[ale] [OT] any experience with low self discharge NIMH batteries

[Ron Frazier (ALE)]

Hi all,

I've completed my battery and lighting research (for now).  My plans for LED emergency lighting and rechargeable batteries have taken a turn South and I thought I'd share what I concluded.

PS For those who wished me well after the flu, I appreciate it.  Being human again is good.

I had two main objectives starting this thread.  A) convert all my emergency lighting to LED, and B) convert it all to rechargeable batteries.

The first items I wanted to convert were some small hand flashlights.  3 of these are LED already.  2 use krypton (filament) bulbs, but the beam pattern is not conducive to LED's.  The 3 LED ones use 3 AAA batteries and the 2 krypton ones use 4 AA batteries.  It would be feasible to use LSD NIMH batteries like Imedion or Eneloop.  I think either would be a good brand.  However, I have a large stock of disposables on hand, so I'm going to defer that till later.

The other items I wanted to convert were my big lanterns that I use for area lighting when the storms hit.

I have 2 big Coleman lanterns that use 2 big square 6v lantern batteries and each have 2 6w fluorescent tubes.  They work well, but eat batteries for lunch.

I thought I'd go to LED lights, and mentioned a couple previously in the thread.  For reference, a modern fluorescent lantern, which may be 15 - 18 w, puts out about 300 lumens.  So, I was looking for something in LED in that range.  I found a couple of them online, but like to buy locally if possible in case I need to do returns.

I found a nice Coleman LED Hanging Lantern at Academy Outdoors that's rated at 200 lumens.  It uses 4 D batteries.  I figured I'd get it and test it.  (By the way, their website totally lies about how many lanterns they have in store.  They have a number of them.)

I brought the lantern home and tested it side by side with my old Coleman dual tube lantern.  Sure enough, the new LED lantern was brighter, although my old ones probably are not at peak performance.  The new one is less battery hungry too.  However, I took it back.

The problem with the LED lantern is that the light is very glary, or blinding.  When you approach the lantern to operate the switch once the unit is on, it is very painful.  (This may not bother some people.)  This does not occur with the fluorescent lantern.

The problem is that the LED is a VERY BRIGHT POINT SOURCE.  They try to use reflectors and diffusers, but you still end up seeing a very bright point of light.  The light output of a fluorescent tube is scattered all along the tube on all sides.  It is much easier on the eyes.  Of course, I wouldn't recommend staring at it.

So, I'm going to stick with my old reliable proven technology for now.

Here are two good modern alternatives for fluorescent lanterns.  There are many others.

This one is really nice.  I bought it for a family member and will probably buy one for myself if I need one.  It has a solid case and a good rubber grip and two fluorescent tubes.  Unfortunately, it takes 8 D batteries.  It's rated for 30 hours on half power and 14 hours on full power.  I would only ever use alkaline batteries to prevent leakage.  You can buy industrial alkaline D cells in bulk for about $ 1 / cell.

Raovac Sportsman Lantern

http://www.amazon.com/Rayovac-SP8DA-Sportsman-Lantern-Fluorescent/dp/B00005M283/ref=sr_1_1?ie=UTF8&qid=1363654767&sr=8-1&keywords=fluorescent+lantern+8d

Here is an alternative from Coleman

http://www.amazon.com/Coleman-Square-Pack-Away-Lantern-Control/dp/B00168QWVQ/ref=sr_1_7?ie=UTF8&qid=1363654767&sr=8-7&keywords=fluorescent+lantern+8d

So, I'm keeping my old monster lanterns.  I, at least, decided I wanted to do something about the batteries.  You can buy a shell which holds 4 D batteries and fits in place of the old 6 v square battery.  I plan to convert each lantern to use 8 D cells with 2 of these shells when the old square batteries fail.

I could go with a sealed lead acid battery in the shape of a square one.  SLA batteries are notoriously flaky in terms of surviving when you leave them partially charged for a long time.  So, I don't want to do that.

The other alternative is to put rechargeable D cells in the lanterns.  Here's how that works out.  Note that I would have to buy a D cell charger, since I don't have one.

Alternative 1) NIMH D cells, $ 8 ea, $ 64 total per lantern - 8 cells
     If all are in series - pack would be 10,000 mah
     NIMH cells self discharge quickly and are not ideal for sitting in storage.

Alternative 2) NIMH D cells, low self discharge
     Prices vary.  Cannot use Eneloop's since they're not true D cells, but are constructed of AA cells in parallel.
     Imedion, $ 16.50 ea, $ 132 total per lantern - 8 cells
     Pack capacity 9500 mah.
     This is probably the best alternative technologically.

Alternative 3) NIMH D cells, low self discharge (haven't researched the brand)
     Tenergy, $ 8.50 ea, $ 68 total per lantern - 8 cells
     Pack capacity 8000 mah.
     This could be a good option, but capacity is less than the Imedions.

Alternative 4, LiFePo D cells, $ 21.50 ea, $ 86 per lantern - 4 cells - different voltage
     Pack capacity 5000 mah
     From a battery chemistry point of view, this is probably the best option, if you can even buy the cells.
     These cells are less finicky, and tolerate storage in partially charged state better than others.
     They are much safer than other Lithium chemistry's and are more environmentally friendly than nickel or lead chemistry's.
     However, pack capacity is 1/2 of NIMH.
     Thanks to the person who put me on to these earlier.

So, best chemistry - LiFePo - $ 86 / lantern
     best brand - NIMH Imedion LSD - $ 132 / lantern
     best price - NIMH Tenergy LSD - $ 68 / lantern

One disadvantage of this strategy is that, a couple of times a year, I have to take 8 D cells out of each lantern and charge them, as there is no charging port or built in charger.  Most chargers won't do 8 cells at a time, so I'd either have to stage them, or buy two chargers.

If I were going to do this, I'd probably go with the NIMH Tenergy batteries.  When it's all said and done, though, I don't think I want to spend $ 200 to retrofit two lanterns that are essentially working.

So, plans to convert to LED lighting - down in flames.
     plans to convert to rechargeable batteries - down in flames.
     plans to ditch 6v square batteries - yes - switching to D cells.

So, that's it.  I'm going to keep the old lanterns, convert them to D cells, and buy 8 D batteries once or twice per year when needed.  Hope you guys find this info interesting and helpful.

Sincerely,

Ron



Chris Ricker <chris.ricker at gmail.com> wrote:

>On 3/5/13 12:04 AM, Ron Frazier (ALE) wrote:
>> Enter Low Self Discharge NIMH batteries.  These are relatively new. 
>> They claim to lose only about 15 % of their charge after a year. So, 
>> you could get away with charging the flashlight batteries only every
>6 
>> months or so.
>>
>> Two main brands of LSD NIMH seem to dominate.  Eneloop by Sanyo and 
>> Imedion by Powerex (Maha Energy).  I've used some standard Powerex 
>> NIMH 2700 mah batteries and I like them, but I have to charge them if
>
>> they've been sitting a while.
>
>I've been using Eneloops for a few years. They work well
>
>Amazon usually has good pricing on them and appropriate chargers -- and
>
>if nothing else, entertaining reviews because some of the people buying
>
>Eneloops from there reach levels of obsessive geekery that even this 
>list can't dream of touching :-)
>
>
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Ron Frazier
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