We need to purchase a number of switchgear and UPS battery banks and have been debating whether to use the traditional flooded lead calcium and lead selenium batteries or whether we should buy Ni-cad. The ni-cad batteries cost more but they last 30-40 years instead of 15 years for the lead acid family. Is anyone familiar with the differences or have field experience with Ni-cad batteries?
Battery Chemistry for battery banks
- Thread starter jdsmith
- Start date
- Status
brian john
Senior Member
- Location
- Leesburg, VA
Personal preference for switchgear I like the Ni-Cads. IF THE CUSTOMER does maintenance on any of them flooded lead acid or Ni-Cad.
Well I have worked with FLA, SLA, and VRLA batteries for about 30+ years in UPS and battery plants. Now when you get to FLA there are three types.
Pure Lead
Lead Antimony
Lead Calcium
The Telco biz pretty much avoids Lead Calcium like the plague because the plates tend to grow and bulge from being placed in float service.
The second most used is lead antimony as it gives about 15 to 20 years of service if cared for properly before dropping below 80% capacity.
The preferred battery is pure lead or what we call the round cell made by C&D now days. Really cannot tell you how long they last because after 50 years they still hold over 90% of their capacity. Only down size is the round construction of the jars.
Pure Lead
Lead Antimony
Lead Calcium
The Telco biz pretty much avoids Lead Calcium like the plague because the plates tend to grow and bulge from being placed in float service.
The second most used is lead antimony as it gives about 15 to 20 years of service if cared for properly before dropping below 80% capacity.
The preferred battery is pure lead or what we call the round cell made by C&D now days. Really cannot tell you how long they last because after 50 years they still hold over 90% of their capacity. Only down size is the round construction of the jars.
brian john
Senior Member
- Location
- Leesburg, VA
Love those round jars.
zog
Senior Member
- Location
- Charlotte, NC
I agree with both of you, if the owner is actually going to maintain the batreries go with lead, if they will be neglected, go NiCad.
Cold Fusion
Senior Member
- Location
- way north
There really is not any one-size fits all answer. Ni-Cd is pretty good, but before you decide they are the best, check the disposal costs. That alone may end the love affair
IEEE Std 446
5.3.2 Stationary batteries In standby service
There are two types of stationary batteries used in standby applications: the lead-acid type (figure 5-3), and the nickel-cadmium (NiCd) type (figure 5-4). Of these two types, lead-acid is the most often used. (Within the USA, lead-acid batteries are used almost exclusively, while in Europe, nickel-cadmium batteries are used more often, particularly for switchgear tripping.) The lead-acid battery is less costly than the equivalent nickel-cadmium cell, requires less cells to make up a battery of any specific voltage, and is available in larger capacities than nickel-cadmium cells. More recently, the requirements within the USA for disposal of nickel-cadmium cells under federal, state, and local environmental guidelines has also limited their use. Under these guidelines, spent nickel-cadmium cell are considered hazardous waste, while spent lead-acid cells are considered hazardous material. In the USA, the owner of the battery is responsible for the battery ?from cradle to grave,? including the beneficial recycling of the battery (Migliaro 1993 [B19]). (Many other countries have similar requirements for recycling, and others are in the process of adopting such requirements
The experience I have (with Ni-Cd), is similar to that already stated ? they are tough, long lived, suffer abuse well, but disposal is generally a deal killer
I have a few questions that will help with making a recommendation:
1. Are these new or replacement? If replacement, look at your maintenance records and service. What do they suggest? Maintenance ok? Design changed and the loading is now too much or too deep DoD? They worked fine for 15years and maintenance was low? Maintenance was substandard and they died quick? They were never speced right in the beginning and they died quick ? twice:-?
If the application is new, what is the design spec?
2. What is the duty? Switchgear batteries are pretty well defined. But UPS service is not. Some are short term, high load (15 minute), some are longer term, low load (3 hour minimum). Generally different batteries are speced for different service
You are likely already faminiar with the IEEE guides and recommended practices on batteries. This one is a good place to start:
IEEE Std 446, IEEE Recommended Practice for Emergency and Standby Power Systems for Industrial and Commercial Applications
The IEEE doesn?t have much to say about lead selenium. However this paper is pretty good
http://www.battcon.com/PapersFinal2004/ODonnellPaper2004.pdf
As was already said, lead calcium takes maintenance. If they are not watered they will die. As for longevity, I?ve seen systems more than 25 years old, still holding more than 80% capacity. (If they were sized correctly, that will still meet spec
If lack of maintenance is an issue, I?d be looking at industrial grade VLRA, sized to hold the load with no more than 50% DoD, worst case. High end units should last 15 years. There will be plenty of nay-sayers on this, but if the chargers are set right, they will last. They are inexpensive, high energy density, and low maintenance ? check them once a year for leaks and capacity, walk away. When they hit 80% capacity (maybe 15 years later) replace them
For the nay-sayers, it?s a lifecycle cost issue, not an, ?Ick ? I don?t like them.?
As for the lead-selenium, I have not seen any in the US ? probably some around, I just haven?t seen them. I?ve been doing some research the last few months with an eye toward suggesting them for replacing lead-calcium in the 100 ? 600AH range. They look pretty good, but they appear to require the same maintenance as lead calcium.
dereck -
Your comments about lead-calcium are interesting. I rarely ever see lead-antimony in serious stationary battery applications. Almost all are low s.g. lead calcuim. As for lead calcium, I haven?t seen any evidence of plate creep. I think it is because all the systems I have worked were limited to 50% DoD. I suspect the Telcom boys go to 80% DoD and then charge hard, and that causes the positive plate swelling ? but I don?t know that. I'm wondering if the lead-antimony you speak of are lead-low antimony-selenium. I understand they are a lot more common in Europe than the US.
cf
- Status