I think that switching from primaries to secondaries in business is a good idea wherever it may be done. I have been through it with body mics in a theatre. It has saved an amazing amount of money even on our small scale.
First of all it must be determined that the device will, in fact, run on eneloops and have an acceptable runtime. Also make sure that the swapping out of cells may be accomplished without tearing the cell wrapper or causing the cells to deform in any way. I have seen some devices that were very hard on cells with every insertion and extraction. This is hardly noticed with primaries as they are thrown away after only one insertion/extraction.
Unless I've missed some post covering this you will need to give much more thought to the
human factors involved in the
behavioral changes that your users will have to make if the switch is going to be cost effective.
You are into secondaries -- everyone responding here is into secondaries. That will probably not be the case with the user base you've mentioned. Don't take your
somewhat specialized knowledge for granted. Projecting it onto your users could lead to disaster if you make the switch without giving it serious thought. In my own experience I have been nearly continually amazed at what casual users
do not know and also
have a very hard time grasping and implementing even after I've tried to explain it to them
a few different ways.
Below are a few traps that may lie in wait for your project when
uninitiated users become involved:
- The users will have to be reminded not to just throw the discharged cells away.
You have 60 devices and even assuming just one user per device that is a lot of people who are very used to just taking out the cells and throwing them away (perhaps some of them have been doing it for years). You may think that this potential problem is rather far fetched. It is not. It has happened to CPFers and they have written about it. If one person does it once it may be bad enough but this problem may be more serious, depending on your user base. Bear in mind that the casual throwing away of ANY secondaries will have a negative impact on your program's bottom line. It will also adversely affect the numbers on your 'carbon footprint' if that's one of your sacraments.
- Those who have only used primary cells (most if not all of your user base) have no idea how casual handling will shorten the projected life span of secondaries. Consider two scenarios: one with primary cells and one with secondaries. First, a primary AA cell rolls across a desk and falls to a hard floor. The impact of the impact
is uncertain. If the cell was being transferred to a storage container it may begin to leak in the months ahead. If the cell is going directly into equipment it may leak during discharge but that's probably a long shot. More than likely it will perform normally and be thrown away when discharged without the user ever giving it another thought.
In the second scenario a secondary cell falls off the desk onto the same hard floor. What will happen? Who knows? This is just one more knock on a cell that was designed to be reused 500-1,000 times. The cumulative effects of the casual handling of secondaries may be devastating in terms of reducing their productive life span and it is important that your users understand that incidents that seem to have no impact at all on primaries will drastically shorten the lives of secondaries. This is somewhat counterintuitive. In general, your users will never have given a thought to this.
- Every step in the handling of the secondary sells needs to be carefully thought out. Thought should be given to the container(s) that hold both charged and discharged cells so that needless accidents may be avoided and cells may be evenly rotated. If everyone replaces their own cells in their personal devices at the same counter countless charge cycles may be gained by something as simple as adding a strip of wood that will prevent cells from repeatedly just rolling off the counter.
I know that much of this sounds improbable but these issues are very real and have great potential to adversely affect your program. Consider this: IMO the Eneloops are rock solid for many applications. There is a bit more
Voodoo involved in selecting a good charger but that part of it is still pretty simple and under your control. The Users, however, are a whole 'nother story. They are the wildcard in this whole project.
They will do things that you never anticipated. It will amaze you.
Having said all of that I still think it's a very worthwhile project and I am not trying to turn you off on it at all. (Really) It's just that I have went through some of this in the real world and in reading through this thread I noticed that IMO the most challenging issue of all -- the human factor -- had not been addressed.
The next time I start a project like this I will consider starting a thread that will attract the attention of those who have administered these kind of projects and how they dealt with the problems that their neophyte users introduced
after the hardware problems were solved.
