread in the past. Its what told me two different makes would work together. The morningstar was being sold by our neighbor for half what it would cost new. Thanks to that thread I saved having to buy a brand new charge controller. I haven't read it recently.

I am not quite sure what I mean by work smoothly. I seemed to have worked out the kinks. I think smoothly to me means one charge controller controls the other one, or what I also mean is one charge controller is an accessory. Sort of like a master/slave setup. I am not sure if this exist. As it seems right now I have two independent masters trying to achieve one goal.

Yep. They are doing their own thing completely ignorant of the other's activity, but they react based on the changes in voltage.

It's as described in that thread. Once you hit absorption, the highest current charger will typically finish the charge and the weaker one(s) will drop off. Voltage and accuracy can also play into it. If you set one charger to 14.5 and the other to 14.4, the 14.4 charger will fall off to 0 before the other.

The only way to set a master/slave arrangement is with something like Victron MPPT in VE.Smart or VE.CAN network. They actually communicate with each other and coordinate their efforts.

The only way to have two independent chargers operate in exactly the same fashion is to simply get lucky... every single day, because every charge condition can be a little different.

Simply programming them to the correct absorption and float will ensure that you get the maximum output from your arrays when you need it.

 

[NotToFast]

I guess if you think about it, it's like the RV Converter on shore power and the solar charge controller working together. They are both sending power to the battery. The battery decides which "Straw" it want to drink from. If its full, then it pushes back and nothing comes through the straw.

Thanks for all the chatter. It does make things clearer. It just makes you wonder if the Victron coordination really makes much difference?

Rick

 

[Texas-Mark]

just makes you wonder if the Victron coordination really makes much difference?

I doubt it makes much difference in the real world. By the time CCs are getting ready to stop charging, the batteries are nearly full anyway.

 

[sunshine_eggo]

Thanks for all the chatter. It does make things clearer. It just makes you wonder if the Victron coordination really makes much difference?

Hot much. it's mostly about load sharing, e.g., once the battery is fully charged and all are in float, all respond to changes in load rather than just one.