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Author Topic: Identifying the ampage of a sealed lead acid battery  (Read 5665 times)

dpbarry

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Identifying the ampage of a sealed lead acid battery
« on: May 12, 2015, 08:57:16 PM »

Hi folks..


Could I ask for a bit of help in identifying the amps of a sealed lead acid batterry.


Its marked as HR 1234W F2 and tinternet searches identify it as a 9 Ah battery but i'd like to be sure before I program my mercury ex charger. I'll try and post a picture.


Regards


Declan
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cos918

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #1 on: May 12, 2015, 09:00:04 PM »

whats are its dimensions ? eg width length
 height


john
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Shipmate60

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malcolmfrary

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #3 on: May 12, 2015, 09:11:32 PM »

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dpbarry

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #4 on: May 12, 2015, 09:43:44 PM »

Here's a photograph..


http://i719.photobucket.com/albums/ww194/dpbarry/Radio%20Control/image.jpg1.jpg

Just trying to work out if it is a 9Ah battery.

Declan
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Howard

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #5 on: May 12, 2015, 09:51:45 PM »

If am right it says 12v on the side (photo)
Regards Howard
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Shipmate60

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #6 on: May 12, 2015, 09:56:02 PM »

It will be 12 volt 7 or 9 amp battery.


Bob
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dpbarry

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #7 on: May 12, 2015, 10:10:37 PM »

 >>:-( <*<


Lol!! I know its 12V. What I don't know is whether its 7Ah or 9Ah


 %%


Declan
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dpbarry

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #8 on: May 12, 2015, 10:18:33 PM »

Further tinternet searching produced this


http://www.hardwarexpress.co.uk/hr1234w-f2-csb-battery-12v-9ah-457-p.asp




Specifications for CSB HR1234WF2 Battery
Voltage 12V
Capacity 9Ah (34W)
Weight 3Kg
Dimensions 151mm x 94mm x 65mm
Lifespan 3 - 5 years
Type Sealed Lead acid battery rechargeable highly efficient, leak proof and maintenance free
Warranty 12 months
[size=78%]Declan[/size]
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Howard

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #9 on: May 12, 2015, 10:32:53 PM »

Sorry Declan,
I some how miss read it.
            Regards Howard.
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dpbarry

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #10 on: May 12, 2015, 10:58:23 PM »

Sorry Declan,
I some how miss read it.
            Regards Howard.


Lol!! No problem at all. It was funny reading the replies


From what I can see it looks to be a 9Ah battery


Cheers


Declan
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AlexC

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #11 on: May 12, 2015, 11:05:58 PM »

Further tinternet searching produced this


http://www.hardwarexpress.co.uk/hr1234w-f2-csb-battery-12v-9ah-457-p.asp




Specifications for CSB HR1234WF2 Battery
Voltage 12V
Capacity 9Ah (34W)
Weight 3Kg
Dimensions 151mm x 94mm x 65mm
Lifespan 3 - 5 years
Type Sealed Lead acid battery rechargeable highly efficient, leak proof and maintenance free
Warranty 12 months
[size=78%]Declan[/size]

That spec does not make any sense...

34W @ 12v = 2.8Ah not 9Ah. %%

12v x 9Ah = 108W.

Unless they have found a way round Ohm's law, which I doubt.

Sandy. :-)
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Paul Swainson

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #12 on: May 13, 2015, 12:23:02 AM »

34 w = P
12v = E
X = I


therefore to find the value of I (amps) 34w/12v = 2.83 amps
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Shipmate60

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #13 on: May 13, 2015, 08:58:13 AM »

Gell cells are not overcharging sensitive as in fire alarms they are on permanent trickle charge.


Bob
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Netleyned

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #14 on: May 13, 2015, 09:44:16 AM »

Would that 2.83 A /34W be the max initial charge?


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inertia

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #15 on: May 13, 2015, 10:05:17 AM »

"Ampage" isn't a term which is familiar to me. If you mean "capacity" then the unit of measurement is Amp.Hours, not Amps, and so Ohm's Law isn't relevant. It's a factor which is dictated by the physical size of the internal plates and the strength of the electrolyte. I'd say that if it's the same size as a 7AH battery then that's probably what it is.
DM
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malcolmfrary

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #16 on: May 13, 2015, 10:16:18 AM »

Could be 34 watt-hours stored per kilogram weight.
Few lead-acid batteries are amenable to fast charging, and trying to pre-determine the amount of charge it needs to become fully charged is usually doomed to failure since the inefficiency of charging is unknown.  As has been said above, this type of battery is designed to be left on a permanent trickle.
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vnkiwi

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #17 on: May 13, 2015, 10:27:33 AM »

Maybe its just me, and myself and electricity combine, produce all that grey smoke escaping that Dave so kindly puts in, but

Volts x Amps = Watts

12 x 2.83 = 34

or so my plastic brain tells me.

What's all this thowing hours into the pot?

If you download the PDF that has the link posted in one of the early posts, then ALL the charging rates etc are listed in text and graph form.

Otherwise, its what Inertia, (DM) said, isn't it.
 :o %) :-))
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derekwarner

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #18 on: May 13, 2015, 10:56:59 AM »

 :-)...an alternate view on this seemingly simple calculation is to convert electro potential battery box of energy to an equivalent boiler of potential steam energy  :kiss:

After all........essentially and all things being equal they are both of the same potential.......just created, stored and transmitted in a different medium ....

PS...I do have an answer.........just wondering if I am correct  :o & on the correct thought line.....[and the steam equivalent of Ohms Law is not a value in the calculation] .......Derek
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inertia

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #19 on: May 13, 2015, 12:01:31 PM »

Vnkiwi
Ohm's Law describes the relationship between the current, the voltage and the resistance in a circuit when current is flowing. There is no mention of a unit of time because it's not part of that relationship.
I've just Googled the word "ampage" and the only definition I can find actually describes what most folk would call "current". You can't describe a battery by its current - such a definition would be meaningless.
However if you wish to describe the capacity of a battery to deliver a current then time comes into the equation, in as much as the capacity is a measure of a battery's ability to supply an amount of charge over a period of time. If you drain the battery very quickly then the charge it contains will not be delivered for as long a period as if you were to drain it slowly. Its capacity is the arithmetical product of the current it can supply and the time for which it can maintain that supply. Imagine it as like having a bucket full of water. If you drill a small hole in the bottom of it then the water will drain away very slowly while a large hole will drain it much faster, but the size of the hole doesn't affect how much water the bucket will hold before you start to drain it (its capacity).
In the equation V x I = W the W value is the power which is being supplied to a load where the voltage across that load is 12v and the current flowing through it is 2.83 Amps. The battery could equally be a 0.6AH lead-acid battery or a 5AH LiPo pack; it's just that the latter will last a lot longer than the former.
None of this stuff is clever or mysterious, guys. If it really was rocket science then I'd have taken up collecting car numbers years ago. There's more basic information here http://www.modelboats.co.uk/news/article/but-i-don-t-understand-electronics/18054
Dave M
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vnkiwi

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #20 on: May 13, 2015, 12:10:40 PM »

see, I knew someone could explain it all.

 :-))

all I know about 'tricity, is that when I fiddle,the smoke comes out.
Been trying to find and buy the "LUCAS" machine that puts the smoke back in, for years.
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Jerry C

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #21 on: May 13, 2015, 01:11:24 PM »

Lead acid batteries are classified as say 12V 7Amp hrs. What isn't said is the rate. Commonly, deep cycle batteries are quoted at the 20hour rate. Starter batteries are quoted at the 10hour rate. This method is used to be able to compare different battery capacities. Rather similar to car mpg figures. They are not accurate but give comparisons.
So, a 12V 7Ah battery can be expected to give 7/20 of an amp over 20 hours. Over 10 hours it will give less than 7/10 of an amp and over 30 hours it will give more than 7/30 of an amp. If you draw 7 amps from it then it will last less than 1 hour.
Jerry.

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #22 on: May 13, 2015, 01:18:15 PM »

Vnkiwi
Ohm's Law describes the relationship between the current, the voltage and the resistance in a circuit when current is flowing. There is no mention of a unit of time because it's not part of that relationship.
I've just Googled the word "ampage" and the only definition I can find actually describes what most folk would call "current". You can't describe a battery by its current - such a definition would be meaningless.
However if you wish to describe the capacity of a battery to deliver a current then time comes into the equation, in as much as the capacity is a measure of a battery's ability to supply an amount of charge over a period of time. If you drain the battery very quickly then the charge it contains will not be delivered for as long a period as if you were to drain it slowly. Its capacity is the arithmetical product of the current it can supply and the time for which it can maintain that supply. Imagine it as like having a bucket full of water. If you drill a small hole in the bottom of it then the water will drain away very slowly while a large hole will drain it much faster, but the size of the hole doesn't affect how much water the bucket will hold before you start to drain it (its capacity).
In the equation V x I = W the W value is the power which is being supplied to a load where the voltage across that load is 12v and the current flowing through it is 2.83 Amps. The battery could equally be a 0.6AH lead-acid battery or a 5AH LiPo pack; it's just that the latter will last a lot longer than the former.
None of this stuff is clever or mysterious, guys. If it really was rocket science then I'd have taken up collecting car numbers years ago. There's more basic information here http://www.modelboats.co.uk/news/article/but-i-don-t-understand-electronics/18054
Dave M

Hi Dave,

Yes I understand all that, however, I am somewhat puzzled by the figure of 34W in brackets next to the 9Ah capacity rating.

In theory
9Ah means the battery can deliver 1 amp for 9hrs
or 9A for 1 hr etc. etc.
But this can vary depending on the Rate of the battery (10hr rate or 20hr rate) which is determined by battery construction and intended use.

Ohms law only applies when calculating the power (E x I =W)
The hrs part is derived from the battery rate.

12v at 1 amp = 12W which can be delivered for 9hrs.
12v at 9 amps = 108W which can be delivered for 1hr.

I am beginning to suspect the 34W value relates to the Max Discharge rate for the cells to prevent over heating...
This would imply 12v at 2.8 amps Max (= 34W) which would result in maximum of approx 3.2hrs at 9Ahr capacity.... which does not make a lot of sense for a battery of this type and would limit it's usefulness.

Keep Happy,

Best regards.

Sandy. :-))
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Calimero

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #23 on: May 13, 2015, 02:05:02 PM »


Quote from: AlexC
12v at 1 amp = 12W which can be delivered for 9hrs.
12v at 9 amps = 108W which can be delivered for 1hr.

Drawing 9A from a 9Ah battery will get you around 20 minutes ...

The rated capacity of SLA batteries borders on fraudulent advertising as it is usually given at C/20.


If power draw is closer to C/5 or higher, actual capacity drops very quickly. At 1C (rated C) you end up with actually only 1/3rd of the rated capacity ...


Well they're not too expensive, abuse-tolerant and we usually need ballast in our scale boats anyway ...[/size][/font]
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inertia

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Re: Identifying the ampage of a sealed lead acid battery
« Reply #24 on: May 13, 2015, 02:32:37 PM »

Well said, Monsieur!
Far too many modellers are fooled by those seductive capacity ratings, to the extent that some believe they can even run two brushless motors from one SLA battery and obtain an hour's sailing from one charge. If I've seen one Huntsman or Perkasa lumbering round a pond like a narrowboat, weighed down by a huge brick of a battery, then I've seen a hundred. It makes me weep. It takes a great percentage of the motor's power just to get the battery moving, never mind getting the model up on the plane. Fitting a bigger/faster motor will simply make it worse in that it will drain the battery even faster. SLA batteries are large and cumbersome things and in consequence can be very awkward to fit. They have to be charged at a relatively slow rate and so can't be recharged at the lakeside (unless it's overnight, maybe). OK - if your tug operates fine with them then carry on, but you might get a helluva surprise if you replaced them with modern fast-charge high-current cells.
Unless they are of the special high-current, deep-discharge "leisure" type, SLA batteries are intended for low-current applications (usually with trickle charging) like alarm systems or emergency lighting. I use them only for our show demo boards and as weights in the workshop. My models are all fitted with either NiMH or LiPo battery packs; in my book the only use for lead-acid batteries in a model - as Calimero says - is as ballast.
Suit yourselves - as someone used to say.
DM
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