Suggestions for 'simple' power station

Wits' End

Old guy, wanting to learn new tricks.
Joined
Mar 14, 2021
Messages
33
Location
North Shore of Lake Superior's northwoods
I'm running my home from a basic 48v solar system. I'm off grid, have generator for backup charging. Or take to work for AC charging. I've found I sometimes need more, or portable power for a specific task.

Have watched lots of YouTube videos, and basic knowledge. I'll start off with my 'plans', add questions. Please comment, suggest, link to solutions or alternative ideas.

Looking at a large toolbox or weather resistant container. Ideally outside compartments or space inside for needed cords etc, so I can leave this for months or weeks, and have everything I need still in one spot.

*2x12v 100Ah batteries. Series for 24v
*Batteries will have BT BMS. Low temperature cutoff. I will add heating mat and insulation.
*It looks like most, USB, 12v sockets, etc. ports can be powered by 12-24v.
*I can use 24v to more quickly charge/power DC inputs, that allow 12-24-36v. Rather than 12v.

¿Best and economic way to get AC out and in?¿Thinking 1000-1500-2000 Watt inverter
¿20-50amp charger
¿Is there a decent- compact -economic inverter/charger available? <I do know pick 2 of the 3>
***I'm aware and plan on fusing and switching circuits, heavy/appropriate wire guage. Any other obvious & "common sense" things that are often missed?
Thank-you in advance, Herb [Wits' End]
Please move to a different forum if appropriate!
 
I think there are 24v batteries you can buy.
24v at 100amps is 2.4kW, but you don't want to run at more than half (1.2kW) on a continuous basis. So 1,500 watts that can surge to 2.4kW works.

Also, charging at 0.25c (25 amps) or less us best for the battery.
 
I think there are 24v batteries you can buy.
24v at 100amps is 2.4kW, but you don't want to run at more than half (1.2kW) on a continuous basis. So 1,500 watts that can surge to 2.4kW works.
From what I have seen 2@12 v 100 amp batteries are quite a bit less than 24v 100 amp. By a few $100.

As I was thinking last night I might do 2 separate 12v 100 amp cases. With one just USB & 12v out. The other being able to fit the second battery in and use when AC is needed.
Or it it reasonable to put Anderson connectors in place to series connect two small boxes together?


Though each battery at 12-(20) amp charging max, might be restrictive.
 
With one 24v battery there should be a bms that keeps all the cells balanced. With two 12v batteties the internal cells are balanced, but the batteries could be unbalanced between each other.

Drawing off 12v from one battery for other uses will mess up the 24v battery.

You charge a 24v battery with 24v. Don't charge the individual cells (12v) unless you know what you are doing (like the bms is designed to do).
 
Last edited:
I would go with two "mini" 12V 100Ah batteries, big space savings versus the regular size batteries that have a ton of empty space inside.
 
May want to consider a growwatt 24 all in one inverter for $399. 2kw mppt and 3kw inverter. Buying a decent inverter and charge controller will cost about the same. This has added benefit of allowing grid connection for charging.

I admit I'm new to the game, but those seem like the best bang for the buck unit for a small budget system.
 
May want to consider a growwatt 24 all in one inverter for $399. 2kw mppt and 3kw inverter. Buying a decent inverter and charge controller will cost about the same. This has added benefit of allowing grid connection for charging.

Sold out unfortunately
 
From what I have seen 2@12 v 100 amp batteries are quite a bit less than 24v 100 amp. By a few $100.

As I was thinking last night I might do 2 separate 12v 100 amp cases. With one just USB & 12v out. The other being able to fit the second battery in and use when AC is needed.
Or it it reasonable to put Anderson connectors in place to series connect two small boxes together?


Though each battery at 12-(20) amp charging max, might be restrictive.
Superior Northshore - hey neighbour!
I run a main 48v stationary system, and separate 12v and 24v mobile systems. Here is what I have learned using all three:

a 12v system will be limited in what it can reasonably be expected to run. I find it best for some small-ish 120v AC loads like portable hand tools - think of things like a drill, angle grinder, jigsaw kind of stuff. Can you set up a 12v to do more? sure you can, but is it that portable or practical? I find not so much. I keep my 12v system to about 8A 120v output, ie 1000W, and use an MPP 1012.

a 24v system will run loads up to about 20A 120v plug would run. But to have any "real" capacity, I find this set up is best mounted on a garden cart, or sit on the tail gate of the truck, occationally I have set it on the back of the quad, but it is a bit heavy for this at about 230 lbs.

The 24v system should be 24 volt. Two series connected 12v batteries is not ideal.
I used a 24v All-In-One inverter for mine - that can handle grid charging, PV input, and convert the DC battery to 120vAC. I used the MPP 2724 since this model has outlets built right into the side of the inverter - no separate plugs needed. It also has 5v USB A & C outlets for charging phones and such which is also handy.
I have added heating and lights to my unit, and working on a weather proof enclosure - maybe a large heavy duty tool tote would work.
Still a work in progress - see:
https://diysolarforum.com/threads/building-a-mobile-8s-cart-based-solar-generator-sort-of.74722/
 
Superior Northshore - hey neighbour!
Hello neighbor 👋🏼
Thank you for your input, and my apologies for lack of clarity. I'm looking to build a small toolbox type power station. Like a Jackery or Ecoflow of a few years ago.

After the input above I've decided to 'play' with one battery EG4 WP 12V 100 Ah. For another week Signature Solar has free shipping. So with taxes (and 0 shipping) a reasonably trusted LiPo4, Bluetooth BMS, low temperature shut off, for ~$250.

I'm going to start with just 12v out ports. A variety of USB, maybe an area & a throw LED.

I'm thinking to use Anderson connectors for charging input and output to a not physically connected inverter. I can keep this a battery box, with attachments.

After input above...I think I confused things when I said I was looking for an inverter/charger. I'm hoping there is something the size/volume of a 400-600 page hardcover book (dead tree). 20-30A charging 800-1500 watt AC output.

(Choosing 2, I know) a small, inexpensive, decent quality 20-30A charger stand alone. As I play my biggest "NEED" will be to easily charge this ~25 pound box at work, off AC.

I also have 2@ 20 year old solar panels. IIRC they WERE 350 12V. I'll need to check. My in use arrays are too big for something this small. I assume there is a solar controller that I could use my 48V battery output or my panels to charge my 12V lithium battery?


Any other thoughts? I'll post some links to the Amazon USB and 12 volt accessories I'm looking at. Increase in costs of 10-20% or more is worth it if the quality and appropriateness for the project warrant.
 
(Choosing 2, I know) a small, inexpensive, decent quality 20-30A charger stand alone. As I play my biggest "NEED" will be to easily charge this ~25 pound box at work, off AC.



I also have 2@ 20 year old solar panels. IIRC they WERE 350 12V. I'll need to check. My in use arrays are too big for something this small. I assume there is a solar controller that I could use my 48V battery output or my panels to charge my 12V lithium battery?

You might be better off with a 12v all-in-one
 
Back
Top