Adding Vents to the Classic 150

Started by Matrix, March 07, 2018, 12:38:58 PM

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Matrix

FYI ... the room temp today at 1pm EST is 62*F (a bit cooler than yesterday) ... but the FETs 62.1C (or 144F).  My production on this again cloudless day is almost the same at the same time from yesterday. 

I did just put a small fan to the left of the CC blowing across it,  and the temp dropped to 57.7C.   

I also just purchased the 15.5x8.25x1 heat sink.  So that will fit all the way under the CC.  I hope to NOT have to leave a fan on it .
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REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Vic

Hi Matrix,

Thanks for all of the added data and the graph.

It would surprise me,   that your PV array could produce much more than about 1900 watts at prime sun,   sustained,   in FL,  unless the outside temps were cold.

The graph shows WB current,   but probably you have only the inverter tare as a load before the Absorb stage.   IIRC,   that peaked at about 65 A,  which would be the approx expected current if all of the PV power was going into the battery.

Have seen that a fan  blowing onto Classics can reduce the temperatures reported a bit.   At some point,   one might wonder about an external fan disturbing exit airflow from the slots in the upper part of the Classic front cover.

The heatsink  with its fan  seems like it could help a reasonable amount.

Will look for your report on that.

IMO,  your PV array it not too large.  If one was concerned about the heating of the Classic,   the output current could be limited,   BUT,   that would reduce power into your Dump load,   obviously.

FWIW,   just a drive-by post,   good luck,  Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

mike90045

I too, had thermal issues with a 2Kw array into a classic 200.   Always toasty hot, and primary fans running.  I finally
moved the cover to the side (keeping it bolted on for more thermal mass, and  use a cheap fan on a timer to blow cold ground level air, to the base of the classic.  Worked for 2 summers now.  Battery shed gets to about 95F daytimes, when it's 100F outside.
http://tinyurl.com/LMR-Solar

Classic 200| 2Kw PV, 160Voc | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph )| Listeroid 6/1, st5 gen head | XW6048 inverter/chgr | midnight ePanel & 4 SPDs | 48V, 800A NiFe battery bank | MS-TS-MPPT60 w/3Kw PV

Matrix

Thanks Vic,

Yes I did order the one heat sink from ebay today.   It does not have a built in fan ... but that would not be that hard to install in run off AUX 1 ... IF ... I could also use AUX 1 to continue to power my SSR.  I guess it could do that if i had a 12v fan? Yes?  Then the fan would come on when the dump load came on ... which is at least part of the reason for the higher amps and heat.

But I am wondering,  any chance I might be having some trouble with the internal fans of the classic?  It's 4 months old.  I would guess not,  but the temps (before I blew a fan at it - and before today's lower temps) did seem quite hot and my concern is not now ... but when summer hits.
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Matrix

Quote from: mike90045 on March 08, 2018, 05:30:07 PM
I too, had thermal issues with a 2Kw array into a classic 200.   Always toasty hot, and primary fans running.  I finally
moved the cover to the side (keeping it bolted on for more thermal mass, and  use a cheap fan on a timer to blow cold ground level air, to the base of the classic.  Worked for 2 summers now.  Battery shed gets to about 95F daytimes, when it's 100F outside.
Not sure I follow you with the "moved the cover to the side" ... as it took it off,  or left it bolted at the top and swung it to the side?  Pics? 

If it's not my internal fans,  I still think drilling holes in the front cover near the bottom would help,  especially if I had a fan blowing up from the bottom on the outside.
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Vic

#20
Matrix,

A   12  V fan should be fine,   it should not need to move too much air.   Try it to see how it works.   Many/most 12 V fans do not need more than about 200 mA of current,   but look at the specs   ...

The two internal fans in the Classics  are high quality Ball Bearing type fans.   They will generally last a long time.

boB,  of course knows how hot,   is a HOT Classic.  But,  to me,   a Classic that is approaching  70 C,   is warmer than I would like to run any electronics,   particularly,  power electronics.   Electronics,   like the Classic,   are often operated for long periods of time when charging batteries and/or running opportunity loads.   70 degrees C   is often the maximum temperature limit the Commercial temperature limit for semiconductors.   MidNite may have specified  some of these devices that will tolerate higher temperatures,  like 85 C.   But,   still  there are other components inside Classics that benefit from cooler temperatures that those that your Classic is "seeing".

In time,   perhaps you may choose to add a Classic  to divide the work,   or,  perhaps better yet,   upgrade to 48 V ...   OH,  that is expensiver.

Forgot to add the following attachment,   last PM,  from the Classic Sizer,   which shows that you should be OK.   Had to guess about your temperatures.

Should add the obvious,   that if you were running strings of two PVs,   instead of three,   that there would be a bit less heating in the Classic.   But,  this might be difficult, with  possible racking and cabling issues,  reduced power if you dropped back to eight PVs,     etc ...   

And,   so on,   Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

Matrix

Thanks ... yeah that is the numbers I get with the sizing tool too.  And to think ... I WANTED TO MAKE A LARGER ARRAY. I think I could do a 3s4p of 285w panels ... as long as they played nice and only operated at there 214v nominal rating.  But honestly,  at 80*F the other day.  I saw the array produce 2306 Watts for a few minutes at solar noon.    That equates to 256 watts per panel and if I increased the array to 12 would be 3074 watts.  Might be a bit too much.

Any way,  here is what I saw for temps in the control room today.  Keep in mind the outside temp did not get above 65,  but I think the control room yesterday was NOT the source of my over heat.  I will continue to monitor as the temps rise.  Also note,  at 12:30-1:00 pm I did put a fan on the CC.  So you can see the FET temp drop by about 5*C.   The spike in the room temp before lunch as due to use opening the garage door. 

Note: the times in the charge on top correspond to the times in the MyNidNite2 chart
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Matrix

Quote from: Vic on March 08, 2018, 05:23:24 PM
Hi Matrix,

It would surprise me,   that your PV array could produce much more than about 1900 watts at prime sun,   sustained,   in FL,  unless the outside temps were cold.

It surprises me too ... but for now ... it does.   At 12:08 pm yesterday,  with highs around 82*F,   I was seeing about 2225 watts for a small block.   Managed to product a total of 12.5 kWh yesterday
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

mike90045

 left it bolted at the top and swung it to the side, still soaks up a lot of heat from the base chassis
http://tinyurl.com/LMR-Solar

Classic 200| 2Kw PV, 160Voc | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph )| Listeroid 6/1, st5 gen head | XW6048 inverter/chgr | midnight ePanel & 4 SPDs | 48V, 800A NiFe battery bank | MS-TS-MPPT60 w/3Kw PV

Matrix

#24
Ok ... Holes are not going to help me a much. I have the 2 lower screws removed from the face so that I could swing the entire bottom of the case open 1/2".  So I have a 1/2" gap across the entire bottom. 

And today's numbers

- Out side right now 65.8°F 
- Control Room Temp 67.5°F
- FET 150.3°F / 65.7°C
- PCB 135.5°F / 57.5°C

So conditions outside and current charging conditions are similar to my first post,  but even with a large lower vent,  I get almost no change in FET / PCB temps

I did put a small fan on the CC a few days ago and that dropped the temp about 10-15°F.   Going out now to power on that fan. 

But I will have the 15.5" x 8" x 1" heatsink arriving today.  Will mount it tomorrow.  Will check numbers.  And then if necessary I will I have a 12v 4" PC fan I can mount next to the CC to blow across it that I will connect to AUX 1 Waste Not Hi to come on when my dump, water heater load comes on which will help too.

Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Matrix

Little fan running to the mid left of the CC for just over 30 min (even with the 1/2" gap of the opened up CC case) and the temp has only dropped from 150.3°F to 144.9°F.    Room temp is 66.7°F
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Vic

OK,   and,   with that heat sink,   ideally,  its fins should be vertical,   allowing natural convection to cause air flow from the bottom to top of the sink,  AND have the sink  having  good contact with all/most of the Classic casting   ...   if possible with that heatsink.

Loosening the Classic mounting screws,   and opening the top cover to be open at the bottom reduces the thermal conductivity between the back of the case.   This reduces the convective/convective cooling of the Classic.   The added fan helps alleviate this.   But,   a good experiment.

    FWIW,  Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

Matrix

#27
Quote from: Vic on March 12, 2018, 03:06:39 PM
OK,   and,   with that heat sink,   ideally,  its fins should be vertical,   allowing natural convection to cause air flow from the bottom to top of the sink,  AND have the sink  having  good contact with all/most of the Classic casting   ...   if possible with that heatsink.
The 1" thick fins will indeed be vertical and the sink will be larger than the CC.  So it should be really good.

But I hear what you are saying about having the cover partly removed.  So Adding Air Holes still might be better than the 1/2" gap.   ??
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Vic

Hi Matrix,

Thanks for the info on the heatsink.  That should be about as good as one can do for external heat removal from Classics.

It is difficult to say just  how much benefit might result from adding some holes in the bottom of the front cover.

Going to two of your PVs per string  would also help,   but,   that too is difficult to quantify.   There is no curve in the Classic manual for 70 V Vmp PVs,   just one data point,  @48 V,   IIRC.   Realize that restringing your existing PVs from strings of three,   to strings of two  would be a bit of a task,   and  probably would result in eight,   rather than nine PVs (at least initially),  and so on.

Good Luck,   and thanks for reporting your future results with the heatsink and fan.

Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

Matrix

#29
One Heat Sink in hand.  Should fit perfectly.   Probably tomorrow. 
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install