I Flipped the Switch on my Over Paneled MN Classic & Array Upgrade Today

[Ceberha]

@SpongeboB Sinewave I also asked you about the Classic 250 above, but that post may have gotten lost in the White Paper post. Any ideas on the 250 (see above)

The "special edition" Classic 250s lack arc fault and follow me capabilities. It would work fine in parallel with your 150, but they could not talk to each other. They also cannot talk to a Wiz bang jr.

They were made for portable system for a company which went bankrupt. I purchased one directly from Mid nite a few years ago and it has been great.

 

[MrM1]

The "special edition" Classic 250s lack arc fault and follow me capabilities. It would work fine in parallel with your 150, but they could not talk to each other. They also cannot talk to a Wiz bang jr.

They were made for portable system for a company which went bankrupt. I purchased one directly from Mid nite a few years ago and it has been great.

I'll probably just get a 150 because I do want them to talk and use a Whizbang jr. But if I have 2 classics, do I also need 2 Whizbang Jr's? And 2 shunts?

 

[SpongeboB Sinewave]

Ok. Have now had time to do this experiment.

What I found
- using the "white paper" hack to limit only charge current (not total output current of the Classic) does not help when off grid because with loads, even if I limit current to 75 charge amps, the Classic still puts out 94 amps with charge + loads. So it still heats up to 89c +/-
- this would only help if I limited charge so much that charge + load never got to 94 amps. Kinda defeats the purpose
- limiting total output amps to 90 amps is better. Keeps the FET temp under 85c

It seems amp limit and temp at the FETs are about a 1:1 (at least to a point of about 80amps). 1 amp drop in current = 1 degree C at the FETs

My concern with Temps is this is with Ambient room is 60 F and days are shirt. Summer might be a problem.

I'll probably save up for a 2nd SCC

I still don't think that I have seen this "hack" paper ?

I am also not sure what you mean by "charge current" here. Do you mean the current going only into the battery itself or the current coming out of the Classic ? If you adjusted the Classic's output current limit to 75 amps, that Classic should limit its output current to around 75 amps. Definitely less than 80 amps. Then there is a current limit adjustment in the Classic for INPUT current limit (PV current) which won't help you here most likely.

There is a battery charge current limit to the battery that requires the use of an external Whizbang Junior battery shunt monitor. Do you have that connected to the Classic ? That will limit the current into the battery but let the Classic output the complete output current limited by the
I am guessing that this is the "hack" you have spoken about but I am not sure. I will now Google for that white paper using some specific search terms.

boB

 

[SpongeboB Sinewave]

I'll probably just get a 150 because I do want them to talk and use a Whizbang jr. But if I have 2 classics, do I also need 2 Whizbang Jr's? And 2 shunts?

With the Follow Me, you only need one shunt and one WB Jr. shunt monitor. The WB Jr. cost, last I know was $59

We were giving them away for a while with each Classic but had to stop doing that.

Since you guys are talking about WB Jrs and stuff, I will assume that this "hack" has to do with that feature of limiting the "battery" charge current. It is probably called a hack because you have to go into a special modbus editor to change the adjustments rather than going in to a regular menu item in the MNGP remote. It's a round-about method until the menus get updated.

I think that with this adjustment set in the modbus editor but no WB Jr. shunt monitor, you just won't see any difference.

You might see what happens when adjusting the Classic's output current limit to 75 amps on a sunny day for that experiment.

boB

 

[BMcL]

I'll probably just get a 150 because I do want them to talk and use a Whizbang jr. But if I have 2 classics, do I also need 2 Whizbang Jr's? And 2 shunts?

I have two Classic 150's and I just ordered a WB jr with the 500 amp shunt. Thanks for the tip

 

[MrM1]

I still don't think that I have seen this "hack" paper?
boB

 

[MrM1]

I still don't think that I have seen this "hack" paper ?

I am also not sure what you mean by "charge current" here. Do you mean the current going only into the battery itself or the current coming out of the Classic ? If you adjusted the Classic's output current limit to 75 amps, that Classic should limit its output current to around 75 amps. Definitely less than 80 amps. Then there is a current limit adjustment in the Classic for INPUT current limit (PV current) which won't help you here most likely.

There is a battery charge current limit to the battery that requires the use of an external Whizbang Junior battery shunt monitor. Do you have that connected to the Classic ? That will limit the current into the battery but let the Classic output the complete output current limited by the
I am guessing that this is the "hack" you have spoken about but I am not sure. I will now Google for that white paper using some specific search terms.

boB

I do have a Whizbang Jr. And yes I think we are on the same page.

The white paper (above. I got it a few years ago off the MN forum from someone?) let's the user set a battery charge current limit that only effects battery charge current without effecting total output of the classic. So I can change batteries at say 50 amps max but still be able to get another 44 amps out of the classic 150 for loads

 

[MrM1]

Since you guys are talking about WB Jrs and stuff, I will assume that this "hack" has to do with that feature of limiting the "battery" charge current. It is probably called a hack because you have to go into a special modbus editor to change the adjustments rather than going in to a regular menu item in the MNGP remote. It's a round-about method until the menus get updated.


boB

Yes This ^^

I wasn't looking at the paper when I called it a "hack". It's the WBjr Limit using modbus (whatever that is ?). I just think of an idea, and you guys come up with a solution. Then I just read it and follow the directions. I have no idea what I'm doing, and no idea what I'm talking about.! LOL

 

[SpongeboB Sinewave]

WheW ! Glad I finally got it !

I'm old and a little slow

 

[MrM1]

I'm typing all this on a phone, no wonder my links don't work.

And I developed double vision back in June, It's a wonder anything I say/type makes sense.

 

[BMcL]

WheW ! Glad I finally got it !

I'm old and a little slow

I think you're a genius, so guess how I feel ! LOL

 

[MrM1]

You're in no danger of damaging them until you hit 105+C.

That said, any electrolytic capacitors nearby will also get heated up by the FET heat dissipation, which can lead to dramatic shortening of lifespan. That's something I'd ask midnite about.

Thanks for the info

Today, as it is a perfectly clear day, I set the Classic back to 94 amps at 24v output as a test.

At 2600w (which is about where the classic clips), and 94 amps, the FETs and PCBs are as follows

 

[MrM1]

And now 10 later...

 

[MrM1]

It seems more than fans, the way to keep the FETs and PCBs cooler is to lower the output amps of the classic to 85-89 amps.

All this tells me the heat does not appear to be a product of over paneling, BUT rather from the classic running at max wide open full output

 

[MrM1]

After the classic hit 90c at 94 amps out put I placed a large fan in front of it. (already had the 120mm pc fan running)

After 20 min with the big fan there is not much change in the FET temp



FET and PCB temp after 20 min

 

[MrM1]

And 6 min later, even with the big fan and things are worse

 

[Wibla]

Would be interesting to know the location of that PCB sensor - if it's close to the capacitors, they'll probably be fine, as long as they're rated high enough.

 

[MrM1]

Would be interesting to know the location of that PCB sensor - if it's close to the capacitors, they'll probably be fine, as long as they're rated high enough.

That would be a question for @SpongeboB Sinewave

 

[Tecnodave]

Best way to destroy high quality electronics, Run it at full max on a very hot day.

 

[MrM1]

Yeah just dropped output amps of the classic to 85 amps 10 min ago. Unplugged the big fan

FETs dropped to 80.6c
PCBs dropped to 71.3c