Battery LA 120amp

[Shaz77]

If as many people have stated on here and which I am inclined to believe myself a120amp lead acid battery is only good for 60amps before you risk damaging it or having a problem rechargeing it how under the sale of goods act can the manufactures describe it as 120amp. Surely this is a misdescription.

 

[simonfraser]

also a spelling error

 

[Shaz77]

also a spelling error

Trivial nit picker, plenty of those around.

 

[PaulRainbow]

If as many people have stated on here and which I am inclined to believe myself a120amp lead acid battery is only good for 60amps before you risk damaging it or having a problem rechargeing it how under the sale of goods act can the manufactures describe it as 120amp. Surely this is a misdescription.

It's amp hours, not amps.

120Ah is the capacity of a 120Ah battery, at a given discharge rate and temperature, so it will vary depending on those parameters. You can use as many of those Ah as you wish, but the more you use the shorter the battery life. 50% is considered to be a reasonable compromise between the amount of power you use and the lifespan of the battery.

 

[Shaz77]

It's amp hours, not amps.

120Ah is the capacity of a 120Ah battery, at a given discharge rate and temperature, so it will vary depending on those parameters. You can use as many of those Ah as you wish, but the more you use the shorter the battery life. 50% is considered to be a reasonable compromise between the amount of power you use and the lifespan of the battery.

So if you left it drawing a 1amp load for 120hours it should do the job and if you left it drawing a 120amp load for one hour it should do the job but then it might be damaged or non rechargable.

 

[Alex_Blackwood]

It's amp hours, not amps.

120Ah is the capacity of a 120Ah battery, at a given discharge rate and temperature, so it will vary depending on those parameters. You can use as many of those Ah as you wish, but the more you use the shorter the battery life. 50% is considered to be a reasonable compromise between the amount of power you use and the lifespan of the battery.

What Paul says. It is recommended not to discharge below 50% of capacity.
Also you may find that the battery is rated at 120Ah @ 10hr, or 20 hr. rate. i.e. it will discharge at 12 or 6 amps for these time periods. It is a measure of capacity. Rate is also what was recommended, in the days of simple chargers, for a constant current charger to charge the battery from flat to full. i.e. 12 amps for 10 hrs. or 6 amps for 20 hrs.

 

[PaulRainbow]

So if you left it drawing a 1amp load for 120hours it should do the job and if you left it drawing a 120amp load for one hour it should do the job but then it might be damaged or non rechargable.

So if you left it drawing a 1amp load for 120hours it should do the job and if you left it drawing a 120amp load for one hour it should do the job but then it might be damaged or non rechargable.

In either case the battery would be totally flat, which would significantly shorten it's life, some batteries would be knackered if you did that a handful of times. Additionally, it wouldn't be wise to draw 120A from a 125Ah battery.

It isn't like your butcher saying "this joint of beef weighs 1Kg". It's a 125Ah battery, but that has caveats, it is a useful figure for comparison to other batteries.

 

[S04]

So if you left it drawing a 1amp load for 120hours it should do the job and if you left it drawing a 120amp load for one hour it should do the job .........................................

No that is not the case. The 120Ah capacity is qualified by a notional discharge rate, perhaps 120Ah at the 5h rate (this may otherwise be expressed in current e.g 120Ah at the 5A rate). If discharging at that rate you might expect a battery in good condition to deliver its rated capacity. At any other rate you cannot expect that. This feature is described by Peukert's law q.v.

 

[Shaz77]

I say if I plug my 5amp inverter in to my 120 amp hour battery I am not going to get 24 hours. Probably 10 to 12 hours before the inverter shuts it's self down due to low current. So back to my original question, how under the sale of goods act can they call it a 120 amp hour battery when it is probably good for half that.

 

[Shaz77]

Where as (correct me if I am wrong)
a life po4 @ 120amp hours will give you the whole 120 without much of a drop in volts plus it should recharge with ease.

 

[Alex_Blackwood]

I say if I plug my 5amp inverter in to my 120 amp hour battery I am not going to get 24 hours. Probably 10 to 12 hours before the inverter shuts it's self down due to low current. So back to my original question, how under the sale of goods act can they call it a 120 amp hour battery when it is probably good for half that.

See#5&6

 

[PaulRainbow]

Where as (correct me if I am wrong)
a life po4 @ 120amp hours will give you the whole 120 without much of a drop in volts plus it should recharge with ease.

Not quite. Volts are good until about 20% SOC. If you completely discharge a LFP battery you will irreparably damage it.

Nothing to do with sale of goods act (which no longer exists), you just need to understand how batteries work, especially on a boat.

 

[PabloPicasso]

I say if I plug my 5amp inverter in to my 120 amp hour battery I am not going to get 24 hours. Probably 10 to 12 hours before the inverter shuts it's self down due to low current. So back to my original question, how under the sale of goods act can they call it a 120 amp hour battery when it is probably good for half that.

Shaz 77 has a point. It does misrepresent the function.

Imagine buying a ketle that only raises water to 50degrees C, or a car advertised as a 4 seater that could only carry 2 people without damaging it.

I imagine its a throwback to an earlier time when LA was all there was and it was allowed.

Time for change, but nuffin like a bit of edumicating oneself prior to purchase

Go on Shaz77, complain to trading stadards and see what happens....

 

[PaulRainbow]

I just opened a 1kg bag of apples to make a crumble. By the time i'd peeled them, cored them and cut a few bruises out i only had 600g, stitched up ?

Bought some tyres, supposed to do 10,000 miles, i only got 8,000 miles, apparently i went round too many corners.

I was told the car would do 155 MPH, but the speed limit in the UK is 70 MPH max, stitched up again.

If i bought a 125Ah LA battery i know i can only use half of it, without shortening it's life. I know that it has the same usable Ah as the next make of LA battery because they all use agreed standards for describing batteries, happy days.

 

[KompetentKrew]

….my original question, how under the sale of goods act can they call it a 120 amp hour battery when it is probably good for half that.

You're never going to challenge manufacturers on this under the Sale of Goods Act today because all lead-acid batteries are rated this way and have been for years. It's the industry standard and everyone knows what it means.

Manufacturers' spec sheets (the likes of Trojan and Victron) state clearly how much discharge you'll get from a battery and its life expectancy based on the number of discharges, so they're not hiding anything from you.

The industry - thousands of manufacturers and wholesalers worldwide - is not going to change how all lead-acid batteries are labelled and specified just because Sharon from Margate thinks they're doing it wrong..

So the answer to your question is that no judge or trading standards officer is going to deem it in the public interest for you to be able to kill batteries by discharging them too deeply and be entitled to a refund every time. They will decline your claim.

 

[Rappey]

, how under the sale of goods act can they call it a 120 amp hour battery when it is probably good for half that.

Or solar panels where you never get the stated wattage out of them.
Mppt charge controllers that are really pwm.
Torches that may do 5% of the claimed lumens.
Car mpg or m/kwh yet none manage what's claimed.
Ebay free to sell yet its not..
Watches that are 100m water resistant, but they are not.
Just the way things are Unfortunately.

 

[PabloPicasso]

buyer beware

 

[wingcommander]

Love honour and respect/ obey .. .....Na never happening

 

[Bouba]

To completely change the subject.....I replaced my 140 amp battery with two smaller batteries connected in parallel. I did this to make changing the batteries much easier on the back....an added benefit is you can often fit two batteries with a higher overall capacity in the same footprint. So you still get 50% but gives more power
In my case two 80 amp batteries fitted in exactly the same battery box. The original box even had two straps which perfectly fitted both new batteries

 

[wonkywinch]

Try some old Amstrad adverts "100 watts peak instantaneous music power", ie 25 watts RMS with 10% THD!