What do you think is the ultimate battery setup?

[bobblangley]

It's time to upgrade the single low grade battery currently in my 1994 Bigfoot 17 so I'd appreciate input from others who have made what they consider to be significant upgrades.

I don't plan on hooking up to shore power very often and will probably travel 200 miles or so every other day or two or three. All lights are converted to LED except for one halogen reading lamp which will be the main light source. Often the heater fan or a roof vent fan will be operated for approx 60 minutes/day.

I figure that I will definitely want deep cycle marine batteries but am undecided about:

--whether to use 1 battery or two
--if two, whether to wire two 12-v in parall or 2 6-v in series
--the merits of AGM batteries

If anyone has modified the front area of an older Bigfoot trailer to accommodate dual batteries, I would love to hear how well they fit, exactly where you put them, if the cover still fit as it should, etc.

I can have a generator available if need be but would also appreciate input from those who use non-permanently-mounted solar panels.

[Alex Adams]

Originally Posted by bobblangley

I can have a generator available if need be but would also appreciate input from those who use non-permanently-mounted solar panels.

I use 2 100 watt flexible panels clamped to a clothes drying rack I bought on Amazon:



If it gets windy, I use stakes and bungee cords to prevent tipping. Real easy to move around and the panels can go from the angle you see to horizontal.

[WizWid]

Originally Posted by bobblangley

It's time to upgrade the single low grade battery currently in my 1994 Bigfoot 17 so I'd appreciate input from others who have made what they consider to be significant upgrades.


If anyone has modified the front area of an older Bigfoot trailer to accommodate dual batteries, I would love to hear how well they fit, exactly where you put them, if the cover still fit as it should, etc.

Robert,

My 2002 17CB came with 2 12v group 24 batteries. There is room under the cover but I assume the previous owner lengthened the battery "tray". We use a 100W portable solar panel when off grid.

Jim

[Fred762]

WE used the 120 free-standing solar panels we got w our Casita Indy 17 last Spring on a 3 week 'boondocking outing' in VT last August. WE were at a VT state park where they have no elec OR water hookups (statewide ). We had our gen w us, but they also limit gen hours so we used the solar daily.
At first we hated the panels not being mounted atop the roof, but after one day, we decided it was indeed better to be able to MOVE the panels to take advantage of sunlight direction. We have the single 12V battery w. the AGM battery option and all LED lighting.
No problemo for the whole time except for not having AC during the hottest part of the days..VT had a hot summer this year..much warmer than we have experienced while vising there in the past. That said we really did not need the AC much as we do not sit in the TT much during the nice days.
Note, we do keep the panel array chained to the frame of the TT..just to discourage theft of the solar rig while we were away.

[patrick crawford]

i recently upgraded the battery situation in my casita 16'er to a pair of agm 6v golf cart batteries (220 amp hours). they live under the permanent bed. primary charging is thru solar panels. 100w mounted on the roof of the trailer wired so it charges the batteries while underway (assuming weather is cooperating) and one on the roof of the truck's topper. i've 2 20' sets of cables so if i'm in the shade i'll at least have a chance to put the truck in the sun. to keep up with what's going on i've installed a victron battery condition meter. i'm currently (pun intended) really testing this setup on a winter trip to the southwest us. so far the results are great...i've not seen the batteries dip below 12.3v. the real test will be desert boondocking coming up soon. the failsafe element is provided by a honda 2000i mounted over the propane tanks and hardwired to the onboard converter. i can even run that little honda while underway if for some reason it was necessary. it was kinda expensive to accomplish all this but i did it in stages so the hit to my wallet was at least spread out over time (i try not to remain aware of what this trailer stuff costs and spend only when i have the $ to spare). i'm retired, travel solo and this obsession with wandering is, for me, unavoidable, so it costs what it costs. at my age (mid 70's) i've no idea how long i can maintain this roaming addiction and am determined to make the voyage as comfortable and worry free as i can.

p@

[Franswa]

not sure there is an "ultimate" batt. set-up...doesn't exist really...


for anybody the ultimate is what is going to be lightest, cheapest AND supply you with the power you will usually consume in a "cycle" (24hr period)....you could add 1000lbs of batteries and NEVER want for power...but who wants to do that????


here's one example (mine)...look at many... that is what a site like this is for...then "get to work"....LOL


My starting point was a 97 BF17CB...the PO had installed (badly) 2 golf cart batteries under the left dinette seat, forward...that needed a rework and as I think CB models are all overweight on the left side anyway...I located the batteries on the RIGHT side, forward (an area that is sort of hard to access/use anyway)



Box material is 3/4" pine laminated shelving material (screwed to the floor) with 1/4" ply for the lid.
I have 70W of solar on the roof and 40W "deployable" stored in the trailer. In normal summer use (mine) my batteries never drop below 12.4V
The forward area in the propane locker (where the original single battery from the factory used to be) now houses all my landing gear/blocks etc


just another way to "skin a cat"...good luck

[M Scott]

How do you connect the 100 watt flexible solar panels to the trailer? Would appreciate a step-by-step process for this greenhorn. Thanks.

[Mike_L]

The ultimate battery solution is really the one that works best for the particular user. I've played with this for over 40 years, trying various arrangements to get to what works for me in my current situation. I boondock for 2 -3 months a year in the back country, no hookups and without moving my trailer much so no option to charge batteries with my tug.
I have a 2500 watt generator which I have used once in 10 years during a snow storm but no more winter camping for me so the generator lives in my garage. It is certainly a reliable power source but the cost of fuel can be prohibitive for long term use.
I have found solar power to be a much more viable option. I have 150 watts capacity which is about twice what I need but it also means I don't have to worry about orienting the panels as the sun moves. At the end of 3 months boondocking last season I put my batteries on charge and my smart charger said they were full. I have brackets on the roof of my TT that I slide my solar panels into when needed and remove them easily if I leave my TT unattended.

I use only LED lights. I use the furnace and water pump as necessary.

I have 2 group 27 Deep cycle batteries. Marine batteries are a cross between starting batteries and deep cycle batteries. They will work in both applications but are not the best choice for either. Deep cycle batteries are the best for RV use.
I use two 12 volt batteries wired independently from each other. I originally had them wired in parallel arrangement until the breakaway switch on my TT malfunctioned and applied the brakes over night, leaving me with two dead batteries the following morning. Wiring the batteries separately means the worst case situation is now one dead battery. Total capacity remains the same.
It's a popular misconception that 6 volt batteries give you more amp/hours of power. While these batteries usually have in excess of 200 amp/hours capacity, they have to be connected in series. Two 6 volt batteries each with 200 amp/hours capacity connected in series produce 12 volts with 200 amp/hours total. Two 12 volt batteries with 100 amp hours each, connected in parallel or separately will produce the same amp/hours.
Flooded lead acid batteries are dependable, easy to charge and cheapest of all options to replace. They may occasionally need water, especially if cycled however I've found that solar keeps them constantly charged so cycling is minimal which means they need less water and last longer. I get about 7 years out of them.

The advantage of AGM is that they don't off gas (flammable) hydrogen like flooded lead acid so they can be stored inside. On the down side they are heavier and more expensive.
Minimize your power consumption and calculate your maximum likely usage. Double this number to determine your battery capacity and solar power needs. A small portable generator now becomes an option for use as necessary.

[Mike_L]

Solar panels should come with a charge controller, necessary components and instructions for connection.

[CarlD]

Robert, You might want to take a look a Lithium batteries (Lithium Iron Phosphate LFP). I purchased one for my Lil Hauley build. It is a Battleborn 100 ahr which can be fully discharge with no ill affects (equivalent to 2 100 ahr lead acid batteries because they should only be discharged to 50%). LFP only takes up 1/2 the space compared to lead acid). They are expensive $950 but but if you consider the total cost of ownership they are a bargain. They do not vent and can be mounted inside the trailer. They have a simple charge requirement, the internal BMS makes it so. Can be recharged at .5C for over 3000 cycles, both values much higher than lead acid. It weighs 27 pounds (way less than equivalent lead acid). No problems interfacing with solar. One caveat is interfacing with the tow vehicle, (you need an isolation circuit, (DC-DC converter (Victron makes them.)



Depending on your budget you may want to consider one. Some folks on this forum have installed them with excellent results.

[Franswa]

I know you can't believe everything you read on the internet....but....
I thought this one was put to rest a while back...if one can get by with one 12V battery, great!....but after that (???)



Battery School | Batteriesnorthwest.com | Advantages and Disadvantages of using two 12 volt batteries connected in parallel or two 6 volt batteries connected in series.


The true cost per cycle delivered favors 2 six volt by a WIDE margin...that is what suppliers of solar systems for off-grid customers have to say about it anyway




I don't know if you are familiar with "Handy Bob".....(google it)
This is his take on it:

[redbarron55]

Originally Posted by Mike_L

Solar panels should come with a charge controller, necessary components and instructions for connection.

They should, but they don't

[Franswa]

after a few years of "playing" with solar I got a box full of the "package" controllers....LOL...I just bought two 50W panels on a good sale...and both of them had one of those controllers...(they are not the best, that's for sure)

[WALT2013]

We installed a second 12 volt AGM battery in our 2004 Bigfoot 17 CB; it fit perfectly under the left dinette bench seat, where the hot water tank and electric panel and converter are located; it is in a covered, plastic battery box. So we have 2 - 12 volt deep-cycle AGM batteries connected in parallel and a total of 225 watts of solar panels, 145 mounted permanently on the roof and an 80 watt Zamp portable. We can go an indefinite amount of time without shore power or generator, unless we encounter cloudy days. Importantly, we use very little electricity while boondocking, i.e. light computer use, no TV, LED lights, bottled water instead of using the pump, wintering in warm areas that require no furnace use, etc. Make sure your portable solar panel is facing where the sun will rise the night before in order to get as much sun as possible. Make sure your battery charger amperage is sufficient for 2 batteries. We usually have plenty of amp hours left at the end of most days, for those just in case moments. I also wouldn't go without our 2KW Honda generator, either. Have fun!

[Mike_L]

How well do the AGM batteries perform? Are they comparable to the wet cell batteries?

[WALT2013]

I'm no battery expert; I wanted the no maintenance aspect of AGM batteries; they also are supposed to charge faster and hold more charging cycles; they are heavier, and I forgot to mention before that adding the second battery subtracts from your overall load capacity; our Bigfoot weighs about 2700 pounds empty and has a 3500 pound gross weight rating; I don't remember exactly but I think the 2 AGMs are around 50-60 pounds each, at about 110-120 pounds total vs one lead acid at about 50 pounds; so that's maybe another 60-70 pounds overall added to my dry weight. And, not that we take our trailer through rough terrain, but AGMs can take more physical abuse that wet cells. They were expensive, but I did the installation myself, and we just feel more secure.

[minke]

Originally Posted by CarlD

... One caveat is interfacing with the tow vehicle, (you need an isolation circuit, (DC-DC converter (Victron makes them.)
...

I'd like to understand that. Could you elaborate please?


thanx,,,

[Jon Vermilye]

Originally Posted by Mike_L

Solar panels should come with a charge controller, necessary components and instructions for connection.

They do if you purchase a kit from companies such as GoPower or Zamp, but the kits generally cost far more than purchasing the individual parts and putting them together yourself. Most portable systems come with a panel mounted controller. Not the best location, but hundreds use them with few problems.

[Alben]

The OP asks what is the ultimate, not necessarily the most cost effective battery setup. If money was no object, I would choose LiFePO4 batteries such as the 100Ah Battle Born batteries which only weigh 31 lbs each. A pair of GC2 deep cycle lead acid batteries weighing a total of 120 lbs have 215 Ah, of which only 105Ah is useable. So with LiFePO4 you are getting the same Ah for 1/4th the weight.

However there are some drawbacks to LiFePO4, cost being the biggest. LiFePO4 cannot be charged below freezing, although they can be discharged. Also needs a converter optimized for the charge characteristics for LiFePO4.

[Harlan C]

Originally Posted by Mike_L

The ultimate battery solution is really the one that works best for the particular user. I've played with this for over 40 years, trying various arrangements to get to what works for me in my current situation. I boondock for 2 -3 months a year in the back country, no hookups and without moving my trailer much so no option to charge batteries with my tug.
I have a 2500 watt generator which I have used once in 10 years during a snow storm but no more winter camping for me so the generator lives in my garage. It is certainly a reliable power source but the cost of fuel can be prohibitive for long term use.
I have found solar power to be a much more viable option. I have 150 watts capacity which is about twice what I need but it also means I don't have to worry about orienting the panels as the sun moves. At the end of 3 months boondocking last season I put my batteries on charge and my smart charger said they were full. I have brackets on the roof of my TT that I slide my solar panels into when needed and remove them easily if I leave my TT unattended.

I use only LED lights. I use the furnace and water pump as necessary.

I have 2 group 27 Deep cycle batteries. Marine batteries are a cross between starting batteries and deep cycle batteries. They will work in both applications but are not the best choice for either. Deep cycle batteries are the best for RV use.
I use two 12 volt batteries wired independently from each other. I originally had them wired in parallel arrangement until the breakaway switch on my TT malfunctioned and applied the brakes over night, leaving me with two dead batteries the following morning. Wiring the batteries separately means the worst case situation is now one dead battery. Total capacity remains the same.
It's a popular misconception that 6 volt batteries give you more amp/hours of power. While these batteries usually have in excess of 200 amp/hours capacity, they have to be connected in series. Two 6 volt batteries each with 200 amp/hours capacity connected in series produce 12 volts with 200 amp/hours total. Two 12 volt batteries with 100 amp hours each, connected in parallel or separately will produce the same amp/hours.
Flooded lead acid batteries are dependable, easy to charge and cheapest of all options to replace. They may occasionally need water, especially if cycled however I've found that solar keeps them constantly charged so cycling is minimal which means they need less water and last longer. I get about 7 years out of them.

The advantage of AGM is that they don't off gas (flammable) hydrogen like flooded lead acid so they can be stored inside. On the down side they are heavier and more expensive.
Minimize your power consumption and calculate your maximum likely usage. Double this number to determine your battery capacity and solar power needs. A small portable generator now becomes an option for use as necessary.

Mike L...thanks for the informative and clearly written post!! (I printed it for reference)