First Build | A portable solar power station that isn’t ugly

[SolarOhio]

I wanted to make a stand-alone home backup unit that was modular and small enough to move easily— but robust enough for sustained power tool use and 2+ days of emergency lighting and refrigeration. Stretch goal: an attractive form factor that doesn’t involve a hand truck.

To keep the build simple, I rolled the dice on a battery pack by Mr. Li via AliExpress. Amazingly, the unit arrived in about 2 weeks even w/ free shipping, and so far it has tested true to spec.

-Battery: 2.4kw/24v 8s1p 100ah prismatic lifepo4 w/ built-in BMS (I plan to build from raw cells next time)
-Inverter: 2500w/5000 surge single phase by CNSPower/Xijia
-Charge controller: Epever Tracer MPPT 40amp w/ MT-50
-AILI battery monitor - 150 amp
-2x 24v USB QC 3.0 ports w/ volt meter (bypasses inverter)
-2x USB 2.4 ports (run off AC outlets)
-4x 120v AC outlets protected by GFCI
-Protections: 200amp main breaker; 50amp breaker to charge controller; 15 amp fuse to USB 3.0; multiple on-board protections for the BMS, inverter, and MPPT
-SAE port for mobile solar array (coming soon); will charge fully in 1 day on 4x100w - I plan to add wind capability at some point. No grid input. Ever.
-Lightning bolt flair painted by 8 y/o helper

My total system cost was around $1600, and Will’s videos/links/book and this community were hugely helpful! This medium suitcase-sized box runs cool and quiet with plenty of room to expand, and it’s nice to be able to point things out through the acrylic door to help our kids learn. Happy so far!

Questions or suggestions or want component detail/links — please let me know!

 

[Bob142]

Nice job, thanks for sharing. It looks very organized and solidly built. The one question I have is how does it vent? At some point during extended operation the inverter and charge controller will generate some heat.

 

[mrdavvv]

Really nice, i really like it, very well organized and good work with the cabling..... i might do something similar in the future!.

Altough ill do it probably with aluminum / plastic sheets as i don't trust wood with electronics that much (Or maybe ill just add some internal paint to make it less flammable).

I concur with Bob, maybe a little fan will help a lot.

Do you have links to the battery / battery case?

 

[Deleted-User]

Was curious how you are handling low voltage disconnect (LVD)?

 

[Pacer]

Loving this! It’s so cool to see each persons ideas come to life to address their particular needs. I’m brainstorming hard still, and have a cool idea I’m bringing to life as well. I may borrow a bit of inspiration from this build!

 

[SolarOhio]

Nice job, thanks for sharing. It looks very organized and solidly built. The one question I have is how does it vent? At some point during extended operation the inverter and charge controller will generate some heat.

I do plan to add bottom/top vents near the inverter, but so far heat has not been an issue due to airspace in the box. The fan on this inverter seems to only kick in for loads above 300-400w. For a 50% drain test I ran a full-sized refrigerator for 18hrs, did a load of laundry, and charged multiple devices simultaneously — everything stayed cool and the fan only ran a few times w/ 93% overall efficiency. I think with vents near the inverter there won’t ever be a need to add a cooling fan.

 

[SolarOhio]

Was curious how you are handling low voltage disconnect (LVD)?

I tested the built-in BMS with a 100% discharge, and it disconnects at 19.9v and requires the charger wires to be reconnected, but this can be done at the MPPT instead of the terminals. I don’t love “flying blind” with the BMS, so I plan to baby the system and avoid triggering protect mode again. With all breakers open for storage, only the AiLi monitor stays always-connected and has a minimal drain of ~0.007ah.

 

[Pacer]

Also- where in OH? 330 here.

 

[SolarOhio]

Also- where in OH? 330 here.

740 - Licking Co. here.

 

[SolarOhio]

Really nice, i really like it, very well organized and good work with the cabling..... i might do something similar in the future!.

Altough ill do it probably with aluminum / plastic sheets as i don't trust wood with electronics that much (Or maybe ill just add some internal paint to make it less flammable).

I concur with Bob, maybe a little fan will help a lot.

Do you have links to the battery / battery case?

I hope to do a heavy simultaneous load/charge test soon to really know what sort of heat this will output. I only have 400w of panels available at the moment. Internal paint is a great idea — had I not kind of built the box around the system mid-flight I definitely would have done that. Battery pack here — cost is 20% more than what I paid in early May: https://m.aliexpress.com/item/4000833136355.html

 

[BigIslandRyan]

Excellent job SolarOhio! Love it!!!

 

[SolarOhio]

Pics of the latest updates. Lights, grounding and more.

 

[AmboLander]

I wanted to make a stand-alone home backup unit that was modular and small enough to move easily— but robust enough for sustained power tool use and 2+ days of emergency lighting and refrigeration. Stretch goal: an attractive form factor that doesn’t involve a hand truck.

To keep the build simple, I rolled the dice on a battery pack by Mr. Li via AliExpress. Amazingly, the unit arrived in about 2 weeks even w/ free shipping, and so far it has tested true to spec.

-Battery: 2.4kw/24v 8s1p 100ah prismatic lifepo4 w/ built-in BMS (I plan to build from raw cells next time)
-Inverter: 2500w/5000 surge single phase by CNSPower/Xijia
-Charge controller: Epever Tracer MPPT 40amp w/ MT-50
-AILI battery monitor - 150 amp
-2x 24v USB QC 3.0 ports w/ volt meter (bypasses inverter)
-2x USB 2.4 ports (run off AC outlets)
-4x 120v AC outlets protected by GFCI
-Protections: 200amp main breaker; 50amp breaker to charge controller; 15 amp fuse to USB 3.0; multiple on-board protections for the BMS, inverter, and MPPT
-SAE port for mobile solar array (coming soon); will charge fully in 1 day on 4x100w - I plan to add wind capability at some point. No grid input. Ever.
-Lightning bolt flair painted by 8 y/o helper

My total system cost was around $1600, and Will’s videos/links/book and this community were hugely helpful! This medium suitcase-sized box runs cool and quiet with plenty of room to expand, and it’s nice to be able to point things out through the acrylic door to help our kids learn. Happy so far!

Questions or suggestions or want component detail/links — please let me know!

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Nice rig!

I built mine focused more on 12 volt for efficiency reasons, but they sure are fun to build, huh?
(It has since been upgraded to a MPPT)

I like seeing everyone's vision and originality. #CoolStuff

Mine:

 

[AE4KR]

I'm curious about everyone's experience with GCFI outlets powering refrigerators. 120-volt outlets behind refrigerators in homes are generally not GCFI, because motor starts may pop the GF breakers.

I learned this after a small chest freezer in my garage popped the GCFI breaker while I was on vacation. Hundreds of dollars worth of food was ruined. I've temporarily put an isolation transformer on the freezer to prevent a recurrence, while I determine whether I can put a non-GFCI outlet in the garage for the freezer without violating code.

Even the outlets on larger inverters seems to come with GFCI standard. Am I the only one who's experienced this failure mode?

 

[SolarOhio]

I'm curious about everyone's experience with GCFI outlets powering refrigerators.

My solar station is manual enough (no tie/ATS) that you wouldn’t miss something like that in an outage —you’d be around checking on it regularly. But I was planning to replace our main refrigerator outlet with a gfci because it’s box is in the floor and not the wall. It would not be great if that tripped during normal cycling.

 

[SolarOhio]

2 years update: Station had performed well until a recent low voltage disconnect. I believe my setup with lights and small inverter continuously connected caused a slow drain that the battery monitor did not pickup on. LVD occurred with monitor showing 80%.

Currently, battery pack will not charge and only powers up to 14.5v when connected to 42v x 4 amps — I believe it is only powering up the BMS/display. I’m hoping that disconnecting the positive terminal side on the BMS will reset it and allow it to charge again.

Attached are pics after I pried open the protective case. The inside is pretty simple, but there is no access to the BMS unless I cut open the packing.

 

[SolarOhio]

Another inside view.