1st joined here a couple years ago when I got my bus--then work put the bus on the back burner..Retired last month and finally getting back to it.
Ive searched for, but not found, some guidance on what Im going to need, top to bottom, to power a/c, appliances, lighting, and whatever else may come up.
81 MC9, 24 volt system.
Would like to put in a single 240 volt mini split, to run 2 units, as opposed to 2 110 units- finding a spot for that 2nd outside unit seems to be a challenge without getting real close to the engine bay.
I have a 11KW Kubota quiet gen coming.
No battery bank--just starting batteries--2 8Ds--Ive read where some do away with those monsters for group 31s?
I'd like to know what I'll need for batteries, inverter, charger, etc.
I can run 240 I believe, straight off the gen, but can I do this without relying on the gen all the time? And will I be able to also run 110 off the gen at the same time?
Any guidance, directions to any resources would be much appreciated.
Thanks
They make mini-splits with just one outside unit and two inside heads. Sorry I don't have a link for you.
There are all sorts of routes that you can go for the house battery bank and solar, just depends on how much of a tinker that you are and how much you want to spend.
Your might read through my recent posts and build thread.
Quote from: freds on May 03, 2021, 01:21:36 PM
They make mini-splits with just one outside unit and two inside heads. Sorry I don't have a link for you.
There are all sorts of routes that you can go for the house battery bank and solar, just depends on how much of a tinker that you are and how much you want to spend.
Your might read through my recent posts and build thread.
Right--but those require 240 volts, correct?
Thanks
Quote from: freds on May 03, 2021, 01:21:36 PM
They make mini-splits with just one outside unit and two inside heads. Sorry I don't have a link for you.
There are all sorts of routes that you can go for the house battery bank and solar, just depends on how much of a tinker that you are and how much you want to spend.
Your might read through my recent posts and build thread.
Yea---its the "all sorts of routes" that Im struggling with.
Not planning solar at this time.
I'll look through your posts---Thanks again!
You can always get 110v off one leg of 220. Best to try and balance your loads though.
Relying on 220 for your AC will handicap you at any campground that only has 110.
Half the AC running on 110 is better than no AC at all.
Jim
I do believe most, if not all, dual fan mini-splits are 220v. I never found one that ran on 120v when I was shopping last year.
does your stock AC work for going down road?
Quote from: robertglines1 on May 03, 2021, 04:40:30 PM
does your stock AC work for going down road?
No stock a/c
Quote from: OKIE9ERS on May 03, 2021, 11:08:56 AM
1st joined here a couple years ago when I got my bus--then work put the bus on the back burner..Retired last month and finally getting back to it.
Ive searched for, but not found, some guidance on what Im going to need, top to bottom, to power a/c, appliances, lighting, and whatever else may come up.
81 MC9, 24 volt system.
Would like to put in a single 240 volt mini split, to run 2 units, as opposed to 2 110 units- finding a spot for that 2nd outside unit seems to be a challenge without getting real close to the engine bay.
I have a 11KW Kubota quiet gen coming.
No battery bank--just starting batteries--2 8Ds--Ive read where some do away with those monsters for group 31s?
I'd like to know what I'll need for batteries, inverter, charger, etc.
I can run 240 I believe, straight off the gen, but can I do this without relying on the gen all the time? And will I be able to also run 110 off the gen at the same time?
Any guidance, directions to any resources would be much appreciated.
Thanks
So the way 50amp 220v power works. You have 4 legs. 2 legs, providing 110v each, common, and ground. Providing you can find a camp ground with 50 amp hookups consistently, you wouldt have a problem with 220. However when you visit your cousins and park in their driveway, hooking to their house hold outlet, you will only have 110. Making it not fun. Either you are hot or running generator. A normal motorhome setup, is all 110v, with careful balancing between the 2 legs. It is important to keep both legs drawing similar amounts of electricity, especially off the generator.
I hope you can understand that....
Mason
Quote
However when you visit your cousins and park in their driveway, hooking to their house hold outlet, you will only have 110. Making it not fun.
I hope you can understand that....
Mason
Not fun is right, but I found with our S&S travel trailer the average "110" outlet could not run our single roof air without getting too hot (sometimes melting down) or tripping the breaker if it was a 15amp circuit. (And if it was a GFCI it would not work at all.) We would plug in over night when it was cool enough but had to run the generator during the day anyway for the AC.
I plan to have my wiring split up in my bus in such a way to be able to plug in my 120volt low amperage items to my cousins porch outlet and run the generator for the rest as needed. I even thought about having two 120volt plugs for each half of the panel box and just make sure to find two circuits that would give me both legs of the house 240 current. It would take some careful verification the first time, but for us we are usually staying at the same places year after year when we visit family.
Quote from: lovetofix on May 04, 2021, 05:01:24 AM
Not fun is right, but I found with our S&S travel trailer the average "110" outlet could not run our single roof air without getting too hot (sometimes melting down) or tripping the breaker if it was a 15amp circuit. (And if it was a GFCI it would not work at all.) We would plug in over night when it was cool enough but had to run the generator during the day anyway for the AC.
I plan to have my wiring split up in my bus in such a way to be able to plug in my 120volt low amperage items to my cousins porch outlet and run the generator for the rest as needed. I even thought about having two 120volt plugs for each half of the panel box and just make sure to find two circuits that would give me both legs of the house 240 current. It would take some careful verification the first time, but for us we are usually staying at the same places year after year when we visit family.
Now that is a interesting idea.... ;)
You should order Bus Wiring for Bus Nuts. It is available here: https://www.busconversionmagazine.com/product-category/books/
Or if you are a subscriber to BCM, you will have access to this book and all of these other books free 24/7 for your reading pleasure. ;D
Quote from: lovetofix on May 04, 2021, 05:01:24 AM
Not fun is right, but I found with our S&S travel trailer the average "110" outlet could not run our single roof air without getting too hot (sometimes melting down) or tripping the breaker if it was a 15amp circuit. (And if it was a GFCI it would not work at all.) We would plug in over night when it was cool enough but had to run the generator during the day anyway for the AC.
I plan to have my wiring split up in my bus in such a way to be able to plug in my 120volt low amperage items to my cousins porch outlet and run the generator for the rest as needed. I even thought about having two 120volt plugs for each half of the panel box and just make sure to find two circuits that would give me both legs of the house 240 current. It would take some careful verification the first time, but for us we are usually staying at the same places year after year when we visit family.
The problem will still be there anywhere else you want to go. You'd be surprised how many campgrounds are 30-amp only, and how many times in a campground with 50 amp service you end up on a 30-amp only site.
I'd strongly recommend finding a way to keep everything on your coach able to run on a single phase 120v input.
Here's an idea...
Set up your bus with hybrid inverter(s) capable of providing 240v split phase to your load center. Your a/c will be power from this. When you are plugged into a 50-amp split phase service the inverter(s) will simply pass it along to the load center.
When you are plugged into anything less than a 50-amp pedestal, the inverter(s) will use the incoming ac power to provide what it can, and it will pull from the batteries to make up the difference.
Victron is coming out with a new model of their Multiplus II inverters which can automatically do the phase switching, so no matter what's coming in from the pedestal it will power both sides of your load center. I believe that there is a way to run these in parallel to provide true 240 service which can power the a/c unit you're talking about.
The inverters need a big enough battery bank to draw from when one is making up the difference in the power load it is not like one just makes the power
Quote from: richard5933 on May 04, 2021, 08:56:58 AM
The problem will still be there anywhere else you want to go. You'd be surprised how many campgrounds are 30-amp only, and how many times in a campground with 50 amp service you end up on a 30-amp only site.
I'd strongly recommend finding a way to keep everything on your coach able to run on a single phase 120v input.
Here's an idea...
Set up your bus with hybrid inverter(s) capable of providing 240v split phase to your load center. Your a/c will be power from this. When you are plugged into a 50-amp split phase service the inverter(s) will simply pass it along to the load center.
When you are plugged into anything less than a 50-amp pedestal, the inverter(s) will use the incoming ac power to provide what it can, and it will pull from the batteries to make up the difference.
Victron is coming out with a new model of their Multiplus II inverters which can automatically do the phase switching, so no matter what's coming in from the pedestal it will power both sides of your load center. I believe that there is a way to run these in parallel to provide true 240 service which can power the a/c unit you're talking about.
Now that is interesting
Quote from: OKIE9ERS on May 04, 2021, 10:51:35 AM
Now that is interesting
The other solution which I am leaning towards in reconfiguring my system is to simply do a UPS (uninterruptable power supply) type solution. Everything draws from house battery/inverter and the input side is either solar or AC power from either the generator or shore power from being plugged in.
In my case the transfer switch takes up a significant amount of space on a storage bay wall where I could mount other stuff...
If you've got a big enough charger, that could be the only thing which received power from shore power/generator.
The charger keeps the batteries topped off when the solar isn't doing enough, and everything pulls from the batteries via the inverter(s).
I like it.
Quote from: luvrbus on May 04, 2021, 10:24:18 AM
The inverters need a big enough battery bank to draw from when one is making up the difference in the power load it is not like one just makes the power
Exactly, I am also thinking a rooftop of solar and big alternator will take care of sunny days and driving time (usually night). And of course the generator covers all the other time when not plugged into 50A 240V.
Quote from: lovetofix on May 04, 2021, 04:56:15 PM
Exactly, I am also thinking a rooftop of solar and big alternator will take care of sunny days and driving time (usually night). And of course the generator covers all the other time when not plugged into 50A 240V.
If you read my build thread I am using multiple server power supplies to simulate solar input when the sun goes down if AC power is available.
I just picked up a 1700 watt DC to DC converter (24 volt to 48 volt) so looking to make up the difference between solar and demand draw for both roof top air conditioners when I am driving.
What happened to the simple step-up transformer?
Price a suitable sized transformer before committing to all these boxes full of expensive smoke...
Happy coaching!
Buswarrior
What he is doing is taking in AC and outputting DC to feed to DC battery bank. That way he can draw all power to be used via the battery and inverter.
The 24 to 48 volt DC-DC step up transformer inputs alternator and outputs and connects to the PV output side. Then that feeds the battery bank that feeds the AC.
That's my understanding based on Fred's idea to push all house usage via the battery bank and inverter.
Quote from: buswarrior on May 05, 2021, 05:27:40 AM
What happened to the simple step-up transformer?
Price a suitable sized transformer before committing to all these boxes full of expensive smoke...
Happy coaching!
Buswarrior
The step-up transformer discussion was for my system planning and is still my plan for the 240V to power my split system. Freds is doing something quite a bit different though as I believe he has a 240V inverter. Okie could use the 120 to 240 step up transformer to power his mini split if that works for him. I am thinking the step up transformer will only be useful for me while driving down the road (alternator power) or sunny days (solar power) both through a 120volt inverter I already have. When I have a 50A plug I will already have 240V and a 120 porch receptacle won't keep up with the mini split requiring the generator to run anyway which will give 240V.
This discussion is helping me to refine my plans for my AC system, specifically in terms of ducting with an eye to low power operation. If there's only a 30A 110v receptacle available, (Bearing in mind that many household outlets are 15A) Much depends on the energy efficiency rating (EER) but on average there's a decent chance of powering a 1-1/2 ton unit with a good extension cord. So that has to be the default, lowest powered option and anything more is a bonus. In some cases it could be possible to do twice that, or 3 tons if the A/C was especially efficient.
Now I'm using the overhead bin mounted units for my mid level evaporators and they have a 1-1/2 ton capacity each so a compressor to drive one of those should be well able to run on said extension cord, but then it's a question of maximizing the effective use of that cooling.
I don't think it would be at all reasonable to expect it to keep up with the whole bus, but since I have bulkheads between the rear bedroom and bathroom, and again between the bathroom and the ballroom (rest of the RV) I can shut those doors and what I need then is a flapper to shut off the ductwork to the rear. And as long as I'm doing that it might make sense to do the same to the front so that I can send all the cold air either to the front, to the back, or both.
A useful refinement that I don't think I would have thought of otherwise, so thanks.
Jim
Again, with a simple hybrid inverter (one which can provide AC power boost from batteries) you should be able to provide a short-term boost to the incoming 15-amp extension cord to help with start-up loads.
Depending on how large your battery bank is, that short-term boost can be used for a much longer time period.
Mini-split been running 120V INVERTER type mini split.. 3 in coach. will run on 30 amp 120 volt (all 3) you have no suden start up surge. The units ramp up slowly to full operation. the highest amp (max load) of a 12,000 unit is 8 amp at 120 v ac. No other hardware (transformer etc) to fail. I'm using 2ea 9,000 and 1 ea 12,000. on a 45ft coach. hottest temp I have used in was 96 F lowest was 9 F (on heat side)
No room for the condensers except maybe on the bumpers?
Quote from: Dave5Cs on May 06, 2021, 09:57:54 AM
No room for the condensers except maybe on the bumpers?
That is exactly my problem. Our bus will be our only home in the USA and for 2 months at a time so we need the storage bay space.
The only option I have to stay with 120V systems would be to build a custom rear cap and house the multiple condensers back there but that will take a lot of engineering and work to deal with the negative pressure behind the bus, plus there is all the dirt that gets sucked up back there.
This is why, if I can figure how to do it, run 1 condenser@240 volts, and put it in the factory air condenser bay..Can run 2 or 3 inside units off of that.
Have heard many good ideas, but that has not lessened my confusion much...lol.
Thanks everyone for your input..
And...it may not be practical to go 240...
I've always considered my self mechanically inclined,, but dang!! This electrical is tough on another level..
If there is no room in the bays, what about on the roof?
There are lots of a/c systems made for roof mounting - you see them on the roof of transit buses all the time.
What if you got the fiberglass shell from one of those and used the guts out of a mini split inside it?
Quote from: richard5933 on May 06, 2021, 05:29:08 PM
If there is no room in the bays, what about on the roof?
There are lots of a/c systems made for roof mounting - you see them on the roof of transit buses all the time.
What if you got the fiberglass shell from one of those and used the guts out of a mini split inside it?
I don't have the headroom to do that, 10" roof raise. :-\
I think with a step up transformer I can run a 240V inverter style 3ton condenser off a 30A 120V connection or my 3500W inverter (continual rating). Even if I can't run all three evaporators that will keep me going most of the time. I believe the wiring difficulties will be easier than trying to find someone to make me a custom rear cap for my MC9.
Quote from: lovetofix on May 06, 2021, 07:55:11 PM
I don't have the headroom to do that, 10" roof raise. :-\
I think with a step up transformer I can run a 240V inverter style 3ton condenser off a 30A 120V connection or my 3500W inverter (continual rating). Even if I can't run all three evaporators that will keep me going most of the time. I believe the wiring difficulties will be easier than trying to find someone to make me a custom rear cap for my MC9.
How tall is your bus with the roof raise?
Quote from: lovetofix on May 06, 2021, 07:55:11 PM
I don't have the headroom to do that, 10" roof raise. :-\
I think with a step up transformer I can run a 240V inverter style 3ton condenser off a 30A 120V connection or my 3500W inverter (continual rating). Even if I can't run all three evaporators that will keep me going most of the time. I believe the wiring difficulties will be easier than trying to find someone to make me a custom rear cap for my MC9.
What are your plans for battery bank?
The big power hog is the compressor, the rest are just fans.
Substitute other space for a pair of 120 units, and use the old ac compartment for storage, if two won't fit into the space?
Not a big deal to fabricate a solid door for the purpose...
We get so hung up on assigning spaces to certain things, and block free thoughts from popping into our heads...
Also, think about how small a space the two of them can take up, and still have appropriate air flow... if you are stuck thinking they have to face a certain way... unstuck it!
Happy coaching!
Buswarrior