diy solar

diy solar

Mobile cart build

EastTexCowboy

EastTexCowboy

Solar Wizard
Joined
Jan 19, 2022
Messages
1,598
Location
East Texas
I'm going to do a mobile cart build based on the video Will did with the EG4 3K. I could simply duplicate everything he did and I'd have a great system, but I'd like to refine the design a little with some specific goals in mind. I'm hoping for some input from the brain trust on this forum. I have no doubt I'll get some really innovative ideas. I'll document the build here, although it's so simple I can't see that taking a lot of effort.

This build is going to be for my daughter and her husband who have zero experience with solar but considerable experience with power outages. They're in north central Arkansas, which is a ways from me so I want to keep it simple and hopefully fairly reliable. Here's where I'm at -

  • Inverter - I've looked at a lot of other options but the EG4 3K seems to be the best option due to physical size, weight, and capabilities. From the posts here and videos it seems to be reliable. I'm open to suggestions on this as well as any of the build.
  • Battery - Will used the Trophy and gave his reasoning which I think was primarily the battery connections. The Trophy has been on backorder for a while so I'm looking at the SOK from Current Connected. I'm an EG4 fan but the battery connections are not positioned very well for this application. The SOK seems solid, has decent connections for the application, and Dexter is very active here so I have no qualms about going that direction.
  • Connections - There are three I/O connections needed - (1) AC input, (2) AC output, and (3) PV input.
    • AC Input - Will used a basic 120v cord which would certainly work. But I'm thinking maybe a mounted connection in a metal switch box or similar bolted to the cart frame which would allow the user to connect with a standard extension cord without any cords hanging out of the unit.
    • AC Output - Again, Will simply connected a power strip or surge strip which would certainly work. I'm thinking a two gang metal switch box, once again mounted to the cart frame. Mostly just to clean it up and not have cords dangling.
    • PV Input - I'd like something a little easier to connect and disconnect than MC4 connectors. @OffGridForGood suggested a 175A Anderson connector, which I'll admit looks pretty good. It's going to mean a dangling cord but it would be a pretty simple solution. I also thought about mounting something like a male NEMA 14-30R on the cart and building a matching cable with the MC4 connectors on the other end to connect to the panels. I know, I'm running out of room on this little cart to mount stuff. I'd love some input or ideas on this.
  • Mounting the battery
    • The orientation has bugged me a little on this because if you mount the battery so the connectors are towards the cart and the LED screen is oriented where you can read it standing in front of the cart you won't be able to lay the cart down on its back while using it. The battery would be upside down. I don't know that this is a big deal but I can see people laying it down on its back. I suppose I just need to advise them not to do that.
    • Will mounted his with a ratchet strap. I'm trying to come up with another way but I've been struggling. If I had a metal brake I could make a sheet metal box, but I don't have one. I can't really justify one. It would be nice to have it easy to remove the battery for loading it in a pickup and the strap would be fine for that but then you have to connect and disconnect the battery cables so maybe not.
  • Solar panels - I haven't thought about this a lot. I may not even give them any panels at first and just let them charge from the grid. If I do it's probably going to be some smaller output panels due to size, weight, storage space. I have some spare 445w panels I can use just to test it but they're heavy beasts. Maybe I'll just order a bunch of small panels then I can have some for myself for future projects, because you know I'm going to want to build one of these for myself.
Looking forward to any ideas or suggestions.

Here's Will's video in case you haven't watched it. He also has a follow up video.

@Gavin Stone has done a couple videos on the EG4 3K inverter as well. If you haven't seen those they're very informative. Here's the first one -
 
For the battery mounting. I would build a tray out of small angle. On the foot of the cart. So that the battery can be set in it. Then make a bracket for the top. Using the mounting holes for the original server rack brackets.
 
OffGridForGood said:
Ya-All are cutting into my time, I supposed to be processing some poultry not reading all this stuff right now!
LOL
(yeah, the read is a lot more interesting)
Click to expand...
Even though I kinda have the weekend off.
I have 4 bids to get together. And 3 jobs to order materials for.
Here, is evidently more preferable. lol
 
EastTexCowboy said:
PV Input - I'd like something a little easier to connect and disconnect than MC4 connectors. @OffGridForGood suggested a 175A Anderson connector, which I'll admit looks pretty good. It's going to mean a dangling cord but it would be a pretty simple solution. I also thought about mounting something like a male NEMA 14-30R on the cart and building a matching cable with the MC4 connectors on the other end to connect to the panels. I know, I'm running out of room on this little cart to mount stuff. I'd love some input or ideas on this.
Click to expand...
Another option is to pick some rarely used NEMA plugs - so there is little chance someone plugs in something other than the intended PV input!
I was considering a 20A 250V twist lock, since none of my generators use this, it would be unique at my site, and with three conductors, Pos Neg and Ground could be connected. This allows an easy male end on the cart, in a box, no dangling cords, similar to a generator plug in supply.
 
IMG_8640.jpeg

Would something like this work for the Anderson? Mount it into a pocket on the frame?
 
OffGridForGood said:
Lordy would I! too bad you-all are so darn far away! LOL
actually we do trade with a neighbour - they have honey and black angus beef, we have fresh eggs, poultry and turkey.
Click to expand...
We have a cull cow going to the butcher late September. A friend is taking half and the other half goes in the new freezer, but we'll have plenty. Two steers are scheduled for freezer camp about a year from now. That's the earliest appointment I could get at a state inspected processor and I made that appointment two months ago. It's a little crazy. Another steer and a cull heifer probably next September or so. Not a lot of beef but we're just getting ramped up. We should have a rhythm going in about two or three years. All grass fed, grass finished Dexter.
 
EastTexCowboy said:
. If I had a metal brake I could make a sheet metal box, but I don't have one. I can't really justify one.
  • Solar panels - I haven't thought about this a lot. I may not even give them any panels at first and just let them charge from the grid. If I do it's probably going to be some smaller output panels due to size, weight, storage space. I have some spare 445w panels I can use just to test it but they're heavy beasts. Maybe I'll just order a bunch of small panels then I can have some for myself for future projects, because you know I'm going to want to build one of these for myself.
Click to expand...
Sir, it sounds to me like you “need” one to complete your vision for your kid.

On the panels, a few of the 400w briefcase type may do the trick? Freestanding, collapsible, portable. Overpriced and idk if it would bring in the power needed though. But seems like an opportune form factor for this design. Maybe have a sleeve they slide in on the backside of the cart when not in use, but not permanently affixed either
 
GOO5E said:
Sir, it sounds to me like you “need” one to complete your vision for your kid.

On the panels, a few of the 400w briefcase type may do the trick? Freestanding, collapsible, portable. Overpriced and idk if it would bring in the power needed though. But seems like an opportune form factor for this design. Maybe have a sleeve they slide in on the backside of the cart when not in use, but not permanently affixed either
Click to expand...
If I'm going down that road I really "need" a CNC plasma cutter too. :ROFLMAO:

I looked at something like that a long time ago. Probably need to revisit. The sleeve idea makes sense if I found something that worked. I suspect the cost is going to be a factor. I don't mind investing money but I don't like wasting it and those things are typically way overpriced. Thanks!
 
Or instead of a two-wheeled cart like Will used, get a Garden Wagon on four wheels, rack batteries stack up in angle iron slots welded at one end of the wagon (secure as Tim said using the original tabs lined up with angle), and the inverter/outlet electrical panel/plugs/breakers attached to a bracket welded to support these vertically at the other end of the wagon. Maybe some room on their for useful stuff like an extension cord. Wire in the connections for PV for just in case/future with it's own combiner box and everything ready to go.
{Then apply for a patent and send me and Tim a couple prototyes to "test" for ya!, Tim will "drive" his like it's stolen}
 
I was thinking a cart would be better as well.
If you got one long/wide enough you could make a nice storage area for ~1kw of grid tie panels... If you really wanted to get fancy you could make the framework out of strut and also use it as the framework for the ground mount....
Wow thinking about it that would be pretty darn simple...
 
You must log in or register to reply here.

Similar threads

W
PowerPro battery for a golf cart?
Replies
3
Views
140
sunshine_eggo
sunshine_eggo
Q-Dog
Building a power cart, need some GFCI clarification
2
Replies
24
Views
464
timselectric
T
Pueo
Charging lower soc 51.2v lithium battery directly from higher soc 51.2v lithium batteries.
Replies
4
Views
247
Pueo
Pueo
A
A thread on battery carts.
2
Replies
34
Views
1K
G20
G
W
Small 12V system? 200-300W of panels, 200AH of 12V battery, 48V boost converter?
Replies
1
Views
89
MTM98290
MTM98290
Back
Top