More Electrical Planning

[Glennman]

I've been reading on planning an electrical system, and more specifically on the solar side and general equipment sizing. My reading takes me to the installation of a 24v system (i.e. 24v inverter, then 24v-12v converter, etc. everything being sized for 24v). I have some 39v 305 watt solar panels that I plan to install, because as I understand it, it's ok to have larger voltage panels than the system and utilizing a 24v system enables me to use smaller wire from the roof to the storage bay where the 24v inverter and 12v batteries (in series for 24v) will be located. I plan to install a 24v MPPT controller to convert from 39v to 24v (to control the voltage).

Assuming what I've stated so far makes sense, I've read quite a bit about the Victron Multiplus II inverters. However, it appears that there is no such thing as a 24v input model (one unit I've seen actually says 48v on the front but are for producing foreign power levels (not for USA use)).

What inverters are you guys installing? I know this is a very complicated question, especially with the backdrop I started with. This planning stage is very difficult to manage. It makes me want to hire it all out! I'm not sure if I am even asking the right questions(?)

[buswarrior]

Peeps get distracted and blinded by the journey.

What is your destination?

What do you want the system to do for you?

All the advice will be biased to what the writer assumes is the goal, and each post contradicts the next.

How much generator run time are you willing to have, vs the roof being packed full of $$$ solar panels and charge controllers?

What loads do you want available, for how long? Running a house refrigerator and roof top AC all night on the batteries is very different from a few lights and a phone charger. Overnight is different from 3 day$ of dark cloud$.

Do you want the coach to function on the end of a single extension cord without tripping the breaker?

Do you want redundancy in multiples of smaller equipment, or all the eggs in one  big basket? Another way of saying, what are the consequences of equipment failure? Weekend camper, ho hum, full time living couple hundred miles into the back country, serious business.

What's your destination? Then peeps advice will get you there!

Happy coaching!
Buswarrior

[chessie4905]

well said! Solar is great, but my coach won't be seeing it. I got enough complexity now. And we don't  get enough hours of sunlight in the NE to justify it for limited roof capacity.

[Lee Bradley]

I haven't had to look for equipment for a while but I would want a power sharing model like the MSH4024M. I run two panels in series for 70-80 volts through a Midnite solar controller.

[richard5933]

I haven't had to look for equipment for a while but I would want a power sharing model like the MSH4024M. I run two panels in series for 70-80 volts through a Midnite solar controller.

A hybrid inverter that can do power assist is a great thing. We have a Victron with that capability and it makes camping on a 30-amp site much easier. We don't have to worry about someone running the microwave or something if the a/c is on - the inverter just supplements with power drawn from the batteries.

[epretot]

Let me encourage you a bit...

I knew absolutely noting about solar when I started designing the electrical system. However, I have researched for months.

Explorist.life have been a great resource. Both blog articles and videos.

I had to adapt from some of his designs as I needed two ac inputs to my inverter. I settled on the Victron Quatro.

As I have stated here before, I'm all in. It will be our home as well as a refuge for those we plan to help.

Our bus needs to be able to go anywhere, so we are trying to prepare for that.

With that said, it doesn't have to be complex. It's actually quite simple once someone breaks it down for you. Some explain better than others. So, sort through the crap and after awhile, you will find how DIY it is.

[jozef]

Glennman:

I have recently completed the AC and DC systems on our 102D3.  We have gone with eight BattleBorn batteries wired as four banks of 24 volt batteries.  This provides 400 amp hours at 24 volts which is 9600 watts of power.  These feed a 3000 watt Victron MultiPlus 24|3000|70 inverter/charger that provides 120v AC and has 70 amps of battery charging capacity.  Five 440 watt solar panels are mounted on the roof and wired in parallel providing 2200 watts of peak capacity.  These panels are rated at 40.7v Optimum Operating Voltage and 48.7v Open Circuit Voltage.  To prevent excess load on the engine alternator I have installed a 840 watt Sterling Power battery to battery charger.  This B to B charger is likely too small but is the largest currently available.  Sterling Power are developing larger units and we may have to upgrade in the future. Please note that Lithium Ion batteries have very low internal resistance and can be charged at very high amperage rates.  With 8 batteries there is a possibility that the engine alternator could be heavily loaded if the Lithium batteries are deeply discharged.

Why this system:  We have installed one mini split AC (120v) that draws 975 watts maximum.  This is very efficient.  Our fridge will be a 24 volt Nova Kool RFU9000 (about 1200 watts per day) and we will have a 1000 watt microwave.  Stove/oven will be propane only.  With this equipment the batteries, solar panels and 3000 watt inverter will be adequate for our AC needs and provided that the solar panels are providing sufficient output we will be able to run the AC for some of the time.  Our backup power will be a Honda 2200 watt inverter generator.  Heat and hot water is provided by a ITR Oasis Zephyr diesel fired boiler.

We will have to manage our power usage but for our style of camping we expect that we will be able to dry camp for 10 to 15 days in reasonable warm weather.   This is our third conversion and we are basing this system on our experience with the previous units.  For our needs it should work well.  I will take a photo of the electrical system and post at a later date. 

[Glennman]

Glennman:

I have recently completed the AC and DC systems on our 102D3.  We have gone with eight BattleBorn batteries wired as four banks of 24 volt batteries.  This provides 400 amp hours at 24 volts which is 9600 watts of power.  These feed a 3000 watt Victron MultiPlus 24|3000|70 inverter/charger that provides 120v AC and has 70 amps of battery charging capacity.  Five 440 watt solar panels are mounted on the roof and wired in parallel providing 2200 watts of peak capacity.  These panels are rated at 40.7v Optimum Operating Voltage and 48.7v Open Circuit Voltage.  To prevent excess load on the engine alternator I have installed a 840 watt Sterling Power battery to battery charger.  This B to B charger is likely too small but is the largest currently available.  Sterling Power are developing larger units and we may have to upgrade in the future. Please note that Lithium Ion batteries have very low internal resistance and can be charged at very high amperage rates.  With 8 batteries there is a possibility that the engine alternator could be heavily loaded if the Lithium batteries are deeply discharged.

Why this system:  We have installed one mini split AC (120v) that draws 975 watts maximum.  This is very efficient.  Our fridge will be a 24 volt Nova Kool RFU9000 (about 1200 watts per day) and we will have a 1000 watt microwave.  Stove/oven will be propane only.  With this equipment the batteries, solar panels and 3000 watt inverter will be adequate for our AC needs and provided that the solar panels are providing sufficient output we will be able to run the AC for some of the time.  Our backup power will be a Honda 2200 watt inverter generator.  Heat and hot water is provided by a ITR Oasis Zephyr diesel fired boiler.

We will have to manage our power usage but for our style of camping we expect that we will be able to dry camp for 10 to 15 days in reasonable warm weather.   This is our third conversion and we are basing this system on our experience with the previous units.  For our needs it should work well.  I will take a photo of the electrical system and post at a later date.

This sounds like something I would want to do. My goal is to be able to boondock for several days at a time. I'll be researching the equipment you mentioned. This is exactly what I was looking for!!! Thanks!

[jozef]

Here are two photos of the electrical system in our bus.

[Fred Mc]

 Good info.You may also want to go to this site. Lots of knowledge  and they are VERY nubie-friendly. https://diysolarforum.com/
The site owner(Will Prouse) also has about a gazillion utube videos laying out many many designs. He also suggests product for the layouts but does not endorse any particular brands but suggests what he thinks is good and not so good..You can buy thru his site as well although he
doesnt sell anything.He gets paid when you buy thru his site.,

[epretot]

@ jozef

I will have a similar setup. Very well photographed.

You should label that photo for the forum. It would help novices like us.

I especially like the channels you used to cover the wire. Could you share the brand?

Two questions:

What component is the white and red box?

Do I see two lynx distributors?

E-

[jozef]

epretot:

Thank you for the suggestion to label photos.

The white and red box is a Sterling Power battery to battery charger, model 24v - 24v/35.  This unit will be charging the Lithium batteries as we travel down the road and limits the draw from the alternator to 35 amps.

The blue unit next to the batteries is a Victron Lynx Power In that I modified to hold four 100 amp fuses (just add bolts).  This unit then feeds power to a Victron Lynx Distributor. The distributor connects to the inverter, solar charge controller, 24v to 12v converter (70 amp) and the Sterling Power B to B charger.

The gray channels are 2" by 2" Panduit, also called wire raceway, that I obtained locally at a electrical supply outlet.  Also available on Amazon.

[epretot]

epretot:

The blue unit next to the batteries is a Victron Lynx Power In that I modified to hold four 100 amp fuses (just add bolts).  This unit then feeds power to a Victron Lynx Distributor.

Can you help me understand the integration of both? I was under the impression the Distributor was an upgraded Power In.

I'm familiar with the mod for the Power In.

[Glennman]

Very very nice jozef! The pics say way more than 1000 words!

[freds]

Let me encourage you a bit...
So, sort through the crap and after awhile, you will find how DIY it is.

Got to say a very neat installation!!!!

So what's the grand total that you have invested in your system?