R
I ordered the 4/3A Sanyo 4.0 Amp hour NIMH battery cells from NiCad
Lady. $6.50 per cell, 5 per pack, plus $5 to seld them together in
series to create a 6 volt battery pack. $37.50 per pack. Two packs
ordered. Plus about $10 shipping. Net about $42.50 per battery pack.
OK so far. Had a friend solder the cables from my current NiteRider
packs onto the new battery packs. The NiteRider original batteries
were 3.8 Amp hour Sanyo cells. I still have two functioning old 3.8
amp hour NiteRider battery packs in addition to the two new 4.0 rebuilt
battery packs.
Tried to charge them. Plugged the charger from my late 1990s NiteRider
Digital Head Trip into one of the new 4.0 battery packs. Heard a
"pop". Charger has not worked since. Charger did not charge the new
battery pack. Charger can no longer charge up my other original
NiteRider battery packs. This Digital charger charged at full power
for 14 hours and then went to a trickle charge.
Plugged the charger from my late 1990s NiteRider non digital Head Trip
into the new 4.0 battery pack. Nothing popped. This charger just
charges at full power until you unplug it. Simple charger. Left the
charger on the new 4.0 battery pack overnight and nothing was charged.
New 4.0 battery pack was still completely dead. I have used this
charger on my old NiteRider 3.8 battery packs and it charges them up
just fine overnight. So the charger still works. Before charging the
new 4.0 battery packs I did plug them into my helmet light and the
cells had enough juice in them from the factory to light up the light
for a minute. So the cells in the new 4.0 battery pack seem to be
welded together correctly based on this simple test of lighting up a 6
volt light.
Why can't I charge up the new 4.0 amp hour battery packs? Do the 4.0
amp hour cells have so much extra resistance over the original 3.8 that
a new high power charger is needed? Does it make any difference which
set of wires is connected to the + and - terminals of the in series
battery pack? The original battery packs had two wires going to the +
terminal and two wires going to the - terminal. My friend put them
back together the same way they were on the original battery packs.
Based upon my experience with 120 volt house wiring, it makes no
difference if you attach the hot or neutral wires to the brass or
silver screws on the outlet. As long as you don't put them on the same
screw at the same time, they work either way.
Below is the original posting and replies from October 2006.
1 From: [email protected] - view profile
Date: Tues, Oct 24 2006 9:46 am
Email: [email protected]
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I am replacing the battery cells in some NiteRider NiMH battery packs.
Battery size is 4/3A. They are available in mAh capacities of 3500,
3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
4500 is $7.00 each. I need ten of them. Original NiteRider cells are
3800 capacity.
How much real world difference is there between a 3500 and a 4200 and a
4500 capacity?
Will the NiteRider chargers charge all of these sizes of NiMH cells?
The chargers are two kinds. One is a charge at full power until you
unplug the thing. The other is charge at full power for 14 hours and
then it goes to a trickle charge.
Reply
2 From: Art Harris - view profile
Date: Tues, Oct 24 2006 11:28 am
Email: "Art Harris" <[email protected]>
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[email protected] wrote:
> I am replacing the battery cells in some NiteRider NiMH battery packs.
> Battery size is 4/3A. They are available in mAh capacities of 3500,
> 3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
> is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
> 4500 is $7.00 each. I need ten of them. Original NiteRider cells are
> 3800 capacity.
That doesn't make sense. The 4200 mAh is cheaper than the 3800 and 4000
mAh?
Are these all the same brand?
A higher mAh capacity should last a proportionately longer time before
needing to be recharged. Determine how much current your nightrider
draws and how long you need it to operate between charges. From that
you can determine your required mAh rating.Then add a safety margin and
compare prices. If you can get a 4200 mAh capacity cheaper than a 3800,
get it.
Art Harris
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3 From: [email protected] - view profile
Date: Tues, Oct 24 2006 3:01 pm
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Art Harris wrote:
> [email protected] wrote:
> > I am replacing the battery cells in some NiteRider NiMH battery packs.
> > Battery size is 4/3A. They are available in mAh capacities of 3500,
> > 3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
> > is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
> > 4500 is $7.00 each. I need ten of them. Original NiteRider cells are
> > 3800 capacity.
> That doesn't make sense. The 4200 mAh is cheaper than the 3800 and 4000
> mAh?
> Are these all the same brand?
Different brands, different internet mail order places. The cheapest
internet mail order place only carries 3500 and 4200 capacity. Not
sure what brand other than the picture is of green batteries. Other
source carries name brand 3800, 4000, 4200, and 4500. Sanyo and
Panasonic.
> A higher mAh capacity should last a proportionately longer time before
> needing to be recharged. Determine how much current your nightrider
> draws and how long you need it to operate between charges. From that
> you can determine your required mAh rating.Then add a safety margin and
> compare prices. If you can get a 4200 mAh capacity cheaper than a 3800,
> get it.
So it is a linear relationship. If the original 3800 capacity
batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
minutes longer.
Given the two low cost options of 3500 capacity for $2.60 each and the
4200 capacity for $4.30 each and the fact I need 10 batteries total.
It looks like an extra $1.70 buys me 18 minutes difference between the
two cells.
- Hide quoted text -
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> Art Harris
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4 From: Ben C - view profile
Date: Tues, Oct 24 2006 3:44 pm
Email: Ben C <[email protected]>
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On 2006-10-24, [email protected] <[email protected]>
wrote:
> Art Harris wrote:
[snip]
> So it is a linear relationship. If the original 3800 capacity
> batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
> 10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
> less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
> minutes longer.
It may not be quite linear, especially with filament bulbs (like
halogens). As soon as the battery voltage drops a bit, the bulb gets a
bit dimmer, the filament cools, its resistance drops, and the current
drawn is higher. This vicious circle soon finishes off the battery.
This, I've heard, is one of the reasons the batteries last a lot longer
with LED lights, because they don't have that characteristic. The
resistance is constant above some threshold voltage (and below that you
get nothing).
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5 From: [email protected] - view profile
Date: Tues, Oct 24 2006 6:22 pm
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On Tue, 24 Oct 2006 16:44:21 -0500, Ben C <[email protected]> wrote:
>On 2006-10-24, [email protected] <[email protected]> wrote:
>> Art Harris wrote:
>[snip]
>> So it is a linear relationship. If the original 3800 capacity
>> batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
>> 10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
>> less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
>> minutes longer.
>It may not be quite linear, especially with filament bulbs (like
>halogens). As soon as the battery voltage drops a bit, the bulb gets a
>bit dimmer, the filament cools, its resistance drops, and the current
>drawn is higher. This vicious circle soon finishes off the battery.
This is essentially a non-issue with common secondary cells; they have
such a sharp knee in the discharge curve that any cascading effect
such as you describe makes no difference.
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6 From: RonSonic - view profile
Date: Tues, Oct 24 2006 9:49 pm
Email: RonSonic <[email protected]>
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On 24 Oct 2006 14:01:07 -0700, [email protected] wrote:
- Hide quoted text -
- Show quoted text -
>Art Harris wrote:
>> [email protected] wrote:
>> > I am replacing the battery cells in some NiteRider NiMH battery packs.
>> > Battery size is 4/3A. They are available in mAh capacities of 3500,
>> > 3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
>> > is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
>> > 4500 is $7.00 each. I need ten of them. Original NiteRider cells are
>> > 3800 capacity.
>> That doesn't make sense. The 4200 mAh is cheaper than the 3800 and 4000
>> mAh?
>> Are these all the same brand?
>Different brands, different internet mail order places. The cheapest
>internet mail order place only carries 3500 and 4200 capacity. Not
>sure what brand other than the picture is of green batteries. Other
>source carries name brand 3800, 4000, 4200, and 4500. Sanyo and
>Panasonic.
>> A higher mAh capacity should last a proportionately longer time before
>> needing to be recharged. Determine how much current your nightrider
>> draws and how long you need it to operate between charges. From that
>> you can determine your required mAh rating.Then add a safety margin and
>> compare prices. If you can get a 4200 mAh capacity cheaper than a 3800,
>> get it.
>So it is a linear relationship. If the original 3800 capacity
>batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
>10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
>less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
>minutes longer.
>Given the two low cost options of 3500 capacity for $2.60 each and the
>4200 capacity for $4.30 each and the fact I need 10 batteries total.
>It looks like an extra $1.70 buys me 18 minutes difference between the
>two cells.
While you're shopping, batteryspace.com took good care of me last year.
They've
got good prices on complete packs assembled in a bottle with cable.
Hard to beat
even doing your own soldering.
Ron
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7 From: amakyonin - view profile
Date: Wed, Oct 25 2006 10:55 am
Email: "amakyonin" <[email protected]>
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[email protected] wrote:
> > A higher mAh capacity should last a proportionately longer time before
> > needing to be recharged. Determine how much current your nightrider
> > draws and how long you need it to operate between charges. From that
> > you can determine your required mAh rating.Then add a safety margin and
> > compare prices. If you can get a 4200 mAh capacity cheaper than a 3800,
> > get it.
> So it is a linear relationship. If the original 3800 capacity
> batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
> 10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
> less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
> minutes longer.
It isn't quite so simple. The usable capacity depends on the load on
the battery. A good example of this is shown here
(http://www.powerstream.com/4_3.htm) where the higher capacity 4500 mAH
Panasonic is demonstrated to have a higher internal resistance (slope
of the line) than another brand. If you extend the line of the
Panasonic to the right it will intersect the PowerStream 3850 mAH cells
at about 6.25A. With any higher load the lower rated battery will
outlast the Panasonic. The lost energy in the Panasonic is dissipated
as heat in the battery.
In a 6V system with a 10W and a 20W halogen you can draw 1.6A, 3.3A, or
5A so the Panasonic is still the better choice among these two. For
typical bike halogen systems you won't be operating at high enough
loads where the intersection of the load lines makes a difference in
your selection so you can still base your decision on the rated
capacity alone.
> Given the two low cost options of 3500 capacity for $2.60 each and the
> 4200 capacity for $4.30 each and the fact I need 10 batteries total.
> It looks like an extra $1.70 buys me 18 minutes difference between the
> two cells.
I would go for the 4200 just because that extra 18 minutes is still
very useful in the dark.
Note that you should consider adding a Raychem Polyswitch in series
somewhere in the pack to guard against a short circuit.
Powerizer/Batteryspace has some of the battery pack specific versions
but there is a bigger selection of the general purpose types at
Digi-key. Make sure you get one with the trip point higher than the
maximum current you expect to draw from the battery (or drive while
charging).
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8 From: dankap - view profile
Date: Wed, Oct 25 2006 1:22 pm
Email: "dankap" <[email protected]>
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Beware the mysterious green batteries! Here at work, we needed eight
AA rechargeable batteries. Since our office manager didn't like the
radio shack prices, she found a set online. There were the dreaded
green "value" batteries. After a few weeks of messing around with
short, unreliable battery life, we ended up ordering a complete new
set.
The original green batteries are "Digi-USA Hitech" brand, and have
small orange stripes on each end. I'm sure I could get permission to
mail them out to you if you covered shipping, since I was told to
dispose of them a while ago. The only reason I still have them is I
wanted to recycle as opposed to trash, and have not taken the time. I
sincerely believe they would not be worth the shipping cost, much less
whatever "deal" they are advertised at. If the batteries you found are
not the same as I described, this post may still serve as a warning.
I'm all for the best price and the best deal, but the least expensive
isn't always the best deal, and I'll never buy cheap batteries again.
The same holds true racing RC's, the fastest batteries with the longest
run times cost more than the cheap ones.
As an aside, the replacements for the dreaded green paperweights were
energizer brand, and they have performed great. I don't know where she
got them, but she found the store through froogle or a similar site. I
use maxamps.com for all my RC racing needs, but they may be overkill
for what you are looking to do.
Good luck, and let us know your battery choice and light life. I've
been considering a helmet-mounted niterider for some time.
- Hide quoted text -
- Show quoted text -
[email protected] wrote:
> Art Harris wrote:
> > [email protected] wrote:
> > > I am replacing the battery cells in some NiteRider NiMH battery packs.
> > > Battery size is 4/3A. They are available in mAh capacities of 3500,
> > > 3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
> > > is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
> > > 4500 is $7.00 each. I need ten of them. Original NiteRider cells are
> > > 3800 capacity.
> > That doesn't make sense. The 4200 mAh is cheaper than the 3800 and 4000
> > mAh?
> > Are these all the same brand?
> Different brands, different internet mail order places. The cheapest
> internet mail order place only carries 3500 and 4200 capacity. Not
> sure what brand other than the picture is of green batteries. Other
> source carries name brand 3800, 4000, 4200, and 4500. Sanyo and
> Panasonic.
> > A higher mAh capacity should last a proportionately longer time before
> > needing to be recharged. Determine how much current your nightrider
> > draws and how long you need it to operate between charges. From that
> > you can determine your required mAh rating.Then add a safety margin and
> > compare prices. If you can get a 4200 mAh capacity cheaper than a 3800,
> > get it.
> So it is a linear relationship. If the original 3800 capacity
> batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
> 10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
> less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
> minutes longer.
> Given the two low cost options of 3500 capacity for $2.60 each and the
> 4200 capacity for $4.30 each and the fact I need 10 batteries total.
> It looks like an extra $1.70 buys me 18 minutes difference between the
> two cells.
> > Art Harris
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9 From: Donald Gillies - view profile
Date: Tues, Oct 24 2006 4:30 pm
Email: [email protected] (Donald Gillies)
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[email protected] writes:
>I am replacing the battery cells in some NiteRider NiMH battery packs.
>Battery size is 4/3A. They are available in mAh capacities of 3500,
>3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
>is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
>4500 is $7.00 each. I need ten of them. Original NiteRider cells are
>3800 capacity.
The 3500 mAh for $2.60/ea are the cheapest. The 4200 mAh for $4.30
are 2nd cheapest.
>How much real world difference is there between a 3500 and a 4200 and a
>4500 capacity?
NiMH batteries have a fairly steep failure curve. I think that the
mAh rating scheme is fixed no matter what the battery type,
i.e. something like "when power drops to 80% of initial level, battery
is finished." So you should get roughly 20% more life out of a 4200
mAh battery than a 3500 mAh battery.
>Will the NiteRider chargers charge all of these sizes of NiMH cells?
>The chargers are two kinds. One is a charge at full power until you
>unplug the thing. The other is charge at full power for 14 hours and
>then it goes to a trickle charge.
When a charger switches over to trickle-charge, the charging rate is
drastically reduced, e.g. by a factor of 30x (1000 mA to 35 mA)
http://www.powerstream.com/NiMHWMm.htm
so the charger is effectively finished doing work.
- Don Gillies
San Diego, CA
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10 From: Art Harris - view profile
Date: Wed, Oct 25 2006 6:04 am
Email: "Art Harris" <[email protected]>
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[email protected] wrote:
> Will the NiteRider chargers charge all of these sizes of NiMH cells?
> The chargers are two kinds. One is a charge at full power until you
> unplug the thing. The other is charge at full power for 14 hours and
> then it goes to a trickle charge.
Neither of those sounds like a "smart charger." If the cells are not
run down to the "knee in the curve," 14 hours may overcharge them. A
smart charger senses when full charge has taken place and then switches
to trickle.
If you really want to do it right, connect a 4-digit digital voltmeter
across the battery, and stop charging when the voltage just starts to
drop. That works for Ni-Cds, not sure about Ni-mH. At any rate, a 14
hour charger is considered a slow charger, so if you left it on for 16
hours, it wouldn't be too bad.
Art Harris
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Lady. $6.50 per cell, 5 per pack, plus $5 to seld them together in
series to create a 6 volt battery pack. $37.50 per pack. Two packs
ordered. Plus about $10 shipping. Net about $42.50 per battery pack.
OK so far. Had a friend solder the cables from my current NiteRider
packs onto the new battery packs. The NiteRider original batteries
were 3.8 Amp hour Sanyo cells. I still have two functioning old 3.8
amp hour NiteRider battery packs in addition to the two new 4.0 rebuilt
battery packs.
Tried to charge them. Plugged the charger from my late 1990s NiteRider
Digital Head Trip into one of the new 4.0 battery packs. Heard a
"pop". Charger has not worked since. Charger did not charge the new
battery pack. Charger can no longer charge up my other original
NiteRider battery packs. This Digital charger charged at full power
for 14 hours and then went to a trickle charge.
Plugged the charger from my late 1990s NiteRider non digital Head Trip
into the new 4.0 battery pack. Nothing popped. This charger just
charges at full power until you unplug it. Simple charger. Left the
charger on the new 4.0 battery pack overnight and nothing was charged.
New 4.0 battery pack was still completely dead. I have used this
charger on my old NiteRider 3.8 battery packs and it charges them up
just fine overnight. So the charger still works. Before charging the
new 4.0 battery packs I did plug them into my helmet light and the
cells had enough juice in them from the factory to light up the light
for a minute. So the cells in the new 4.0 battery pack seem to be
welded together correctly based on this simple test of lighting up a 6
volt light.
Why can't I charge up the new 4.0 amp hour battery packs? Do the 4.0
amp hour cells have so much extra resistance over the original 3.8 that
a new high power charger is needed? Does it make any difference which
set of wires is connected to the + and - terminals of the in series
battery pack? The original battery packs had two wires going to the +
terminal and two wires going to the - terminal. My friend put them
back together the same way they were on the original battery packs.
Based upon my experience with 120 volt house wiring, it makes no
difference if you attach the hot or neutral wires to the brass or
silver screws on the outlet. As long as you don't put them on the same
screw at the same time, they work either way.
Below is the original posting and replies from October 2006.
1 From: [email protected] - view profile
Date: Tues, Oct 24 2006 9:46 am
Email: [email protected]
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I am replacing the battery cells in some NiteRider NiMH battery packs.
Battery size is 4/3A. They are available in mAh capacities of 3500,
3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
4500 is $7.00 each. I need ten of them. Original NiteRider cells are
3800 capacity.
How much real world difference is there between a 3500 and a 4200 and a
4500 capacity?
Will the NiteRider chargers charge all of these sizes of NiMH cells?
The chargers are two kinds. One is a charge at full power until you
unplug the thing. The other is charge at full power for 14 hours and
then it goes to a trickle charge.
Reply
2 From: Art Harris - view profile
Date: Tues, Oct 24 2006 11:28 am
Email: "Art Harris" <[email protected]>
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[email protected] wrote:
> I am replacing the battery cells in some NiteRider NiMH battery packs.
> Battery size is 4/3A. They are available in mAh capacities of 3500,
> 3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
> is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
> 4500 is $7.00 each. I need ten of them. Original NiteRider cells are
> 3800 capacity.
That doesn't make sense. The 4200 mAh is cheaper than the 3800 and 4000
mAh?
Are these all the same brand?
A higher mAh capacity should last a proportionately longer time before
needing to be recharged. Determine how much current your nightrider
draws and how long you need it to operate between charges. From that
you can determine your required mAh rating.Then add a safety margin and
compare prices. If you can get a 4200 mAh capacity cheaper than a 3800,
get it.
Art Harris
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3 From: [email protected] - view profile
Date: Tues, Oct 24 2006 3:01 pm
Email: [email protected]
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Art Harris wrote:
> [email protected] wrote:
> > I am replacing the battery cells in some NiteRider NiMH battery packs.
> > Battery size is 4/3A. They are available in mAh capacities of 3500,
> > 3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
> > is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
> > 4500 is $7.00 each. I need ten of them. Original NiteRider cells are
> > 3800 capacity.
> That doesn't make sense. The 4200 mAh is cheaper than the 3800 and 4000
> mAh?
> Are these all the same brand?
Different brands, different internet mail order places. The cheapest
internet mail order place only carries 3500 and 4200 capacity. Not
sure what brand other than the picture is of green batteries. Other
source carries name brand 3800, 4000, 4200, and 4500. Sanyo and
Panasonic.
> A higher mAh capacity should last a proportionately longer time before
> needing to be recharged. Determine how much current your nightrider
> draws and how long you need it to operate between charges. From that
> you can determine your required mAh rating.Then add a safety margin and
> compare prices. If you can get a 4200 mAh capacity cheaper than a 3800,
> get it.
So it is a linear relationship. If the original 3800 capacity
batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
minutes longer.
Given the two low cost options of 3500 capacity for $2.60 each and the
4200 capacity for $4.30 each and the fact I need 10 batteries total.
It looks like an extra $1.70 buys me 18 minutes difference between the
two cells.
- Hide quoted text -
- Show quoted text -
> Art Harris
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4 From: Ben C - view profile
Date: Tues, Oct 24 2006 3:44 pm
Email: Ben C <[email protected]>
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On 2006-10-24, [email protected] <[email protected]>
wrote:
> Art Harris wrote:
[snip]
> So it is a linear relationship. If the original 3800 capacity
> batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
> 10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
> less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
> minutes longer.
It may not be quite linear, especially with filament bulbs (like
halogens). As soon as the battery voltage drops a bit, the bulb gets a
bit dimmer, the filament cools, its resistance drops, and the current
drawn is higher. This vicious circle soon finishes off the battery.
This, I've heard, is one of the reasons the batteries last a lot longer
with LED lights, because they don't have that characteristic. The
resistance is constant above some threshold voltage (and below that you
get nothing).
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5 From: [email protected] - view profile
Date: Tues, Oct 24 2006 6:22 pm
Email: [email protected]
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On Tue, 24 Oct 2006 16:44:21 -0500, Ben C <[email protected]> wrote:
>On 2006-10-24, [email protected] <[email protected]> wrote:
>> Art Harris wrote:
>[snip]
>> So it is a linear relationship. If the original 3800 capacity
>> batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
>> 10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
>> less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
>> minutes longer.
>It may not be quite linear, especially with filament bulbs (like
>halogens). As soon as the battery voltage drops a bit, the bulb gets a
>bit dimmer, the filament cools, its resistance drops, and the current
>drawn is higher. This vicious circle soon finishes off the battery.
This is essentially a non-issue with common secondary cells; they have
such a sharp knee in the discharge curve that any cascading effect
such as you describe makes no difference.
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6 From: RonSonic - view profile
Date: Tues, Oct 24 2006 9:49 pm
Email: RonSonic <[email protected]>
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On 24 Oct 2006 14:01:07 -0700, [email protected] wrote:
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>Art Harris wrote:
>> [email protected] wrote:
>> > I am replacing the battery cells in some NiteRider NiMH battery packs.
>> > Battery size is 4/3A. They are available in mAh capacities of 3500,
>> > 3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
>> > is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
>> > 4500 is $7.00 each. I need ten of them. Original NiteRider cells are
>> > 3800 capacity.
>> That doesn't make sense. The 4200 mAh is cheaper than the 3800 and 4000
>> mAh?
>> Are these all the same brand?
>Different brands, different internet mail order places. The cheapest
>internet mail order place only carries 3500 and 4200 capacity. Not
>sure what brand other than the picture is of green batteries. Other
>source carries name brand 3800, 4000, 4200, and 4500. Sanyo and
>Panasonic.
>> A higher mAh capacity should last a proportionately longer time before
>> needing to be recharged. Determine how much current your nightrider
>> draws and how long you need it to operate between charges. From that
>> you can determine your required mAh rating.Then add a safety margin and
>> compare prices. If you can get a 4200 mAh capacity cheaper than a 3800,
>> get it.
>So it is a linear relationship. If the original 3800 capacity
>batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
>10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
>less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
>minutes longer.
>Given the two low cost options of 3500 capacity for $2.60 each and the
>4200 capacity for $4.30 each and the fact I need 10 batteries total.
>It looks like an extra $1.70 buys me 18 minutes difference between the
>two cells.
While you're shopping, batteryspace.com took good care of me last year.
They've
got good prices on complete packs assembled in a bottle with cable.
Hard to beat
even doing your own soldering.
Ron
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7 From: amakyonin - view profile
Date: Wed, Oct 25 2006 10:55 am
Email: "amakyonin" <[email protected]>
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[email protected] wrote:
> > A higher mAh capacity should last a proportionately longer time before
> > needing to be recharged. Determine how much current your nightrider
> > draws and how long you need it to operate between charges. From that
> > you can determine your required mAh rating.Then add a safety margin and
> > compare prices. If you can get a 4200 mAh capacity cheaper than a 3800,
> > get it.
> So it is a linear relationship. If the original 3800 capacity
> batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
> 10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
> less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
> minutes longer.
It isn't quite so simple. The usable capacity depends on the load on
the battery. A good example of this is shown here
(http://www.powerstream.com/4_3.htm) where the higher capacity 4500 mAH
Panasonic is demonstrated to have a higher internal resistance (slope
of the line) than another brand. If you extend the line of the
Panasonic to the right it will intersect the PowerStream 3850 mAH cells
at about 6.25A. With any higher load the lower rated battery will
outlast the Panasonic. The lost energy in the Panasonic is dissipated
as heat in the battery.
In a 6V system with a 10W and a 20W halogen you can draw 1.6A, 3.3A, or
5A so the Panasonic is still the better choice among these two. For
typical bike halogen systems you won't be operating at high enough
loads where the intersection of the load lines makes a difference in
your selection so you can still base your decision on the rated
capacity alone.
> Given the two low cost options of 3500 capacity for $2.60 each and the
> 4200 capacity for $4.30 each and the fact I need 10 batteries total.
> It looks like an extra $1.70 buys me 18 minutes difference between the
> two cells.
I would go for the 4200 just because that extra 18 minutes is still
very useful in the dark.
Note that you should consider adding a Raychem Polyswitch in series
somewhere in the pack to guard against a short circuit.
Powerizer/Batteryspace has some of the battery pack specific versions
but there is a bigger selection of the general purpose types at
Digi-key. Make sure you get one with the trip point higher than the
maximum current you expect to draw from the battery (or drive while
charging).
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8 From: dankap - view profile
Date: Wed, Oct 25 2006 1:22 pm
Email: "dankap" <[email protected]>
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Beware the mysterious green batteries! Here at work, we needed eight
AA rechargeable batteries. Since our office manager didn't like the
radio shack prices, she found a set online. There were the dreaded
green "value" batteries. After a few weeks of messing around with
short, unreliable battery life, we ended up ordering a complete new
set.
The original green batteries are "Digi-USA Hitech" brand, and have
small orange stripes on each end. I'm sure I could get permission to
mail them out to you if you covered shipping, since I was told to
dispose of them a while ago. The only reason I still have them is I
wanted to recycle as opposed to trash, and have not taken the time. I
sincerely believe they would not be worth the shipping cost, much less
whatever "deal" they are advertised at. If the batteries you found are
not the same as I described, this post may still serve as a warning.
I'm all for the best price and the best deal, but the least expensive
isn't always the best deal, and I'll never buy cheap batteries again.
The same holds true racing RC's, the fastest batteries with the longest
run times cost more than the cheap ones.
As an aside, the replacements for the dreaded green paperweights were
energizer brand, and they have performed great. I don't know where she
got them, but she found the store through froogle or a similar site. I
use maxamps.com for all my RC racing needs, but they may be overkill
for what you are looking to do.
Good luck, and let us know your battery choice and light life. I've
been considering a helmet-mounted niterider for some time.
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[email protected] wrote:
> Art Harris wrote:
> > [email protected] wrote:
> > > I am replacing the battery cells in some NiteRider NiMH battery packs.
> > > Battery size is 4/3A. They are available in mAh capacities of 3500,
> > > 3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
> > > is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
> > > 4500 is $7.00 each. I need ten of them. Original NiteRider cells are
> > > 3800 capacity.
> > That doesn't make sense. The 4200 mAh is cheaper than the 3800 and 4000
> > mAh?
> > Are these all the same brand?
> Different brands, different internet mail order places. The cheapest
> internet mail order place only carries 3500 and 4200 capacity. Not
> sure what brand other than the picture is of green batteries. Other
> source carries name brand 3800, 4000, 4200, and 4500. Sanyo and
> Panasonic.
> > A higher mAh capacity should last a proportionately longer time before
> > needing to be recharged. Determine how much current your nightrider
> > draws and how long you need it to operate between charges. From that
> > you can determine your required mAh rating.Then add a safety margin and
> > compare prices. If you can get a 4200 mAh capacity cheaper than a 3800,
> > get it.
> So it is a linear relationship. If the original 3800 capacity
> batteries last 1:30 on 15 watt halogen, then a 4200 capacity will last
> 10% longer. Or 9 minutes more. Or a 3500 capacity will last about 10%
> less. About 9 minutes less. Or a 4500 will last 18% longer, about 16
> minutes longer.
> Given the two low cost options of 3500 capacity for $2.60 each and the
> 4200 capacity for $4.30 each and the fact I need 10 batteries total.
> It looks like an extra $1.70 buys me 18 minutes difference between the
> two cells.
> > Art Harris
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9 From: Donald Gillies - view profile
Date: Tues, Oct 24 2006 4:30 pm
Email: [email protected] (Donald Gillies)
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[email protected] writes:
>I am replacing the battery cells in some NiteRider NiMH battery packs.
>Battery size is 4/3A. They are available in mAh capacities of 3500,
>3800, 4000, 4200, and 4500. The 3500 capacity is $2.60 each. The 3800
>is $5.00 each. The 4000 is $6.50 each. The 4200 is $4.30 each. The
>4500 is $7.00 each. I need ten of them. Original NiteRider cells are
>3800 capacity.
The 3500 mAh for $2.60/ea are the cheapest. The 4200 mAh for $4.30
are 2nd cheapest.
>How much real world difference is there between a 3500 and a 4200 and a
>4500 capacity?
NiMH batteries have a fairly steep failure curve. I think that the
mAh rating scheme is fixed no matter what the battery type,
i.e. something like "when power drops to 80% of initial level, battery
is finished." So you should get roughly 20% more life out of a 4200
mAh battery than a 3500 mAh battery.
>Will the NiteRider chargers charge all of these sizes of NiMH cells?
>The chargers are two kinds. One is a charge at full power until you
>unplug the thing. The other is charge at full power for 14 hours and
>then it goes to a trickle charge.
When a charger switches over to trickle-charge, the charging rate is
drastically reduced, e.g. by a factor of 30x (1000 mA to 35 mA)
http://www.powerstream.com/NiMHWMm.htm
so the charger is effectively finished doing work.
- Don Gillies
San Diego, CA
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10 From: Art Harris - view profile
Date: Wed, Oct 25 2006 6:04 am
Email: "Art Harris" <[email protected]>
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[email protected] wrote:
> Will the NiteRider chargers charge all of these sizes of NiMH cells?
> The chargers are two kinds. One is a charge at full power until you
> unplug the thing. The other is charge at full power for 14 hours and
> then it goes to a trickle charge.
Neither of those sounds like a "smart charger." If the cells are not
run down to the "knee in the curve," 14 hours may overcharge them. A
smart charger senses when full charge has taken place and then switches
to trickle.
If you really want to do it right, connect a 4-digit digital voltmeter
across the battery, and stop charging when the voltage just starts to
drop. That works for Ni-Cds, not sure about Ni-mH. At any rate, a 14
hour charger is considered a slow charger, so if you left it on for 16
hours, it wouldn't be too bad.
Art Harris
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