# Charging time for 12 V battery

Started by December 24, 2012
```I have a 12 Volt battery, 9.5 Ah that uses a 12 volt charger 1.0 amp.

Assuming the battery is completely discharged, is there a way to determine how long to charge ?

Thanks,
Andy
```
```On Mon, 24 Dec 2012 13:02:57 -0800 (PST), andrew_kennedy7@yahoo.com
wrote:

>I have a 12 Volt battery, 9.5 Ah that uses a 12 volt charger 1.0 amp.

I'll assume that it's an SLA (sealed lead acid) or AGM (Absorbed Glass
Mat) battery.  Makers and model numbers are a good thing to disclose.

>Assuming the battery is completely discharged, is there a way to determine how long to charge ?

Yep.  Math.

Incidentally, if your battery is completely discharged (i.e. zero

A new lead acid battery has a Coulombic Efficiency of about 75%.  That
means for every amp you feed the battery, only 75% of it stays in the
battery.
12v * 9.5 Amp-Hr / 0.75 = 152 watt-hrs
will be needed to recharge the battery.  If your charger actually
delivers 1 amp, it will take:
152 watt-hrs / (12v * 1 amp) = 13 hrs

This is under ideal and simplified circumstances.  Coulombic charge
efficiency varies from 50% to 98% depending on battery type and age.
(maker and model please?) may be capable of delivering a 1 Amp
maximum, but will probably deliver much less while charging.  SLA
batteries just hate going over their rated maximum voltage.  So, it's
likely that the charger is set to a conservative voltage, that may not
fully charge the battery.  The charge current is also not constant
over the entire charge cycle.  Lots of variables, potential errors,
and guesswork here.

My wild guess(tm) is about 8-10 hours will be about right.  Better to
undercharge than to go over.  I can make a more accurate guess(tm)
when you find the makers and model numbers.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558
```
```On Monday, December 24, 2012 3:02:57 PM UTC-6, andrew_...@yahoo.com wrote:
> I have a 12 Volt battery, 9.5 Ah that uses a 12 volt charger 1.0 amp.
>
>
>
> Assuming the battery is completely discharged, is there a way to determine how long to charge ?
>
>
>
> Thanks,
>
>         Andy

Power Wheels Charger for Gray 12v Battery 00801-1778
```
```<andrew_kennedy7@yahoo.com

> Power Wheels Charger for Gray 12v Battery 00801-1778
>

DO NOT expect others to do the running around for you.

And BTW -  this is the WRONG  NG for such a question.

....   Phil

```
```On 12/25/2012 2:50 AM, Phil Allison wrote:
> <andrew_kennedy7@yahoo.com
>
>> Power Wheels Charger for Gray 12v Battery 00801-1778
>>
>
>
>
>   DO NOT expect others to do the running around for you.
>
>   And BTW -  this is the WRONG  NG for such a question.
>
>
>
> ....   Phil
>
>
>
>
>
That number shows up as several different devices.
Don't think you have any choice but to measure what your
charger does.

I think your bigger problem is gonna be sulfation.
The kids are gonna ride it until it stops dead.
The next time you hear about it is next spring
when the battery won't take a charge.

I lost a set of electric scooter batteries because
it got shuffled around in the garage and the power
switch was turned on all winter.

It might also be interesting to compare the calculated time
to charge against the attention span of kids.

Unless you want to pay close attention, you need something
automatic.
```
```On Tuesday, 25 December 2012 11:50:30 UTC+1, Phil Allison  wrote:
> <andrew_kennedy7@yahoo.com
>
>
>
> > Power Wheels Charger for Gray 12v Battery 00801-1778
>
> >
>
>
>
>
>
>
>
>
>  DO NOT expect others to do the running around for you.
>
>
>
>  And BTW -  this is the WRONG  NG for such a question.
>
>
>
>
>
>
>
> ....   Phil

Autistic?
```
```orion.osiris@virgin.net wrote:
>
> Phil Allison wrote:
> >
> > <andrew_kennedy7@yahoo.com
> >
> > > Power Wheels Charger for Gray 12v Battery 00801-1778
> >
> > ** Always post links.
> >
> >  DO NOT expect others to do the running around for you.
> >
> >  And BTW -  this is the WRONG  NG for such a question.
> >
> > ....   Phil
>
> Autistic?

Free lobotomy gone bad. Another of Dr. Frankenstein's failed
experiments. :(
```
```>
>   And BTW -  this is the WRONG  NG for such a question.

> ....   Phil

Yes, this is the newsgroup for people down under to go on a Tourettes rant.

```
```On Tue, 25 Dec 2012 01:46:34 -0800 (PST), andrew_kennedy7@yahoo.com
wrote:

>Power Wheels Charger for Gray 12v Battery 00801-1778

This might help:
<http://www.modifiedpowerwheels.com/forum/topic.asp?TOPIC_ID=15855>
About 14 hrs and no more, assuming a totally discharged battery.

Looks like the Power Wheels fans are going for replacement chargers. I
can see why as the stock charger appears to be a constant current
charge with no automatic shutoff.  Leave it on for extended periods,
and you have a dead battery.
<http://www.modifiedpowerwheels.com/forum/topic.asp?TOPIC_ID=695>
<http://www.modifiedpowerwheels.com/forum/topic.asp?TOPIC_ID=4156>

There's also some advice on batteries and chargers on the FAQ:
<http://www.modifiedpowerwheels.com/forum/forum.asp?FORUM_ID=12>
Looks like a good place to start reading.
--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558
```
```On Tue, 25 Dec 2012 21:50:30 +1100, "Phil Allison" <phil_a@tpg.com.au>
wrote:

><andrew_kennedy7@yahoo.com
>> Power Wheels Charger for Gray 12v Battery 00801-1778

> DO NOT expect others to do the running around for you.

Yeah, that would be nice.  However, I have a different formula for

1.  What problem are you trying to solve?  A one sentence description
is sufficient.  Details can come later.

2.  What do you have to work with?  Hardware, software, versions,
makers, models, photos, etc.  Numbers please, not prose.  Also test
equipment available, level of expertiese, and such.

3.  What have you done so far and what happened?

There are plenty of other things that would be helpful, but these are
the basics.

> And BTW -  this is the WRONG  NG for such a question.

Yeah, but I like off topic questions.  It suggests that the OP is
either clueless, lazy, or both.  That makes it easier for them to
accept my guesswork and pontifications.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558
```