Wondering if there is any advantage to adding perforated 1/4" (+/-) size holes to the lower section front cover below the fans of the classic 150. I seem to run a touch on the hot side ... Bat 86*F / FET 154.6*F / PCB 136.6*F / WB Jr Shunt 84.2*F. The array is producing 2100 Watts and it is 68* F outside. In the summer we will be up near 100.
Of the 4 pre cut screen covered air holes in my classic, the one on the left side got used for incoming data and the one on the bottom left got used for incoming power. All I have open is the one on the bottom right and side right. The SW inverter's MidNite Solar Switch Gear box sits 2 inches from the right of the Classic. The box is fully vented and when the SW needs cooling it does send air from Right to Left thus sending a cool lite draft toward the CC. But would it help matters to drill several vent holes in the front bottom of the classic face plate and cover they with screen on the inside?
Would that void the warranty?
I do have the Classic mounted on plywood, BUT, the whole CC is raised up off the ply about 3/8's " so air can move all the way around the Classic. I am sure not as good as mounted on a heat dispersing piece of aluminum, but probably better than flat on the ply wood.
Matrix,
Looks like the power room is HOT, based primarily on the Tbat.
That 155 F temperature is about 68 C, the Classic is HOT, HOT.
All of your power system will have temperature rises above ambient temperatures. If you can ventilate/cool the room everything there will be cooler, at least with present outside conditions.
Drilling additional holes for more air inlet for the Classic should help a bit.
Mounting the Classic on a finned Al heatsink which has its own fan should help.
BUT, really, the room seems HOT.
What is the measured room ambient temperature?
Thanks, Vic
I also believe you are pushing the classic too much considering the environment it is working in...
look at page 11 of the online manual and you will see the max values 91 Amps, 2611W at 28.7V.
My quick estimate is that you are pushing/crowding those maximums...
The high temps on those batteries is worrisome too...
As stated by Westbranch and Vic (two of the smartest guys on the boards) you might be running your system too hard for the environment it is in.
The entire outside case acts like a heatsink, mounting it on plywood is not doing you any favors. I have a couple of customers in the deserts of Utah and California that swear that mounting their Classics on Aircraft aluminum drops their temperatures by 10 to 25 degrees. I can not confirm those numbers, but that is what they say.
If the room you have the equipment in is not providing enough ventilation drilling holes in the Classic is not going to help. The Classic pulls incoming air from the bottom, up through the body and out of the top. If you can keep the lower screens empty and bring cooler air to that part of the Classic, it might help.
Personally I find it much easier to change the environment rather than messing with my system once I have it working.
-Kyle
Quote from: Vic on March 07, 2018, 02:55:21 PM
Matrix,
BUT, really, the room seems HOT.
What is the measured room ambient temperature?
Thanks, Vic
The room is basically the temp of the out side ... even cooler. Todays hi was right at 70* and the room was lower by a slight bit. Why is this CC getting so hot. My array is 3S3P and 2565 Watts STC producing up to 2250 Watts. Voltage coming off the panels is 88-98v
Quote from: Westbranch on March 07, 2018, 03:32:29 PM
I also believe you are pushing the classic too much considering the environment it is working in...
look at page 11 of the online manual and you will see the max values 91 Amps, 2611W at 28.7V.
My quick estimate is that you are pushing/crowding those maximums...
The high temps on those batteries is worrisome too...
Should I limit the Amps in the CC limiter?
Right now the outside temp is 57*
The batteries which are not in the same room but in a vented box in the shaded carport next to this room are at 29C discharging at 10 Amps DC. The FET of the Resting for the past 3 hours is 43C / the PCB is 33C
Does that sound right for a CC in a room that would be about 60*F?
I can go home and measure the case temp with my temp gun.
But is my Array just too big? How do I solve this? Decrease the Amps?
OK temp in the room right now is 72*F.
The case of the CC is 72f and if I shot down into the top vent with my temp gun I am getting about 84*F. The CC has been resting for about 3 hrs now.
The recorded FET on the local app reads 43C and the PCB reads 33C Seems awful hot for a unit that is resting for 3 hrs.
Would something like this help with the fins going away from the CC sitting underneath on the ply wood. I know it would not cover the whole CC but it would cover most of the area of the electronics
https://www.amazon.com/dp/B073R5GRHT/ref=psdc_2998409011_t3_B00EY70R0S
Or would this be better?
https://www.ebay.com/itm/Used-large-finned-aluminum-heat-sink-measure-15-5-x-8-25-x-1-/162922166901
And I found this which would be the perfect size, but much more expensive
http://www.mpja.com/15-3_4-X-7-13_16-X-2-Large-Aluminum-Heat-Sink/productinfo/33306+HK/
68 degrees C is kind of warm but not too hot. If that's all the higher it gets you're probably fine.
If you want to, try a wall-wart driving a fan pointed at the Classic.
BTW, what is the input voltage, output current and voltage ?
boB
Here is what today looked like.
Highest FET was 69.6C (Pink)
Charge Battery volts highest was 31.8v (Yellow)
Highest PV voltage was 105v (Red)
Highest charge amps was 67 amps (Orange)
Total KWhs was 12.5
As a foot note, this is the largest single power production day I have had in 4 months since I brought the system on line.
I also just tonight added a digital wall mount room temp gauge to the room that is programed to my weather station so I can read and graph the room temps through out the day. So I will have a room temp graph for you tomorrow. The temp gauge is mounted 2 foot from the CC and other electrical equipment.
Quote from: Matrix on March 07, 2018, 10:06:27 PM
Here is what today looked like.
Highest FET was 69.6C (Pink)
Charge Battery volts highest was 31.8v (Yellow)
Highest PV voltage was 105v (Red)
Highest charge amps was 67 amps (Orange)
Total KWhs was 12.5
What about the battery temp?
That high FET temp seems to have come down, ist it possible you had an EDGE of CLOUD event while taking the readings?
Quote from: Westbranch on March 08, 2018, 11:27:00 AM
Quote from: Matrix on March 07, 2018, 10:06:27 PM
Here is what today looked like.
Highest FET was 69.6C (Pink)
Charge Battery volts highest was 31.8v (Yellow)
Highest PV voltage was 105v (Red)
Highest charge amps was 67 amps (Orange)
Total KWhs was 12.5
What about the battery temp?
That high FET temp seems to have come down, ist it possible you had an EDGE of CLOUD event while taking the readings?
It was a full sun no cloud day yesterday.
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 .
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
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.
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.
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.
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
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
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
left it bolted at the top and swung it to the side, still soaks up a lot of heat from the base chassis
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.
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
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
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. ??
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
One Heat Sink in hand. Should fit perfectly. Probably tomorrow.
I'm mounting it fin side "down" with the smooth side toward the classic. That would be the correct way yes?
Yes that should give you max contact between Sink and Classic
Quote from: Matrix on March 12, 2018, 06:00:02 PM
I'm mounting it fin side "down" with the smooth side toward the classic. That would be the correct way yes?
Yes. Hope that the back (un-finned side) is fairly flat.
Conductive grease (while messy) might help heat transfer from the Classic's back side, and the heatsink. Probably too obsessive.
Looks nice, have fun, Vic
Quote from: Vic on March 12, 2018, 07:57:21 PM
Quote from: Matrix on March 12, 2018, 06:00:02 PM
I'm mounting it fin side "down" with the smooth side toward the classic. That would be the correct way yes?
Yes. Hope that the back (un-finned side) is fairly flat.
Conductive grease (while messy) might help heat transfer from the Classic's back side, and the heatsink. Probably too obsessive.
Looks nice, have fun, Vic
It is indeed perfectly flat. Seems like $42 dollars well spent. :D And my PC repair friend already volunteered his heat sink grease, but I understand that stuff is toxic. lol.
Back in the day (aka 1992) we used to use Desitin Diaper Rash Cream in a pinch if we did not have any heat sink grease for CPUs ... lol
I am wondering if I have this correct - you are trying to squeeze every bit of power from your PV and you run it into an electric hot water heater to make sure you do right ? And you are concerned about the Classic getting too hot in the summer ? Wouldn't it be easier to just heat the water using a simple hot water heating panel ? I think you are in Florida right ? You don't even have to worry about things freezing down there like we do up north. Maybe still would want to have a heat exchanger. But with that extra power seems like you could run an air conditioner which would help cool your house and if you had the system in cooled space it would also keep your controls and battery cool too. That would seem like a more practical use of the energy in that it would increase the life of your equipment too especially the batteries.
Larry
Not liking the sound of CC fans running a lot I mounted a 120v muffin fan above my Classic 250, already had a SSR and outlet handy, runs when there's "daylight" (aux 1 option). Never hear the CC fan run now/yet.
Quote from: ClassicCrazy on March 13, 2018, 12:49:49 AM
I am wondering if I have this correct - you are trying to squeeze every bit of power from your PV and you run it into an electric hot water heater to make sure you do right ? And you are concerned about the Classic getting too hot in the summer ? Wouldn't it be easier to just heat the water using a simple hot water heating panel ? I think you are in Florida right ? You don't even have to worry about things freezing down there like we do up north. Maybe still would want to have a heat exchanger. But with that extra power seems like you could run an air conditioner which would help cool your house and if you had the system in cooled space it would also keep your controls and battery cool too. That would seem like a more practical use of the energy in that it would increase the life of your equipment too especially the batteries.
Larry
Thanks for the suggestions ... Im very new at all this (as you can tell)
Yes the water heater is a simple dump. And yes concerned about the CC getting too hot in the summer because it gets as hot as it does now in temps at 65°F in the room, and that is not even with the excess power dump being on (it does not get any hotter with the water heater on, although it does stay hot longer at the same temp with the use of the excess power). My big concern is, if this hot now, what about when summer comes.
I did not think I had enough power to run an AC reliably. But man that is in the though processes, at least for one 14x14 small bed room. I thought about a mini split, but even the hi SEER ones seem to still want 11 AC amps which would be a large demand from the solar, or a large drain on my 24v battery bank. Still kicking my self I did not set it up 48v from the beginning. (I just was not seeing things clearly). I am right now leaning toward the smallest of small window units as they can be as low as 4.5 AC amps for the 5000 btu models (I think). Seems that might be more realistic on my loads. would still pull about 12-15 DC amps at 24v.
And Yes I have thought about running the water heater from 3 solo panels. A friend of mine want to set up a system "just like mine" (I am trying to steer him to 48v, but if he does not want that route he will by my gear) ... but when / IF he ever does ... I will tag on about 6 more panels for myself in his freight order. 3 for a solo water heating system, and 3 for storage in case of damage and back up.
But right now, the biggest hog to my AC consumption is the water heater, and this is about the only thing I could power off of a diversion load that is on again / off again. water heating is not mission critical as the top is still AC connected, so we get about 10-12 gallons even if the sun does not shine. But if it does, the top never comes on. = less grid power. I cut my typical historical February power bill in half this last month.
But none of it is worth much if I melt down the CC ???
Larry, you also mention cool batteries.
What is a good charging temp for batteries? I thought the happy spot was about 25°C, with 30-35°C for the upper end of the charge amp intake (like when the amps are hi or you are doing an EQ) is OK. What kind of temps am I looking for at different points in the cycle? At night for loads, in the day for heavy charging?
Heat Sink installed, but I do not know how much good it will do. Seems the plastic "channel" (maybe) that goes up to the top vent of the Classic does not allow for full good metal to metal contact of the Classic and the heat sink. Kinda disappointed with that.
There is metal to metal contact, but not everywhere and not really good at the places that would be the warmest.
I wonder, can that plastic "channel" in the back of the classic to the top vent be removed? I am guessing it is needed. But it does stick out further than the metal case by a few millimeters, just enough to keep from being a tight fit of the case and heat sink.
Any way. Here is the install ...
But not sure why this sink, the way that the case did not lay tight to the sink, is going to be better than 1/2" stand offs from the ply wood that i had before so that Air could move all the way around the CC. We will see. I will get the temps today. But the fore cast hi supposed to be 66°F so not really a heat wave 8)
Quote from: ralph day on March 13, 2018, 07:49:37 AM
Not liking the sound of CC fans running a lot I mounted a 120v muffin fan above my Classic 250, already had a SSR and outlet handy, runs when there's "daylight" (aux 1 option). Never hear the CC fan run now/yet.
What is your set up that you never hear the CC fans run? How is the CC installed? On Metal?
Mine came on 5 minutes after I switched the CC back on and the room was at 49°F. My system at 10am began to run in Bulk and was producing 1200wattts about 45 amps charging my 435Ah 24v battery bank. The fans came on within 5 minutes. The FET temp was at about 48°C.
Hi Matrix,
That sink, with the Classic on top looks good.
Believe that you could "mill" the part of the air channel for the Turbo fan down a bit on its back side. Perhaps you could use coarse sandpaper that is on a flat surface to do this.
As you know, this air channel guides air up, and around the heat dissipating nibs that are behind the FET mounting rib. If you need to mill so much of that air channel that there is a bit of a slot formed between the plastic air channel and the Classic case, you could carefully caulk any gap with Silicone caulk.
Am certain that the back of the Classic case is not truly dead flat, but your heatsink will be an interesting experiment, and your reports on its function will be beneficial for many of us here.
Yes, Larry is correct about your batteries;
Heat is the real killer for LA batteries. Your batteries are OUTSIDE (in FL), in some type of box. This will expose them to outdoor temperatures, AND the box will probably trap some of the heat that comes along with Gassing (Absorb and EQ stages). This will certainly shorten their lives.
Here, we do A/C the power room, and that A/C has priority, over A/C in living spaces.
More later, Vic
Quote from: Matrix on March 13, 2018, 11:08:26 AM
Quote from: ralph day on March 13, 2018, 07:49:37 AM
Not liking the sound of CC fans running a lot I mounted a 120v muffin fan above my Classic 250, already had a SSR and outlet handy, runs when there's "daylight" (aux 1 option). Never hear the CC fan run now/yet.
What is your set up that you never hear the CC fans run? How is the CC installed? On Metal?
Mine came on 5 minutes after I switched the CC back on and the room was at 49°F. My system at 10am began to run in Bulk and was producing 1200wattts about 45 amps charging my 435Ah 24v battery bank. The fans came on within 5 minutes. The FET temp was at about 48°C.
A number of us have the luxury of NOT having our power electronics IN living spaces.
The Power Room here is a sea-going Cargo Container, 225 feet from the Cabin (in one case). Cannot hear any of the system acoustic noise from this system, when outside, near the cabin.
Assume that the Classic in in your living space, somewhere. AND, perhaps this is why your batteries appear to be outside (?).
Anyway, I am NOT Ralph, but this was just my design choice. FWIW, Vic
Thanks Vic for the info. The good news (if you can call it good) my batteries are in a box yes, but in a car port which will shield them from direct sun and full summer heat, but I might just add 2 more 16" x 4" vents across the top for extra head and gas release. I have it built so I can put the foam cut outs back in for winter to almost completely seal it off except for enough for gas venting. My control room is an attached garage, it has ventilation from under the house which helps keep it cooler than the outside air in summer. but nothing is AC'ed
And I probably should have waited until I could fully test the heat sink by itself .... but I had the fan and time ... so I installed a 4" PC fan connected to AUX1's SSR that controllers the AC water hearter. Whenever AUX 1 comes on and sends 1150 watts to the water heater the fan comes on.
I actually have 2 fans on hand. The one I installed is a 4" that provides a nice gentle blow over the Classic. It should probably work, BUT ... if it does not, the other one I have is about 1/2" thicker, and provides a small hurricane of wind that would blow over the CC. The first one pulls .07 amps, the other pulls .85 amps. So it moves a good bit of air. If the smaller / quieter one does not produce successful results, I will swap to the higher amp fan.
Here is how it looks so far. The SSR connection is in the bottom right corner of the last open pic, and is itself on a small heat sink
Quote from: Vic on March 13, 2018, 11:20:22 AM
Hi Matrix,
That sink, with the Classic on top looks good.
Believe that you could "mill" the part of the air channel for the Turbo fan down a bit on its back side. Perhaps you could use coarse sandpaper that is on a flat surface to do this.
As you know, this air channel guides air up, and around the heat dissipating nibs that are behind the FET mounting rib. If you need to mill so much of that air channel that there is a bit of a slot formed between the plastic air channel and the Classic case, you could carefully caulk any gap with Silicone caulk.
Am certain that the back of the Classic case is not truly dead flat, but your heatsink will be an interesting experiment, and your reports on its function will be beneficial for many of us here.
I am wondering what a piece of copper shim, slightly thicker than the plastic air channel would do if I made it the size of the back of the CC and cut out for the air channel so that the air channel was no longer a problem. That way all metal on the CC would contact copper and all the copper would contact the sink.
A friend of mine who does computers said there was once a lap top model that was over heating and being recalled, but people like him were fixing them with copper shims ... similar but on a smaller scale to what I'm doing. He is shopping for me some copper today about the thickness of a quarter. That should do it. And should get me great contact and heat transfer.
So what is a Good Battery Killing Temp? What should be the target for discharge and charge temps?
BUT ... I just had a massive brain thought !!!!!
Because my battery box sits next to my house, and I have a craw space that is 4' tall, AND my lower vent of the battery box is facing the house (and pulled off the house about 3"s. But I could easily add a 4" piece of PVC pipe or 2 from the bottom of the box, and up under the house to draw cooler summer air from up under the house effectively cooling the battery box even more. And added benefit, it the winter, my under house is ALWAYS warmer than the outside air, so it would possibly also help warm the batteries in the winter. Hmmmmm ???
For that matter I could run a 2nd 12v 4" fan off AUX 1 in the pipe to blow under house air into the box from the bottom. It would vent out the top. So gas mingling with sparks / archs from the fan would not be a problem BC the fan would be low (gas rises) and not even in the box ... it could be mounted several feet away on a pipe.
Well update after 45 minutes of Fan
Water heater is heating, Fan is blowing, Charger is finishing up the batteries and the CC is pumping out 46.1 amps.
Out side air is not really a factor at 55°F
But the control room is 63.1°F so pretty close to yesterday.
But the Temps on the FET / PCB is the lowest it has ever been.
Not much of a test yet, but I will let you know know as the week progresses and we warm up. So far so good
Well the larger amp 4" fan wont work. Keeps shutting the CC down and causes it to restart. OR at best you can hear it drag down the RPM of the internal fans. So I guess I am "stuck" with the lesser amp 4" fan.
Good news is ... today the FET / PBC was the coolest I have seen.
Quote from: Matrix on March 13, 2018, 07:21:52 PM
Well the larger amp 4" fan wont work. Keeps shutting the CC down and causes it to restart. OR at best you can hear it drag down the RPM of the internal fans. So I guess I am "stuck" with the lesser amp 4" fan.
Good news is ... today the FET / PBC was the coolest I have seen.
The Classic can only supply so much power at the AUX relays - should be documented in the manual.
You would have to use a relay to get the larger fan to work.
I don't know what the worst temps are for batteries. The warmer they are the faster they age. Room temp is okay but lower than that is probably better since you need to compensate for the internal heating that happens when they are charging. Battery manual might have some temp compensation graphs showing what happens to capacity when they are either hot or cold.
Larry
Hi Matrix,
Yes, Larry is correct. The Aux outputs can only supply
*** EDIT: 200 mA of current (0.2 Amps) ***. If that is exceeded, believe that the Classic re-boots, as some of the control electronics in the Classic are also dragged below operating voltage. There is a self-resetting current limiter that protects the Classic from providing too much current on the Aux outputs.
On Flooded and other Lead Acid batteries, cooler is better. IMO, about 50 F would be fine.
For each 10 degree C (18 F) temperature increase above about 75 F battery life is halved, and for every 10 degree C decrease below 75 F, battery life is doubled. BUT, one must really look at average temperature for each day, as the total time spent at a given temperature is what counts, not just a momentary excursion.
Most batteries have a lot of thermal mass, so, their temperature change is relatively slow.
FWIW, IMO, Vic
Quote from: Vic on March 13, 2018, 10:07:16 PM
Hi Matrix,
The Aux outputs can only supply 500 mA of current (0.5 Amps). If that is exceeded, believe that the Classic re-boots...
Oh Yeah ... it does. :D My big fan was .7 amps and my smaller fan was .18 amps. both are 4".
I really dont need the big fan. I think I have the heat under control now for the CC. I will probably get some copper to space under it to compensate for the air channel, but other than that, I think I am golden.
the battery box and batteries probably will need better ventilation and I am thinking under house air might be the ticket. I just will not be able to run a 2nd fan off the AUX to push the air in from under the house as I might have thought. Unless you mean that the CC can supply 500 mA for each AUX. Could I run a small 2nd fan off AUX 2 that is running the Whiz Bang jR? It would be on all the time, but that would not bother much.
Or could I run a fan off the battery directly? 24v? Some way to step it down to 12v?
Thanks guys, you are the best. Very patient and helpful.
Here is a Quick and Dirty on Heat for anyone interested
http://batteryuniversity.com/learn/article/how_heat_and_harsh_loading_reduces_battery_life
Likely better to make the "shim" or spacer, from aluminum and not copper. Copper is a better thermal conductor, but you are making a sandwich of differing expansion coefficients.
Heat sink greases:
Beryllium is a good thermal conductor, but toxic. only a tiny bit better than copper
Zinc Oxide is an ok grease,
Silver powder is awfully good.
https://www.engineeringtoolbox.com/thermal-conductivity-metals-d_858.html
Thanks Mike,
Hey looking at your FB picks, I see a battery box in a building. How do you keep those batteries cool? OR maybe where you are temp is not that big of an issue. As I start to move into summer cooling is going to be my next project, cooling the batteries.
Also, how is that Battery Saver working out?
AND, Matrix:
Sorry, I was WRONG on the amount of current that the Classic Aux outputs can source. The correct value IS 200 mA.
I did edit the earlier post to correct that ...
Our battery banks sit in an insulated box. There is a hinged top cover, which always remains open, these days. A window A/C is above this box, about 3.5 feet. At times there is a 120 VAC circulating fan that runs on a timer, usually Spring, Summer, and Fall. There should really be two fans, ... someday.
Have never tried to retain battery heat in the Winter, as the climate here is fairly moderate.
Cooler is better for our FLA batteries, in general.
FWIW, Vic
OK, have not seen a temp on the FETs higher than 59°C since the install of the sink / fan. But not a good test day yet until today. Expect temps to "sore" to nearly 80°F outside. So today will be the test if I hit 70°C on the FETs as I have in the past at that temp.
matrix, my CC is mounted on my old Xantrex powerboard (metal) and the fan blows down from above. The basement temp is low 20's Celsius year round. I've heard the Classic 250 for my wind turbine run before, but not the solar Classic.
Ralph
batteries in a building. Yep, they just ride with the ambient temps. 95f days in the summer, 25f nights in the winter. But they have little self heating, and so are mostly just ambient
Quote from: mike90045 on March 14, 2018, 12:59:29 AM
Likely better to make the "shim" or spacer, from aluminum and not copper. Copper is a better thermal conductor, but you are making a sandwich of differing expansion coefficients.
Heat sink greases:
Beryllium is a good thermal conductor, but toxic. only a tiny bit better than copper
Zinc Oxide is an ok grease,
Silver powder is awfully good.
https://www.engineeringtoolbox.com/thermal-conductivity-metals-d_858.html
Got a nice piece of 28 gauge aluminum today. So all I need to do is cut it to size for a shim under the Classic.
Quote from: ClassicCrazy on March 13, 2018, 12:49:49 AM
... if you had the system in cooled space it would also keep your controls and battery cool too.
Larry
I did today add 2 additional 18"x2" vents to my battery box on the top for a total of 4. I already had one such vent at the bottom back as well, but it was backed against the wall with about a 3" gap.
So today I also, cut a 4" hole in the lower back of the battery box and added a 4" toilet drain top to 4" PVC pipe 18" long that now draws from under my house. I know that temps under the house are way cooler in the summer and warmer in the winter than outside air. So I am hoping this is a double win for both summer and winter battery temps.
I also have the option to close any or all of these now 6 vents.
We will see how the battery do the next warm day I charge. But already, with the install of the underhouse vent, I can feel a draft in the box.
FET, Classic Cooling and Venting the Battery box update:
Finally got some warmish weather today. 80*F hi out side.
- 15x8 heatsink installed behind classic. Found aluminum sheet metal to cut for shims for a more "full contact" connection with the sink
- 4" fan on the mid right of the CC that comes on when AUX 1 Waste Not Hi comes on.
- Doubled my Battery box vent on the top and added a 4" PVC pipe into the box at the bottom from under the house
Max Results and Temps today:
- Generated 10.5 kWh for the loads / dump loads and 24v battery bank
- Batteries got fully charged up to 1.286 SG in the lowest cell
-Heated the water in my 40 gallon water heater to 165*F
- FETs never went above 60.7*C (down from almost 70*C last time temps where this hi). 60.7*C was highest, but that temp only hit there 2 times thru the later part of the day and only for about 1 hour total. The average for the day once charging began was probably more like 56*C
- Battery temps Max inside the closed box never went above 28*C and again that was only for an hour at the end of the day. So down about 4*C.
Overall happy. And probably about the best it will be unless I AC the control room.
Battery Box vents attached:
Just as a point of reference, what should the Temp of the FETs be of a MidNite Classic at Rest?
- The sun went down over 4 hours ago
- CC is Resting: 4 Input voltage lower than battery voltage
- Outside temp is 68*F
- Control room is 73*F
- Battery Temp is 79*F
- Input voltage is 11v DC
- Battery Volts are 25.4v
- Discharge Amps range between 1-10 amps 24v DC
FET Temp = 46.4*C / 115.5*F
They never seem to get any much cooler than that, regardless of room temp. Is the FET supposed to stay that warm all the time?
Yep. I've noticed the same thing. Even pre dawn, that classic is sucking some watts to heat the boards and fets on the heatsink that warm.