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Old 06-23-2022, 04:34 AM   #1
coralcruze
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Default Battery dieing quick.

First I will start by saying that usually we go to campgrounds. But lately since I am fixing the TM on weekends I have been seeing some battery issues. My 6 YO battery seem to have died and wasn't holding a charge. Brought it into a Walmart and they did a battery test with a battery testing machine. Told me it's a dead battery. So I purchased a new deep cycle 80cca battery. Just as before I am using a generator to recharge after about two days. Once again I am seeing the new battery can't seem to hold a charge after charging it using my generator. I charged it completely to 12.6v at around 9pm and shut all light for the night at around 12. At 5 am woke up to TM beeping. Tested battery and was 6.5v. When I use my generator I hook up me electrical plug from the TM and can see my inboard void meter is at 13.4‐7 so the converter seems to be doing its job.

I do see slight discoloration on the threaded stem on the positive terminal which I am reading could be a sign of short circuit... I took a pic of it and will post it later for input from folks that know alot more than I do about this stuff.

Obviously I want to know if it's just a baby battery that I picked up and no issues with my converter or generator causing this. I should mention that the old original battery died when I started to boondock and draw power all way down. Should these deep cycle batteries be charged at a specific voltage when boondocking. Sorry newbie here with boondocking. Thanks in advance for all assistance.
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Old 06-23-2022, 09:23 AM   #2
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1st..... 80AH (not cca "cold cranking amps") of battery gives you about 40AH before the battery must be recharged @ around 12.5V-12.2V or slightly less. If the battery drops below 12V it should be immediately disconnected. Damage occurs below 12V. Below 10.5 volts, the batter will be permanently damaged and will never be able to accept a 100(% charge. If you let the battery get down to 6.5V, the damage "can" be so severe that the battery "May not" be able to even reach 12.5V>

OK...... having said all that, I would recommend taking that battery back to Walmart and ask for a new one. They probably will give you no hassle.

To properly charge your battery, charge the new one fully when you get it installed. After charging, let the battery rest over-night then check the voltage the next day. It should rest above 12.7V for a few days.

When you are using the battery, check the voltage often and don't let it get below 12.2V (ever) before recharging. When you charge the battery, your voltmeter will only show the "Surface charge" of the battery. It takes several hours for that surface charge to "soak in". Checking the voltage right after charging is very deceiving.

If you start charging when your battery is at 12.2V (basically "0" state of charge), your charger will put out around 50A (or whatever your TM controller max is) for a very short period of time (maybe 10 minutes, then the charge rate tapers off until it is putting out around 10A. This means, if you have used 50% of your battery's capacity (around 40AH), it would take 4 plus hours of charging before you are back to 100%, charging at 10A.

If you are running your generator for 1-hour, your voltmeter will show a very high surface charge (maybe even "Full"). In reality, you have put maybe 12 AH of charge in a battery that wants 40AH of charge to be fully charged. I would recommend charging for 1 hour in the morning and check the voltage just before dark or 1 hour before the end of generator hours. If the voltage is 12.5V or below (and it will be), charge for another hour (at minimum). See how that works out for you. Most people that boondock go with around 200AH of batteries and charge twice a day or have solar panels.

Hope this makes some sense and helps you.
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Old 06-23-2022, 12:39 PM   #3
coralcruze
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Quote:
Originally Posted by Wavery View Post
1st..... 80AH (not cca "cold cranking amps") of battery gives you about 40AH before the battery must be recharged @ around 12.5V-12.2V or slightly less. If the battery drops below 12V it should be immediately disconnected. Damage occurs below 12V. Below 10.5 volts, the batter will be permanently damaged and will never be able to accept a 100(% charge. If you let the battery get down to 6.5V, the damage "can" be so severe that the battery "May not" be able to even reach 12.5V>

OK...... having said all that, I would recommend taking that battery back to Walmart and ask for a new one. They probably will give you no hassle.

To properly charge your battery, charge the new one fully when you get it installed. After charging, let the battery rest over-night then check the voltage the next day. It should rest above 12.7V for a few days.

When you are using the battery, check the voltage often and don't let it get below 12.2V (ever) before recharging. When you charge the battery, your voltmeter will only show the "Surface charge" of the battery. It takes several hours for that surface charge to "soak in". Checking the voltage right after charging is very deceiving.

If you start charging when your battery is at 12.2V (basically "0" state of charge), your charger will put out around 50A (or whatever your TM controller max is) for a very short period of time (maybe 10 minutes, then the charge rate tapers off until it is putting out around 10A. This means, if you have used 50% of your battery's capacity (around 40AH), it would take 4 plus hours of charging before you are back to 100%, charging at 10A.

If you are running your generator for 1-hour, your voltmeter will show a very high surface charge (maybe even "Full"). In reality, you have put maybe 12 AH of charge in a battery that wants 40AH of charge to be fully charged. I would recommend charging for 1 hour in the morning and check the voltage just before dark or 1 hour before the end of generator hours. If the voltage is 12.5V or below (and it will be), charge for another hour (at minimum). See how that works out for you. Most people that boondock go with around 200AH of batteries and charge twice a day or have solar panels.

Hope this makes some sense and helps you.
Thank you so much for taking thr time to write this out. It' is very helpful especially being that I am a newbie weekend boondocker. I just installed a USB and voltmeter to keep am eye on the battery.

Did what you said and returned the battery being that I probably damaged it letting it go down to 6.5 volts. And Walmart gave me a bit of a heard time which is surprising but they did replace it. They said they can't replace the battery if thier battery tester shows a good battery which it did. I will share this with my wife so she can be aware of this as well.
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Old 06-23-2022, 09:28 AM   #4
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Unless you're running the fridge on 12v in camp (and you absolutely shouldn't do that), your battery should have held up through the night, with maybe 10-20Ah of total power loss during the night. At 12.6V, you started with about 90% State-Of-Charge, and that voltage (as a resting voltage, not immediately following charging) was just a slightly low target - you want the battery to be around 12.73 (at 25 degrees C, it varies with temperature). With lead-acid batteries, it is desirable to keep them at 100% State-of-Charge for the maximum possible amount of time. The charger running at around 13.4V will be fine, if given lots of time for the batteries to recover. It will not be capable of overcharging the battery, because there is a "hump" of about 0.7 volts which the charger must overcome, in order to charge Lead-Acid batteries. The current and power from the charger (into the battery(s) will drop to almost zero, when the batteries have reached 100%.

The inexpensive Walmart 'deep cycle batteries' are actually combination batteries, attempting to balance the goals of deep-cycle use and motor starting use. True "Deep Cycle" batteries are built with fewer but thicker plates, while 'motor start' batteries are built more but thinner plates. The Walmart batteries should not be taken below about 12.15 volts, 50% state-of-Charge. Having been pulled down to 6.5V is pretty bad, but it might be recoverable, to some degree.

If you were NOT running the fridge on 12v from the battery alone, there is likely something wrong within your TM.
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Old 06-23-2022, 10:03 AM   #5
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To address boondocking , I always use fairy lights and/or battery (AA) powered lights. Amazon has lots of rechargeable lights that would mitigate needing to use the camper battery. Tea lights for the bathroom work great so the overhead lights don't blind ya.
I use a CPAP and for boondocking, for that I use either a small 300 Wh power pack for weekends. If it's for 4-6 days, I use my Goal Zero Yeti 400Wh Lithium power pack.
Reserve the camper battery power for the water pump or furnace usage.
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Old 06-23-2022, 05:33 PM   #6
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Quote:
Originally Posted by Kidkraz View Post
To address boondocking , I always use fairy lights and/or battery (AA) powered lights. Tea lights for the bathroom work great so the overhead lights don't blind ya.
We do a similar thing (Mostly when its cool) We use Wallyworld three wick candles in three locations. Two on the front end (2720 SL shelf) and one on the stove. Makes for a real homey feel (Homey... NOT Homie!)

We also have the smaller version one wick candle in the bathroom. Scent is consistent, and helps with any odors that may/will occur.

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If it's for 4-6 days, I use my Goal Zero Yeti 400Wh Lithium power pack. Reserve the camper battery power for the water pump or furnace usage.
We are not THAT frugal (We now have a 100 Watt solar system) but every little bit helps.

And to the OP.. I had he same feeling that you purchased a "Marine" battery that is for boats. Is it a true group 27?
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Old 06-23-2022, 11:50 AM   #7
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Originally Posted by rickst29 View Post
Unless you're running the fridge on 12v in camp (and you absolutely shouldn't do that), your battery should have held up through the night, with maybe 10-20Ah of total power loss during the night.
Unless you are also running the furnace, which consumes a lot of power if the temps are even moderately cold.

Quote:
The inexpensive Walmart 'deep cycle batteries' are actually combination batteries, attempting to balance the goals of deep-cycle use and motor starting use.
If the battery in question has a cca rating, it is most likely a pure motor-start battery, and not a deep cycle battery or a combination (aka marine) battery. Among the three, a motor start battery is the worst choice. Walmart sometimes has true deep cycle batteries in stock, but my experience says not often

Quote:
I brought it into a Walmart and they did a battery test with a battery testing machine. Told me it's a dead battery.
Some WalMarts (not necessarily all) test your battery with a simple handheld voltmeter - in other words, no load. This tells you pretty much nothing, but they will still tell you your battery is bad, and you should buy a new one. I even caught a Ford dealer doing this to my F-150 once. A true battery tester is a sheet metal enclosure maybe 6 inches on a side, with a carry handle, vent holes, and heavy cables and clips.

I have had decent luck with WalMart batteries - but you need to know what is happening.

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Old 06-23-2022, 12:50 PM   #8
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Unless you are also running the furnace, which consumes a lot of power if the temps are even moderately cold.

If the battery in question has a cca rating, it is most likely a pure motor-start battery, and not a deep cycle battery or a combination (aka marine) battery. Among the three, a motor start battery is the worst choice. Walmart sometimes has true deep cycle batteries in stock, but my experience says not often

Some WalMarts (not necessarily all) test your battery with a simple handheld voltmeter - in other words, no load. This tells you pretty much nothing, but they will still tell you your battery is bad, and you should buy a new one. I even caught a Ford dealer doing this to my F-150 once. A true battery tester is a sheet metal enclosure maybe 6 inches on a side, with a carry handle, vent holes, and heavy cables and clips.

I have had decent luck with WalMart batteries - but you need to know what is happening.

Bill
I believe I took a picture of the battery last week. I think it states deep cycle and 80 ah. OI will post the picture as soon as I find it.
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Old 06-23-2022, 03:26 PM   #9
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Just keep in mind that the working amp hours available is only 50% of the rated amp hours (AH). That means that you have a maximum of 40AH available from a fully charged (brand new) battery. That constantly changes with age.... Just like us...

That means if you have 3, original light bulbs in your camper that are rated at 1.7A each, you can run those 3 bulbs (total of 5.1 amps) for 7.8 hours (5.1A bulbs for 7.8 hours = 40AH (amp hours).... total useable capacity of the battery.

Throw in water pump usage, ceiling fan and whatever else and you're done until the battery is recharged. The trick is though (as I said before) if you only charge that battery for an hour, you've only put about 12AH back in the battery and it will be dead again with about 2.35 hours of those 3 bulbs (instead of 5.1hrs).

When your battery is fully discharged, you would have to plug your trailer into house current or your battery for 4+ hours to about 90% charge. (the calculation gets a little fuzzy because you have to allow for absorption and other things).

If you intend to do much boondocking (real camping) you may want to think about adding solar. 1, 100w solar panel would work nicely with that battery and probably keep you fully charged with what you can use. a 100W panel will give you about 45AH of charging (your battery's capacity) each day (depending on amount of direct Sunshine). No matter what, it would do better than running your generator for an hour a day.
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Old 06-24-2022, 10:22 AM   #10
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Quote:
Originally Posted by coralcruze
So I purchased a new deep cycle 80cca battery.
Quote:
Originally Posted by Bill View Post
If the battery in question has a cca rating, it is most likely a pure motor-start battery, and not a deep cycle battery or a combination (aka marine) battery.
Small but important difference. The label says 80 mca (marine cranking amps), not 80 cca (cold cranking amps) as in your original post.

I've got to agree with Wavery. There is an enormous amount of unregulated marketing hype in this area. True deep cycle batteries are available, though more expensive, and I can no longer find one at Walmart. Regardless, the bottom line lesson is to treat your battery tenderly, and expect to get a few years out of it. Or treat it wrong and get much less. I learned this the hard way, many years ago.

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