Solar idiot

Thanks Athol , I better get em both checked out .

Yep , it's not the first time , I has stuffed something up , won't be the last .

The reg seems ok , I checked it with my multimeter .

I'm having trouble with my 24 year old Engel , pulling the batt down to 12.4-12.3v overnight .
Might be time for a new fridge .

Thanks Jacko .

Jacko,

It would be a good idea to have your battery checked out by having a load test done on it.
The Engel, regardless of its age, should not be drawing the battery down from "full charge" to 10.4v overnight.
10.4v is FLAT and may mean that it is your battery and not the Engel that is your real problem.
You could connect an ammeter in line with the fridge lead to determine exactly what the current draw is, but I would be suspecting the battery myself.

While you are probably right regarding the battery, he didn't state what size battery it was, so getting down to 12.4V ( NOT 10.4 ) overnight is not too much out of the ordinary for say a 80a/h battery.

Oh bugger!

Your absolutely right Gronk. I claim a Seniors moment and it was early in the morning.
12.4v is not all that bad and is definitely not flat.

Jacko, take my advise with a grain of salt:-)

LOL . Bill we all do it
Battery is a Marine -Intimidator - AGM - 92 AH @ 20H how , never really understood how that works out in straight Amp-hr

92 AH @ 20H indicates it has a capacity of 92AH when discharged at a constant 20A.

HKB,

Doesn't the 20H mean it has 92Ah if discharged over a period of 20 hours. The current required to do that would be 92 divided by 20, = 4.6 amps.

That's the way I understand it.

Cheers

Hi Frank,

I'll stand corrected, I assumed the expression was not quite correct as I'm more used to seeing it expressed as RC capacity, ie 125 minutes @ 25A rate.

92AH at 20H makes sense as you put it though it seems quite a slow rate of discharge to achieve only 92AH.

Seems I not the only one confused , why can they can't just say Amp Hours ,

The OP has a 92 Ah battery. There is no way it will deliver 92 A over a 20 hour period. It will only deliver 4.6 A. If it supplies 4.6 A for 20 hours that gives 4.6 X 20 = 92 Ah.
Amperes (A) is the flow rate at a particular time. If you have 1 A flowing for one hour you have delivered 1 Ah. If the 1 A flows continuously for 4 hours then you have 4 Ah. If you have something that switches on and off every 10 minutes, it draws 1 A when switched on then it will consume 2 Ah over a 4 hour period.
Do you now get the difference between amps and amp hours.

LOL, I just love threads about electrickery stuff :)))

Regards

I need someone to help me understand the term "amps per hour" that many people use.

Flame suit on, head below parapet.

Cheers

Quote "I need someone to help me understand the term "amps per hour" that many people use."

Amps per hour is not a standard term that knowledgeable people use. It's only used by those who don't know much about electricity. I have seen it used in several ways.

The correct term to use is amp hour or ampere hour. I explained it above. Or see Battery Ratings

Ok if my Batt is 92Amps @ 20Hours what is that in , Ampere-hour.

Jackolux,

You wouldn't have a 92 amp battery. You would have a 92 amp-HOUR battery. Amps is the measure of instantaneous current in a circuit. Amp-hours is a measure of battery capacity.

If that was a 20 hour rating, which you have indicated, it means if you discharge the battery with a steady current in standard conditions over a period of 20 hours it will deliver 92 amp-hours. The steady current in that case would be 4.6 amps.

If you discharge it over a shorter period of time, ie with a greater current, there is a law worked out over 100 years ago by a man called Peukert, which says you won't get 92 amp-hours out of it, you will get less. If you took, say 10 amps out of it, you wouldn't get 9.2 hours, you'd get fewer.

Under the same law, if you took less current, say 2 amps, you might get more than 92 amp-hours.

Cheers

Yep ok I do get Amp/Hr , I typed it wrong .
All I was really asking , you go to buy a new battery some are rated at '' X Amp Hrs - 90-100-125ect

Then others like mine are rated @ 92Amp/Hr @20Hr .

How do you compare batteries one rated a X AH the other X-AH @ 20 Hr's

You can't really compare them unless you have the Hours figure quoted. The most common in my experience is 20 Hrs, often called the C20 rate, so perhaps you could risk an assumption.

If it's missing it would be better to try to find out from the seller/distributor/manufacturer what specification they are using.

Cheers

Quote "How do you compare batteries one rated a X AH the other X-AH @ 20 Hr's"

It's a bit like comparing litres of fuel in the fuel tanks. A 120 Ah battery will store 20% more energy than a 100 Ah battery.

I say a bit like comparing tanks as you will have seen that a battery changes its size a bit with the the rate you discharge it. However as a rule of thumb you can say a 200 Ah battery contains twice the amount of energy as a 100 Ah battery or two 100 Ah batteries contain twice the energy as one 100 Ah battery (a battery is just a collection of cells working as one unit, when you parallel two 12 V batteries what you have created is actually one battery containing 12 cells.)