Max charging current while charging 72v nominal battery bank Classic 150

[Watt]

Hello again folks.

My question is what to limit the charging current to while charging a 72v nominal battery bank with the Classic 150?  I will be using solar if that matters.


Thank you.

[Westbranch]

Make, model size of battery and manuf charging recommendations are needed for an answer to be worked out. Array specs etc too would help.

[Watt]

Thank you for the reply but, I am not worried over the specs of the batteries accepting the charge, they are 1000ah cells.  The array is not an issue for me either as I can add and delete as required. 

My question relates to the limits of the charge controller.  The Classic 150 safe setting at 72v nominal. 

Thanks again.

[Westbranch]

As an example using a 120W 12 v panel with Imp of ~ 6.84 A, you would need ~ 15 panels to charge a 12 v battery at 10% rate.

To charge a 72 V battery will need 6 x 15 ~ 90 panels.  less if you use higher V panels

Still, that is getting to be pretty large array...
and you have to be able to wire them in series to get ~72V (nominal) or at least 85V of PV output  PLUS  consideration of the  temperature correction coefficient for your location to make sure the CC can handle that over voltage.

[Watt]

Thanks for the information.

I am after the current limit setting.

Here is what I am after.  http://www.midnitesolar.com/images/classicFrontPage/graphs.php

Where the 150 is in question and 72v is the nominal voltage for battery bank.  What is the max current I should include in my settings of the 150. 

thanks again.

[boB]

Thanks for the information.

I am after the current limit setting.

Here is what I am after.  http://www.midnitesolar.com/images/classicFrontPage/graphs.php

Where the 150 is in question and 72v is the nominal voltage for battery bank.  What is the max current I should include in my settings of the 150. 

thanks again.

Are you charging a car ??

Right now, the 72V battery current limit, I think, is the same as 48V current limit for the
various input voltages.

boB

[Watt]

Thanks Bob for your reply.  That's exactly what I was looking for.  Just didn't see it in black and white and didn't want to assume anything.   No, this is not a car application.  Hmmmm.... Nah, better not ever go there.   

I've been playing around with different panel configurations and with and without the classic.  I've charged 12, 24, 48 and soon to be 72v  battery groups looking for the best output and total watts for these panels.  I think my playing doesn't mean a thing but, seems the higher voltage being charged the more watts available through the classic into the batteries.  I don't know though but, I just have to experiment and see what I can see.  Anyway, I've got a tripp lite 3kva UPS coming that operates on 72v.  I know the efficiency is not so good for the UPS but, that's all I could find that would operate at that voltage.  Just want to try a wind turbine and some panels at that voltage just to see what I can see. 

[Watt]

I've rewired my battery bank to 72v and have programmed the classic 150 for a 72v nominal battery and all works good with the one concern.  I hear a bit more noise from the classic, kind of a high freq. noise of sorts.  Works good like this, although I have not had a chance to check the output as I've had clouds daily since the change, but the noise is a bit of a concern.  Anyway, thanks for the help so far. 

Next is a higher voltage neo turbine with the classic 150 if this 72v solar works out. 

Awesome Classics by the way.

[Vic]

Hi Watt,

Out of curiosity,  what are the PV module specs?
What string voltage are you running @ STC?
Vic

[Watt]

Hi Watt,

Out of curiosity,  what are the PV module specs?
What string voltage are you running @ STC?
Vic

3 panels per string and 9 panels total currently.  I am building this array with more panels coming.  I've been buying as I can afford them.  I've seen well over 750 watts just with 3 panels connected in a total of 1 string.  I have yet to watch all 9 panels output as I have been away or it has been cloudy or raining. 

Canadian Solar

Model   CS6P-230-P
Power (W)   230 Watts
Open Circuit Voltage (V)   36.80 Voc
Short Circuit Current (A)   8.34 Isc
Maximum Power Voltage (V)   29.60 Vmp
Maximum Power Current (A)   7.78 Imp

[Halfcrazy]

This noise is most likely the inductors. When the Input voltage gets close to Battery voltage the Inductors sing. This happened in the MX/FM series as well. There is a mode in the Tweaks menus called "LMX" or LoMax this if turned off will keep a spread of voltage between the 2 and should quite the inductors down. This noise will not hurt anything but some people do not want to listen to it.

Ryan

[Vic]

OK Watt,

Thanks for the detail on your configuration.

HC answered the question.  Very nice that the Classic has all of that flexibility!

Vic

[Watt]

Thank you both for your reply.  Today is the first full clear day ( so far ) I've had to compare the ouput to the 48v and 24v charging scheme.  I have to tell you I am impressed.  It is 1:30ish pm and with just three of the 230w panels hooked up in series at 72v they have already produced more power at 72v than the other ways connected.  3.2kwh so far.  Also, the fans on the classic have not come on and the classic is cool to the touch. Before with 24 volts the fans really run and was warm with an ambient air tem around 50 to 60 degrees f during the day in my garage.  At 48v, the fan did run occasionally and was also warm at the same ambient temps.  I mean, this thing is actually cool and the garage is a little warmer today because outside temps are warmer today than days past.  I am running loads on the Tripp Lite UPS just as I did the other 48v UPS and 24v sine inverter units.  The best I did with 24v was 3.9kwh and at 48v was 4.1kwh.  As I said, there is really no control in place but, just a country boy playing.

Anyone know of a 72v actual inverter?

Thank you again for the suggestion HC but I can live with and actual enjoy knowing the thing is doing something. 

Just starting on a higher voltage wind turbine today.  20 pole 2x1x.5" direct drive axial. 

Oh ya, with this Tripp Lite, I did not have to disable the arc fault like I did with the 24v inverter and occasionally did with the apc su3000rmnet ups.

[Watt]

Well, it's 3:45ish pm and so far the classic indicates 4.7kwh for the day out of the three panels.  I'm impressed whether that means anything or not.  Still a couple more producing hours of daylight to go, although, the fixed panels won't produce much as the sun is pretty well down by 5:30pm.  Anyway, that's the end of that.  Just gonna keep it going for another week or so to see what the average is.  Thanks again.

[Watt]

5.4kwh for the day.  Out of 690 advertised watt array fixed on the roof.  I'm happy.  I only ever counted on 3.8kwh per 3 panels.  < smiling and grinning >.