You are correct in not using a deep-cycle battery for starting. There is a difference in the plate topology between deep-cycle and starting batteries. Using a deep-cycle battery to start engines risks buckling the plates inside the battery.
Assistance with Amp Hour calculations
- Thread starter ShockBoy
- Start date
What does that mean? Assuming an Amp Hour is equivalent to One Hour, it will take 140 hours to recharge the battery @ 1A per Hr, Is this correct? So my panels average amperage @ 4 lets say for 5 hours per day would take 7 days assuming no other load was on the battery after initial drain?
Did you read my post #14?
Many (most) people seem to think that if a lead acid battery is say 50AH down, then it will need say 10A for 5 hours to recharge it. This is not correct.... it would require 10A for around 8 hours to ensure it is fully charged. (that is also assuming that you can provide a constant current). Chargers only give a constant current for a period of their charge cycle (cheaper chargers have no constant current facility at all). With constant voltage charging, the charging current will decrease as the battery's terminal voltage rises.
BTW, there is no such animal as "1A per hour". There are amps and there are ampere hours but no amps per hour.
Here is my 2 cents, I'm tired, and I apologize.. But I have been sucessfuly through Physics and I CAN find the bullet (if you know what I'm talking about). But when it comes to electricity; it's like nobody Really knows what it is and how it works. You can break down the electron, but do we really know 'HOW' it works? I get a little frustrated now and then.
Yes, I do ... and I qualified Expert...
We have a pretty good idea.
We don't know EVERYTHING about it, but we've been building on the knowledge accumulated for the last few centuries.Everyone gets frustrated every now and then. When you find yourself getting frustrated, it's time to think about something else for a bit, until something "clicks" - and then come back to it.
AH, by it's very definition, is Amperes per hour.
You must be about as tired as I am. Mistakes come all too easy when we're tired.
No biggie - come back when your plate has emptied out a bit.
No it's not. By definition it's AMPERES x HOURS (A.H) (ie: multiplied together) not Amps per Hour (A/H) as you are suggesting.
It's a common mistake which a lot of people make. The two quantities should be multiplied together not divided by one another. "Per" means one quantity divided by the other which therefore cannot be ampere hours. eg: miles per hour means the miles covered divided by the time taken.
Amperes themselves are already a "per" quantity being Coulombs per second.
You must be more tired than you realised.
I have to throw something in that is relevant to the thread.
The OP wants to take a refrigerator off-grid, so the numbers he is using for power consumption should be "todays" numbers. Not the numbers printed on the data panel from 8 years ago.
The standard ~16cf refrigerator runs 13hrs a day. (avg) To bring that number DOWN (sometimes 30-40%) You should do a few simple things.
Fill your freezer and fridge!
MASS holds temp longer. If you are in a colder climate, sit some 75% filled waterbottles outside until they freeze. (That way you wont use the freezers power for the initial freeze) Then place them in your freezer. This will work as a great buffer for when you open the door to get a tv-dinner. The compressor doesn't need to do so much work to get it back to temp.
More mass in the refrigerator acts the same way.
Also, by letting items cool to room temperature before putting them in the fridge also keeps compressor time down.
CLEAN your coils! Most refrigerators I have worked on have the compressors mounted in the bottom, by the floor. DIRTY, DUSTY, place! 1/16th inch of dust on a fan blade reduces effiency by 30%or more. The dust on a coil works as a blanket to keep heat in the coil, exactly what you do not want.
SO, clean coil, clean fan, cooler condenser. That a BIGGIE.
The heat exchanger on the back of a fridge needs to be cleaned also for the same reason. Also, if you don't have any reflective foil between the back of the fridge and the coils, you want to add some. And, last thing, make sure you have enough room between the back of the fridge and the wall. More room, more air. More air makes for a cooler fridge.
The OP wants to take a refrigerator off-grid, so the numbers he is using for power consumption should be "todays" numbers. Not the numbers printed on the data panel from 8 years ago.
The standard ~16cf refrigerator runs 13hrs a day. (avg) To bring that number DOWN (sometimes 30-40%) You should do a few simple things.
Fill your freezer and fridge!
MASS holds temp longer. If you are in a colder climate, sit some 75% filled waterbottles outside until they freeze. (That way you wont use the freezers power for the initial freeze) Then place them in your freezer. This will work as a great buffer for when you open the door to get a tv-dinner. The compressor doesn't need to do so much work to get it back to temp.
More mass in the refrigerator acts the same way.
Also, by letting items cool to room temperature before putting them in the fridge also keeps compressor time down.
CLEAN your coils! Most refrigerators I have worked on have the compressors mounted in the bottom, by the floor. DIRTY, DUSTY, place! 1/16th inch of dust on a fan blade reduces effiency by 30%or more. The dust on a coil works as a blanket to keep heat in the coil, exactly what you do not want.
SO, clean coil, clean fan, cooler condenser. That a BIGGIE.
The heat exchanger on the back of a fridge needs to be cleaned also for the same reason. Also, if you don't have any reflective foil between the back of the fridge and the coils, you want to add some. And, last thing, make sure you have enough room between the back of the fridge and the wall. More room, more air. More air makes for a cooler fridge.
I agree with Retched's post. Further, on my 12v boat fridge, I connected a small computer fan, behind the fridge, ducted so as to assist in heat extraction when the compressor runs. These fans have a very small current draw so don't add any significant power loss and are so cheap as to be effectively free.
However, the results are amazing; the fridge compressor comes on far less often than it used to do. I would say only about 60% of the start-ups that it did previously, thus saving significant battery power. I was hoping it would make a difference but I was truly astonished at the result.
However, the results are amazing; the fridge compressor comes on far less often than it used to do. I would say only about 60% of the start-ups that it did previously, thus saving significant battery power. I was hoping it would make a difference but I was truly astonished at the result.
