Battery Amps

It should be marked in Ah - amp hours. Usually measured at the 20 hour rate. So a 40 Ah battery should last 20 hours with a 2 amp load.

BTW, if you load the battery and it's only reading 12 volts, it's not fully charged.

--
*Why are they called apartments, when they're all stuck together? *

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

Go on the battery's web site and read the specs for that size battery. If all the cells are working it should be similar.

By "leisure" I presume you mean a lead-acid deep discharge type, not a car battery! Example: marine or traction types; these have a different internal construction. Anyway, none of all them hold amps (a flow measure); they hold "amps x hours", a measure of energy stored, a quantity measure. But all "amp x hours" are not equal! At a large discharge rate the product of amperes x hours is smaller than that at a lower current. The rating for "amp hours" at a given current may be on the battery case. If not, and if you know the make and model number, you might be able to look it up. But this capacity drops with age and usage so it may not be very useful except when replacing the battery. It is possible to set up an experiment to measure the capacity, i.e. fully charge the battery, discharge as a known rate and measure the time until the voltage drops below 12 volts, but you may find that time consuming. BTW, after charging, voltage should be about 12.6 volts (not 12 volts.) During charging it should read between about 13.6 and 14.5 volts depending on the charging rate. There's more to lead acid batteries than this, I suggest you google "lead-acid battery" and see what you find. Here's a good start:

Cheers, Roger

thanks to all for the replies. I'll check it all out and see if I can figure it out.I have a Halfords charger that I use when charging my caravan battery[110Amps] and when it is charged the light goes green and is is switched off.These two batteries I have are 12 volt but there is no Amp total on it.It merely states output 12VDC and Max DC

2.6Amps.What I wanted to know is; although it shows 12.6 Volts how do I know it has 2.6Amps in it.Thanks anyway.

Two ways to test - one is to check it under load and see how many volts. The other is to check the SG of the electrolyte with a float tester - possibly from a "One Pound" store.

--
N

Sorry to mess you all about but although nothing is marked on the battery I had another look at the instructions.It says its a "lead acid storage battery ,normal capacity 17AH 12V,charging time 250 times. I have a feeling it is not fully amped up[if thats right!] but my Halfords charger switches to green when the volts is up to above 12 volts. How can I tell that they have 17 AH stored in there. PS. They are golf trolley batteries and the charger that came with them has no measurement to say what's going on.I could leave them charged for a week for all I know with no indication when they are charged.Got me beat.Thanks again.

What do you mean 2.6 amps in it? That statement doesn't mean anything, amps are an instantaneous measurement, not an accumulated quantity. May be a little confusing but saying a battery has 2.6 amps in it is like saying it's

15 mph to the grocery store, you have no way to know the total quantity (distance) from that statement.

You can put the battery under a known load and measure what the voltage drops to over a period of time and calculate it from that. If the charger switches off (assuming the charger is working which sounds like the case) then it's as fully charged as the battery will get, if the capacity is under

17 AH then it's due to wear on the battery and not anything with the charger. The voltage of the battery rises as it charges, the charger should shut off when it hits about 13.8V for a 12V battery.

Dave Plowman:

*Why are they called apartments, when they're all stuck together? *

Why does cargo go by ship... and shipments go by car/truck/train ? Why do we park on driveways and drive on parkways? electriciym

A 17 Ah battery is rather small for a golf trolley. I'd expect more like

1. Unless you only do 9 hole courses. ;-)

Fully charged will do.

It will likely only switch off at rather higher than that.

It's likely the batteries are simply knackered. If the charger is saying they are fully charged by switching off, you could try discharging them with a known load - say a car headlamp bulb at 55 watts. A 17 Ah battery will have a capacity of 17 x 12 ie about 200 watt hours, so should run that bulb for more than 3 hours.

--
*If all is not lost, where the hell is it?

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

Is your question now--How do I tell if the battery is fully charged?

Check the specific gravity of the fluid in the cells.

"Dave Plowman (News)" bravely wrote to "All" (15 May 05 22:55:39) --- on the heady topic of "Re: Battery Amps"

DP(> From: "Dave Plowman (News)" DP(> Xref: aeinews sci.electronics.repair:48281

DP(> In article , DP(> Harry Collingwood wrote: > Sorry to mess you all about but although nothing is marked on the > battery I had another look at the instructions.It says its a "lead > acid storage battery ,normal capacity 17AH 12V,charging time 250 > times.

DP(> A 17 Ah battery is rather small for a golf trolley. I'd expect more DP(> like 70. Unless you only do 9 hole courses. ;-)

DP(> Fully charged will do.

DP(> It will likely only switch off at rather higher than that.

DP(> It's likely the batteries are simply knackered. If the charger is DP(> saying they are fully charged by switching off, you could try DP(> discharging them with a known load - say a car headlamp bulb at 55 DP(> watts. A 17 Ah battery will have a capacity of 17 x 12 ie about 200 DP(> watt hours, so should run that bulb for more than 3 hours.

That would be true below some rated current. The 55 watts may be greater than this value and the battery might drain faster than expected by what the math is telling us. If the battery under this condition shows less capacity does it then mean it is bad?

A*s*i*m*o*v

... I worked hard to attach the electrodes to it.

Thanks for all the help,figured this out later.It must mean that it charges at 2.6A max.When you have a battery with no info on it you just wander about seeking answers,for instance,as it is a cheap Chinese item it really could be anything at all as a battery, especially as it's not marked.Thanks for all inputs.

Not really,it says it will run fully charged for 20Km and as I play links it's pretty flat.Thanks

Thanks for that but is not like my caravan battery with top up cells.This one is completely sealed with no way to check.I suppose you buy new when it looks knackered.Regards

There are clever electronic testers that give chapter and verse on a battery's condition these days. Any decent supplier should have one and test it for free.

--
*Too many clicks spoil the browse *

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

Thank you all,one last question and I'll leave you in peace! if,as stated,17 AH seems a bit low will it hurt my two 150 motors that drive both wheels,if I tried it, with say a 90AH battery? I have one in the caravan and thought better to ask in case I knacker everything up.Thanks a lot.regards Harry

90AH should give approximately 5x the run time of the 17AH battery. As long as it is the same nominal voltage and has some type of current limiting in series (a fuse or a circuit breaker) then it should be fine as long as it can physically fit into the space and be safely mounted. Good luck.

Bob

Amp hours are like gallons of gas (litres of petrol). The car doesn't care if the gas tank is 5 gallons or 50 gallons. The charger will fill either up, it just takes longer if the tank is bigger.

--
N