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Batteries for Solar System

SamSpring

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Apr 7, 2021
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Hello, I just wanted to learn more about battery selection. These batteries were given to me and I decided to use them for my solar panel system in my off-grid cabin.

TEL-12-210FA (x2)

As well, I have these:

US 185HC XC US Battery (x2) 12V Flooded Lead Acid

Each battery is hooked up in series, then in parallel, to provide 424AH @24V

I just wanted to know if mixing these batteries is a bad idea and if the "TEL-12-210FA" is not suited for this kind of application.

Thank you
 
Welcome to the forum.

The TEL-12-210FA appears to be designed for standby operation, i.e., held at 100% for long periods of time and then used briefly to provide emergency backup power. The basis for my opinion is:

the emphasis in the data on "Long life float service design"
ratings consistent with C10 or higher discharges, not the typical C20 of deep cycle batteries
I see no cycle life vs. depth of discharge data
I see no reference to "deep cycle"
They appear to be targeted to telco applications

BUT

They were free. :)

from (for XC2, can't find XC):


C10 is 195Ah, so less than the TEL batteries.

They have compatible cyclic absorption values, but the 185HC appear to prefer a much lower float voltage of 13.02V. If you're cycling them daily, that's not a big deal, but if you're going to be cycling them rarely, they should be floated separately and connected only when needed for use.

If you're talking the TEL in 2S for 24V in parallel with 2S 185HC, then that should be fine.

Worst case, the TEL batteries will wear out faster, but they are still reducing the workload on the 185HC batteries extending their life.

See "Wiring" in link #2 in my signature for best practices when connecting batteries in banks.

Best to use a clamp ammeter to confirm the currently flowing through each battery set is within limits for the battery under high charge and discharge scenarios.
 
Welcome to the forum.

The TEL-12-210FA appears to be designed for standby operation, i.e., held at 100% for long periods of time and then used briefly to provide emergency backup power. The basis for my opinion is:

the emphasis in the data on "Long life float service design"
ratings consistent with C10 or higher discharges, not the typical C20 of deep cycle batteries
I see no cycle life vs. depth of discharge data
I see no reference to "deep cycle"
They appear to be targeted to telco applications

BUT

They were free. :)

from (for XC2, can't find XC):


C10 is 195Ah, so less than the TEL batteries.

They have compatible cyclic absorption values, but the 185HC appear to prefer a much lower float voltage of 13.02V. If you're cycling them daily, that's not a big deal, but if you're going to be cycling them rarely, they should be floated separately and connected only when needed for use.

If you're talking the TEL in 2S for 24V in parallel with 2S 185HC, then that should be fine.

Worst case, the TEL batteries will wear out faster, but they are still reducing the workload on the 185HC batteries extending their life.

See "Wiring" in link #2 in my signature for best practices when connecting batteries in banks.

Best to use a clamp ammeter to confirm the currently flowing through each battery set is within limits for the battery under high charge and discharge scenarios.
I see, thank you for that. Just to add on to connecting batteries in banks, because they are different batteries with different resistances, is there a possibility of each battery being charged and discharged at a different rate? or as long as I use the correct size wire they should be fine?
 
I see, thank you for that. Just to add on to connecting batteries in banks, because they are different batteries with different resistances, is there a possibility of each battery being charged and discharged at a different rate? or as long as I use the correct size wire they should be fine?

It's not just a possibility, it's probable - hence the check with an ammeter to confirm the setup is still operating within battery specs for each string.
 
do a capacity test at the rate you intend to pull amps from each battery(especially important with unknown battery history)...this way you will know what you can expect when put into service.
Once you know the capacity of each put them in series to best match each other (try to get same capacity per string).

make sure to get a bms, and enjoy your free batteries hehe
 
do a capacity test at the rate you intend to pull amps from each battery(especially important with unknown battery history)...this way you will know what you can expect when put into service.
Once you know the capacity of each put them in series to best match each other (try to get same capacity per string).

make sure to get a bms, and enjoy your free batteries hehe

These are lead acid. No BMS.
 
Those C&D Tel's are primarily for standby telco service in "float mode" as mentioned above.

You'll notice in the spec-sheet that there is a category for "equalize and cyclic service" of 14.4 to 14.8v CV.

But, while they *can* be cycled in an emergency, service life will be very short. They are not primarily designed for that.

So your best option, is to set up your chargers / controllers to charge at no more than 13.5 - 13.8v as per the spec sheet. Temperature compensated. Full charge will take DAYS to weeks depending on charge rate.

Your best usage will be to serve as originally designed - as a backup that lives on float. It will give you more days of autonomy when your primary bank gets low during long winter hours, bad weather, and so forth.

If you didn't get them new, then a capacity test would be beneficial to figure out if you are just holding on to e-waste.

The reason I mention that is that some get hoodwinked by places that find it cheaper to offload telco-type batteries to "hobbiests", rather than to dispose / recycle them properly and gets them off the property fast.
 
If you didn't get them new, then a capacity test would be beneficial to figure out if you are just holding on to e-waste.

The reason I mention that is that some get hoodwinked by places that find it cheaper to offload telco-type batteries to "hobbiests", rather than to dispose / recycle them properly and gets them off the property fast.

I picked up 4 x 190Ah batteries of a similar type and I use them in series for a 48V bank. Mine were Enersys SBS190F.

I load tested them a few times and they were great. Fortunately where I get mine the seller will replace any that are not performing as they should.

But it's always a lottery. Still, free is good :)

Telco/data centres here tend to cycle out these batteries after a certain duration and usually well before they have degraded all that much as they can't afford for their backup energy supply to not perform when they really need it to. How much they've actually been used is variable I guess depending on the stability of the grid where they are deployed.

My use case is for grid outage power backup so pretty much exactly what they were designed for, but ultimately I'll also use them to provide a bit of ballast for an off-grid solar PV array to supply power to a pool pump.
 
Ah cool! You actually had a seller.

Just a warning to lurkers - some places would dump dead batteries to "experimenters" rather than pay the cost to properly dispose of them.

Now proper disposal if they are useless is YOUR problem. And in many cases since they are industrial batteries, no auto parts store will even accept them as cores, so basically you are on the hook to $$ dispose properly. :)
 
Now proper disposal if they are useless is YOUR problem.

In our state we have what are called Community Recycling Centres, usually co-located with the local Council's waste management and recycling facility.

The CRCs have a dedicated collection facility for all sorts of stuff, including batteries of various chemistries, old smoke detectors, light globes/tubes of various types, electronics, oils, paints and various other chemicals, gas bottles, fire extinguishers. I've used it for discarding old tins of paint, and when my used motor oil container gets full I empty it there into the dedicated collection tank.

The lead acid batteries they collect are sent to dedicated LA battery recycling facilities.

The service is free to use.
 
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