Power Buddy Senior




About: I am an automation engineer but I will give anything a go. I don't know if you call if pessimism or just being an engineer, but I look for problems everywhere, then I look for some weird, left field way to s...

Following on from the success of Power Buddy (
I decided to go for the ultimate in portable solar power systems with the Power Buddy Senior.
This is a sack truck mounted 100w solar power system with a 100Ah battery 1000W 230V ac supply, a 110V power tool supply and a 500W flood light system.

Step 1: The Design

I wanted to be able to provide a reasonably large amount of power on site without the use of a generator. With a generator there are issues surrounding the transport of fuel, exhaust of fumes and the sheer physical weight of some of the more useful units.
I had hit on a solution with the Power Buddy but the 200W power output was restrictive.
I had all of these parts on my recycling pile from old decommissioned projects.
The power system consists of a 1000W 12Vdc to 230Vac sine wave inverter. I won't go into huge detail on inverters but a sine wave unit while more expensive is preferred over a square wave or simulated sine wave inverter.
The battery is a 12V 100Ah UPS style battery and feeding the inverter at full load will allow a run time of approximately 30 mins.
This is based on 230V load at 1000W, the battery is 12V at 100Ah this translates to 1200W. Given that the battery should not discharge passed 50% and the solar controller and the circuitry within the inverter will not allow deeper discharge.
50% of 1200W is 600W, which is 60% of 1000W. 60% of 1 hr is 36 mins.
The solar system is 100w so for every 1 hour running 10 solar charge hours are required to recharge, this may seem like a lot but it's free power.

Step 2: The Inverter

The inverter, battery and controller are all to be mounted inside a metal industrial control box. This box was ip65 rated when I started but I needed access to the sockets on the inverter so to make it waterproof again I will need to add a cover. I'm not worried about that at this point as I only intend using the unit in fair weather.
The inverter is lined up with the inside of the box where I want the opening. I used dry erase markers with these boxes as it's easy to fix mistakes and when I'm done my guidelines wipe clean.
I marked the outline of the inverter on the inside wall then removed the inveter to take measurements which I transferred to the outside.
I wanted to round the corners so I marked in 11mm front the edges to give me a centre for my holesaw.
The corners were drilled out to give the rounded edge, the rest of the material was removed with a 4" grinder and the edges filed. I wasn't too worried that the straight sides weren't exactly straight (I was never good at staying in the lines) as I was adding a rubber edge strip, this tidies the edge and keeps me safe from cutting myself on the steel.
The inverter was offered up and riveted to the back plate with 5mm pop rivets.

Step 3: Mount the Box

I decided to mount the system on an old sack truck to make it easy to move around (100Ah batteries are not light).
I lay the truck down and makes where the box made contact.
I have a back plate with channel, this is the same stuff road signs are mounted with.
I drilled through the frame at an angle to allow for the lie of the box.
I then booted the box on using the compatible T-nuts for the channel.
This was tricky and after I had it bolted up I realised I had forgotten to install washers (live and learn...).
I was now having counter balance problems that would come back to haunt me.
The counter balance issue was temporary resolved by adding my 110V transformer.

Step 4: Solar Panel

The solar panel should be tilted back, the design of the sack truck was ideal for this.
I drilled the frame at the top where the panel contacts the truck and bolted with the T-nuts.
At the bottom 2 self tapping tech screws hold the panel.
I drilled the side of the box and inserted an electrical gland, this stops the cable from fraying against the metal.

Step 5: Solar Controller and Battery

The solar controller is a 20A PWM unit this is overkill for.my project and can support up to 240W of solar panel.
Wiring is straight forward as the configuration is marked.
The controller prevents over charging and over discharge of the battery.
The battery was installed and the power system is complete.
The added weight of the battery brought back my balance problem so I will have to add a support leg, for now my hammer is the perfect length.

Step 6: Flood Lights and Done

I mounted a 500W set of halogen lamps, these guys were I a damaged tripod but are a handy addition.
The plug right into the inverter and will run for an hour, great for an emergency.
This is the finished unit, hope you like it.

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    7 Discussions


    3 years ago

    I want so badly to get off the grid. I would love for someone to walk me through the steps. I am not tech minded, and I don't know anyone who is. Do any of you live near DC?

    2 replies
    altE StoreYolandaG7

    Reply 2 years ago

    We created over 150 free videos teaching people about solar. You can check out our YouTube channel, here's a playlist to get you started. https://www.youtube.com/playlist?list=PLoHd6hGDqS06g0umrn4XO0Wk9JyZcTfMa

    Left-field DesignsYolandaG7

    Reply 3 years ago

    Yolanda, sorry but I live in Ireland so no use locally. If you need any advise I'd be glad to help where I can. By off grid what are you looking to achieve, solar, wind, combined heat and power. Is it electricity, water or heating you are after. There are some basic non tech questions you need to answer first. Also there is the matter of your budget and your own technical ability. There are some easy ones to start with. Check out my beer can solar space heater ible for instance.


    2 years ago

    If you put LED floodlights on it, they would last longer on a charge, would they not?

    1 reply
    Left-field Designsblodefood

    Reply 2 years ago

    Absolutely, however this was the set I had and they work pretty well, they are only really for emergency use on this rig anyway


    this panel is an atersa unit, it was part of a kit that was removed. most of my other panels come from www.sunstore.co.uk