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Battery Upgrade Project Help Required


Peter_DM

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Hi All,

I'm a NOOB on this forum, but have had a Solar installation for several years, and hope some of the knowledgeable people here can assist me with some questions regarding a battery upgrade project.

As a bit of background, I have 2 Axpert 5KVA Inverters, each with 12 Canadian Solar 270W panels, currently hooked up to a battery array of 8 strings of 4 100Ah Lead Acid batteries (i.e. 32 batteries total).

During the first few years of my installation, I had endless problems causing the Inverters to die every few months with major corrosion problems; the area I'm in (KZN coast) has very high humidity. I then decided to "steal" one meter from the back of the garage, and build a server room with an air-con fitted. Since moving the Inverters (plus all my computer servers, etc.) in there, I've had no more issues. I’ve set the air-con to DRY mode; it generally runs at about 16°C.

I've now decided it's time to upgrade the storage side of my installation, and what I've decided (haven't ordered yet, but about to) is to get 4 x Pylontech 2.4kWh units. I have also looked into the 2nd Life batteries from Herholdts, but the price delta doesn't make sense to me - I'd rather have the full cycle life for not very much more money.

So, now to my questions:

  1. Air-con or not: For obvious reasons, my existing battery bank is in an adjacent room (basically a lean-to behind the garage), with plenty of ventilation. I'm faced with the choice of mounting the new batteries either in the Air-con Server Room, or modifying the existing Battery Storage Room (i.e. enclosing it better). What my research assistant (Google) and I have discovered is that batteries are negatively affected (pun intended) by lower temperature. However, when delving deeper into the actual research, it's generally focused on sub-zero (Celsius) temperatures. My gut feeling is that I'd rather live with reduced efficiency due to the lower temperature, rather than the increased wear and tear due to the humidity; I’d appreciate any thoughts on this matter.
  2. Mounting direction: All images of these form factor batteries show the batteries in the same direction – horizontal and usually in a rack mount case. However, given that I have a severely limited area that I wish to mount them in, mounting them vertically against a wall would be far more convenient. As far as I can tell, this would not be an issue with these batteries, and I’d make up my own brackets to ensure they are well attached to the wall. Again, any thoughts?
  3. Legality: With the looming legislation that we will all have to conform to at some point in time, I’d rather get things right up front, rather than having to correct them later, so I have two sub questions:
  4. If I do mount the batteries vertically, would I run into issues with the CoC?
  5. I seem to recall reading that several components (by my understanding anything with wires that could be accidentally pulled) need to be behind lock and key. My entire “Server Room” is behind lock and key, but would this be sufficient for the CoC?

Thanks in advance for any help / thoughts.

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Welcome Peter. I'll comment on on some.

4 hours ago, Peter_DM said:

What my research assistant (Google) and I have discovered is that batteries are negatively affected (pun intended) by lower temperature

I would have kept the room DRY at +-24/25 degrees celcius, and it uses less electricity, as that is where most lead acid batts would be quite happy at. Electronics too.

4 hours ago, Peter_DM said:

Mounting direction:

My gut tells me you can mount them any which way you want. No acid can leak out as there is none. 

4 hours ago, Peter_DM said:

My entire “Server Room” is behind lock and key, but would this be sufficient for the CoC?

My recent journey to a CoC, yes, that is quite acceptable, with a warning label on the door. Just also confirm with a local electrician.

4 hours ago, Peter_DM said:

With the looming legislation ...

What does KZN say about Axperts and DB connections?

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4 hours ago, Peter_DM said:

Mounting direction: All images of these form factor batteries show the batteries in the same direction – horizontal and usually in a rack mount case. However, given that I have a severely limited area that I wish to mount them in, mounting them vertically against a wall would be far more convenient. As far as I can tell, this would not be an issue with these batteries, and I’d make up my own brackets to ensure they are well attached to the wall. Again, any thoughts?

Pylons can be mounted vertically.. 

https://www.s-power.cz/wp-content/uploads/pylontech-us2000b-manual.pdf ... page 16 ... they can be mounted vertically or horizontally

Edited by stoic
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37 minutes ago, The Terrible Triplett said:

Welcome Peter. I'll comment on on some.

I would have kept the room DRY at +-24/25 degrees celcius, and it uses less electricity, as that is where most lead acid batts would be quite happy at. Electronics too.

My gut tells me you can mount them any which way you want. No acid can leak out as there is none. 

My recent journey to a CoC, yes, that is quite acceptable, with a warning label on the door. Just also confirm with a local electrician.

What does KZN say about Axperts and DB connections?

Thanks TTT.

My reasoning for dropping the temperature was for the computer servers - they prefer the lower temperatures. I'll experiment with that though.

I will also check with my local sparky, but I suspect he won't know - there's not many solar installations locally.

As at now, I'm still very much in the preparation phase for the legislation. I wasn't even aware that there are differences between provinces; I thought it was per municipality, so was waiting for further details locally. I'll check this as well with my sparky.

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29 minutes ago, stoic said:

Pylons can be mounted vertically.. 

https://www.s-power.cz/wp-content/uploads/pylontech-us2000b-manual.pdf ... page 16 ... they can be mounted vertically or horizontally

Thanks for that Stoic.

I should have clarified though - I'm looking to mount them vertically, and rotated i.e. cables pointing upwards unlike their sample diagram. This is a problem with some older hard drives - they could be mounted any way except on their "head" - I'm hoping the same does not apply to these batteries

I guess I'll have to experiment once I have them.

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12 minutes ago, Peter_DM said:

... dropping the temperature was for the computer servers ...

My Intel Xeon blade servers (used as desktops PC's) have ferocious sounding fans (4 x small jet engines) in them if the temp is a wee bit too high. You cannot speak on the phone if they get hot.

Further to that, read an article a long while back where Google server farms, to save on electricity ito cooling, allowed them go higher in temps ... 

Found it: https://community.spiceworks.com/topic/1704357-server-rooms-temperatures-how-hot-is-too-hot

So in your case, 24/25 degrees is 100% perfect, and you will save on electricity. 🙂 

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22 minutes ago, Peter_DM said:

Thanks for that Stoic.

I should have clarified though - I'm looking to mount them vertically, and rotated i.e. cables pointing upwards unlike their sample diagram. This is a problem with some older hard drives - they could be mounted any way except on their "head" - I'm hoping the same does not apply to these batteries

I guess I'll have to experiment once I have them.

Whether the terminals point up or to the side... the battery cells will be on their side. and is allowed.

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Another one : https://www.geek.com/chips/googles-most-efficient-data-center-runs-at-95-degrees-1478473/

Caveat: What I have learnt. When a machine of mine or a client blatantly fails or starts to freeze on a very hot day, your case say you up the temp, don't blame the increased temperature.

It basically means a part was on its way out that would have gone in any event in the future ... normally when least expected.

The rule of thumb with servers, and hard working PC's, try and keep them constantly at the same temperature as far as possible.

Excessive heating and cooling cycles, like also on/off, are the cause for earlier than expected replacements of most computers that are working on peak levels.

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8 minutes ago, The Terrible Triplett said:

My Intel Xeon blade servers (used as desktops PC's) have ferocious sounding fans (4 x small jet engines) in them if the temp is a wee bit too high. You cannot speak on the phone if they get hot.

Further to that, read an article a long while back where Google server farms, to save on electricity ito cooling, allowed them go higher in temps ... 

Found it: https://community.spiceworks.com/topic/1704357-server-rooms-temperatures-how-hot-is-too-hot

So in your case, 24/25 degrees is 100% perfect, and you will save on electricity. 🙂 

I have 2 older HP Xeon servers in there, plus 2 newer i7 servers, 2 NAS servers, plus sundry other tin. It all adds up temperature wise!

The article you refer to does make for interesting reading, but my worry with raising the temperature would still be that I'm then also raising the humidity (not a good thing); albeit the reduction in electricity required would be nice.

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1 hour ago, The Terrible Triplett said:

I would have kept the room DRY at +-24/25 degrees celcius, and it uses less electricity, as that is where most lead acid batts would be quite happy at. Electronics too.

Earlier this morning I very almost wrote this same comment. Then something occured to me, and that something is called the dew point. Water only condenses out of the air if you drop the temperature below the dew point. So for the air to actually dry, you have to set the temperature at or below the dew point. Now chances are that the dew point isn't just 25°C...

So in principle I agree that one should aim for a higher temperature (to save energy and because the batteries usually prefer it a bit warmer), but one also have to keep the physics in mind. Of course this can be empirically tested: Jack the temperature up and measure how much water comes out of the drain pipe, then do a comparison.

Edited by plonkster
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14 minutes ago, plonkster said:

Earlier this morning I very almost wrote this same comment. Then something occured to me, and that something is called the dew point. Water only condenses out of the air if you drop the temperature below the dew point. So for the air to actually dry, you have to set the temperature at or below the dew point. Now chances are that the dew point isn't just 25°C...

So in principle I agree that one should aim for a higher temperature (to save energy and because the batteries usually prefer it a bit warmer), but one also have to keep the physics in mind. Of course this can be empirically tested: Jack the temperature up and measure how much water comes out of the drain pipe, then do a comparison.

I do also have a weather station, and right now the temp is 23.5; dew point 19.6; to be taken with a pinch of salt though.

This was measured at my inside monitoring point, not in the Server Room.

I've never paid much attention to it, but I'll keep an eye on it n ow.

Temp.PNG

Edited by Peter_DM
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Here's my temperature / dewpoint over the last 24 hours.

 

One other thought I had was to program the air-con to power on in the morning and off in the late afternoon in order to reduce the load at night; but given some of these discussions, I'm changing my mind about that idea.

Dewpoint.PNG

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Well, then I'd say that if my scientific understanding is correct, you could push up the AC to 18°C without reducing the amount of water it drains from the air, but if you push it to 20°C the amount will reduce drastically. Or that is what I would expect.

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I would agree with that understanding, but if I look at a full year's worth of history, the dew point can go as low as 9.6. There do appear to be some bad readings in my data, but the dew point does dip well below ambient on many occasions.

I'm not too keen on changing the air-con settings every few weeks or month.

Dewpoint2.PNG

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KZN is much more humid than say Cape Town but with a aircon drying out the air in a enclosed room, maybe that makes the dew point similar to say Jhb without a aircon.

My point being one needs to factor in what is the dew point in that room where the aircon is running. 

And I keep on thinking. What happens when one keeps that room cold at 16deg on a hot humid KZN day ... and the aircon goes off. 🙂 

I would guess with a aircon on 24deg the dew point in that small enclosed would not be an issue for any electronics, and if the aircon does go down on a hot day, the condensation will be less.

 

Edited by Guest
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8 minutes ago, phil.g00 said:

Would it not be a dehumidifier that you need?

When I initially installed the air-con, I did ask the supplier about the possibility of using a dehumidifier rather than an air-con.

Their answer was that given the size of the room (roughly 1m x 8m), it was pointless.

Dunno how accurate their assessment was

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