Amp Hours - Are you Right Sized? Post your Charge Method

[MiRV]

Amp Hour usage is always a question for people who looking at the idea of Boondocking. Since the batteries are one of the most crucial part of your electrical system, it's important to have the House Batteries "right sized" for a successful Boondock.

Please post the following:

1 - Projected Amp Hours for 24 hours (amp hour worksheet):
2 - Current # of batteries:
3 - Current # of Amp Hours [AH] your batteries have (or Reserve Capacity [RC]):
4 - Battery Voltage (6 or 12):
5 - How long do your batteries last based on #1:
6 - How long each day do you run your generator to get "recharged":
7 - Provide any other info like if you use solar and how you recharge, etc.:

THANK YOU!!!!

[MiRV]

red31 wrote:
asking and sharing with others about their trial and error experiences shouldn't be stifled. The one that stifles should be.

red31,

The posts from MOST of the contributors has been very helpful. As I prepare for more boon docking camping over the next year, I see I will need more AH so that I don't have to run my generator as often.

Planned changes right now is:
Install 4 6volt batteries to get 400AH and not add solar at this time. If I do add solar it will be a mobile panel vs full installation on the roof. This will allow me to stay at 75% within a 24 hours period without the generator (or go 2 days before generator runs).

With my current configuration (150AH with 2 12volt batteries), I am running my batteries to empty over the 8 hours of nighttime if I run a small dc fan. After getting behind in the batteries (low voltage from draining), I never seem to catch up after the 1st 24-48 hours.

I'd like to stay boon docking for 5-10 days and we can do it with the other resources (water and black/grey tanks). However, the electrical has me limited. I found this out during our first boon docking in Acadia NP in May. Day 1 - Great power, Day 2 - limited power, Day 3-6 - ran out of power every night even though I ran the genet for 3-4 hours daily.

I am very appreciative of the info from the others posting on the thread with their rv configs.

[MiRV]

Mena66,

I have 150AH, 12V, 2 batteries Group24 (older batteries). I'm trying to figure out the best solution to improve my current AH availability and allow me to go longer between generator runs since I don't have solar.

Over the next 12 months, we will be boon docking MORE in the southwest and west...therefore, before I head out, I want to replace my battery configuration and/or add solar to help.

[MiRV]

KJINTF wrote:
1 - 200 >> 500 or even more during heavy usage
2 - 2
3 - 220
4 - 6
5 - Months
6 - 0 - start it every now and then to make sure it still runs or once in a great while to use the AC
7 - 550watts of solar power

As you can see everyone does this stuff differently
My solar PV array is a power source NOT a simple battery charger
Can't remember if we have ever gone to a camping site with "Hook ups"

KJINTF,

WOW...so what's your solar configuration. I'd love to have this capability (run months with no generator).

THanks

[mena661]

MiRV, what size bank do you have?

[MiRV]

RJsfishin wrote:
It doesn't.....or shouldn't matter what others have, because you probably wouldn't like it anyway. You have to fit your system to what you like.
I have 220 AHs, only because it fits my liking to charging approx. 2 hrs per day. I could possibly do it on one battery, but would push the limits on the 50% discharge rule.
I could have 4 batteries, and charge 4 hrs every other day, but I don't like the weight and maintaining and burning up 2 more batts every 6-10 yrs. If I wanted to bank some solar for those cloudy rainy days, I should have 6 or 8 batteries, but I don't like the trade off. Each to their own.

RJsfishin,

It DOES matter, since I'm trying to "right size" my rig for better boon docking opportunities that allows me the MOST time on the batteries with running the generator the LEAST. From the inputs already provided, I is proving my hypothesis that more AHs with limited use means less generator run time and that solar will only help even more.

I believe in learning from others, vs learning from the school of hard knocks. Better to learn from those who have gone before me...and I like the input from those more experienced with the boon docking and battery usage.

Thanks

[MiRV]

Almot wrote:
MiRV, are you close to drawing any useful conclusions yet? 🙂

The number of daily AH varies from ~0 to 500 AH.
The size of battery bank - from 80 to 800.
The number of days for battery - from ~0 to unlimited.
Enough said...

Almot,

Not yet. I'm finding it very interesting on the various sizes of AH, battery banks and charge methods. It appears that those with Solar are doing much better, Also, the "usage" is very interesting. From my own experiences, I'm not getting quite the same results from my battery bank. However, they are a little older...

I was asking this to help me see if there was ONE good way for implementing my charge and battery changes.

Thanks

[MiRV]

Almot wrote:

MiRV wrote:
it's important to have the House Batteries "right sized" for a successful Boondock.

Please post the following:

1 - Projected Amp Hours for 24 hours (amp hour worksheet):
2 - Current # of batteries:
3 - Current # of Amp Hours [AH] your batteries have (or Reserve Capacity [RC]):
4 - Battery Voltage (6 or 12):
5 - How long do your batteries last based on #1:
6 - How long each day do you run your generator to get "recharged":
7 - Provide any other info like if you use solar and how you recharge, etc.:

I would say it is even more important to have energy needs "right sized" for your charging method.

1) 50 or less
2) 15 or less (correction - you got me confused with "current #". Current from the bank is 15A, number of batts is 3. Why the number of batts is even important?)
3) 300 AH total @12V
4) 12
5) Like how long until they drop below 50%? In location where it usually is - forever.
6) No generator run, no need.
7) Solar. Don't know what you mean by "how you recharge". It's just getting recharged by 11 am without my help. Or by 2pm next day if it was overcast.

Almot,

Regarding your solar, what;s your setup? 400amps, 4 solar panels and type of panels, etc.

[Almot]

MEXICOWANDERER wrote:
Señor Almot.

With the greatest and most humble respect, I don't believe the OP's question is a troll. But he needs to understand point blank that trying to estimate future power usage is a waste of time. Trial and error is the only way to get the job done right. Telling my customers this point raised a lot of eyebrows. "But, but, you're an engineer!" My stock answer was (and is) "But, you're not an engine".

Señor Mex;
This isn't the case of machine. Humans have (or should have) the ability know their needs and set goals. Asking about the "right size" of battery bank for boondocking without further clarification is like asking about the "right size" of shoes. Such a clarification was asked for, but never provided by the OP.

[red31]

asking and sharing with others about their trial and error experiences shouldn't be stifled. The one that stifles should be.

[MEXICOWANDERER]

Señor Almot.

With the greatest and most humble respect, I don't believe the OP's question is a troll. But he needs to understand point blank that trying to estimate future power usage is a waste of time. Trial and error is the only way to get the job done right. Telling my customers this point raised a lot of eyebrows. "But, but, you're an engineer!" My stock answer was (and is) "But, you're not an engine".

[Almot]

trolley-trolli-troll...

[mena661]

RJ and Mex are exactly right although in my case knowing what other people had AND how they used it helped me decide my setup. When I came here I had a totally different plan and BOTH of those points of info helped immensely.

[MEXICOWANDERER]

IMPOSSIBLE to guesstimate

Try using all the battery you can stuff into your rig.

Too little capacity? Add more.

Too much capacity? Don't worry you'll find more ways to chew up the excess than you can shake a stick at.

[JiminDenver]

At one time I knew how many amp hours we used in a day, then we got solar and I stopped worrying about it. It's never the same trip to trip. Last trip it was cold and the furnace used the most. This trip we added a big inverter to run a microwave, hairdryer, coffee maker and the TV/satellite. So I have no idea.

We have two batteries. 95 ah for the TT and 250 ah for the inverter.

We have 490 watts of solar and left the generator home. I have it set up so we can combine both panels on one bank or split them up. With both panels on the Inverter bank we get little voltage drop and recovery is in minutes. A single panel will hold the voltage up for a 6 minute run of the microwave or a pot of coffee and recovery is around a hour.

[RoyB]

It does take planning to be successful. We get by just fine with our 255AHs battery bank setup and run just about everything we would normally run at a electric camp site with the exception of the high wattage items like the air Conditioner or microwave.

Our concept of run all the things we want to have using an INVERTER for the 120VAC items and Direct connected to the batteries for the 12DC items. All was planned out to drop my batteries down to around 12.0VDC (approximately 50% charge state) by 8AM the next morning.

Then when allowed to run our gnerator i would re-charge my battery back to its 90% charge state by connecting my trailer directly to my 2KW Honda generator using a RV30A-15A adapter(WALMART). Using smart mode charging techniques this takes around three hours of generator run time.

We can do a good 12-14 cycles of the 50% to 90% charge states on our 255AH battery bank but after that we will need to do a full 100% charge state re-charge which of course takes over twelve hours to do. The camps never let us run our generator that long here on the East side of the US so this is usually when we head for the house.

Been doing this method of camping off the power grids since 2009 and can say we are pretty much successful now doing it. It is all second nature now.

Now I am just considering adding some solar panels to my off-road POPUP to cut back some on running my generator. Our high use of the 255AH battery bank would last alot longer if we only used flashlights and candles when camping but we are lit up like we didn't have good sense and in the evening enjoy our HDTV TV and home entertainment items just like we do at regular electric camp sites... My number one rule is to always start my evening run from the batteries with at least a 90% charge state otherwise i will not be able to make it to 8AM the next morning with a 50% charge state system. Getting to that point every evening could be a chore running solar panels if you consider a single 120WATT Solar panel will only produce 14.4VDC BOOST charging DC voltages at 5-6 amps for a few hours during high sun. We all know it takes 14.4VDC at around 20AMPS of DC current to re-charge each depleted 12VDC battery in your battery bank if you want it to be done in a three hour time frame.

It does take planning for sure to be able to do this...

We use around 300WATTS from our 255AH battery bank each day/night it seems that has to be re-charged back to their 90% charge state before dark. This relates to drawing around 20AMP DC current from 8PM to 11PM in addition to drawing around 1-2 amps for the whole day/night period for the parasitic drain items.

My success is to keep a watchful eye on the DC Monitor panel when camping off the power grids.

Just my experiences here
Roy Ken