Can the battery take it?

Buy a charger that is self regulating. They don't cost much more than the crummy [censored] deliverd with
the lights and battery you buy. With a real charger you just plug it in when you get off the bike
and leave it in until next time you go out. They will charge until the battery is full and then they
will go down to a minimal charge that will get those last 10% filled up. You can leave them on as
long as you like and it will only make your battery healthier.

Just make sure you buy one that is intended for the type of battery you have. Lead-acid, Ni-Cd and
Ni-Mh have different charging characteristics. In Sweden where I live you can get one for maybe $60
at ELFA. Well spent money in my opinion.

--
Perre

"Hjalmar Duklæt" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

My battery charger stopped working the other day.I used it to charge my

30W

Quoted message said:

hour NightSun battery. I've ordered a new one but it will take a couple of weeks to get it over I
guess. As I'm not a very patient fellow I took the car battery charger and hooked it up to the
NightSun battery. After two hours 45 minutes the battery started to feel warm on the outside so I
figured it was fully charged. I've charged it a few times after that and

it

Quoted message said:

seems to work very well. What I'm affraid of is if this fast charging will finally destroy my
battery. As the battery is getting old (about 7 years) and I've already ordered a new one I'll
ready to take the risk. I need

the

Quoted message said:

light to be able to ride at this time of year. Can anybody tell me if this charging is harmful to
the battery? It's sure nice to be able to use less than three hours to fully charge the battery
instead of the 15 hours required by the NightSun charger. Hjalmar

Hei Perre, I've already done that, but can't wait till I get it. Guess it takes about 10 days to get
it over the pond. Meanwhile I need the lights to go to work
5:30 in the morning. As the battery is getting old and I've also ordered a new one I thought maybe I
could use my car batteri charger until the new battery/charger arrives. I've done so a few times
now and it seems to work fine. Takes under 3 hours to charge it up compared to the charger that
comes with the light that takes about 15 hours (can be convenient). The battery is a NiCad type
battery and my question is what impact does the "fast charging" have to the battery. Hjalmar "Per
Elmsäter" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Buy a charger that is self regulating. They don't cost much more than the crummy [censored] deliverd
with the lights and battery you buy. With a real charger you just plug it in when you get off the
bike and leave it in

until

Quoted message said:

next time you go out. They will charge until the battery is full and then they will go down to a
minimal charge that will get those last 10% filled up. You can leave them

on

Quoted message said:

as long as you like and it will only make your battery healthier.

Just make sure you buy one that is intended for the type of battery you have. Lead-acid, Ni-Cd and
Ni-Mh have different charging characteristics.

In

Quoted message said:

Sweden where I live you can get one for maybe $60 at ELFA. Well spent

money

Quoted message said:

in my opinion.

--
Perre

"Hjalmar Duklæt" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

My battery charger stopped working the other day.I used it to charge my

30W

Quoted message said:

hour NightSun battery. I've ordered a new one but it will take a couple

of

Quoted message said:

Quoted message said:

weeks to get it over I guess. As I'm not a very patient fellow I took

the

Quoted message said:

Quoted message said:

car battery charger and hooked it up to the NightSun battery. After two hours 45 minutes the
battery started to feel warm on the outside so I figured it was fully charged. I've charged it a
few times after that and

it

Quoted message said:

seems to work very well. What I'm affraid of is if this fast charging

will

Quoted message said:

Quoted message said:

finally destroy my battery. As the battery is getting old (about 7

years)

Quoted message said:

Quoted message said:

and I've already ordered a new one I'll ready to take the risk. I need

the

Quoted message said:

light to be able to ride at this time of year. Can anybody tell me if

this

Quoted message said:

Quoted message said:

charging is harmful to the battery? It's sure nice to be able to use

less

Quoted message said:

Quoted message said:

than three hours to fully charge the battery instead of the 15 hours required by the NightSun
charger. Hjalmar

"Hjalmar Duklæt" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Hei Perre, I've already done that, but can't wait till I get it. Guess it takes about 10 days to
get it over the pond. Meanwhile I need the lights to go to work
5:30 in the morning. As the battery is getting old and I've also ordered a new one I thought
maybe I could use my car batteri charger until the new battery/charger arrives. I've done so a
few times now and it seems to work fine. Takes under 3 hours to charge it up compared to the
charger that

comes

Quoted message said:

with the light that takes about 15 hours (can be convenient). The battery

is

Quoted message said:

a NiCad type battery and my question is what impact does the "fast

charging"

Quoted message said:

have to the battery. Hjalmar

You will have to be a little careful there I believe due to the different charging characteristics
of Lead and NiCad batterys. A lead battery is charged with voltage, V ( Spänning ) and NiCad battery
I believe is charged with current, A ( Ström ). Your car battery charger is probably giving 14.4 V
and maybe 6A. I believe that NiCad batterys are charged with a lot fewer Amps than that so you will
probably harm it in the long run. You can see on the ELFA website how many amps they use with their
chargers for NiCad. If it was a brand new NiCad battery I'd strongly advice you not to. But since
you say you will be replacing it anyway you can probably get away with what you are doing as long as
you don't let it overheat. Maybe leave it in the garage or something in case it explodes ;(

--
Perre

">

Quoted message said:

You will have to be a little careful there I believe due to the different charging characteristics
of Lead and NiCad batterys. A lead battery is charged with voltage, V ( Spänning ) and NiCad
battery I believe is

charged

Quoted message said:

with current, A ( Ström ). Your car battery charger is probably giving

14.4

Quoted message said:

V and maybe 6A. I believe that NiCad batterys are charged with a lot fewer Amps than that so you
will probably harm it in the long run. You can see

on

Quoted message said:

the ELFA website how many amps they use with their chargers for NiCad. If it was a brand new NiCad
battery I'd strongly advice you not to. But since you say you will be replacing it anyway you can
probably get away

with

Quoted message said:

what you are doing as long as you don't let it overheat. Maybe leave it in the garage or something
in case it explodes ;(

No, I wouldn't do that to a new battery. The A-meter on the charger says it's putting out about 2
Amps and I'm keeping it in the garage while charging. The originale charger is a 13V/450mW charger.
I will only be doing this for a short while with my old battery only until the new battery/charger
arrives. Maybe I shall continue for a longer periode just as a test and see if the battery
deteriorates quickly. I don't think the risk of an explosion is very high as long as I remember to
switch off the charger in time before overheating the battery. Hjalmar

Quoted message said:

--
Perre

"Hjalmar Duklæt" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

... I took the car battery charger and hooked it up to the NightSun battery. After two hours 45
minutes the battery started to feel warm on the outside so I figured it was fully charged. ...It's
sure nice to be able to use less than three hours to fully charge the battery instead of the 15
hours required by the NightSun charger.
---------------------

probably *not* a good idea. usually the batteries/chargers are matched to give longest life of the
battery and minimize risk of explosion, etc. hooking a fast-charge to a battery designed for a slow
charge is probably risky and might damage the battery.

Have you tried contacting the NightSun people to see if the battery can handle the amps that a car
charge dumps in?

d

"Hjalmar Duklæt" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

My battery charger stopped working the other day.I used it to charge my 30W hour NightSun battery.
I've ordered a new one but it will take a couple of weeks to get it over I guess. As I'm not a
very patient fellow I took the car battery charger and hooked it up to the NightSun battery. After
two hours 45 minutes the battery started to feel warm on the outside so I figured it was fully
charged. I've charged it a few times after that and it seems to work very well. What I'm affraid
of is if this fast charging will finally destroy my battery. As the battery is getting old (about
7 years) and I've already ordered a new one I'll ready to take the risk. I need the light to be
able to ride at this time of year. Can anybody tell me if this charging is harmful to the battery?
It's sure nice to be able to use less than three hours to fully charge the battery instead of the
15 hours required by the NightSun charger. Hjalmar

If your battery is 7 years old, I'd guess it is a nickel cadmium (NiCd) battery. These may be fast
charged without damage or hazard if they are NOT OVERCHARGED. If overcharged, they will become hot,
possibly evolve gas at a rate that is too high for the vent to handle and explode (worst case.) Most
likely, overcharging will overheat and kill the battery. The overheating may be enough to melt items
nearby and start a fire. The watchwords when fast charging NiCds is to be careful and stop as soon
as the batteries become warm.

Fast chargers are available for NiCd batteries and I have one that cost me about $80.00. This
charger looks for a characteristic voltage drop that occurs when NiCds reach full charge and then,
it automatically drops the charging current to a trickle level. It can easily, safely, charge a
battery of 1 to 16 cells and several amp hours in 15 minutes.

Nickel metal hydride (Nimh) batteries behave in a similar way to NiCd batteries except that the
voltage drop at full charge is less and, therefore, more difficult to detect. I do not know of fast
chargers for Nimh batteries.

I do not know much about charging lithium ion batteries. These are the best choice from an ampacity
vs. weight standpoint. But they are very expensive and should be charged using the supplied charger.

Steve Shapiro

Hjalmar Duklæt said:

My battery charger stopped working the other day.I used it to charge my 30W hour NightSun battery.

Battery capacity is usually given in Ampere-hours or milliAmpere-hours, NOT Watt Hours. Is this
battery a lead-acid or NiCd?

Whether or not the battery explodes, it may be damaged or its life shortened by improper charging.
NiCd batts want to be charged at a constant current, Lead acid batts want to be charged at a
constant voltage.

Art Harris

Matt O'Toole said:

Hjalmar Duklæt said:

Quoted message said:

Your car battery charger is probably giving
14.4 V and maybe 6A.

Most car battery chargers seem to have a "start" mode of 20-50A, a regular charge rate of 10A or
so, and a "trickle" charge setting of 2A.

Quoted message said:

No, I wouldn't do that to a new battery. The A-meter on the charger says it's putting out about 2
Amps and I'm keeping it in the garage while charging. The originale charger is a 13V/450mW
charger. I will only be doing this for a short while with my old battery only until the new
battery/charger arrives. Maybe I shall continue for a longer periode just as a test and see if the
battery deteriorates quickly. I don't think the risk of an explosion is very high as long as I
remember to switch off the charger in time before overheating the battery.

You're doing fine. Nicads are high current batteries, and in fact can be charged with even more
current than that. But the more current, the more you risk damage from overcharging -- everything
happens faster! 2A should be fine, though, as long as you can stop the charge before the batteries
warm up significantly -- which is actually a very good indicator of full charge. You said you
ordered a new charger already. That's good, but in the meantime you can certainly keep using your
car battery charger, as long as you're careful.

I thought that the battery had to be designed for fast charging. I know that I've read that not
all NiCads can be fast charged -- however, that could just be someone trying to sell THEIR
SPECIAL battery 🙂. I personally wouldn't do it. I'd try something like a car light bulb in
series with it to drop the current down. The problem then becomes determining the full charge
voltage (when to stop).

David

Hjalmar Duklæt said:

Quoted message said:

Your car battery charger is probably giving
14.4 V and maybe 6A.

Most car battery chargers seem to have a "start" mode of 20-50A, a regular charge rate of 10A or so,
and a "trickle" charge setting of 2A.

Quoted message said:

No, I wouldn't do that to a new battery. The A-meter on the charger says it's putting out about 2
Amps and I'm keeping it in the garage while charging. The originale charger is a 13V/450mW
charger. I will only be doing this for a short while with my old battery only until the new
battery/charger arrives. Maybe I shall continue for a longer periode just as a test and see if the
battery deteriorates quickly. I don't think the risk of an explosion is very high as long as I
remember to switch off the charger in time before overheating the battery.

You're doing fine. Nicads are high current batteries, and in fact can be charged with even more
current than that. But the more current, the more you risk damage from overcharging -- everything
happens faster! 2A should be fine, though, as long as you can stop the charge before the batteries
warm up significantly -- which is actually a very good indicator of full charge. You said you
ordered a new charger already. That's good, but in the meantime you can certainly keep using your
car battery charger, as long as you're careful.

Matt O.

"Harris" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Hjalmar Duklæt said:

My battery charger stopped working the other day.I used it to charge my

30W

Quoted message said:

Quoted message said:

hour NightSun battery.

Battery capacity is usually given in Ampere-hours or milliAmpere-hours, NOT Watt Hours. Is this
battery a lead-acid or NiCd?

Yes, I know that but NightSun give the capasity in Watt Hours which makes it easier to understand
for most people I guess. 30 WHrs is 3 hrs. @ 10W. Calculating how long a 2.5 AHrs battery will last
@ 10W is a bit trickier. I=P/U=10/12=0.8333W. 2.5WHrs/0.833W=3 Hrs.

Quoted message said:

Whether or not the battery explodes, it may be damaged or its life shortened by improper charging.
NiCd batts want to be charged at a constant current, Lead acid batts want to be charged at a
constant voltage.

Yes, I know that too, but as this is an old battery I'm willing to take the risk and hope it will
last a couple of weeks until I receive the new one from NightSun.. I know by now that it takes 2.5
hrs. to fully charge an empty battery and I check it regularly and stop charging as soon as I feel
the battery is getting warm on the outside.

Hjalmar

Quoted message said:

Art Harris

"David Kunz" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Matt O'Toole said:

Hjalmar Duklæt said:

>Your car battery charger is probably giving
>14.4 V and maybe 6A.

Most car battery chargers seem to have a "start" mode of 20-50A, a

regular

Quoted message said:

Quoted message said:

charge rate of 10A or so, and a "trickle" charge setting of 2A.

Quoted message said:

No, I wouldn't do that to a new battery. The A-meter on the charger says it's putting out about
2 Amps and I'm keeping it in the garage while charging. The originale charger is a 13V/450mW
charger. I will only be doing this for a short while with my old battery only until the new
battery/charger arrives. Maybe I shall continue for a longer periode

just

Quoted message said:

Quoted message said:

Quoted message said:

as a test and see if the battery deteriorates quickly. I don't think the risk of an explosion is
very high as long as I remember to switch off

the

Quoted message said:

Quoted message said:

Quoted message said:

charger in time before overheating the battery.

You're doing fine. Nicads are high current batteries, and in fact can

be

Quoted message said:

Quoted message said:

charged with even more current than that. But the more current, the

more

Quoted message said:

Quoted message said:

you risk damage from overcharging -- everything happens faster! 2A

should

Quoted message said:

Quoted message said:

be fine, though, as long as you can stop the charge before the batteries warm up significantly
-- which is actually a very good indicator of full charge. You said you ordered a new charger
already. That's good, but

in

Quoted message said:

Quoted message said:

the meantime you can certainly keep using your car battery charger, as

long

Quoted message said:

Quoted message said:

as you're careful.

I thought that the battery had to be designed for fast charging. I know that I've read that not
all NiCads can be fast charged -- however, that could just be someone trying to sell THEIR
SPECIAL battery 🙂. I personally wouldn't do it. I'd try something like a car light bulb in
series with it to drop the current down. The problem then becomes determining the full charge
voltage (when to stop).

David

I really don't know but according to Matt it should be ok and I'll trust him. I know that I have
to watch it carefully and stop charging as soon as it gets warm on the outside. But if it can be
done without reducing the battery's life, then why can't they deliver such charger with the
battery in the first place? With the original charger it takes about 15 hours to fully charge an
empty battery and I have no more than 12 hours from coming home in the afternoon till I have to
take off in the morning.

Hjalmar

NiCd batteries are charged by a constant CURRENT usually specified to be
C/10.

That is, the capacity of the battery is AMP-HOURS divided by 10.

At this rate they can generally be left on charge for a long time. Actual use by people is to leave
them on charge indefinitely. NiMh battery chargers are also constant current but usually have a
timer built in to shut them off after 6-10 hours.

I don't know the capacity of a night sun battery, but you said the charger was 450 mWATTS - Are you
sure it wasn't 450 mAMPS?

450 mA would imply a 4.5 A-Hr battery which seems about right for a nightsun.

13V/450 mW would imply 35 mA and a 0.35 A-Hr battery which is way too small for this application. An
alkaline AA battery is about 1 A-hr even though it's only 1.5 Volts.

SEE THE FIRST SENTENCE. A car battery charger is a constant VOLTAGE not CURRENT. The
current is HIGH.

YOU WILL DAMAGE THE BATTERY. It is also a safety hazard - it could blow up but will certainly vent
and spew toxic gases.

Since it's going to be trashed - charge it for 30 MINUTES only (assumes 10A charger) and outside
downwind of your house.

better to take public transportation until your new battery arrives.

Rocky

"Hjalmar Duklæt" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

"David Kunz" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Matt O'Toole said:

Hjalmar Duklæt wrote:

>>Your car battery charger is probably giving
>>14.4 V and maybe 6A.

Most car battery chargers seem to have a "start" mode of 20-50A, a

regular

Quoted message said:

Quoted message said:

charge rate of 10A or so, and a "trickle" charge setting of 2A.

>No, I wouldn't do that to a new battery. The A-meter on the charger

says

Quoted message said:

Quoted message said:

Quoted message said:

>it's putting out about 2 Amps and I'm keeping it in the garage while charging. The originale
>charger is a 13V/450mW charger. I will only be doing this for a short while with my old
>battery only until the new battery/charger arrives. Maybe I shall continue for a longer
>periode

just

Quoted message said:

Quoted message said:

>as a test and see if the battery deteriorates quickly. I don't think

the

Quoted message said:

Quoted message said:

Quoted message said:

>risk of an explosion is very high as long as I remember to switch off

the

Quoted message said:

Quoted message said:

>charger in time before overheating the battery.

You're doing fine. Nicads are high current batteries, and in fact can

be

Quoted message said:

Quoted message said:

charged with even more current than that. But the more current, the

more

Quoted message said:

Quoted message said:

you risk damage from overcharging -- everything happens faster! 2A

should

Quoted message said:

Quoted message said:

be fine, though, as long as you can stop the charge before the

batteries

Quoted message said:

Quoted message said:

Quoted message said:

warm up significantly -- which is actually a very good indicator of

full

Quoted message said:

Quoted message said:

Quoted message said:

charge. You said you ordered a new charger already. That's good, but

in

Quoted message said:

Quoted message said:

the meantime you can certainly keep using your car battery charger, as

long

Quoted message said:

Quoted message said:

as you're careful.

I thought that the battery had to be designed for fast charging. I know that I've read that not
all NiCads can be fast charged -- however, that could just be someone trying to sell THEIR
SPECIAL battery 🙂. I personally wouldn't do it. I'd try something like a car light bulb in
series with it to drop the current down. The problem then becomes determining the full charge
voltage (when to stop).

David

I really don't know but according to Matt it should be ok and I'll trust him. I know that I
have to watch it carefully and stop charging as soon as it gets warm on the outside. But if it
can be done without reducing the battery's life, then why can't they deliver such charger with
the battery

in

Quoted message said:

the first place? With the original charger it takes about 15 hours to

fully

Quoted message said:

charge an empty battery and I have no more than 12 hours from coming home

in

Quoted message said:

the afternoon till I have to take off in the morning.

Hjalmar

l used to charge a 7.2V battery pack for a radio controled car of a car battery (with four BIG
resistors to drop the voltage) in 15 minutes thats 6x1.2 Ampere-hour batterys they get warn to hot
and you don't get a full charge into them l don't think it does them any harm as long as you stop at
about the right time NiCds have a very high charge/discharge rate. most rechargerable drills have a
1 hour quick charge, but they have a timer built in BE WARNED l set fire to the front of a car by
leaving them on charge for somewhere over 4 hours

"Rocky" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

NiCd batteries are charged by a constant CURRENT usually specified to be
C/10.

That is, the capacity of the battery is AMP-HOURS divided by 10.

At this rate they can generally be left on charge for a long time. Actual use by people is to
leave them on charge indefinitely. NiMh battery chargers are also constant current but usually
have a timer built in to

shut

Quoted message said:

them off after 6-10 hours.

I don't know the capacity of a night sun battery, but you said the charger was 450 mWATTS - Are
you sure it wasn't 450 mAMPS?

It's actually 300mA.

Quoted message said:

450 mA would imply a 4.5 A-Hr battery which seems about right for a nightsun.

13V/450 mW would imply 35 mA and a 0.35 A-Hr battery which is way too

small

Quoted message said:

for this application. An alkaline AA battery is about 1 A-hr even though it's only 1.5 Volts.

SEE THE FIRST SENTENCE. A car battery charger is a constant VOLTAGE not CURRENT. The current
is HIGH.

Well, the Amp. meter on the charger starts at 2A and goes down to about 1A after a while. Don't know
how exact this is but the battery starts to get warm on the outside after approx. 3 hours. I know I
have to watch it carefully and stop the charging before the battery gets overheated and it's only a
temporary solution. So far it seems to work.

Quoted message said:

YOU WILL DAMAGE THE BATTERY. It is also a safety hazard - it could blow

up

Quoted message said:

but will certainly vent and spew toxic gases.

I'm chaging it in the garage so it should not be that dangerous.

Quoted message said:

Since it's going to be trashed - charge it for 30 MINUTES only (assumes

10A

Quoted message said:

charger) and outside downwind of your house.

better to take public transportation until your new battery arrives.

Probably, but then I don't get my daily exercise.

Quoted message said:

Rocky

Hjalmar

Rocky said:

NiCd batteries are charged by a constant CURRENT usually specified to be
C/10.

Nicads are high current batteries which can be used in high drain devices like power tools and 20W+
bike lights. Their ability to deliver high current is the same thing as being able to take high
current. A c/10 charger is a good compromise between charging time, battery protection, and cost.
It's still a fairly slow charger (10 hours). Much faster, high current chargers are used often with
nicads, but they don't come with bike light kits because they cost too much. C/2 to 4C chargers are
common for power tools, etc.

Quoted message said:

At this rate they can generally be left on charge for a long time. Actual use by people is to
leave them on charge indefinitely.

Exactly, that's what the designers had in mind. However, if you take care to monitor your charger,
you can use a much higher current for a faster charge. Proper fast chargers do this automatically by
detecting voltage taper-off and/or temperature. You can do temperature sensing yourself with your
bare hands -- if the battery starts to warm up, charging is done.

Quoted message said:

NiMh battery chargers are also constant current but usually have a timer built in to shut them off
after 6-10 hours.

So do fast chargers for nicads. However, this is more important for NiMH because they're more easily
damaged by overcharging. If you're worried about this, you can plug your charger into a lamp timer.

Quoted message said:

I don't know the capacity of a night sun battery, but you said the charger was 450 mWATTS - Are
you sure it wasn't 450 mAMPS?

450 mA would imply a 4.5 A-Hr battery which seems about right for a nightsun.

That's even a little hot for a trickle charger, but it's within the normal range.

Quoted message said:

SEE THE FIRST SENTENCE. A car battery charger is a constant VOLTAGE not CURRENT. The current
is HIGH.

...and constant, at 2A. I think you're a little confused here.

Quoted message said:

YOU WILL DAMAGE THE BATTERY

Nonsense.

Quoted message said:

It is also a safety hazard - it could blow up but will certainly vent and spew toxic gases.

Only if you don't keep an eye on it. With proper knowledge, can handle these things without worry.

Quoted message said:

Since it's going to be trashed - charge it for 30 MINUTES only (assumes 10A charger) and outside
downwind of your house.

If you're going to forget about it and leave it on the charger that's not a bad idea, but if you
keep an eye on it you'll be fine.

Rocky, you seem to be regurgitating a bunch of stuff you read somewhere, without any real
understanding of the underlying principles.

Matt O.