New to RV

[rvlifer]

I had two lifeline 110AH AGM's that were D.O.A once they touched 12.3. Who knows how accurate the meter was, but they were far too weak for my use and I replaced with 460AH of lithium and its not even a concern anymore. Tied together they were technically 220AH but it sure didnt seem like it! 3-4 hours of just a max air fan and some device charging was all it took to deplete them. Seemed more like 110AH than 220AH. Put me in the 50% camp, from experience.

Something seems wrong there for sure. Maxxairs dont use much power even on high. I swapped our oem fantastic fans for maxxairs in part cause they use less power than the fantastic fans

 

[Mark_K5LXP]

The 50% Rule has become the boogieman - whatever ails your batteries, it was because they were discharged below 50%. It will kill your batteries! Once that horse leaves the barn and the batteries have been scrapped, it's difficult to prove otherwise and the myth stands. At least it's not just batteries, we can always discuss motor oil, or what PSI is best for tires.

Mark B.
Albuquerque, NM

 

[rvlifer]

The 50% Rule has become the boogieman - whatever ails your batteries, it was because they were discharged below 50%. It will kill your batteries! Once that horse leaves the barn and the batteries have been scrapped, it's difficult to prove otherwise and the myth stands. At least it's not just batteries, we can always discuss motor oil, or what PSI is best for tires.

Mark B.
Albuquerque, NM

I never believed it would kill the batteries but i do believe it can shorten their life. By how much is debatable

 

[Mark_K5LXP]

No, DoD vs cycle life (and by extrapolation service life) is actually pretty well characterized and documented for the major brands of batteries. What becomes debatable are user variables like proper charging and storage. A deep cycle battery is very resilient to discharge but quite sensitive to charge profile and state of charge during storage. But discharge gets the blame because few people pay attention to proper charging and storage. Other unaccounted variables are things like measurement precision, temperature compensation, partial state of discharge conditions and other minutia that by simply saying only use half your battery you reduce their impact. You bought the capacity and like tires it will age out if you don't wear it out, so why not use it. It is within manufacturer specifications.

Mark B.
Albuquerque, NM

 

[RV_Lee]

The manufacturers of them say to not deplete more than 50%. Its not a myth lol

 

[rvlifer]

It isnt that i dont believe you guys and would be interested in learning more but i think we should move this discussion to another thread.

I would love to see the evidence you are referring to but so far you havent provided anything better than the article i posted.

 

[Mark_K5LXP]

The manufacturers of them say to not deplete more than 50%. Its not a myth lol

That's a pretty specific directive. Can you show me one?

I would love to see the evidence you are referring to but so far you havent provided anything better than the article i posted.

Agree we hijacked the thread, and we can engage this offline or in a different post. If you do a search on this forum with my user name and a keyword like battery or depth of discharge, you will be rewarded with lots of posts with specifics I've made on this subject over several years (to which the regulars here will attest...).

Mark B.
Albuquerque, NM

 

[solarman]

That's a pretty specific directive. Can you show me one?


Agree we hijacked the thread, and we can engage this offline or in a different post. If you do a search on this forum with my user name and a keyword like battery or depth of discharge, you will be rewarded with lots of posts with specifics I've made on this subject over several years (to which the regulars here will attest...).

Mark B.
Albuquerque, NM

I'll hijack it some more.. LOL

as a now retired professional electrical engineer who has designed off grid solar and scada systems for the past 20 years or so, I fully endorse Mark's comments on lead acid batteries, The 50% "rule" is somewhat contentious, especially when parroted across the internet as being hard and fast, I have news for you.. it's not a rule, it's a RECOMMENDATION by battery manufacturers for non technical people to give a good life vs cycle count. draining a battery to a specific DOD is application specific, I've implemented systems that range from 25% to 75% DOD and all of those cases the batteries did not explode or a black hole form and swallow them up just because they were discharged below this magical 50% point. 50% DOD is the least of your worries with lead acid chemistry, I suggest you ignore it and concentrate more on charge and discharge currents, these have more effect on lifespan than DOD.
as a point of interest, in talks with battery engineers over the years, the biggest cause of battery failure is sulfation caused by undercharging. Pay more attention to charging and periodic equalization and your batteries will last.

we could start another thread on batteries if you so desire..

 

[solarman]

I am waiting for my RV to arrive an it is a 29' trailer. Now let me know if i get this correct retaining to power. It is the battery and the Amps per Hour that i need to be concerned with if i want power to las a long as possible off the grid. Now my understanding is that it is the battery hooked to the inverter that supplies the power to the devices. And it is the solar panels and the battery are hooked to the charge controller. and all the solar panels does is charge the battery. Meaning is i had two 300Ah 12v batteries in a 29ft trailer, will this be enough to run a trailer with a washer, dryer, stove, fridge, projector, surround sound, 65" TV for 3 days straight with no charging? And how do i find this out? Is there a calculator online that i can use?

that's a lot of power, yes you can run all that but for perhaps an hour..
I have a simple calculator for solar wattage and battery sizing, you will get sticker shock for what you are trying to achieve. first detail you need for battery and solar sizing is a very good estimate of your loads, others have mentioned using a battery monitor or shunt, that's a good starting point. my suggestion is to read the wattage label on all your equipment, then estimate the likely runtime for each device, then enter those figures into my spreadsheet. it's not difficult to do and will get you a better idea of what you will need to satisfy your requirements.

Link to spreadsheet

 

[Adventurous Traveler]

I carry a small generator to help top off the battery when the solar isnt enough

Way too complicated of a thread for me. Plus, the OP hasn't given the location and RV type to fill in more particulars of his quest. His original post is somewhat a contradiction of RV'in/Camping to most of us (I know, to each his own) by running 65" TVs, washers and dryers, screen projectors, and other electricity-driven appliances while dry camping.

Being from the East Coast where we do not have the multitude of boondocking opportunities as many West Coasters do, I'm quite happy with my motorhome with 4 CG batteries and a 5500W generator to get me by any situation I find myself in when off-grid, the longest being 4-5 days.

 

[rvlifer]

Way too complicated of a thread for me. Plus, the OP hasn't given the location and RV type to fill in more particulars of his quest. His original post is somewhat a contradiction of RV'in/Camping to most of us (I know, to each his own) by running 65" TVs, washers and dryers, screen projectors, and other electricity-driven appliances while dry camping.

Being from the East Coast where we do not have the multitude of boondocking opportunities as many West Coasters do, I'm quite happy with my motorhome with 4 CG batteries and a 5500W generator to get me by any situation I find myself in when off-grid, the longest being 4-5 days.

I agree There are so many ways to use an rv. Similar to suvs and offroad vehicles i dont understand why so many people buy them and rvs and then dont really use their capabilities. I get some of tbe reasons why but a lot of people buy expensive rvs and then cant or wont ever stay at anything but luxury rv resorts. Might as well skip the rv and do regular vacations at that point.

I spent most of my life on the east coast and set up my rv for boondocking while we still lived there. Other than run a projector i have done all that stuff while boondocking including laundry and running the dryer. I can get 2 loads done before my holding tanks are full and batteries drained. I didnt set my rv up to do those things regularly but it is a nice bonus that i can if i want to

Everyone does things a little bit differently and i respect their right to do so. Not many would do what i did but the op's original post indicated he wanted to do at least some of the stuff i have done

 

[Kirk]

His original post is somewhat a contradiction of RV'in/Camping to most of us (I know, to each his own) by running 65" TVs, washers and dryers, screen projectors, and other electricity-driven appliances while dry camping.

It doesn't appear that he has been back in several days, but in reading his posts he states that he was an electrician before becoming a network expert. He must have forgotten most of what electricians deal with on the job to have under estimated his power availability by so much.

There are so many ways to use an rv.

I have often said that the only limit to the ways one can use their RV is their own imagination. After reading his posts I think that I should add budget as another limitation.