Large battery bank storage location question

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Large battery bank storage location question

June 18, 2019, 04:42:21 am

Hello all,

I'm on the one to one and a half year waiting list for a new 27ft rear bath LD. I want to install a huge solar system. Ill build a light weight metal/aluminum roof rack that I can fill the entire roof with solar panels (around 2000w) that are 8in - 12in high to clear the fantastic fans. Next I want to install 6-8 battle born lithium 12v 100amp 1200watt hr batterys (wired @ 24v). The batteries will need to be inside to protect against freezing temps and extream heat. Lithium batterys dont need to be vented, so I'm all good there. I'm estimating the solar system will weigh 1000lbs out of the 2900lbs available. The reason I need this is I have working dogs and need the ability to run a 5000btu (420w) 120v window air conditioner for up to 8 hours when they are in there by themselves, and we have no shore power.

Now I just need to figure out where to put all the batterys. They all need to be close together for wiring them together, so the two stock house batterys located outside down low will not be part of the large battery bank I dont think.

My question is are the dinnete seats hollow inside for battery storage? How about under the two couches? If those spots wont work, I'm thinking my only other choice would be to remove one couch and put them there. Makes it hard to plan it out when i dont have a LD yet, hehe. There's a used one for sale quite far from me, but I think it might be worth a trip to get measurements.

Thanks for reading,
Gabe

Re: Large battery bank storage location question

Reply #1 – June 18, 2019, 12:16:43 pm

You can add two, maybe three batteries under the forward dinette seat. Insulate the battery box's exterior door and cut ventilation holes into the interior and use it for two more.
Having a framework sitting so high off the roof is going to be a tree magnet, if one good size branch gets under the panels, they could be badly damaged or torn off. Seen it happen a few times.
On a hot summer day, such a small A/C is not going to keep the interior very cool, I would guess a reduction of only 10-12 degrees.
In the best of situations, the much larger Factory rooftop A/C produces a maximum of 25-30 degrees of temperature drop.
Where is the inverter going to be located?
So much added weight is going to severely reduce the CCC, you may think there is plenty left and will probably be surprised about how easy it will be to overload it. It isn't going to cheap either. You will also need to consider how the weight distribution, adding so many batteries to one side could cause all sorts of issues.
Be careful not to damage or change the interior very much, you may end up with a hard to sell LD in the future.

You may want to rethink how this is going to work, I suggest a return visit to the Mothership for through examination of the RB and determine then if this is going to be possible without unseen consequences.

Larry

Re: Large battery bank storage location question

Reply #2 – June 18, 2019, 12:59:14 pm

I would add a reasonably sized solar system and battery bank, always good to have.
As for the dogs comfort, I'd budget some generator time into your life.
8 hours of generator time isn't great, but doable on occasion.

Re: Large battery bank storage location question

Reply #3 – June 18, 2019, 02:06:42 pm

At a consumption rate of about 1/2 gallon of fuel per hour of run time, using your generator and the rooftop AC unit sounds rather economical to me. The cost of those lithium batteries would buy a LOT of gas. That being said...

I have a MB with 5 panels on the roof. I can't fit any more. Your track system might get you quite a bit more. If the spacing works out, per Larry's comment about tree limbs, consider setting up the track and spacing to leave gaps for the fans, and placing the panels and rails much closer to the roof line. If you know what you will need to mount the racks, discuss with the factory having frame members added for your track attachment points during the build. As you plan to make the track system yourself, perhaps you can get the stock support structure locations marked by the factory, and you make your track mounts to fit the structure.

Inside, I have 6 AGM batteries and a whole house inverter mounted under my forward dinette seat. On the MB floor plan, the forward seat is the longer seat, and the seat bottom lifts up for access underneath. My external battery compartment is now used for storage, assuring that all my batteries are in the same temperature conditions inside the rig. The larger dinette seat measures about 40" x 20" x 14" high. The other dinette seat and the couches are accessible from the sides but not from the top, unless you unscrew the plywood tops.

How did you plan to mount the window AC unit?

In line with Larry's comment about cooling ability, if you close all your shades, that reduces heating from sun load significantly, at least in mine. I have spent quite a few summers in the Teton area without the need to run my AC at all. In hot weather, I close the shades, partly open the windows on the shaded side, and run one of the fans to exhaust the hot air. I have seen it 95 outside, and inside it is in the mid-80's. Naturally, if you are in a hotter climate that would not work.

Ken F in WY

Re: Large battery bank storage location question

Reply #4 – June 18, 2019, 03:47:52 pm

"Now I just need to figure out where to put all the batterys."

I am going to be very blunt, possibly to the point of rudeness!

I find your plans and aspirations totally ludicrous! For your sake and the sake of your wallet I recommend that you start from scratch and plan a reasonable Solar System. You need professional help, that such as AM Solar out of Springfield, OR. You cannot go wrong with them.

RV Solar Panel Kits & Camping Solar Panels, Batteries & Chargers: AM

Re: Large battery bank storage location question

Reply #5 – June 18, 2019, 04:41:16 pm

What about using a mini split system air conditioner (a system where part of the air conditioner is split into two parts with half outside and the other half inside - a popular product in Europe that is used less here in the U.S.),

This uses less electricity and there are some DC12 ones out there. They do need wall space to mount but that could be put inside (or instead of) an upper cabinet

This has been discussed with people who want to run air conditioner off dc12. The technomadic folks (RV bloggers) met some people that had done this install and they considered it but decided they didn't have/want to give up the wall space.

The ideas about covering windows are a must as well as closing off the cab area with a blanket/other insulation when parked. If you cool off one area the pets will move to that area and sit in the cool breeze created by the air conditione, so every spot inside doesn't need to be cooled down. The generator can be run while driving to allow using the roof top air conditioning during drives.

When I looked at the last the indoor portion of the split system was about 3' long (and about 6-8" high and deep). Now there seems to be more square inside parts, Here are some links - I am not recommending any of these I just quickly pulled up some links to give you an idea of what to look for.

120v but explains the setuo well

http://m.youtube.com/watch?v=eFkLrGx6la8

http://m.youtube.com/watch?v=GvdIe0AkXV8

The (Almost) Fantasy of Solar-Powered RV Air Conditioning | Technomadia

Ductless Mini Split Systems - eComfort

DC 9300 12v 24v 48V 400V AC DC split air conditioner

Jane

Sent from Yahoo Mail for iPhone

Re: Large battery bank storage location question

Reply #6 – June 19, 2019, 12:52:38 am

Quote from: Lazy Bones - June 18, 2019, 03:47:52 pm

I find your plans and aspirations totally ludicrous!

That is one of the starting points that the aircraft designer Burt Rutan uses to get new ideas.

New ideas may be ludicrous but as you try to develop them you come up with solutions that work.

In this case the original idea probably is ridiculous. But it is a starting point that will end up with ideas that work.

You may be able to put five Battleborn batteries in the front dinette seat of an RB. I have two there with three battery chargers, a 1500 watt inverter and a transfer switch.

I started with the ludicrous idea of discharging the FLA (flooded lead acid) batteries to 20% through a voltage stabilizer to get enough power to run sat TV and a furnace in freezing conditions. I ended up with a hybrid system of FLA and lithium that provides all the power I need and requires generator runs of less than 30 minutes a day in a stationary RV. At present I am at 10680ft with outside temp predicted in the low 30s, furnace running, TV running and I have plenty of power for the night.

I won't even begin to run A/C by battery. Figure out ways to run it by generator with a Genturi.

You will solve it but I bet your original concept will change radically

Re: Large battery bank storage location question

Reply #7 – June 19, 2019, 07:19:27 pm

Thank you all for your input!

Good to hear the 4kw generator only uses 1/2 gallon per hour.

This project is definitely in the begining baby stages, and I have no idea how this will turn out in the end. Like most of you said running the generator would be much more cost effective, less weight, and much much simpler. I may just go that route. At a minimum I'd like to run a tv and a couple laptop computers with a solar system, and that would simply things......compared to trying to run a small ac unit.

In my crazy head I want to buy this off grid kit Solar Off-Grid Kit OutBack 24V 003 | 1830 Watts PV, 3500 Watts Inverter |... it comes with 6 solar panels and then add 6-8 batterys. All the components are mounted to a board that measure 33.5in tall x 19.25in wide x 13in thick. I was thinking it could go along the wall under the dinnete table, but I think it's a couple inches to tall. I dont think there is any room for that board anywhere unless I remove a couch. I dont think I want to remove a couch so in all reality I'm back to the drawing board. I'm now thinking of using the generator for ac, then put all the batterys and components i can fit under the dinnete seat for laptops, tv, lights, etc. I'd need to put some powerful computer fans to cool the closed dinnete seat as the components will get hot. Lots to think about! I've been on several rv diy solar system Facebook groups for the last 4 months and have gotten a lot of ideas of what possiable or not. Of course I always like to push the limits, and will end up somewhere in the middle of my expectations.

Good to know 5-6 batterys will fit in the front dinnete seat, along with solar components.

Kenneth Fears: great idea about having the factory install or mark mount point areas for the track system on the roof.

Hbn7hj: cool idea about the genturi, never heard of such a thing.

Thank you all again for the feed back

Gabe

Re: Large battery bank storage location question

Reply #8 – June 19, 2019, 07:44:17 pm

Maybe you should consider using a few of these...

Re: Large battery bank storage location question

Reply #9 – June 19, 2019, 07:54:29 pm

Quote from: ChezzeBait - June 19, 2019, 07:19:27 pm

Thank you all for your input!

Good to hear the 4kw generator only uses 1/2 gallon per hour.
At a minimum I'd like to run a tv and a couple laptop computers with a solar system, and that would simply things......compared to trying to run a small ac unit.

In my crazy head I want to buy this off grid kit Solar Off-Grid Kit OutBack 24V 003 | 1830 Watts PV, 3500 Watts Inverter |... it comes with 6 solar panels and then add 6-8 batterys. what possiable or not.

Re: Large battery bank storage location question

Reply #10 – June 20, 2019, 08:49:03 am

Renogade242: the used tesla model s batterys where my first choice intell I learned they operate at a lower voltage and the inverter will kick off at 25% SOC. So you get 63% usable capacity. Out of the 5.2kwh total -------> 3.3kwh are usable. Still more cost effective than battleborns but then you have to factor battery chemistry safety and warrenty. Tesla batterys are great, just not as great as I first thought.

https://youtu.be/1EX4rNvVaG8

Gabe

Re: Large battery bank storage location question

Reply #11 – June 20, 2019, 09:27:42 am

I understand thinking 'new' and 'outrageous'. I have no issue with that. It's well within my wheelhouse but...... you can't change the law of physics. Gravity will always win the battle. Oh you may think you have outsmarted her but she will always have the last word. I'm using the female because I believe females are smarter than us males.

My concern is the stacking panels and whatnot on the roof of the LD. Two issues -- one -- the LD is basically a wood structure. I'm guessing the weight bearing pillars are not overbuilt for overall carry weight issues. Off my head I don't know the weight bearing of a 2x4 without going to some engineering book.
Issue two -- as you put more stuff on the roof you move the center of gravity up. The more weight you put up there the more movement up. This changes the motion character of the LD. I.E. it makes it more unstable and unpredictable when in motion. In a nutshell rollover becomes more of a problem.

Re: Large battery bank storage location question

Reply #12 – June 20, 2019, 09:43:36 am

Cooldog: like this? Hehe

Re: Large battery bank storage location question

Reply #13 – June 20, 2019, 01:28:29 pm

Dear ChezzeBait,

In your original assessment you mentioned that you would be leaving your dogs unattended for up to 8 hours. I suggest you install an accurate temperature monitoring system that will warn you immediately so that you can have someone with a key come and rescue your unattended dogs. Just as in cars, the temperature in an RV rises rapidly when closed up and your prized pets cannot tolerate extreme heat. You would likely feel horrible to return to your RV and find them deceased. Breakers do trip, generators do quit on occasion, AC's can fail! When they do, you need to have a failsafe plan in place to rescue your dogs!

Best,

Gary

Re: Large battery bank storage location question

Reply #14 – June 20, 2019, 04:26:59 pm

Quote from: jakester1201 - June 20, 2019, 01:28:29 pm

Dear ChezzeBait,

In your original assessment you mentioned that you would be leaving your dogs unattended for up to 8 hours. I suggest you install an accurate temperature monitoring system that will warn you immediately so that you can have someone with a key come and rescue your unattended dogs. Just as in cars, the temperature in an RV rises rapidly when closed up and your prized pets cannot tolerate extreme heat. You would likely feel horrible to return to your RV and find them deceased. Breakers do trip, generators do quit on occasion, AC's can fail! When they do, you need to have a failsafe plan in place to rescue your dogs!

Best,

Gary

Yes I would have temp monitoring system with cell phone notifications. I'd for sure hook up a home security system that I can view from a far. Motorhome would have a 4g router that stays inside for internet connection. 8 hours away from the dogs would be very rare, more like a hour or two. I'm in the pacific northwest so it's only hot a few months out of the year also.

Gabe

Re: Large battery bank storage location question

Reply #15 – June 20, 2019, 04:38:19 pm

Quote from: jakester1201 - June 20, 2019, 01:28:29 pm

Dear ChezzeBait,

In your original assessment you mentioned that you would be leaving your dogs unattended for up to 8 hours. I suggest you install an accurate temperature monitoring system that will warn you immediately so that you can have someone with a key come and rescue your unattended dogs. Just as in cars, the temperature in an RV rises rapidly when closed up and your prized pets cannot tolerate extreme heat. You would likely feel horrible to return to your RV and find them deceased. Breakers do trip, generators do quit on occasion, AC's can fail! When they do, you need to have a failsafe plan in place to rescue your dogs!

Best,

Gary

Oh yes, failure IS a possibility. On our first long trip in our new TK, we were parked, plugged in, at the then Caesar’s RV park in Vegas, on our way to Utah. We left our cat inside for the day with the AC on and set to “automatic “ operation. Came back to find the AC blowing hot air and the cat nearly dead on the floor. Long story, but the start capacitor had failed as the automatic cycling allowed the unit to ice up, making it impossible to start. The repair place (two months later— we had to finish our 7 week trip through the Southwest in summer without AC) told us to never run the unit on auto or low fan speed. Always use medium or high. They’d seen a number of such failures. So, leaving animals alone in the rig in high heat can be a disaster. Something very well might go wrong. — Jon

Re: Large battery bank storage location question

Reply #16 – June 20, 2019, 04:59:28 pm

Gary’s comments are on point and critical to any decisions made on “power sources” for your future RV. That said, leaving dogs or any pets unattended in any vehicle for 8 hours in any conditions is a bad idea; there are too many things that could go wrong.

Re: Large battery bank storage location question

Reply #17 – June 20, 2019, 07:04:42 pm

Jon, I didn't know that about the A/Cs. Thanks for passing that along. How awful to go thru that experience you had.

Gabe, we use a Sensorpush sensor with their gateway for internet access to keep an eye on temps in our rig when we are not there.
If we lose power to the gateway and/or internet hotspot we get a notification that the gateway is down which lets us know the entire LD might have lost power (so not air conditioner).
Hotspot or Wifi is required to give the internet access.
We added sensors for the fridge/freezer which helps catch when we left the fridge/freezer door open a crack by accident or the propane was taken out and we forgot to turn it onto electric while we were gone several hours.
It is not perfect but it works well and gives us more piece of mind.

Jane

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Re: Large battery bank storage location question

Reply #18 – June 20, 2019, 08:05:15 pm

Quote from: jakester1201 - June 20, 2019, 01:28:29 pm

Just as in cars, the temperature in an RV rises rapidly when closed up.

This is a common misconception that often leads well intentioned people to worry about pets in RVs. A car left in the sun on a 90 degree day will 120 degrees or more, but that just doesn't happen in a typical RV.

If you screen the drivers window, our Mid-Bath unit will only get a few degrees higher than the temperature outside. With a vent open or a fan running, being inside feels just like sitting outside in the shade.

Our RVs have big white roofs and heavily tinted side windows that are vertical instead of situated at an angle. Even the windshield, which isn't tinted, sits under an overhang (in the shade).

I probably wouldn't leave my dog in the RV on a 90+ degree day without the generator and A/C running, but he's not going to cook if I did. He'll just lie on the non-carpeted part of the floor with his legs stretched out and sleep, getting up every so often to drink some water. Just like dogs have done for years before A/C became common in the south.

Rich
'03 MB in NC

Re: Large battery bank storage location question

Reply #19 – June 20, 2019, 10:37:29 pm

Rich, I think the difference is if the car or RV is locked up (all windows shut and no ventilation) or has some shading and fans going.

Even in Phoeniz Az, with our older RV that doesn't have as good of insulation, with fans on we can be ok up until about 90 degrees outside. Warm but ok (abiut 80-85 inside). Cats are searching out cooler spots at that point. Pets and people could tolerate a little higher heat but would not be comfortable (panting and sweating).

It is the same in a car with windows rolled all the way down especially if there is a breeze blowing thru the car.
However without fans and ventilation it gets worse quickly. Covering up windows makes it better.

Wr also have what I call the blaze factor. When the sun is so strong your skin feels liken you are inches away from a stove burner. Those days the vehicles heat up quicker and there is about a 10 degree difference between standing in the shade or standing directly in the sun. I have not seen that blaze factor in any of the other 3 states I have lived in.

I am like you - I am ok for short trips away with ventilation if is 90 degrees or with some windows covered and ventilation. Especially if the day is starting to cool down. But as people say things can go wrong and I wouldn't it want that ventilation to quit.
Above 90 or above 80 with the blaze factor and I am more cautious.

When we start to get close to 100 degrees the ads start playing all the time saying don't leave pets or young children in the cars unattended. There are still some incidences each year but passer bys get involved and there are many less incidences than there was many years ago.

Jane

Sent from Yahoo Mail for iPhone

Re: Large battery bank storage location question

Reply #20 – June 21, 2019, 09:19:29 am

Quote from: ChezzeBait - June 18, 2019, 04:42:21 am

Hello all,

I'm on the one to one and a half year waiting list for a new 27ft rear bath LD. I want to install a huge solar system. Ill build a light weight metal/aluminum roof rack that I can fill the entire roof with solar panels (around 2000w) that are 8in - 12in high to clear the fantastic fans. Next I want to install 6-8 battle born lithium 12v 100amp 1200watt hr batterys (wired @ 24v). The batteries will need to be inside to protect against freezing temps and extream heat. Lithium batterys dont need to be vented, so I'm all good there. I'm estimating the solar system will weigh 1000lbs out of the 2900lbs available. The reason I need this is I have working dogs and need the ability to run a 5000btu (420w) 120v window air conditioner for up to 8 hours when they are in there by themselves, and we have no shore power.

A look at the numbers -- assuming stock LD with stock equipment.

main coach body width = 8'3"
bumper to bumper for RB = 27'
Total Roof SF = 216
Standard AC install Dometic #651816 uses at cooling mode 1447 watts AC power
Puts out 15,000 BTU enough to reduce from 90 degrees about 15 degrees assumes well insulated room.

Using best highest rated solar panels
325 watt Solar Panels Panasonic
From spec sheet
Dimensions 62.6 x 41.5 x 1.4 inches
Maximum Power Voltage (Vpm) 57.6 V
Maximum Power Current (Ipm) 5.65 A
Panel Weight: 40.8 lbs

At best you will be able to put two maybe three. Let say four that gives you 1300 watts at max output at perfect/laboratory conditions. I would make an educated guess and assume in the real world about 30 to 40 percent average over a sunny day.   On average in the PNW if you are really really lucky 20 percent. Those numbers are based on my use and observation from five years of solar panel use in the PNW and Southwest.

Added wt is about 160 pds.

Will need new wiring.
Cable Size - Type No 12 AWG - PV Cable

Also a new solar controller maybe.   The stock Blue Sky 3000i may work since each panel is about 5 amps.   You would be very close to max amp for this controller.

8 battle born batteries 800 AH = 250 pds and 8 ft by 4 ft sq space.

Your solar rack would also have to clear the AC unit. I'm thinking there might be air flow problems.   Also once you cover all the roof you'll have some issues with maintenance and cleaning of the roof surface.

Don't misunderstand me. I'm all for creative solutions to interesting problems.   I love to spit ball and look over different ways to create. The engineer in me is all over the idea.   I feel the solution can be found but will it be practical for the day to day wear and tear.

glen

Re: Large battery bank storage location question

Reply #21 – June 21, 2019, 01:25:57 pm

"The stock Blue Sky 3000i may work since each panel is about 5 amps."

'Fraid not. That controller can handle a maximum of 290 watts with a 60-cell (high-voltage) panel, and its maximum allowable input voltage is 50 V. Just one of the 325 W/57.6 V Panasonic panels you mentioned would exceed both those numbers.

Re: Large battery bank storage location question

Reply #22 – June 21, 2019, 04:33:45 pm

Hi Gabe and Glen. I saw on Youtube, but couldn't find it again, a solar installation on a van roof. Eight feet wide, double layer, with about 3.5+ feet extending like wings out from under on each side. Those extended pieces could be tilted up, or down to maximize insolation. It appeared well done with mostly aluminun structure, but that high of a weight would be a problem, especially for a van. I don't remember how many watts total it was. Light winds ok, but gusts? I don't think he had any roof stuff in the way. RonB

Re: Large battery bank storage location question

Reply #23 – June 21, 2019, 06:59:45 pm

I respectfully request you keep derogatorily comments against men out of this public forum. Thank you.

Quote from: colddog - June 20, 2019, 09:27:42 am

I'm using the female because I believe females are smarter than us males.

Re: Large battery bank storage location question

Reply #24 – June 21, 2019, 11:08:11 pm

Quote from: Renegade242 - June 21, 2019, 06:59:45 pm

I respectfully request you keep derogatorily comments against men out of this public forum. Thank you.

Chet, if you have followed Glen's (colddog) comments in the past, you will find them dry enough to give you goosebumps and subtle enough to challenge William James Sidis.

Chris

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