Building a 24V System in a converted cargo trailer. Any advice/feedback welcome and appreciated!

[ljohns91]

Hi All!

First of all, thank YOU for reading and thank YOU for posting. I have learned a great deal from this forum and am eager to contribute back to the community at some point in the future.

My family and I are hitting the road in May for three weeks to see Mt. Rushmore, Yellowstone and Zion, along with many other beautiful sites along the way. We plan to be on shore power about 14/21 days for this trip, but plan to go 3 or 4 days at a time in the future without grid power. I decided to build a camper instead of buy with the major goal of learning a few new skills along the way; understanding electricity topped the list. I have watched countless hours of Youtube and read many forums and posts in an attempt to absorb as much knowledge as possible, but YOU are the experts. I have posted a schematic of the planned electrical system as well as listed the components I plan to use with links.

I welcome and appreciate any feedback/advice you have to offer related to safety, price, simplicity or anything else. A few specific questions below:

- What is the best way to ground the system to the trailer frame? Should I run strait from -N busbar as shown in schematic?
- I plan to reduce ALL incoming power to 15/20 amps, mainly for simplicity. Is this advisable? Any major drawbacks other than slower charging?

Thank you!
Lawrence



System Components:

Component	Price	Link
Firman W01682 - Inverter Generator	$484.36	https://www.costco.com/firman-1600w...red-inverter-generator.product.100713858.html
PIP-2024LV-MK 24V 2kW, AIO Inverter and 2kW Solar Charge controller	$588.00	https://watts247.com/product/pip-2024lv-mk/
SunStone Cylindrical Nano 24V 100AH LiFePO4 battery Built in BLUETOOTH BMS	$735.00	https://watts247.com/product/cylindrical-nano-24v-100ah-lifepo4-battery-built-in-bluetooth-bms/
T Tocas 50 A Circuit Breaker amp breakers with Switch Manual Reset	$26.99	https://www.amazon.com/Tocas-Circui...86MWWC5GRAP&psc=1&refRID=N7WC1KQ7R86MWWC5GRAP
DC 24v to DC 12v Step Down 30A 360W Heavy Duty Truck Car Power Supply Adapter Converter	$22.99	https://www.amazon.com/Adapter-Conv...612660153&sprefix=24v+to+12+v,aps,206&sr=8-10
12-Way 12V Blade Fuse Block, 12 Volt Automotive Fuse Box Holder Waterproof with Negative Bus 5A 10A 15A 20A	$20.99	https://www.amazon.com/dp/B0811WP5H...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
4 Post Power Distribution Block Bus Bar Pair with Cover - Made in The USA - 250 Amp Rating	$39.99	https://www.amazon.com/Post-Power-D...ild=1&keywords=++busbar&qid=1612658938&sr=8-4
Outdoor Extension Cord 25ft, ShineKee 12 Gauge	$29.99	https://www.amazon.com/Extension-Sh...7420&s=hi&sprefix=25+ft+12+g,tools,201&sr=1-5
3 inch Desk Power Grommet	$43.99	https://www.amazon.com/Power-Gromme...500+watt"&qid=1613095729&s=electronics&sr=1-8
freneci XT60 connectors, 5 Pair Male and Female with Wire	$14.99	https://www.amazon.com/freneci-XT60...keywords=xt60+connector&qid=1612482234&sr=8-4
4 AWG Gauge Red + Black Pure Copper Battery Inverter Cables Solar, RV, Car, Boat 5 feet 3/8 + 5/16 in Lugs	$27.23	https://www.amazon.com/dp/B01F32MSH...81c97046d2f19983d19b6a508&language=en_US&th=1
4 Gauge Copper 1/4 Ring 10 PK Crimp Battery Lug Terminal	$7.95	https://www.amazon.com/Copper-Batte...nector&qid=1612655503&s=sporting-goods&sr=1-6
10 AWG 10 Gauge Silicone Wire Hook Up Wire Cables 20 Feet	$15.38	https://www.amazon.com/Electrical-S...rds=10+awg+copper+wire&qid=1612656703&sr=8-11
14 Gauge 2pin 2 Color Red Black Cable Hookup Electrical Wire	$20.99	https://www.amazon.com/TYUMEN-Elect...ords=14+awg+copper+wire&qid=1612656152&sr=8-5
Cutequeen 2PCS 100W Watt 8.2 Ohm Aluminum Case Wirewound Chassis Mounted Resistor	$5.99	https://www.amazon.com/Cutequeen-Al...ohm+precharge+resistor&qid=1612397628&sr=8-14
QIFUN 12V Adjustable Dual Head Clip Fan	$29.99	https://www.amazon.com/QIFUN-Adjust...hild=1&keywords=12V+fan&qid=1612569244&sr=8-9
OPOLAR 8 Inch Desk Fan with Timer, USB Operated	$29.99	https://www.amazon.com/dp/B077SDZL8...&pd_rd_r=8d8d8614-30ce-42af-b8b6-e05dd7f8f30e
Suburban NT16SE NT-16SE Series Direct Discharge Furnace 16,000 BTUS, Thermostat and Bug Screen	$549.96	https://www.adventurerv.net/suburba...rerv.net3837&utm_medium=cpc&utm_source=google
MIDEA MAW05M1BWT Window air conditioner 5000 BTU	$169.99	https://www.amazon.com/MAW05M1BWT-c...rden&sprefix=window+ac,garden,320&sr=1-1&th=1
MTI INDUSTRIES 30-442-P-BL Safe-T-Alert 30-442 12V Propane Alarm Flush Mount Black	$47.68	https://www.amazon.com/gp/product/B00F6EWDU0/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1
RICH SOLAR 2 Pieces 100 Watt 12 Volt Polycrystalline Solar Panel Black Frame	$140.99	https://www.amazon.com/RICH-SOLAR-P...Solar+Panel+Black+Frame&qid=1612657881&sr=8-1
RICH SOLAR 20 Feet 10 Gauge Solar Extension Cable One Pair	$27.99	https://www.amazon.com/Electrical-S...rds=10+awg+copper+wire&qid=1612656703&sr=8-11

 

[Nakinto]

I don't know about that CC/inverter combo, remember you usually get what you pay for and I don't see ANYTHING on that stating what voltage the panels need to be, but with most MPPT charge controllers you need at least 25% higher voltage then the battery system. I would say jump down to your hardware store for the 10 gauge wire... $30 for 20 feet (x2) is very expensive usually less then .50 per foot, so for 40 feet it shouldn't be more then $20. I don't know a thing about SunStone batteries, it looks like they might just be 18650's in a box... but I don't know. Everything else looks fine

 

[ljohns91]

Thank you for the feedback Nakinto! Much appreciated. I plan to take a look at buying all components locally, before submitting the Amazon order.

 

[HRTKD]

I have a separate bus bar for grounds. This is ONLY for those devices that call for a ground. I think this would be called an equipment ground. On my MPPT solar charge controller, there is a ground screw on the side. I run wire from that screw to the ground bus bar. Then from the ground bus bar there is a wire going to the frame of the trailer.

I hope your trailer is well insulated. It's friggin cold along your route.

 

[Nakinto]

John, where are located? I am in WA state, and as such both Midnite Solar and Magnum energy are local for me, as in they are manufactured in my state Both my father and I use them both.

Magnum energy has a wonderful customer service center, when my father's Magnum 4448 inverter went capoot the customer service tech talked us through troubleshooting and "it sounds like you have a bad FET board temp sensor, here are the licensed repair locations near you, but since they are both a distance away, we can send you a replacement and a return label for the bad unit, you can send that one back when you receive the new one" There was of course a hold on my fathers credit card for the cost of the new one until he returned the old one, but they paid the shipping and as soon as they received the broken one the hold was gone. Yes, I SHOULD be paid to advertise for them

When I thought I had a problem with my Midnite Solar charge controller, the tech forwarded me to one of the engineers and this guy KNEW what he was talking about, I tell you. We troubleshot and there was nothing wrong with the unit, I had messed up a setting and it was 100% MY FAULT lolol. I also learned there are several adjustments you can make on the boards during this, including a fine tune voltage and amperage readers, wonderful device and it handles just about anything. OH, and Midnite offers replacement boards, anyone can purchase replacement internals for the unit at a fraction of the cost of the unit, so repair IF the unit fails out of warranty is easy and cheap-ish.

I have been running both for almost 7 years now, and none of mine have had any trouble that wasn't user error. My fathers unit was probably due to his AC using WAY more power then my AC and probably overloaded his unit, but Magnum still replaced it under warranty.

DOWNSIDE, The Midnite Solar controller is usually around $700 and the Magnum Energy is around $1700, both FAR more expensive then that charge controller/inverter combo (hence why I am warry of that Sunstone, that and it doesn't tell you the minimum or maximum voltages, anywhere...)

To repeat KRTKD, this can't be stated enough, everything at the center should be grounded together, inverter (both the negative terminal and the AC Neutral) Charge controller (both battery - and PV -) and the batteries -terminals should ALL be grounded to the frame of the vehicle and when the vehicle is parked, it is a good idea to put in a grounding rod if possible (many places it is impractical and in others it is just not going to work, like death valley for example) Now these grounds don't HAVE to be on a bus bar, but it is much easier to run ONE line from the bus to the frame then a separate line from each thing to the frame (cheaper too)

 

[ljohns91]

@ KRTKD
Thank you for your feedback! That makes alot of sense! I checked the primary DC components I plan to use and none require a ground BUT that is a great idea to build in a Ground busbar now to enable simple install for any future equipment that calls for it. The insulation portion of the build is done and the kids couldn't wait to sleep in it; temps got down to mid 20s and a little 750watt heater running on house power was a bit too much! Looking forward to testing when we get the 16,000 BTU propane furnace installed!

@ Nakinto
We are out in New Mexico! I would love to go American made but trying to keep the price down and found the MPP Solar All-In-One units to be the most economical and simplistic for my first jump in DIY power. Hopefully we can expand to a larger trailer in the future if this goes well and we enjoy the open road. I am taking the stance that the first trailer is to learn, test, enjoy for 4 or 5 years and then sell, the second trailer is to really put the money into for the long term.

Specific to the PV input voltage, I found the following in the PIP 2024 LV-MK manual (2KW is the model):


Does that answer what voltage the panels need to be for the system?

 

[jwelter99]

I just saw this listed in another thread. It might be a good low cost and simple solution as an all in one. Would definitely cut down on wiring and bus bars required.

https://www.amazon.com/Inverter-110V-120V-Controller-Batteries-Generator/dp/B08R3MSXTG/ref=sr_1_7?dchild=1&keywords=24v%2B3000w%2Bmppt%2Binverter&qid=1613614940&sr=8-7&th=1

At that price you can almost carry a second one as a backup....

 

[Nakinto]

Yes it does John, max Solar voltage is 115 on that. minimum is 30. You would need at least 3, pref at least 4 of those 100w panels to run that inverter/CC.

Matching the equipment is essential, good to ask before buying this stuff I took almost 2 years matching my system, as there wasn't much support like this at the time.

 

[ljohns91]

@jwelter99
Appreciate the suggestion! That unit is very similar to the PIP 2024 LV-MK that my current system is based on and it certainly has a bit better output at 3000w. Do you happen to know who the manufacturer is? I found that item rebranded a few different ways on Alibaba but couldn't find any information on who actually makes it. Do you know if it is UL listed?

@Nakinto
Great point - you are exactly correct that I would likely want 4 of those panels to ensure that minimum 30 solar voltage is received. Admittedly, I have overlooked much of the solar panel research as that will likely be a future expansion point for my system. We plan to be on rv park shore power a majority of the time for our trip in May so I am leaning towards a small gas powered inverter generator to top off the batteries while we travel for the 2 or 3 days at a time.

 

[jwelter99]

@jwelter99
Appreciate the suggestion! That unit is very similar to the PIP 2024 LV-MK that my current system is based on and it certainly has a bit better output at 3000w. Do you happen to know who the manufacturer is? I found that item rebranded a few different ways on Alibaba but couldn't find any information on who actually makes it. Do you know if it is UL listed?

@Nakinto
Great point - you are exactly correct that I would likely want 4 of those panels to ensure that minimum 30 solar voltage is received. Admittedly, I have overlooked much of the solar panel research as that will likely be a future expansion point for my system. We plan to be on rv park shore power a majority of the time for our trip in May so I am leaning towards a small gas powered inverter generator to top off the batteries while we travel for the 2 or 3 days at a time.

Sorry I do not. I am a big proponent of the Victron line of equipment but do realize it's overkill for some both in features, size of the physical install, and price.

I do wish Victron would do a small all-in-one basically taking a Multiplus 12/3000, a SmartSolar, and an Orion 12 to 12v B2B, all into one box and keeping it the same size, or smaller, of the current 12/3000.....

Wishful thinking but that would be a kick-ass unit for a lot of the van conversion folks.

 

[Q-Dog]

Sorry I do not. I am a big proponent of the Victron line of equipment but do realize it's overkill for some both in features, size of the physical install, and price.

I do wish Victron would do a small all-in-one basically taking a Multiplus 12/3000, a SmartSolar, and an Orion 12 to 12v B2B, all into one box and keeping it the same size, or smaller, of the current 12/3000.....

Wishful thinking but that would be a kick-ass unit for a lot of the van conversion folks.

Are you familiar with the Victron Easy Solar ?

 

[ljohns91]

Updated system schematic attached based on feedback received thus far. Any additional feedback would be much appreciated!

 

[HRTKD]

The 50 amp circuit breaker downstream of your solar panels is probably too much. I think I'm using a 16 amp circuit breaker for 640 watts of panels.

Why is there a connection between the solar panel circuit breaker and your ground bus bar?

It's unlikely that your 24v-12v 40 amp converter will draw 40 amps, but if it does, your 40 amp circuit breaker may trip. A 50 amp circuit breaker may be more appropriate in that position to avoid nuisance trips. But like I said, it's not likely that you'll ever pull 40 amps through the converter.

Most designs are not using a circuit breaker immediately downstream of the battery. Instead, a fuse is used there.

 

[jwelter99]

Are you familiar with the Victron Easy Solar ?

Yes but it is large physically and only 1600VA in the 12V model which is too small for what most people want.

It also is just a frame with the various other stuff installed so a lot of room to optimize packaging, etc.

But the right concept, just a lazy implementation.

 

[ljohns91]

@HRTKD
Great points - oversight on both the solar panel breaker size and solar ground wire. Based on 100w 48v, I think I should be good going all the way down to a 10 amp. Increased the 40 amp to 50 amp.

The main reason I went with the 50amp circuit breaker vs a fuse just downstream of the battery was to integrate a simple battery disconnect - Does that warrant a breaker or would a fuse be the better option?

 

[HRTKD]

The usual recommendation is a fuse, then an actual battery disconnect switch. Something like this.

m-Series Mini On-Off Battery Switch with Knob - Red - Blue Sea Systems

300 Amps continuous rating for outboards and small gasoline or diesel engines.

www.bluesea.com

 

[Nakinto]

Updated system schematic attached based on feedback received thus far. Any additional feedback would be much appreciated

That will be 400w at 48v, The drawing also kinda confused me where you have the - and + to the batteries coming out of the PIP in the same corner, but I got it eventually and it is really my sense of aesthetics with drawings like this. Don't forget proper sized wire and breakers for each of the loads coming from the AC output (better to have multiple breakers then just one big 50, and cheaper wiring that way.) If you only have a 15 amp 240v input, you don't need a 50 amp breaker there. Otherwise looks great! I don't see anything that might go BOOM

To your last question about fuse vs breaker for disconnect. Better to have a dedicated disconnect on the battery as using the breaker a lot WILL damage the breaker (this causes the breaker to degrade so it will trip at lower loads, nothing dangerous just irritating.)

 

[JoeHam]

Scrap the T-Tocas craptastic breaker and buy a brand name like Bussman

Amazon.com: Bussmann CB285-70 Surface-Mount Circuit Breakers, 70 Amps (1 per pack): Automotive

Buy Bussmann CB285-70 Surface-Mount Circuit Breakers, 70 Amps (1 per pack): Circuit Breaker - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

This is NOT an area where you want to save money. And I’m cheap as all get out ?.

You want the 185 series Bussman. The 50 amp is more on Amazon for some reason so shop around if that’s the appropriate size.

 

[JoeHam]

Or use a proper DC breaker on a DIN rail. Multiple amp sizes at this link:

https://www.amazon.com/gp/product/B07VJ2PSLP/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I’ve used mine as a shut off many many times without issue. When I order the C-65H DC breakers from Amazon they usually send a Schneider brand name one even though it’s not shown.