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Old 02-25-2020, 03:44 AM   #1
mazboy
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Batteries

I came across this website regarding batteries.



It is well worth your time to read the article. Bottom line, 2-6-volt batteries, for the most part, are always better than 2-12 volt batteries.



As more of us go into residential refrigerators we need to understand the power of batteries.


https://www.dieselhub.com/towing/6v-...e-battery.html
 
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Old 02-25-2020, 10:02 AM   #2
7.3Ford
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Yes two 6 volts are better than two 12 volts, but one Lithium is the best. If you are going to get a Residential fridge, you need a lot more if you are going to day camp at all. Residential fridge will use around 300 to 340 AH in 24 hours. So if you have a long travel day, you could easily have two 6 volts or two 12 volts batteries very close to the 50% discharge by the time you arrive at you campsite with power.
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Old 02-25-2020, 11:52 AM   #3
Daryles
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I have installed a Victron BMV-712 battery monitor. 1st step to adding solar. Now I can monitor consumption in real time and determine how much I need (for sure running the furnace).
Next step add 2 lithium batteries. Maybe next month. In still researching solar panels, MPPT, inverter, auto switching. So much to learn....
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Old 02-25-2020, 04:07 PM   #4
Keith Schweizer
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I installed 4, 6 volt 225 cca Interstates wired in series when I purchased new. The first set lasted about 7 1/2 years. I know they would have lasted longer but one of the battery posts was loose inside the battery. So I replaced with 4 new Interstates. $ 115.00 per battery, which I think is a good price for Interstates. 1 solar panel on roof with 1500 watt inverter. Plenty of power when dry camping 7 plus days as long as its not cloudy and rain. If its cold I run a small electric heater and that keeps us plenty warm rather than running furnace.I also use the inverter to blow up the air mattress , toaster, coffee TV's, DVD's, etc,. Electric/propane refer. I keep batteries on a charger/ maintainer all winter when not in use . Batteries always 100%. I really never use my 2 Hondas for backup, just for the girls hair dryer.
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Old 02-26-2020, 05:36 AM   #5
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The only negative on Lithium batteries is the cost.

Most RVers, in general, non solar, non dry campers aren't interested in spending $1000 on a battery.
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Old 02-26-2020, 09:24 AM   #6
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Before I purchased my fifth wheel I had a bumper pull TT. When the 12 volts died I went with the 2- 6 volts . No solar panel, inverter ,etc. A Huge increase in power , run time. At that point I knew I would never go back to 12 volt batteries.
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Old 02-26-2020, 12:08 PM   #7
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Originally Posted by 7.3Ford View Post
Yes two 6 volts are better than two 12 volts, but one Lithium is the best.
"Best" is Subjective....

here is why: The single lithium is 90-100AH however that does not mean you can run that full 100AH down as lithium batteries have built in controls that limit Lithium batteries from full 100% discharge so you may get 80-90 out of that battery at a cost of $1000 ea

Two decent AGM 6V will have 225-250AH, while some here tout that 50% is the low threshold of non lithium batts to prevent damage the battery industry suggest 30% (70% discharge) is OK. Regardless take the 250AH 6v combo and only use 50% that is 125AH usable AH that is 32% more than the Lithium AH at roughly 1/2 the cost of Lithium.

SO the argument is Lithium will last longer than AGM or Wet, double is subjective however even if true Lithium at twice the cost makes it all a wash in the long run, and unless you place to keep you RV for 8-15 years, the lithium value is just not there.

While Lithium is a great technology (have a Tesla I have owned for 5 years now) the consumer 12v still needs work to improve AH vs cost.

The big advantage though is Lithium weights much less then lead.

Quote:
Originally Posted by Keith Schweizer View Post
I installed 4, 6 volt 225 cca Interstates wired in series when I purchased new. The first set lasted about 7 1/2 years. I know they would have lasted longer but one of the battery posts was loose inside the battery. So I replaced with 4 new Interstates. $ 115.00 per battery, which I think is a good price for Interstates. 1 solar panel on roof with 1500 watt inverter. Plenty of power when dry camping 7 plus days as long as its not cloudy and rain. If its cold I run a small electric heater and that keeps us plenty warm rather than running furnace.I also use the inverter to blow up the air mattress , toaster, coffee TV's, DVD's, etc,. Electric/propane refer. I keep batteries on a charger/ maintainer all winter when not in use . Batteries always 100%. I really never use my 2 Hondas for backup, just for the girls hair dryer.
I considered buying 4-6 of the Interstate Batteries at Costco who has an amazing price on them however the reviews are HORRIBLE with many saying they barely last 1 year. While you original ones lasted 7 years, how old are your newer ones?

Costco currently has the Interstate 6v at $98 ea which is rediculous.

I have decided I will likely buy AGM 6V, I can buy 4 with a usable AH of 250-300 for a little over the cost of a single 12V Lithium at 90AH.
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Old 02-26-2020, 08:00 PM   #8
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Originally Posted by mazboy View Post
The only negative on Lithium batteries is the cost.

Most RVers, in general, non solar, non dry campers aren't interested in spending $1000 on a battery.
Most RVers also do not full time. As such they rarely carry enough gear so the added weight of the lead acid batteries is not a real issue like it is more likely to be for Full Timers.
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Old 02-26-2020, 08:16 PM   #9
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Lightsout, you make good arguments for AGM but you don't need to diss LFP with erroneous data on usable AHs. Battleborn and reputable others will deliver the AHs they claim because they are actually have more AHs built in than is published.

For most people, (typically not full timers) LFP simply is not justifiable... but LFP has its place, especially when weight is an issue as it relates to CCC.
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Old 02-26-2020, 10:04 PM   #10
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Originally Posted by BiggarView View Post
Lightsout, you make good arguments for AGM but you don't need to diss LFP with erroneous data on usable AHs. Battleborn and reputable others will deliver the AHs they claim because they are actually have more AHs built in than is published.

For most people, (typically not full timers) LFP simply is not justifiable... but LFP has its place, especially when weight is an issue as it relates to CCC.
So lets take the Battleborn which is 100AH still at 50% the two AGM 6v provide more power (AH) . I am not sayin LFP is not a good thing but I was responding to a specific comment and may have been too general. If I knew I was in this RV for 8+ years I would possibly spend the $$$ for LFP, however LFP is still a developing technology and 5 years from now will be lower cost and better performance. I am not much of an early adopter unless needed.

By the way most if not all batteries have more AH then published that keeps them out of trouble for false or misleading advertising...
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Old 02-26-2020, 11:09 PM   #11
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Originally Posted by lightsout View Post
So lets take the Battleborn which is 100AH still at 50% the two AGM 6v provide more power (AH) . I am not sayin LFP is not a good thing but I was responding to a specific comment and may have been too general. If I knew I was in this RV for 8+ years I would possibly spend the $$$ for LFP, however LFP is still a developing technology and 5 years from now will be lower cost and better performance. I am not much of an early adopter unless needed.

By the way most if not all batteries have more AH then published that keeps them out of trouble for false or misleading advertising...
Not sure where you get a Battle Born only being able to discharge to 50% when even on their own websites it says 100% discharge. Yes Lithium is expensive but they do come with a great warranty as well.
Just don’t buy Lion Energy’s Lithium as the have deceptive advertising by saying their Lithium is 100AH when really it’s only 85-90AH so I would go with Battle Born.
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Old 02-27-2020, 06:09 AM   #12
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hey guys/gals when I did this thread I thought I'd just pass along some information, what I thought, was some great information that RVers could use. After all, it seems like more and more RVs are going with residential refrigs.


The information was just to give people an UNDERSTANDING of how batteries operate.


If you have the money $$$ buy lithum, lots of them. If you are like me, poor, I'd probably 2- 6 volt batteries:-)
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Old 02-27-2020, 10:18 AM   #13
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Not sure where you get a Battle Born only being able to discharge to 50% when even on their own websites it says 100% discharge. Yes Lithium is expensive but they do come with a great warranty as well.
Just don’t buy Lion Energy’s Lithium as the have deceptive advertising by saying their Lithium is 100AH when really it’s only 85-90AH so I would go with Battle Born.
I think he worded that oddly. For starts however, LFP batteries come in various AH ratings just like AGM. He really should be comparing apples to apples in the AH department. 400AHs of LFP is about equal in usable capacity to 800AHs of AGM. Yep, AGM will cost less up front and even in the medium term. But AGMS weigh a ton compared to LFP. For fulltimers this could be a critical issue as many full timers are typically at or over their trailer GVWR when you start adding in sought after fulltimer upgrades like solar and batteries among other things. When you are loaded down CCC becomes a real issue. In that instance LFP, being lightweight compared to AGM or SLA, becomes cost effective when you absolutely have to carry everything else. Weekend warriors simply don't have that issue. According the Keystone, "most Montana owners" carry an average 900 lbs of gear and they build their trailers to fit that demographic first, then build in extra to be competitive with the SOBs. So with only 900 lbs of cargo, and a rating upwards 3000 to 3500 give or take, 400 lbs of batteries to run stuff is no real biggie. But when you are hauling everything you own... that 400 lbs of batteries could be a deal breaker, so the ~275 lbs savings with LFP can be worthwhile. YMMV as they say.
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Old 02-27-2020, 02:43 PM   #14
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Not sure where you get a Battle Born only being able to discharge to 50% when even on their own websites it says 100% discharge. Yes Lithium is expensive but they do come with a great warranty as well.
Just don’t buy Lion Energy’s Lithium as the have deceptive advertising by saying their Lithium is 100AH when really it’s only 85-90AH so I would go with Battle Born.
I never said anything about the Battleborn only 50% re-read the sentence that was referring to the 6v AGM whereas even at 50% the AGM still beats the Lithium. You can drain Litium down 100% but it is not a true 100% drain as they have a built in stop on the battery, lithium batteries should never be discharged 100%, again the 100% Battleborn talks about does not include a small reserve that is protected that you cannot discharge anyway.

By the way when I said 85%-90% that was a generic statement not all Lithiums are programmed like Battleborn. Still the point being that 100AH is less then the 125AH of two 250AH AGM at 50% which can go even a little more if needed. 50% on AGM is not the point if no return the battery industry suggest that 30% is where damage really begins.

I just had this conversation with two wet/agm battery manufactures as My RV was in for warranty (3 months) they let the batteries go completely dead so I reached out to two manufactures to quantify what damage was done. They both said 30% and that 50% was a Lithium industry Talking point.

However I think we all agree Lithium is a good solution however at a cost.

Also understand though that Lithium batteries the AH will depreciate over time so in 5 years it will not produce 100AH and at 10 years even less. Just like your Iphone battery does not last as long over time. Our Tesla Model S does not have the range it had 4 years ago. Wet is also affected by depreciation however because is much less $$$ you can replace in 6-7 years and reboot your AH. With Lithium you are stuck long terms with the depreciated AH.

So there is a lot to consider between the two technologies.
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Old 02-27-2020, 04:08 PM   #15
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We do not boondock. We do not have solar panels. We do not have a residential fridge.
We do have 2 deep cycle 12 volt batteries. We have a 2013 3402. We properly maintain the batteries. The original batteries are still in the 3402 they are 6 1/2 years old.
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Old 03-01-2020, 05:39 PM   #16
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Quote:
Originally Posted by 7.3Ford View Post
Yes two 6 volts are better than two 12 volts, but one Lithium is the best. If you are going to get a Residential fridge, you need a lot more if you are going to day camp at all. Residential fridge will use around 300 to 340 AH in 24 hours. So if you have a long travel day, you could easily have two 6 volts or two 12 volts batteries very close to the 50% discharge by the time you arrive at you campsite with power.
I hear people say this and I am wondering won't the TV be charging the battery while you travel? Although I haven't done the math, I would be surprised if the TV can't put out over 100 AMPS of charging power. Mine is 110 amp which would be more than enough to run the fridge, power the TV and charge batteries.
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Old 03-01-2020, 05:41 PM   #17
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It might put out 100 amps, but try and push that through the #12 wire in the harness
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Old 03-01-2020, 08:54 PM   #18
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Maybe it varies by make. My F-350 has a 10 gauge wire on the charge line.
The line from the truck cab to the trailer battery must be less than 30 feet maybe 25 feet. I wasn't saying it would charge a dead battery but just keep it topped off while towing. The fridge doesn't run all of the time.

Here is an article for etrailer about it - https://www.etrailer.com/question-12555.html
Although this shows a smaller number of 10 amps - https://www.engineeringtoolbox.com/a...uge-d_730.html

I just got a 712, once I install it I will run the battery down a bit and take it for a drive to see what it puts out.
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Old 03-02-2020, 03:26 PM   #19
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While you are traveling the batteries should charge to full and remain full while your tow vehicle is running. It is the stop times you need to be concerned about. If your batteries are not charging while you are driving get your system checked by someone who understands RV electrical.
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Old 03-02-2020, 03:38 PM   #20
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I doubt your tow vehicle charges much over 20 amps. The wire is a #10 and #10 is rated at 30 amps. But still your Tow Vehicle should charge adequately to manage the fridge and other loads.
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