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Gabriël

inverter temperature

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i just ask 'cause ours spiked at 68 yesterday but averaged at about 52

herewith another question; how do i set the axpert to just charge the batteries from grid until about 04:00 as there is no need for them to be kept 100% until first light?

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On 6/27/2017 at 8:11 PM, gabriel said:

i just ask 'cause ours spiked at 68 yesterday but averaged at about 52

herewith another question; how do i set the axpert to just charge the batteries from grid until about 04:00 as there is no need for them to be kept 100% until first light?

Does it have enought ventilation?

and how is the ambient temperature in the room where the inverter is installed?

The Axpert inverter can't be set to stop charging at a certain time of the day, but it will stop charging as soon as the batteries are full. I set my charge Ampere to 2A which helped a bit with the Eskom bill.

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thanks @SilverNodashi

i'll check out the airflow to the axpert, maybe a little fan might assist. the ambient C is rather cool - well around low twenties, so the near 70 the axpert hits for about two hours per day is way out, according to my gut feeling - could be dust, i was doing some woodwork in the garage. have to switch it off, open up en blow out.

re the 2a, what do the other axpert fundis say?

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On 27/06/2017 at 6:35 AM, gabriel said:

what would be the ideal operating temperature as reflected by icc for the axpert 5kw?

The Axpert has 3 temp sensors  2 on each of the heat sinks (one on the DC side  and one on the AC side), one near the transformer. I think it reports an average of the three. Reversing the air flow caused a 15°C drop in reported temperatures. Before I reversed the fans 52°C was close to the minimum temperature I would see. After reversing the fans it was the maximum temp I would see.

Addition: With the air flow reversed perhaps I should move the heat sink sensors to the top end of the heat sinks once my warranty has expired. It would be relatively easy to do. 

temp.png.f8423fc6204134f4a54e960b56f43513.png

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7 hours ago, gabriel said:

how do you reverse the airflow and would that not breach the warranty?

Yes it does! You flip the fans on the bottom of the inverter so that the ADDA sticker is at the top. This then blows in the same direction as the natural flow of warm air - UP. I think Solarmahn, an Aussie installer who lives in Papua New Guinea reverses all his fans as a matter of course.

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hi @Chris Hobson, morning! i see its a bit chilly over there but i'm sure you had your coffee and beskuit earlier on :-)

as i am not as electronically skilled as you i will not attempt tinkering on the inside of the axpert box.

would it somehow help to put external fans on the one or other side, or even to boost existing airflow from the top?

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11 minutes ago, gabriel said:

hi @Chris Hobson, morning! i see its a bit chilly over there but i'm sure you had your coffee and beskuit earlier on :-)

as i am not as electronically skilled as you i will not attempt tinkering on the inside of the axpert box.

would it somehow help to put external fans on the one or other side, or even to boost existing airflow from the top?

You could try some PC fans on top of the heatsink, or perhaps even extracting from the sides, like a biltong dryer. There's two vents there that would help ;)

But you don't need to be an engineer to swap the fans around. Open the casing, loosing the 4 screws on the fans, flip then 180 degrees and re-assemble ;)

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9 hours ago, gabriel said:

how do you reverse the airflow and would that not breach the warranty?

See here:

http://forums.aeva.asn.au/pip4048ms-inverter_topic4332_post60086.html#60086

But note the shortcuts contained at the end of that post!

It will void the warranty, since merely opening the case requires breaking a sticker that will void warranty. To me, there are so many reasons that the warranty has to be voided. But others may well see things differently. I like to be very self-reliant in this respect.

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Selection_011.png.b8ca90d08e17fbb9de712668e28707fd.png

I've often wondered about the quality of the case ,how it screws together. This is a screenshot from the video, looks like some effort has been made to pre-thread the hole instead of just sticking a self-cutting in there. Thumbs-up for that (and question answered for myself).

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10 hours ago, gabriel said:

hi @Chris Hobson, morning! i see its a bit chilly over there but i'm sure you had your coffee and beskuit earlier on :-)

Hi Gabriel

Early morning appointment so early start.

10 hours ago, gabriel said:

as i am not as electronically skilled as you i will not attempt tinkering on the inside of the axpert box.

would it somehow help to put external fans on the one or other side, or even to boost existing airflow from the top?

From successive posts  I think most forumites do not think it is "bokant jou vuurmaakplek!"

I know @edmundp wanted to attach fans externally thereby maintaining his warranty.  He however went over to the dark (blue) side :D so I am not sure how he fared with that project.

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eina...

just a thought - if there is a thermistor underneath one of the heat 'spots' and you reverse the airflow, now blowing ambient temp air over the sensor you will in fact get a false value - so should not all fans [even extra ones on the outside] draw air from the axpert in order to let the sensors determine a 'mean' value for the unit?

as you can see i have a correlation between grid watts and inverter temp

 

inv temp000.PNG

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1 hour ago, gabriel said:

thermistor underneath one of the heat 'spots' and you reverse the airflow, now blowing ambient temp air over the sensor you will in fact get a false value

Uuuuhm, no, the thermistor is going to tell you how hot the heatsink is. If it is properly attached :-)

I think this is the main one, as in the picture. That's in the middle.

thermistor.thumb.png.69750c98d5846f699a9b28288cc7e8a4.png

 

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7 hours ago, gabriel said:

just a thought - if there is a thermistor underneath one of the heat 'spots' and you reverse the airflow, now blowing ambient temp air over the sensor you will in fact get a false value - so should not all fans [even extra ones on the outside] draw air from the axpert in order to let the sensors determine a 'mean' value for the unit?

Actually, that is a concern with fan reversal. One of the three thermistors is on the PCB to one side of the main transformer:

PIP_Tx_and_NTC_sm.jpg

From http://forums.aeva.asn.au/forum_posts.asp?TID=4332&PID=60223&title=pip4048ms-inverter#60223 .

That one could be affected by air flow, though the air flow is pretty much blocked by the transformer, so there is no "flow through" effect. But the fans are approximately where the camera is in the above photo, so by reversing the fans and blowing up (towards the HF transformer), you would be cooling the thermistor more, and therefore you may get less cooling than was needed or intended.

But the temperature used is the maximum of the three sensors, not the average/mean, so having one drop out through air flow doesn't make much difference. There doesn't seem to be an issue with the HF transformer getting hotter after a fan reversal.

Note that it's no longer recommended that the fans be replaced with ultra quiet versions, because there can be an issue with nuisance tripping due to fan "locked rotor" warnings and errors.

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4 minutes ago, Chris Hobson said:

It does look like in later models (June 2015) that the thermistor is mounted on the transformer.

thanks guys, the above seems to indicate that the temps indicated by the inverter [axpert 5kw] are the result of more or less accurate thermistor placings and should not be the result of airflow, hence correct airflow would rather have an influence on the objects [transormer etc] than the thermistors; am i correct?

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1 hour ago, gabriel said:

thanks guys, the above seems to indicate that the temps indicated by the inverter [axpert 5kw] are the result of more or less accurate thermistor placings and should not be the result of airflow, hence correct airflow would rather have an influence on the objects [transormer etc] than the thermistors; am i correct?

Yes

With one qualifier, the DC MOSFET heatsink(s) is made up of separate units and there could be disparity between them. I  know @PaulF007 queries each thermistor individually. The SCC thermistor shows a beautiful bell shaped curve of daytime temperatures. @gabriel I have also noticed the highest temperatures coincide with grid usage.

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3 hours ago, Coulomb said:

Actually, that is a concern with fan reversal. One of the three thermistors is on the PCB to one side of the main transformer:

PIP_Tx_and_NTC_sm.jpg

From http://forums.aeva.asn.au/forum_posts.asp?TID=4332&PID=60223&title=pip4048ms-inverter#60223 .

That one could be affected by air flow, though the air flow is pretty much blocked by the transformer, so there is no "flow through" effect. But the fans are approximately where the camera is in the above photo, so by reversing the fans and blowing up (towards the HF transformer), you would be cooling the thermistor more, and therefore you may get less cooling than was needed or intended.

But the temperature used is the maximum of the three sensors, not the average/mean, so having one drop out through air flow doesn't make much difference. There doesn't seem to be an issue with the HF transformer getting hotter after a fan reversal.

Note that it's no longer recommended that the fans be replaced with ultra quiet versions, because there can be an issue with nuisance tripping due to fan "locked rotor" warnings and errors.

Quite some interesting reading... @Coulomb, can't you modify the firmware to fix the problem?

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54 minutes ago, Chris Hobson said:

 I have also noticed the highest temperatures coincide with grid usage.

yes chris, as soon as the grid starts to charge the batteries the inverter has to work harder, hence rise in temp. as soon as soc is 100 , grid switches off and batteries take over and inverter temp drops.

now the question arises why should grid to battery conversion be a more arduous task [as seen from inverter] than battery to home?

 

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37 minutes ago, gabriel said:

now the question arises why should grid to battery conversion be a more arduous task [as seen from inverter] than battery to home?

For me the question is even more puzzling as my inverter has a SOC of 100% or very close to it when the gennie is on so there is very little charging happening and the inverter is in bypass mode - go figure!

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