Herk I think it should be drown down in 10 hours. 5 X 10=50. With a 1 amp draw you would be at 50% after 50 hours.
You will get the full 100 ah capacity (20 hours at 5 amps) only at a 5 amp draw.
At a 1 amp draw, the capacity will actually increase above 100 AH; though it is not shown in that graph. Remember ONE bulb in a 2 bulb fixture draws more than that.
If you want to recharge at the recommended 50% point (12.1 volts), you would most likely need to recharge the battery every day.
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
Amp-Hours - What Are They?
All deep cycle batteries are rated in amp-hours. An amp-hour is one amp for one hour, or 10 amps for 1/10 of an hour and so forth. It is amps x hours. If you have something that pulls 20 amps, and you use it for 20 minutes, then the amp-hours used would be 20 (amps) x .333 (hours), or 6.67 AH. The generally accepted AH rating time period for batteries used in solar electric and backup power systems (and for nearly all deep cycle batteries) is the "20 hour rate". (Some, such as the Concorde AGM, use the 24 hour rate, which is probably a better real-world rating). This means that it is discharged down to 10.5 volts over a 20 hour period while the total actual amp-hours it supplies is measured. Sometimes ratings at the 6 hour rate and 100 hour rate are also given for comparison and for different applications. The 6-hour rate is often used for industrial batteries, as that is a typical daily duty cycle. Sometimes the 100 hour rate is given just to make the battery look better than it really is, but it is also useful for figuring battery capacity for long-term backup amp-hour requirements.
Why amp-hours are specified at a particular rate:
Because of something called the Peukert Effect. The Peukert value is directly related to the internal resistance of the battery. The higher the internal resistance, the higher the losses while charging and discharging, especially at higher currents. This means that the faster a battery is used (discharged), the LOWER the AH capacity. Conversely, if it is drained slower, the AH capacity is higher. This is important because some manufacturers and vendors have chosen to rate their batteries at the 100 hour rate - which makes them look a lot better than they really are. Here are some typical battery capacities from the manufacturers data sheets:
so you will draw down a 100 ah battery at 5 amps in 20 hours but you will draw it down to 50% in 50 hour????
"If your total amp draw is a constant 5 amps you will discharge a 100 AH battery to its 50% discharge point (where it must be recharged to avoid permanent damage to the battery) in 50 hours. "
This was not supposed start an argument just correcting the math, sorry if I offended you.
so you will draw down a 100 ah battery at 5 amps in 20 hours but you will draw it down to 50% in 50 hour????
"If your total amp draw is a constant 5 amps you will discharge a 100 AH battery to its 50% discharge point (where it must be recharged to avoid permanent damage to the battery) in 50 hours. "
Yup; misspoke that; at 5 amps you will be at 50% in 10 hours.
"Herk I think it should be drown down in 10 hours. 5 X 10=50. With a 1 amp draw you would be at 50% after 50 hours. "
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You were correct; Sorry for the confusion.
Going to get drunk now...
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
There are a number of parasitic loads on the battery. Refer needs a tiny bit to operate the controls. Once the voltage drops below 10.5V, the refer shuts down.
Any remote controlled 12v device has a receiver listening for the remote to turn the device on/off, change channels. The TV antenna has an amplifier that draws power to boost the signal - that could be on.
I've decided I am going to run a dedicated 12v line from our refrig to the battery (with a switch and fuse), so I can power down the trailer and still operate the refer.
Radios, clocks, entertainment equipment that have a display that you can see when the camper is not on shore or generator power us using battery power.
I've decided I am going to run a dedicated 12v line from our refrig to the battery (with a switch and fuse), so I can power down the trailer and still operate the refer.
Big warning. If you decide to do this and plan on staying in the camper "at all", you must also power the propane leak detector. It uses camper battery 12 volt power. A leak at the fridge could be fatal.
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
I use a CPAP which uses 6.7amps from 12v battery dry camped. My onboard Cedar Creek charger was only producing 2 amp charge on shore power, therefore draining to less than 12 volts. My AGM battery was not charging. Read AGM blogs and learned it really needs 10 amp charger to keep up. Was successful tricking charger with good 12v battery wired parallel and connecting to 10 amp charger restored my battery to full charge. Now I connect another charger (after cutting off onboard charger with disconnect switch) to restore battery after dry camp.
Thanks for all the info!!! I think we will look into a generator. We do a lot of National Parks(that is why we have a small tv). The dealer mislead us on the ability to dry camp. We also picked up 2 more batteries!!! Yellowstone here we come!!!
Thanks for all the info!!! I think we will look into a generator. We do a lot of National Parks(that is why we have a small tv). The dealer mislead us on the ability to dry camp. We also picked up 2 more batteries!!! Yellowstone here we come!!!
Watch your weight. 3 batteries are pretty heavy.
Make sure they are "marine" or "deep cycle" and not starting batteries.
Here are some tips on how to wire them up and why.
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
Big warning. If you decide to do this and plan on staying in the camper "at all", you must also power the propane leak detector. It uses camper battery 12 volt power. A leak at the fridge could be fatal.
You are right and I had not thought about this possibility. I will consider this in any solution.
We are going to put them in the truck and switch out as needed!!!
Some cautions:
1) Starting type batteries are not appropriate for this application. The plates are too thin and they have too much surface area to store more than a few hours of total charge. They are designed to give up 30-40% of their total capacity in a few minutes; then recharge in about 30 minutes of driving on the alternator.
Marine (Dual Purpose) or true deep cycle batteries are the way to go. They have thicker plates and hold lots more charge for longer life under discharge.
2) If you are going to keep your spare(s) in the bed of your truck, keep it (them) secured and supported (styrofoam?) to avoid cracking the plates from road shocks.
4) You should also rig some kind of trickle charging system (using the truck's power) in the truck bed using the same type of connectors to keep them topped off while driving.
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
Ontario
Linear Mode
