If you have a 100 Amp hour battery, and the charger is 2 Amps rated, it will
take 50 hours to charge the battery. For the large gel cell batteries, and
lead acid batteries it is best to use an auto charger that can automatically
go to a trickle charge after the battery is charged. These use an
auto-sense. This avoids damaging the battery if it is left on.
Typically, a 10 Amp charger is good to use to charge large batteries.
Typical auto batteries are rated at about 80 to 120 Amp hours. Divide the
rating of the charger in to the Amp hours of the battery to know the minimum
approximate time to charge the battery.
Fast charging is not good for these types of batteries. This can cause rapid
internal heating of the cells, and thus reduce the life of the battery.
When charging any type of batteries, the minimum threshold charge current
must be overcome. The nominal charge current rates are published from the
manufacture. The environmental temperature also has an effect on the
extremes of these specs.
For most batteries, a charge current of 25% of the Amp hour rating is the
maximum that should be used. On the average, the minimum charge current
should be in the area of about 5% of the Amp hour rating of the battery.
This means that for a 100 Amp hour battery, a 5 Amp charger is the smallest
size that should be used to charge it efficiently. The charge time would be
20 hours minimum.
For my auto batteries, I have a 15 Amp auto charger. It charges at 15 Amps
maximum. After the battery is charged, it goes to a lower current. It auto
senses the battery. It has a meter that reads out the charge rates. As the
battery reaches full charge, I generally see it sinking down below 2 Amps.
After about 24 hours, it is at about 1/4 of an Amp. If I leave it longer, I
sometimes see it climb to about an Ampere for a while, and then sink down
again. This is when it is doing what they call a float charge.
A typical 12 Volt acid type battery when tested with no load, should read
about 13.2 to about 13.5 Volts right after the charger is removed. During
the charging, it should read about 13.8 to about 14.5 Volts. These are
approximate amounts. After the battery is sitting for 24 hours with no
charger attached, the no load voltage should read about 12.5 to about 13.2
Volts average.
When the typical 12 Volt acid type battery is loaded to 25% of its capacity,
it should typically read about 12.3 to about 12.7 Volts for about 50% of its
rated capacity period. When the battery reaches 10% below its nominal rated
voltage, it would be considered discharged. This would be about 11.2 to
about 11.5 Volts for the average 12.5 Volt acid type battery.
I hope all of this explains things.
--
JANA
_____
"rutman" wrote in message
...
thank you!
since I had the battery back on the charger while reading at 10vs, I
decided to charge i for 2 hours at 2a,
it now reads 12:40 volts
question. since its jsut over 12 volts.. is this good enough or a full
charge?
Most info I have read on the net, including your posts says to charge
it at around 14 volts.
On Sat, 30 Apr 2005 14:26:16 +0800, "Rheilly Phoull"
wrote:
One day rutman got dressed and committed to text
Hello.
To being with, please accept my apologies for the noobie questions I
am about to make.
Heres the info.
1. Two small electrical motors rated 12volts 230 watts powers a
Peg-Perego electrical jeep. it looks like one of them power wheels
ride on toys. Since the original battery died, I started asking
questions and reading previous usenet posts as to replacing the
expensive power wheels battery for an ordinary car battery.
I received quite a few replies. Some were cons others pros regarding
the car battery adaptation idea. Apparently this has been done
sucessfully before my many people. Some replies were concern as to the
safety etc. Following advice from this group as well as having read
meny hours of googles 
, I decided to install a new heavy duty deep
cycle GEL battery. It cost me almost triple as much as buying a
regular 12vs car battery. However, from my own personal research as
other people advices as well, it looks like this was the way to go.
I also bought an inline 40a fuse and installed it on the positive
cable.
My kid took out the jeep for a ride, and he was having a blast,
until..... the jeep started slowing down. WAYYY down.. almost to a
crawl. This is odd, i told myself.. it surely did not seem like the
so called deep cycle battery lasted any longer that the orginal small
power wheel jeep battery! we are talking like 40 minutes of play time
with my kid going around for a ride or two.
So I popped the hood. Checked all the cables. The positive and
negative cable were warm but not Hot.. good sign I guess. I touched
the battery just to get a touchy feeling.. cold.. I went under the
vehicle and touched both motors. I was thinking that maybe the motors
were over heating or something as that, which might caused the jeep to
crawl. They were warm , not hot at all.
Took out my volt meter. Checked the battery for power.
It was reading at 11.40 volts!. thats almost a full charge.!
now heres the really odd part.
left the jeep sitting there for about 40 minutes while i went to a
local canadian tire to purchase a battery charger ( I didnt have one,
and since I just bought this deep cycle.. arghh.. more money )
came back. I was unpacking the goodies and noticed that my son had
already jumped back onto the truck and he was doing some wheelies! all
of sudden the power came back for about 5 minutes before dropping to a
crawl again. Check the battery's voltage. It was reading at 11.20
volts. Had my son drive the jeep until it wouldnt move anymore to see
how fast the deep cycle battery drained.. when the jeep coulnt move
anymore and I connected the volt meter, it read at 10.20 volts.
now here are my questions.
If the battery is reading at 11.40 volts ( almost a full charge ) why
are the motors turning sooo slow.
I know that the motors are rated at 12v 230 watts.. so if the battery
drops below 11 volts should this caused the motors to simply quit
turning the wheel?
I didnt check for the battery Ah rating. I took it for granted that a
deep cycle battery meant for a small boat, rideon lawn mover , or even
a small vehicle should be enough to put out enough juice to run two
12v motors rated at 230watts... but maybe i am wrong?
the original batteries the jeep uses are 12v 10Ah....
Could it be that the deep cycle battery may be defective? could this
explain the drop of power being supplied to the motors?
Finally.
whats the best setting to charge the deep cycle battery? My charger
has a setting for 10a and 2a. I am currently using 2a setting. (
trickle charge )
To me the figures dont quite 'gell', since 2 motors at 230watts in theory
would pull 30amps or more dependant on the wire capacity (thickness). If
the
original batteries were 10a/h then if the motors were used at full
capacity
the they would not have lasted long (the 2 motors would take 30a/h). It
probably would come down to the method of speed control used and very
likely
the total available power of the motors was not utilised. Also the
symptoms
described would fit the battery not being fully charged, you should be
able
to charge it at 10amps, monitor the volts and when when it is around 14v
and
very little current flowing it will be fully charged. Of course there is
much more to charging than that but it is a rough and ready way to check.
See http://www.batteryfaq.org/carfaq9.htm#adjust for more info on
batteries.
I think I would start with a known full charge and check again.