Lead acid batteries: inside the house or outside?

[soylentgreen]

I have a house that has a UPS for my server rack, with extra beefy external batteries. Right now the lead acid batteries are inside the house inside the server closet. These are high-quality telecom lead acid batteries, but I’m doing some renovation and I could easily run some wires so that the batteries lived on the side of the house. My question is from a safety perspective, is it better to have the battery outside of the house, but subjected to higher temperature swings, vs inside the house in a temperature controlled environment. I’m not terribly worried about either scenario, but I’m just curious if anyone has an opinion?

Climate: San Diego, so never below freezing, and rarely above 100 Fahrenheit

 

[Substrate]

From a safety perspective - of course, keep the batteries outside in case you have a massive charging failure.

It's likely you are dealing with sealed telcom batteries that spend their life on float, ready to do limited cycle ups duty. Enersys and others come to mind. Which ordinarily isn't a problem indoors if it is engineered properly.

The question is - and I'm not trying to be an ass about it, but have to ask considering the diy forum we are in:

1) Did you get these "high quality telcom lead-acid batteries" from the back of some guy's van down by the river?

2) Is your UPS charger set up properly for these batteries according to their specifications, or did you just pop them in?

Without knowing these things, from a safety perspective, put those batteries outside and on a remote temperature-compensation probe leash.

 

[OnTheRoadAgain]

Lead acid batteries.......

Best kept at 77F.

For every 15F above that, battery life is reduced by 50%

 

[Substrate]

Yup. You can help minimize that by having accurate "at the battery" temp-comp sensors, instead of relying on ambient.

But this is all moot if the batteries are already abused. Hopefully we'll find out.

 

[soylentgreen]

Great feedback!

• I have two Alcatel Lucent Deka Unigy 12AVR145ET wired in series for 24V
• Not exactly "fell off the truck" but these are definitely used batteries - I got them a few years ago from https://deepcyclebatterystore.com and was quite happy with the price. Since 99% of the time they sit in float, I'm not terribly worried if they have 25% or even 50% capacity loss. I think this is one of the few situations in which Lead acid is a good choice.
• I think I paid about $100 each, so $200 for nearly 300 amp hours (ish) was quite the deal.
• They connect to aUPS (replacing the existing UPS 24V battery pack). The UPS was not desiged for these battery packs, but I made it work by adding some Anderson powerpole connetors.

 

[soylentgreen]

Oh, and funny story: Earlier, the two batteries were in parallel, and connected to a UPS that used 12V batteries. During a recent power failure (there have been sooo many - don't ask) I decided to check on the system, and noticed that the wires connecting the battery to the UPS seemed rather warm (hot!) though the draw was about 10 to 12 amps. WTF? I thought. The wire was 8 gauge, about 1 meter in length, and all the calcuators I've seen suggest "no problem" for 8 gague at 10 amps.

Turns out, this "8 gauge" wire was some crap "heavy duty car amplifier wire" I bought at Fry's Electronics (RIP) and when I cut the wire to look, visually it looked about like 12 or 14 ga. It was mostly insulator.

Long story short: replaced it with some real wire, AND swapped out the 12V UPS for a 24V one, which cut the amperage and power loss 4x.
No more hot wires.

 

[Substrate]

Ok cool - so you know. No more than 2.25v/cell on float charge only. 10-year float design life.

Very limited cycle life - they are high-current ups, not cycling batts.

My flags go off when seeing these, because they are quite often dumped on the beginner solar enthusiast who doesn't know that they aren't designed for cycling, and quite near or past their design life anyway.

In many cases, the people dumping these onto unwitting solar beginners, are just saving themselves the cost of recycling it themselves, and passing that cost to the unwary who drives home thinking he scored!

 

[soylentgreen]

Right! My understanding is that many of these batteries are aged out (contractually) from telecom installations. They are basically fine for what they are, but the contract says "replace at 5 years" so they get replaced.

I want them for perhaps 5 deep discharges during power outages, and that's what they shoud be good for. Definitely not cycing them daily, eek!

 

[Substrate]

You're good because you know your application.

I've just seen this story too often - "Get those blocks of lead off the lot Jim, like today." Jim gives them to diy'er. Diy'er dabbles with them, gets frustrated, and suddenly discovers that the recycling plant doesn't accept "Industrial batteries".

Wait - I can't stop .... Diy'er in frustration sneaks them to a local industrial waste-bin, and to his surprise, there is an open box with 400 trashed computer-type 18650's just waiting to be used!

Sorry - dramatic license...

 

[wattmatters]

My understanding is that many of these batteries are aged out (contractually) from telecom installations.

Yep, this is what I have - the Enersys type, got them from a guy who specialises in the telco/data centre backups when they are due for replacement.

I have 4 x 190Ah/12V units for a 48V set up with an all in one. System is for outage backup, and when I add solar PV to take pool pump off-grid, where the battery will just provided system ballast. I did some capacity tests on them and they are perfect for our application.

 

[mike95490]

SLA batteries , at end of life, can heat up and gas, and so you need venting to get the gas (hydrogen) out of the structure.
And most telecom batteries are rated for a dozen deep cycles, not hundreds of cycles