bus build soon and trying to get a head start

[zynmaster]

i don't have all the components or how much power they draw yet but i want as big of a system as i can without go way overboard which it seems is easy to do. i hope to buy the bus next month. possible room for expansion. i know(or think i do) 24v is safest. i'll list the things i know i want to run in the bus. i've watched a million videos over the last 7-10 years but it was all before i was ready to launch so it's kind of scrambled my brain.

the stuff i want:

mini split ac/heater
large tv
large fridge and freezer
multiple computers with a triple monitor set up on one.
induction cooktop and multiple kitchen appliances (not all at the same time.)
on demand water heater
water pump for running water
starlink
i'd like to experiment with a recycling shower set up
a maker work bench with a 3d printer and 40-60w laser cutter

that's all i can think of off the top of my head. i plan to have redundancies built in camp stoves and propane fueled items as back ups as needed. also plan to have a inverter generator just in case i guess my main question would be what's the minimum battery bank i need? 24v or 48v? would 900ah bank be enough or will i need more? i know it's gonna be expensive but i want to get the high end components like victron at the least and expand the batteries later if it becomes too pricey at first.

the bus is gonna be 36'-40' and kind of a unique design. the plan is to basically build a land version of the millennium falcon (i know i know) with some leds purely for aesthetics. i know a lot depends on more specifics than i've given. just hoping for a starting point

 

[12VoltInstalls]

While I’m not that averse to wildhat guessing that’s a way open-ended kWh demand to just start shooting from the hip.

i know(or think i do) 24v is safest

No.
What you need is 48V.
You may not have room up top for enough panels to support your gaming palace, either.

900Ah at 24VDC is like - wait! - am I reading this correctly?! But anyways that like ~20kWh+ of battery. So 48V makes the most sense- you’ve got an entire household worth of stuff going on

 

[Rocketman]

It you want lots of power go 48v. The size of battery depends on how much you will use in a day, (will you use as much the next day too?), how much solar you have, and how much you want to run the generator.

It just a math question…

 

[HarryN]

Well, anyone that can build a 12 volt system can build a 24 volt system with essentially the same components. Really anything from the bluesea or any marine store will support 12 or 24 volt.

If you go 48 volt, then it requires changing to completely different components that are a bit harder to source - not very difficult, but it is a lot more work.

My suggestion is that if you are going to build it up yourself, go 24 volt. If you are having a pro help you, then it is worth considering 48 volt.

From a power draw perspective, what you have is an off grid home on wheels - and those are mostly 48 volt, but they also are mostly stationary. Stationary and mobile electrical components are not always the same thing due to vibration effects.

Almost for sure you will end up with a generator, either AC or DC to keep up with all of your loads at least sometimes.

 

[zynmaster]

While I’m not that averse to wildhat guessing that’s a way open-ended kWh demand to just start shooting from the hip.

No.
What you need is 48V.
You may not have room up too for enough panels to support your gaming palace, either.

900Ah at 24VDC is like - wait! - am I reading this correctly?! But anyways that like ~20kWh+ of battery. So 48V makes the most sense- you’ve got an entire household worth of stuff going on

video editing and cad software and maybe the occasional gaming but i hear ya. same type of computer. as for hip shooting, got to start somewhere and this me finding my starting point.

i have no clue yet about battery needs. so 900 ah is overkill?

also have considered hauling a trailer with a car and building a rack up top with additional solar if needed. it'll definitely by a much later project

 

[zynmaster]

appreciate all the input. it won't all be on at the same time and i'll have some redundancies like diesel heater.

 

[12VoltInstalls]

My suggestion is that if you are going to build it up yourself, go 24 volt. If you are having a pro help you, then it is worth considering 48 volt.

It’s entirely just as easy if not easier to go 48V once any 12V needs are abandoned.

got to start somewhere and this me finding my starting point.

i have no clue yet about battery needs. so 900 ah is overkill?

No way to tell.

You need to go into the resources section here on diy solar and get the paperwork on doing an energy audit.
It’s simple to figure out what you need but without data it’s not “starting somewhere” - it’s guessing.

If you go 48 volt, then it requires changing to completely different components that are a bit harder to source - not very difficult, but it is a lot more work.

Fwiw I just installed a 3600W system for someone locally with 10kWh of batteries under an LV6548. Lots less “work” than a 12V system, imho; most things just plug in and go. Only been running a week and he’s already ordered a second 6548 and 10kWh more battery for split phase to run the well pump.
Point is it took as long as it took but it was quite simple to install. Not that 12V is difficult- it’s not.

But for this bus that’s gonna beg for 6kWh+ 24V makes no sense from either practical standpoint or unicorn’s perspective.

Just my opinion.

 

[zynmaster]

You need to go into the resources section here on diy solar and get the paperwork on doing an energy audit.
It’s simple to figure out what you need but without data it’s not “starting somewhere” - it’s guessing.

on it

quick question about another comment above. i've literally watched 1000's of videos and never seen anyone bring up a concern about the vibrations of being mobile vs stationary. how big of a concern is that, it there a brand that's less susceptible to it, a way to mitigate it like a vibration dampener etc...

 

[hwy17]

Whatever you do don't put 12v lithium batteries in series to make 24v or 48v.

 

[RV8R]

on it

quick question about another comment above. i've literally watched 1000's of videos and never seen anyone bring up a concern about the vibrations of being mobile vs stationary. how big of a concern is that, it there a brand that's less susceptible to it, a way to mitigate it like a vibration dampener etc...

Vibration ,,, It is a Concern

Especially if looking for “Military / Aviation / Marine” quality components. How Did “Battle-Born” get its name ? ,,, “Mil Spec” ?

RV Industry “Specs” Meh,,,


Ya Can’t Rely on YouTube for all Your Knowledge Base.

 

[HarryN]

We can make some early estimates about your power system operation from your general description.

Let's use kW and kW-hrs to help make it easier to estimate, and you can also improve on these numbers by taking some measurements on your existing power use by looking at the meter or using some simple measurement tools.

Let's start with the bigger items:

Air conditioning:
- In a location like Alabama in the summer, substantial air conditioning is needed.
- More during the day ~ 8 am - 8pm, at least 1 kW average continuous load, so 12 kW-hrs minimum, possibly 2x this
- At night 8 pm - 8 am, we can use the lower number ~ 12 kW-hrs
- Since you will want it fairly quiet during the night, this means right off the bat, 12 kW-hrs of battery pack capacity just for air conditioning

Computers, displays, lighting, starlink, and cutter
- Nominal 12 -1 5 kW-hrs of power used each day

Home size refrigerator and freezer
- Nominal 2 kW-hrs of power each per day, so 4 kW-hrs per day

Electric cooking, water heating, misc
- Nominal 5 kW-hrs per day

So to a first order estimate, 24 + 12 + 4 + 5 ~ 50 kW-hrs per day

Similar to many modern homes.

____________________

On a bus build, it might be possible to put 2 kW of solar panels on, which could generate ~ 6 - 10 kW-hrs of power vs the need for ~ 50 kW-hrs.

____________

In order to run through the night without a generator, you would need at least 12 + 6 + 5 kW-hrs of battery storage ~ 20 kW-hrs minimum

_____________

Each 12 volt x 100 amp-hr battery stores approx 1 kW-hr of electricity, so you would need ~ 20 of these or equivalent. Wiring 12 vs 24 vs 48 volt, still would need the equivalent of ~ 20 of them to run for 12 hrs through the night.

____________

At some point in the day, you will need to find a way to generate the non solar ~ 40 kW-hrs of electricity.

- For example - plugging into an EV charger
- Generator
- RV park
- other

These are just my back of the envelope numbers to get you started on making estimates about your power needs and system.


____________________

There are people on the forum that live full time in RVs, so look at their posts for additional information.

This is a viable, but non trivial project. It is a lot for a first time builder to take on in parallel with the larger bus build aspect.

 

[HarryN]

Whatever you do don't put 12v lithium batteries in series to make 24v or 48v.

It is fine if you use the rights ones, but hardly anyone does because they cost more.

 

[hwy17]

It is fine if you use the rights ones, but hardly anyone does because they cost more.

If you use high quality ones they will stay in balance longer, but they will still eventually need to be rebalanced.

 

[justinm001]

Plan on filling the roof with as much solar as you can and optimizing so there isn't shading. Then consider getting all Victron MPPTs and inverters with their Cerbogx. Go 48v it'll be cheaper and better and easier. Get SOK rack batteries, start with 2 then you can add more as you go.

Solar creates energy, batteries store energy. It doesn't matter how many batteries you have if you're using more than you're making then its just prolongs how much time you have until you need to charge by other means.

I'd want 3-7 days of batteries just incase its storming/cloudy, but you can start with 1-2 days then increase.

 

[zynmaster]

We can make some early estimates about your power system operation from your general description.

Let's use kW and kW-hrs to help make it easier to estimate, and you can also improve on these numbers by taking some measurements on your existing power use by looking at the meter or using some simple measurement tools.

Let's start with the bigger items:

Air conditioning:
- In a location like Alabama in the summer, substantial air conditioning is needed.
- More during the day ~ 8 am - 8pm, at least 1 kW average continuous load, so 12 kW-hrs minimum, possibly 2x this
- At night 8 pm - 8 am, we can use the lower number ~ 12 kW-hrs
- Since you will want it fairly quiet during the night, this means right off the bat, 12 kW-hrs of battery pack capacity just for air conditioning

Computers, displays, lighting, starlink, and cutter
- Nominal 12 -1 5 kW-hrs of power used each day

Home size refrigerator and freezer
- Nominal 2 kW-hrs of power each per day, so 4 kW-hrs per day

Electric cooking, water heating, misc
- Nominal 5 kW-hrs per day

So to a first order estimate, 24 + 12 + 4 + 5 ~ 50 kW-hrs per day

Similar to many modern homes.

____________________

On a bus build, it might be possible to put 2 kW of solar panels on, which could generate ~ 6 - 10 kW-hrs of power vs the need for ~ 50 kW-hrs.

____________

In order to run through the night without a generator, you would need at least 12 + 6 + 5 kW-hrs of battery storage ~ 20 kW-hrs minimum

_____________

Each 12 volt x 100 amp-hr battery stores approx 1 kW-hr of electricity, so you would need ~ 20 of these or equivalent. Wiring 12 vs 24 vs 48 volt, still would need the equivalent of ~ 20 of them to run for 12 hrs through the night.

____________

At some point in the day, you will need to find a way to generate the non solar ~ 40 kW-hrs of electricity.

- For example - plugging into an EV charger
- Generator
- RV park
- other

These are just my back of the envelope numbers to get you started on making estimates about your power needs and system.


____________________

There are people on the forum that live full time in RVs, so look at their posts for additional information.

This is a viable, but non trivial project. It is a lot for a first time builder to take on in parallel with the larger bus build aspect.

good info thanks a bunch. after the build i'll be heading west. hope to mitigate some of the needs with conservative use like maxair fans or similar when possible, some of the maker tools only occasionally or when hooked up to shore power. hopefully i'll be cooking outside as much as possible and when convenient. this is a great starting point. it seems one of the house setups all in one packages may be worth a look. i'll scan the resources for this but just in case someone here has knowledge on it i'll go ahead and ask here.....the eg4 6000xp and eg4 rack batteries a good option or are there better cheaper options. it looks like a decent option at first glance.

 

[zynmaster]

Plan on filling the roof with as much solar as you can and optimizing so there isn't shading. Then consider getting all Victron MPPTs and inverters with their Cerbogx. Go 48v it'll be cheaper and better and easier. Get SOK rack batteries, start with 2 then you can add more as you go.

Solar creates energy, batteries store energy. It doesn't matter how many batteries you have if you're using more than you're making then its just prolongs how much time you have until you need to charge by other means.

I'd want 3-7 days of batteries just incase its storming/cloudy, but you can start with 1-2 days then increase.

that's the plan, even considering a car hauling trailer with a makeshift ladder rack converted into additional solar over the car i haul.

 

[justinm001]

that's the plan, even considering a car hauling trailer with a makeshift ladder rack converted into additional solar over the car i haul.

That's what I'm doing as well, connecting the trailer to the RV using an Anderson plug. I don't use the trailer much so it'll go back and forth from charging itself to charging the bus

Cargo trailer solar build

Finally getting around to installing solar on the cargo trailer (7x16) we tow behind the RV. The goal is to install some POE cameras and a NVR inside the trailer then use it as backup cameras over wifi when driving or as a security system when parked. On top of this I want the solar to keep...

diysolarforum.com

 

[zynmaster]

a side note and maybe should post elsewhere but has anyone looked into edison motors? he's making an electric semi that works like a train with electric axles with motors built in and a diesel generator for charging. basically a hybrid system. he is also doing kits for conversions.

 

[zynmaster]

That's what I'm doing as well, connecting the trailer to the RV using an Anderson plug. I don't use the trailer much so it'll go back and forth from charging itself to charging the bus

Cargo trailer solar build

Finally getting around to installing solar on the cargo trailer (7x16) we tow behind the RV. The goal is to install some POE cameras and a NVR inside the trailer then use it as backup cameras over wifi when driving or as a security system when parked. On top of this I want the solar to keep...

diysolarforum.com

love it. i'm thinking maybe something like a race car hauler with some additional storage for tools and more batteries. the ultimate would be to haul a tesla and have the trailer set up as a charger. not sure my budget will allow but it doesn't hurt to dream

 

[justinm001]

love it. i'm thinking maybe something like a race car hauler with some additional storage for tools and more batteries. the ultimate would be to haul a tesla and have the trailer set up as a charger. not sure my budget will allow but it doesn't hurt to dream

I added a 50a buddy plug on my RV for my daughter to charge up the Tesla I got her. As soon as I can get my hands on a cybertruck that is exactly what I'm planning on doing. Just need the truck to figure out the size trailer i'd need. Many states have a 65ft max length so my 40ft bus plus the current 16ft trailer plus the tongue and hitch is pretty close, I think every car hauler would be over the limit but tons of people are over limit and no one seems to care. Although we just take our RV everywhere when we travel. I sometimes keep a motorcycle on the back but never really use it.

The Cybertruck has 2 way charging so not only is it possible to charge via solar but you can use the massive battery pack to charge the bus too.