We use 12V, 120 to 180AH low maintenance lead acid battery for generators. For some cell tower sites, the generator is supplied prior to obtaining POCO supply. So the battery sits idle along with the generator some times more than a year. When time finally comes for commissioning the tower, it used to see the battery dead beyond revival and the supplier stated only one year warranty. But the battery shelf life now a days is two years. Your opinion please.
Battery shelf life
- Thread starter Sahib
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Are you saying part of your job is to supply a generator for a cell tower that may not be ready for use for a year? Can the generator be programmed to run one a week or so for an hour to keep the battery charged? If not you could try a solar float charger. or not put the battery in until the the tower is ready.
Thanks Daja7 for your reply. Supply of gen set is not part of my job, but designing, supervising installation, acceptance testing etc of the contractor supplied gen set, are part of my job. It is not easy for me to implement your suggestions because I have to get approval from higher levels. So I am thinking if the shelf life of today's battery is two years, the problem could be solved by changing the specification of battery warranty from one year to two years in the contract agreement.
This is easy to answer.
1. First use an AGM battery and stay away from Flooded Lead Acid. AGM batteries have a self discharge rate of roughly 1% per month where as FLA is on the order of 10%.
2. Best solution is to set the Exerciser to run once a week for 15 minutes.
3. If that is not possible get a 20 watt solar panel and a 5 amp charge controller to keep the battery topped off until you get commercial power to run the site battery charger.
4. Not sure where you get a 2 year shelf life out of a battery but is not true with the exception of Dry Charged FLA batteries where the acid is shipped separately. If you put up a wet FLA battery on the shelf for two years without being on a Float Charger it will be a Boat Anchor.
That is your 4 options.
1. First use an AGM battery and stay away from Flooded Lead Acid. AGM batteries have a self discharge rate of roughly 1% per month where as FLA is on the order of 10%.
2. Best solution is to set the Exerciser to run once a week for 15 minutes.
3. If that is not possible get a 20 watt solar panel and a 5 amp charge controller to keep the battery topped off until you get commercial power to run the site battery charger.
4. Not sure where you get a 2 year shelf life out of a battery but is not true with the exception of Dry Charged FLA batteries where the acid is shipped separately. If you put up a wet FLA battery on the shelf for two years without being on a Float Charger it will be a Boat Anchor.
That is your 4 options.
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kwired
Electron manager
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- NE Nebraska
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- EC
None of that necessarily changes the manufacturers 1 year warranty of what they supplied though, and solution #1 replaces their component with another component that they would not have any obligation to warranty.
ADD: I guess OP wasn't talking about a manufacturer warranty as much as the suppliers warranty - but this information still deserves some consideration by whoever is providing any warranty, a supplier may still have their warranty backed up by a manufacturer as well.
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kwired
Electron manager
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- NE Nebraska
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- EC
First, if the shelf life is two years why are they not surviving that long?
If you are selling something you know has a good chance of not being revived after that first year why would you warranty it unless you add some cost to your initial sale to help cover that possibility?
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
And when a battery manufacturer offers a warranty of one year, that is usually conditional on proper maintenance, which is defined to include charging.
Not to mention that the lifetime can be used up sitting on a dealer's shelf unless they keep it charged....
Tapatalk!
Not to mention that the lifetime can be used up sitting on a dealer's shelf unless they keep it charged....
Tapatalk!
- Location
- Bremerton, Washington
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- Master Electrician
I have had great success with Battey Minders
http://batteryminders.com/
I had a couple of expensive 75 AH VRLA batteries that appeared to be dead, the battery minder brought them back to life.
If you have the batteries in your possession just connect a battery minder and you'll be OK.
I have three of these at work as I keep batteries on charge for back up and emergencies. I have one at home for when my truck battery goes dead.
http://batteryminders.com/
I had a couple of expensive 75 AH VRLA batteries that appeared to be dead, the battery minder brought them back to life.
If you have the batteries in your possession just connect a battery minder and you'll be OK.
I have three of these at work as I keep batteries on charge for back up and emergencies. I have one at home for when my truck battery goes dead.
kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
I would recommend you look at lithium ion polymer batteries. They are what is being used in energy storage facilities. They have a self discharge rate of about 5% a month which would be roughly 60% a year.
This sounds like a specification issue more than anything. Modify the spec such that it states the battery must not fall below say 50% charge after sitting for 12 months. But you must also consider the environment. That's what kills batteries. If the EG is not running, do you have conditioning for the space? That needs to be addressed. Extended warranty will do you no good if the manufacturer can claim the environmental conditions killed the battery.
Expensive.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
kingpb
Senior Member
- Location
- SE USA as far as you can go
- Occupation
- Engineer, Registered
But nice projects - 
No one could afford them, and they take special balanced chargers and charging algorithms. Something generators do not come with. Top of the line 10 year warranty FLA batteries cost roughly $0.224/wh. Where as LiPo only comes with 1 to 3 year warranty and cost on the order of $2 to 3/wh over 10 times as much with less cycle life.
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
My opinion, and worth every penny you're paying for it, is that 3. is going to be the best bet, maybe combined with 1. I think 2. is problematic, since the site isn't actually up and running, it's not likely the end user wants to start running the generator, running the clock on warranty before the site is bringing in revenue.
Here lies the crux of the problem I do not understand how an engineer would spec. Telecom sector does not use consumer grade products or materials. They do not buy a 1 year battery from Wallyworld, Agent Orange, Blue Glob or any other retailer. We use commercial grade products that come with 5, 7 and 10 year warranties. Since this battery will be left sitting for a year rules out FLA batteries period unless you can run the exerciser on the generator at least monthly, or use a small solar panel to keep them topped off.
That only leaves AGM. I assume this generator in question is like what most wireless carriers use at remote cell sites on the order of 40 to 55 KVA using diesel fuel. That means a pretty hefty AGM like a BCI size group 31 battery. For those we use two different manufactures Odyssey and Rolls.
The Odyssey PC2250 punches a wallop of 2250 CCA with a 126 AH @ 12 volt capacity and comes with a 4 year warranty. It is also a favorite of DYI EV builders.
The Rolls S12-160 AGM delivers a respectable 975 CCA with a 145 AH capacity and comes with 5 year warranty.
You will be hard pressed to find any other manufacture that carries a 4 and 5 year warranty on a SLI AGM battery. To get the 7 and 10 year you need to use FLA.
10 minute per week is roughly 9 hours. You do not let a generator set out in the elements for a year without running.
It makes no no difference and I really do not care what Sahib does. I am just sharing my experience working in the telecom sector for 33 years doing exactly what is being done.
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
What would be the difference between installing the generator and doing nothing with it for a year and keeping it in the crate/pallet for a year? Assuming that there is at least some minimal protection from weather exposure in the installed condition.
If this is a remote cell site or even in a urban area you would not have to worry about the generator. In a years time someone will take it and use it somewhere unknown to you.
Cell sites are target #1 for crack heads. They take everything that is not bolted down. In DFW area alone Verizon Wireless has on average 4 to 5 cells sites a week hit with copper thieves.
Fulthrotl
~Autocorrect is My Worst Enema.~
- Occupation
- E
the problem could be solved much more effectively by specifying a solar batteryminder be provided with the genset.
you can't specify a battery that will sit there for two years without charging. oddesy batteries are about the only
thing that can do that.
then, lift the negative terminal, hook up the solar charger, and it'll be ready in a year or more.
or.... don't have the genset delivered onsite till you are ready for it.
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