Can the battery take it?

[Hjalmar DuklæT]

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

 

[Per ElmsäTer]

Buy a charger that is self regulating. They don't cost much more than the crummy **** 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 protected]> wrote in message news:[email protected]...
> 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

 

[Hjalmar DuklæT]

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 protected]> wrote in message
news:[email protected]...
> Buy a charger that is self regulating. They don't cost much more than the crummy **** 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 protected]> wrote in message news:[email protected]...
> > 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
> >
>

 

[Per ElmsäTer]

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

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

 

[Hjalmar DuklæT]

">
> 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 ;(
>
>
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
> --
> Perre

 

[Dan Baker]

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

 

[Steve Shapiro]

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

 

[Harris]

Hjalmar Duklæt <[email protected]> wrote:
> 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

 

[David Kunz]

Matt O'Toole wrote:
> 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 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 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

 

[Matt O'Toole]

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 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 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.

 

[Hjalmar DuklæT]

"Harris" <[email protected]> wrote in message
news[email protected]...
> Hjalmar Duklæt <[email protected]> wrote:
> > 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?

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.

> 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
> Art Harris

 

[Hjalmar DuklæT]

"David Kunz" <[email protected]> wrote in message
news:[email protected]...
> Matt O'Toole wrote:
> > 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
> > 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 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
>
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

 

[Rocky]

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 protected]> wrote in message news:[email protected]...
>
> "David Kunz" <[email protected]> wrote in message
> news:[email protected]...
> > Matt O'Toole wrote:
> > > 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
> > > 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
> > >>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
> >
> 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

 

[Stu]

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

 

[Hjalmar DuklæT]

"Rocky" <[email protected]> wrote in message news:[email protected]...
> 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?
>
It's actually 300mA.
>
> 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.
>
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.
>
> YOU WILL DAMAGE THE BATTERY. It is also a safety hazard - it could blow
up
> but will certainly vent and spew toxic gases.
>
I'm chaging it in the garage so it should not be that dangerous.
>
> 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.
>
Probably, but then I don't get my daily exercise.
>
> Rocky
>
Hjalmar

 

[Matt O'Toole]

Rocky wrote:

> 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.

> 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.

> 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.

> 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.

> 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.

> YOU WILL DAMAGE THE BATTERY

Nonsense.

> 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.

> 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.