Where to locate battteries in Tucson, Arizona (easy outside vs more difficult in garage)

[Andrew20252]

I'm planning a 25 panel 10.5kw grid-tied roof mounted PV system on my home in Tucson, Arizona. Electric company is Tucson Electric Power (TEP). Will be using a Sol-Ark 15k inverter to make whole home backup simple and either the Homegrid Stackd series 19.2kWh battery (4 batteries) or four Pytes V5 batteries.

My primary question - where should I locate the inverter and batteries?

My main service panel and meter are on the outside of my living room on the north side of my home. I would really like to locate them on the exterior wall with the panel to keep things simple. It is relatively sun exposed during the summer and we average 106 degrees F everyday, all summer long. More difficult option is inside my non-insulated garage, which still stays relatively cool, but would require a 50-60 foot cable run between the inverter/battery and the panel and back again.

Pytes V5 temperature limitation: charge 113 deg F (45 deg C), discharge 122 deg F (50 deg C)
Homegrid Stackd Series temperature limitation: charge 113 deg F (45 deg C), discharge 140 deg F (60 deg C) - also see 131 deg F (55 deg C) in some documents

Homegrid warranty limitation "damages caused by or resulting from excessive heat (temperatures higher than 113°F (45°C) are considered excessive heat)"

I was considering the Pytes due to the Homegrid excessive heat warning and it has a much more robust outdoor enclosure.

I know the electronics and batteries will last longer the cooler they are, so do I just need to bite the bullet and put them in the garage or is there a way to make them work outside?

Thanks for your input

 

[Supervstech]

I think the AZ heat will reduce the lifespan of any system you put outside.

When I lived in Tucson, I was a young man just learning about Atari video games, so other than remembering hot weather I’m not a resource on the temps there.
A basement would be great, cellar, etc.
If outdoor having shade should improve lifespan.

 

[Andrew20252]

Thanks for your reply and to Bananaman321 for his DM and lots of information.

Brief recap for anyone else looking for answers:

• Electronics always function better when cool, therefore even though the specification says the batteries/inverter can tolerate those temperatures briefly, over time it will reduce their life expectancy
• So, the cooler you can keep them, the longer lifespan you should get
• Some manufacturers state the reduced number of cycles at higher temperatures, like 8k cycles at 25 deg C versus 3k cycles at 45 deg C, that isn't stated for Homegrid or Pytes, but same principal would apply
• With the usual cell temperature rise when charging/discharging, the lack of active cooling in the Pytes outdoor enclosure, the sun load that will be on them during the already hot summer at my location in Arizona, sitting outside isn't going to be an ideal situation.

Thanks

 

[sumpower]

When I lived in Tucson, I only did installs of batteries in conditioned spaces. Lead Acid was the only real option 20 years ago.
But I would still make the same requirement for installations of Li batteries in Tucson today.

 

[Kornbread]

IIRC, temps above the mid 90* can start to shorten LiFePo4 life span. I really need to start bookmarking good info like that cause this is as close as I can come for now:

" ... at higher temperatures (above 30 ◦C(86*f) ), the resistance increases slowly with time compared with the fast fade of capacity. On the contrary, lower temperatures (25 ◦C to 30 ◦C(77*f-86*f)) can significantly reduce the rate of capacity loss, but it is not obvious for suppressing the resistance increase. ... ".

Resource icon

The Degradation Behavior of LiFePO4/C Batteries during Long-Term Calendar Aging

Feb 5, 2022

Study how LiFePO4 cells degrade over long periods of time.

• curiouscarbon
• How-to PDF's or Ebook's

So yeah, hot not good for LiFePo4 or the capacitors inside the electronics.

 

[1 watt]

https://diysolarforum.com/threads/summer-in-arizona-what-options-to-keep-cool.85040/post-1224384