Can she hold it?

[Slavox]

Originally Posted by dssl

Okay, 48v, the weight now makes perfect sense. Since that is very atypical in an RV it would have been a good idea to include that information in your initial inquiry which would have avoided all the weight confusion.

Again you are more likely to find people familiar with your coach on the brand specific topic.

Understood. I have made a thread there. Thank you all for the input.

[cwk]

Originally Posted by Slavox

... we removed the 6gal water heater and went hot on demand, saving another 35-ish lbs...

Plus 49.97 pounds for the weight of 6 gallons of water in the old heater.
Not sure how much water is inside of your new water heater.

By the way... I am guessing that you installed an electric tankless water heater? If so, what size (KW)? I am planning to do so during my remodel and need to select a size. Actually, I am considering two units: one for the sink and shower in the bath, the washing machine, and the dishwasher, Then a small one located under the kitchen sink. Or some similar combination. Thanks!

Also, thanks for the video.

[Slavox]

Originally Posted by cwk

Plus 49.97 pounds for the weight of 6 gallons of water in the old heater.
Not sure how much water is inside of your new water heater.

By the way... I am guessing that you installed an electric tankless water heater? If so, what size (KW)? I am planning to do so during my remodel and need to select a size. Actually, I am considering two units: one for the sink and shower in the bath, the washing machine, and the dishwasher, Then a small one located under the kitchen sink. Or some similar combination. Thanks!

Also, thanks for the video.

I actually am using a gasland 1.6gpm LP gas hot on demand.
As-is, they kinda suck. Too hard to control the temperature, and onboard pumps have a hard time activating them as the pressure and flow is too low on most pumps. Its expecting municipal or campsite provided water pressure, and its designed to work with only that.
So, what I do to keep the electricity of a water heater off my power budget and have done several times in the past, is what I call a 2 step water heater.
I use the LP gas hot on demand at a slightly too hot to touch temperature, and run it into a small 6 gallon undercabinet electric water heater to the cold water inlet. I then remove the 110v heater element, and replace it with a DC12v 300w heater element, and give it a set of panels.
I set its temperature to be a bit more reasonable, and by the time it gets into the tank its already hotter than the thermostat is set.
So the water heater tank, only heats to keep warm. Never from cold. And it never touches the power of my main system. Those panels are 140watt, parallel, and have a 20amp breaker between them and the heater.
That gives you 1-2 hot showers per evening after work, and hot hot water for dishes and dishwasher after that is used up later in the evening.

I also add a sureflow 4.5gpm pump, 40 PSI inline regulator, and a small pressure tank to stabilize water flow and prevent surging. Not terribly expensive an upgrade, not terribly difficult to install if you know PEX plumbing well, and gives you close to household pressure at all faucets and taps. It also turns on that water heater with no issues at all. Making it vastly more reliable.

I mount my gasland heater on the outside of my coach, and its all quick connects. Its something that I expect to replace every 1-2 years. But... at 160$ its not too much to pay to convert the majority of my hot water power usage to LP gas. A 20lb tank lasts over a month with two people showering every day and using the dishwasher.

If it was electric, I would be dedicating 1/8 - 1/4 of my total power budget to it.
The balance I am typically looking for with a totally offgrid system, as in one that may never be near hard power to plug in, is 90% of my budget dedicated to Air conditioning running nearly all the time, and the remaining 10 to run computers, and small appliances. (Toaster, air fryer, microwave, coffee pot, etc.)

Gas fridge, well maintained, is enough to live offgrid with, as long as you don't mind slightly soft ice cream and regular manual defrost.

If you want an electric fridge, it only consumes another 5% of your overall power budget. In my experience. A chest freezer also doesn't consume much once cold.
But every drop I can dedicate to Air conditioning, and keep off the budget, I usually go with whatever option that is.

I can link parts and do videos on the systems I use and how to build them. I am in the early stages of converting this coach. So, everything is on the table still.

I've already bought pretty much everything.

The next two months of my life will be installing, testing, and trim.
(Aka, put it in, make sure it won't burn the coach down, and then put away the wires so my wife stays happy)

:-)

[Danny969]

The math still doesn't add up. I have a 13,500 Watt hours @ 58.8VDC and the battery pack weighs in at 231lbs. While that includes the casing and the electronics that keep the battery pack happy, my pack is lithium NMC which is even lighter per unit of energy than LifePo4. If you have a 43,000Wh pack, I'd expect it to weigh in closer to 750lbs. Anyway, if your floor is mushy, can't you just run some 8020 aluminum or steel bars across the width of the bay and attach the ends of the steel bars to the frame of the chassis? Then, either mount the battery pack directly to those bars or create a subfloor of Baltic birch to mount the battery pack on?

[Slavox]

Originally Posted by Danny969

The math still doesn't add up. I have a 13,500 Watt hours @ 58.8VDC and the battery pack weighs in at 231lbs. While that includes the casing and the electronics that keep the battery pack happy, my pack is lithium NMC which is even lighter per unit of energy than LifePo4. If you have a 43,000Wh pack, I'd expect it to weigh in closer to 750lbs. Anyway, if your floor is mushy, can't you just run some 8020 aluminum or steel bars across the width of the bay and attach the ends of the steel bars to the frame of the chassis? Then, either mount the battery pack directly to those bars or create a subfloor of Baltic birch to mount the battery pack on?

The exact cell characteristics are in the pics at this aliexpress link.
https://www.aliexpress.com/item/1005...21ef1802wvNmUZ

3100g +/- 100g
And I have 64 of them...
So approximately 437.7lbs without hardware.
Then add the rest as from my other post and we will be somewhere in the 650lbs neighborhood.

The original issue is that it feels hollow on my passthrough all the way across. The frame rails are under there somewhere, but the compartment does not appear to sit directly on top of them. There is some metal at the ends, that the deeper side pockets screw into. Its welded underneath. I'm not sure its 650lbs worth of welded, but between that and trying to find a frame spot on both sides and trying to get a bolt in all 4 corners of my platform, It should work. The wood and steel tube platform will hold the weight without deforming. So as long as my edges hold, I think I'll be ok.

[cwk]

Originally Posted by Slavox

The balance I am typically looking for with a totally offgrid system, as in one that may never be near hard power to plug in, is 90% of my budget dedicated to Air conditioning running nearly all the time, and the remaining 10 to run computers, and small appliances. (Toaster, air fryer, microwave, coffee pot, etc.)

Thanks for the response.
Since you mentioned everything is still on the table...

One thought that comes to mind is Air Conditioners. I originally was going to replace my two 30 year old rooftop A/C's with rooftop heatpumps. In fact, I did replace the front unit (old one was very noisy and repair parts not available). However, being a regular heatpump, it cannot produce heat when the outside temps drop below 40F. Also, the brand new unit is LOUD.

My remodel plans include a minisplit. The plan is to have one indoor unit up front over the cockpit facing toward the rear of the coach. The second (smaller) indoor unit will be in the bedroom. They will both be serviced by a single outdoor unit located in the former propane tank compartment. This will require 240VAC, which is part of my new electrical plan (LiFePO4, solar panels, dual inverter/chargers, etc.).

Side note: We have removed all propane from the coach. That includes the two gas-furnaces, water heater, range/oven, and RV fridge.

Yes, the plan is to be independent of shore power. There is an onboard diesel generator, but the plan is to only use it if needed for multiple non-solar days and/or emergencies. With 150 gallons of diesel, 95 gallons of fresh water, and about 3KW of roof solar, I think we should be ok.

Some of the reasons for the minisplit decision:
a) More energy efficient than heatpumps.
b) QUIETER (both indoor and outdoor units) than the heatpumps and/or the original gas furnaces.
c) Minisplit produces heat at 5F ambient temperature (lower for some models).
d) More space on the roof for solar panels.
e) Did I mention that they are quiet???

Anyway, that is my plan.

[Slavox]

Originally Posted by cwk

Thanks for the response.
Since you mentioned everything is still on the table...

One thought that comes to mind is Air Conditioners. I originally was going to replace my two 30 year old rooftop A/C's with rooftop heatpumps. In fact, I did replace the front unit (old one was very noisy and repair parts not available). However, being a regular heatpump, it cannot produce heat when the outside temps drop below 40F. Also, the brand new unit is LOUD.

My remodel plans include a minisplit. The plan is to have one indoor unit up front over the cockpit facing toward the rear of the coach. The second (smaller) indoor unit will be in the bedroom. They will both be serviced by a single outdoor unit located in the former propane tank compartment. This will require 240VAC, which is part of my new electrical plan (LiFePO4, solar panels, dual inverter/chargers, etc.).

Side note: We have removed all propane from the coach. That includes the two gas-furnaces, water heater, range/oven, and RV fridge.

Yes, the plan is to be independent of shore power. There is an onboard diesel generator, but the plan is to only use it if needed for multiple non-solar days and/or emergencies. With 150 gallons of diesel, 95 gallons of fresh water, and about 3KW of roof solar, I think we should be ok.

Some of the reasons for the minisplit decision:
a) More energy efficient than heatpumps.
b) QUIETER (both indoor and outdoor units) than the heatpumps and/or the original gas furnaces.
c) Minisplit produces heat at 5F ambient temperature (lower for some models).
d) More space on the roof for solar panels.
e) Did I mention that they are quiet???

Anyway, that is my plan.

Ok... I might just be able to save you a TON of heartache and money with this one.

Remember one thing about mini split systems. They run on... An inverter.
Inverter to inverter, in my own personal experience, lasted about 3 months before it destroyed the control systems on my 1800$ mini-split.

IF, you want to go minisplit... Start with one. And run it on the system through the life of the warranty before you spend the money on two.

My guess is that it won't hold up. As mine didn't. But with a warranty you can replace it. As my AC guy had no idea what was wrong. Aims had to tell me what actually happened.
The issue is the pure sine wave the minisplit is trying to achieve, and the same wave the inverter from your batteries is trying to create.

It tends to make feedback and noisy power coming off the circuit between the two.

It sounds like a high pitched whine or hiss from the AC unit controls.

Thought it was normal. It wasn't. Fried the control box and completely locked up the compressor from the short that was created.

Any non-inverter units I could find were not mini-split type AC units.

The only type I could find, were running straight DC power, no inverter, and were in the 4k$ range.

Some people have had success, but it all depends on how those two sine waves interact with each other. If it creates dirty feedback, its a limited time offer before it fails.

2 Newer 10-12k BTU AC rooftop units, shop for the quietest ones, and you'll only be at about 2000 watts usage once the compressors are started.

As far as electric heat, its not very efficient at all. Especially on batteries.
Its functionally a short across the terminals of the battery. That is literally how it is generated in such a scenario. A "Soft" short through a resistive coil.

Since you have diesel onboard already, a diesel air heater or diesel air furnace would easily handle the heat in up to a larger 40' coach, for about 2 dollars a day in fuel.

Vs electric heat being 1/2 - 3/4 of your power budget in the colder months.
Similar to a large AC as far as power draw.

[dssl]

Originally Posted by Slavox

Ok... I might just be able to save you a TON of heartache and money with this one.

Remember one thing about mini split systems. They run on... An inverter.
Inverter to inverter, in my own personal experience, lasted about 3 months before it destroyed the control systems on my 1800$ mini-split.

IF, you want to go minisplit... Start with one. And run it on the system through the life of the warranty before you spend the money on two.

My guess is that it won't hold up. As mine didn't. But with a warranty you can replace it. As my AC guy had no idea what was wrong. Aims had to tell me what actually happened.
The issue is the pure sine wave the minisplit is trying to achieve, and the same wave the inverter from your batteries is trying to create.

It tends to make feedback and noisy power coming off the circuit between the two.

It sounds like a high pitched whine or hiss from the AC unit controls.

Thought it was normal. It wasn't. Fried the control box and completely locked up the compressor from the short that was created.

Any non-inverter units I could find were not mini-split type AC units.

The only type I could find, were running straight DC power, no inverter, and were in the 4k$ range.

Some people have had success, but it all depends on how those two sine waves interact with each other. If it creates dirty feedback, its a limited time offer before it fails.

2 Newer 10-12k BTU AC rooftop units, shop for the quietest ones, and you'll only be at about 2000 watts usage once the compressors are started.

As far as electric heat, its not very efficient at all. Especially on batteries.
Its functionally a short across the terminals of the battery. That is literally how it is generated in such a scenario. A "Soft" short through a resistive coil.

Since you have diesel onboard already, a diesel air heater or diesel air furnace would easily handle the heat in up to a larger 40' coach, for about 2 dollars a day in fuel.

Vs electric heat being 1/2 - 3/4 of your power budget in the colder months.
Similar to a large AC as far as power draw.

That's interesting. I guess when you do things that are atypical you can encounter unexpected problems.

48 volts is more efficient and can use smaller wires, but you lose the ability to jump one bank to the other, plus you need a 48 to 12v dc to dc converter to power your 12v circuits

I have a Victron MultiplusII 12v 3000 watt unit and it seems to be very efficient(over 90% I believe), and has lots of great features. If you want more then 3000 watts you can connect two of them together to get 6000 watts split phase. Note with one it passes through split phase, but only inverts in single phase.

[Slavox]

Originally Posted by dssl

That's interesting. I guess when you do things that are atypical you can encounter unexpected problems.

48 volts is more efficient and can use smaller wires, but you lose the ability to jump one bank to the other, plus you need a 48 to 12v dc to dc converter to power your 12v circuits

I have a Victron MultiplusII 12v 3000 watt unit and it seems to be very efficient(over 90% I believe), and has lots of great features. If you want more then 3000 watts you can connect two of them together to get 6000 watts split phase. Note with one it passes through split phase, but only inverts in single phase.

Victron equipment, especially something already designed for stacking, will likely provide better results than what I am using.
I am using Sigineer and Aims products. Which have a relatively clean pure sine, but are susceptible to interference. Hence the cheap price.

I like them because both companies seem willing to assist in DIY repairs of their equipment, and will sell me parts directly. Even with the cheap price.

With Victron gear, you may not have that same issue. Its a more refined/industrial grade product than what I am using. Might have an extra level of protection or a cleaner sine wave than my gear.
(Multiplus series seems tough as nails!)

Just a heads-up/word of caution on what I experienced. Cost me 2200$ between the mini-split and the service calls to install and repair it.

[Holiday1]

I have 8 interstate 225 amh @ 58 lbs each. = 464 lbs.

Doug and Pam
2007 Holiday Rambler, Endeavor
2019 Equinox. Tow v.

[Rev. Roy]

I know that RV because a friend of the family had one. My ultimate concern is that you're going to overload the front axles of the RV. That can lead to all kinds of problems including tire blowouts. It is on a Ford chassis so it likely has a 24000 GVWR. I'm guessing the maximum weight for the front axle is 10000 or less. Because of the location, almost all that added weight is going to be on that axle. I know the weight of the propane tank was only partially on the front axle as well as the furnace. I am also thinking the water heater was mid-ship as well. Weight distribution is very important to consider when doing any remodeling of RVs. It's not just will it fit but will it be best.

[Slavox]

Originally Posted by Rev. Roy

I know that RV because a friend of the family had one. My ultimate concern is that you're going to overload the front axles of the RV. That can lead to all kinds of problems including tire blowouts. It is on a Ford chassis so it likely has a 24000 GVWR. I'm guessing the maximum weight for the front axle is 10000 or less. Because of the location, almost all that added weight is going to be on that axle. I know the weight of the propane tank was only partially on the front axle as well as the furnace. I am also thinking the water heater was mid-ship as well. Weight distribution is very important to consider when doing any remodeling of RVs. It's not just will it fit but will it be best.

Fortunately, The pullout sofa has been removed, which sits just behind the drivers seat, as well as the furnace and water heater. Both are removed. As well as the lead acid batteries. And I will be swapping out the steel built in tank for x4 20lb Aluminum tanks and converting the stock tank location to an enclosure for those tanks.
That is a removal of close to 500lbs.
The carrying capacity from Damon on each compartment left and right side is 150lbs. So I have 300lbs covered in the design, and the 500lbs removal, 240 of it from the pullout sofa, has all been removed from roughly the same section of the coach.

Plus, the cell pack itself is 4 foot by 4 foot, very spread out and short, and will sit very low in the coach which should provide a similar effect to wheel weights.

Additionally, the coach will likely never see highway speeds again.
It is being converted to a Tinyhome, and will be sitting in place most of the rest of its life.

We may bounce around from town to town for new sights and sounds, but I'll never leave Florida in it. So its probably surface streets only, 55-ish mph max for the rest of its driving days.

I think I have removed enough weight and made enough modifications to accommodate the cell pack, I am more concerned with the interface materials between the plastic passthrough bottom, and the frame rails. I just want to avoid deforming the plastic or crushing the interface material/insulation/bushings. But its an inch from the frame either way. If it sags, its still going to be bolted to the frame, and only I will see it.

I'm actually starting the install today.

Wish me luck!

:-D

[dssl]

Originally Posted by Slavox

I'm actually starting the install today.

Wish me luck!

:-D

Good luck.

Curious why you feel the need for so much battery capacity?

[Slavox]

Originally Posted by dssl

Good luck.

Curious why you feel the need for so much battery capacity?

I'll be living in this coach full time with my wife and 4 cats.

In Florida.

So, this system will be big enough to run the bedroom A/C nearly full time, 3 computers, 3 screens, Starlink Internet, Dishwasher, Washer, Dryer, Well pump, lighting and Fridge.

The 100 ah Cell at 48VDC that I have now is already running all that, minus the A/C at night.

We budget our power, so not everything above will be running at once. We for example, turn off the AC and switch to fan only when we are using the microwave, or air fryer, or dishwasher. Then switch the compressor back on after we are finished.

Water heater is all LP gas, and additionally, I'll have another 400 Amp hour of 12vdc Power in my Trailer / Garage / Laundry room, and a backup 4000w Triplite inverter in there paired with it. I may even run my washer and dryer entirely off of that system, and save the other energy for more Air Conditioning.

Backups on backups. Power on tap, and on reserve. Triple redundant generators... The coach has a 48vdc Charge alternator added to the belt path for charging the big battery at 50 amp, that turns freely unless under load. The Onboard Onan 6500 50 Amp Generator is still in good shape, and I have a pair of quiet inverter generators that can be chained up for 50 amp service as well.

Built in a UV/Charcoal/Carbon/Micro/Osmosis purifier, lets me pump water from basically any source and it goes into my fresh tanks clean as a whistle.

This coach can drive into the middle of nowhere, and as long as there is a water source, we are good for months on end.

I have not paid a power bill in 6 years and counting. This is actually my 4th or 5th big battery build now.

So that is why I'm building it so large. This is basically the ultimate prepper tinyhome setup.

Plan for the worst, hope for the best.