A DIY 1,500 Watt Systainer Power Station For $730 USD

[besharp]

I run a sharpening business. A Tormek sharpener uses 200 Watts; a Twice As Sharp scissors machine uses 375 Watts; the Rikon buffer uses 300 W.

Due to my low power needs, I decided to build a power station housed in a Systainer3.

 

[besharp]

Specifications

Size: M187 Systainer3
Battery Capacity: 840 Watt-Hours
120 Volt Power Output: 1,500 Watts
Weight: 8.3kg / 16 lbs 6 oz

Cost

Total cost is $900 CAD / $ 727 USD / 627 Euros:

- M187 Systainer3: $120
- Used 48 V @ 17.5 Ah Lithium-Ion e-bike battery: $500 ($1,000 new)
- 48 VDC to 120 VAC 1,500W inverter: $250
- Miscellaneous Parts: $30

 

[Systainer.Store]

Sweet!  I've noodles some designs for making a battery unit as well.  I don't have a use case other than having some temporary or emergency power in my projects.  I thought it would make a good project though to inspire others, just like you are doing with your post. 

What does the inside look like? 
Did you do some sort of bench testing to confirm this would work well for you before doing systainer modifications?

-Sys Tim

 

[besharp]

M187 Systainer3

The inverter was chosen as it fits inside a M187 systainer (I did have to remove the front handle). No doubt it would fit a taller systainer, but I wanted it to be as short as possible.

I reinforced the front opening with 4" x 4" x .75" steel brackets. They are JB-Welded and bolted in place with black M6 bolts and nuts.  The bolts look out of place; an anthracite or black Systainer would blend the bolts in better.

The back was drilled out for the cooling fans and fan motor mounts.

 

[besharp]

Battery

I used a 48V electric bike battery rated at 17.5 Amp-Hour = 840 Watt-hours:https://ebikebc.com/product/bare-battery-48v-17ah/

There is room inside for another battery on the left side, which would then double the battery capacity to 1,680 Watt-hours.

 

[besharp]

Choosing An Inverter

Inverting 48 VDC to 120 VAC is more efficient than from 12 VDC to 120 VAC (lower current). 12 VDC to 120 VAC inverters are common; 48 VDC to 120 VAC inverters are not. My inverter is from Amazon and is sold under multiple name brands. I picked it due to it fitting inside a M187 Systainer3.

This particular inverter's high voltage alarm is at 60 volts. This means it is possible to use a 52 V e-bike battery (58.8 Volts when fully charged). However, I got a good deal on my used 48V battery. 

 

[besharp]

In Use

Here are pics of it in use at a farmer's market. This Systainer stack holds my Tormek knife jigs at the top (TB M137), various bits and pieces in the middle, and supplies power at the bottom!


Future Expansion

Solar power recharging is next....

 

[besharp]

Sweet!  I've noodles some designs for making a battery unit as well.  I don't have a use case other than having some temporary or emergency power in my projects.  I thought it would make a good project though to inspire others, just like you are doing with your post. 

Did you do some sort of bench testing to confirm this would work well for you before doing systainer modifications?

-Sys Tim

Hi Tim, I wold like to point out that the blue Systainer3 handle was from your store  [big grin]!

I hooked up the battery to the inverter, and the load to the output. That was my "bench testing". Making it fit took a bit of juggling - as you can see from the pics, it's actually quite a tight fit. To install it I had to unplkug all the wires from the front and back panels, them re-plug them. Not difficult at all; make sure you take lots of pictures first before disassembly!

I'd guess it is overrated at "1,500 Watts" but for $250 CAD it was a steal. Seems reasonably well made too.

 

[Systainer.Store]

Thank you for sharing these details.  It is nice to see the effort required to do a mod, I bet it will inspire others.
Thank you too for your order.  I appreciate that.

If I understand your picture right, is there room on the left side for another battery?  You could wire the batteries in parallel then and have more capacity. 

 

[ScotF]

Very cool post and execution! Some great ideas.

 

[Bob D.]

When I looked up the battery you provided the link to the price is $845.

I found a 48V DC to 120V AC 2000W pure sine wave inverter for about $400.

Add in some miscellaneous bits and some wire plus a Systainer to house it all
and it would be about double the $750 you spent.

Still, a nice portable power source and if it fits your need that's what counts.

 

[Coen]

Very nice. But what is the -56 VDC about?? The label suggest there is +56 and -56 available... so that would make 112V in between.

 

[besharp]

If I understand your picture right, is there room on the left side for another battery?  You could wire the batteries in parallel then and have more capacity.

Yes, I mentioned that in Post #5. However, you have to be very careful with lithium ion batteries. It's safe to run two batteries in parallel only if they are of the same and of the same age/usage. So don't parallel a used battery and a new battery, even if they are from the same manufacturer, voltage, and Watt-hour rating.

I think if one insists on using a different age second battery perhaps a battery switch (such as used on boats) could work.

 

[besharp]

When I looked up the battery you provided the link to the price is $845.

I found a 48V DC to 120V AC 2000W pure sine wave inverter for about $400.

Add in some miscellaneous bits and some wire plus a Systainer to house it all
and it would be about double the $750 you spent.

Yes, I was lucky in finding a good quality, (slightly) used battery on Craigslist for $500 CAD (it's $845 CAD + 12% taxes). There are cheaper batteries available, but be suspicious because most are not genuine LG, Sanyo, or Samsung cells, do not put out the current claimed, the cells may not be individually fused, and/or have a poor BMS (Battery Management System). The result could be a fire!

Take current capacity, for example. This battery pack is made from 18650 cells, so-named for its size (18mm diameter x 65mm long). It's now produced by the millions, thanks to it being used in some Tesla cars. Various 18650 cells can produce from 2.2 Amps to 3.5 Amps. My battery pack uses 5 Sanyo GA 3500mA cells in parallel, so 5 x 3.5 A-h = 17.5 A-h. Cheaper battery packs would produce only 5 x 2.2 A-h = 11 A-h, or 37% less capacity, while still taking up the same space and weight!

That's why, IMHO, the Festool SYS-PST Power Station is NOT overpriced. My power station cannot run a Kapex. The SYS-PST can. Its specs are:

- 2,990 Watts available power (11,000 Watts peak for short periods)
- 1,500 Watt-hours battery capacity

Assume $1,000 for a good quality inverter
Good quality 1,500 W-h battery pack - $2,000
Systainer case, parts, etc $200
Festool guarantee and support - $300? (Would they loan you another one if yours fails?)

Total $3,500 CAD ($2,600 USD)

Festool's SYS-PST sells for 2,610 Euros, or about $3,000 USD.

So, not overpriced at all for Festool quality.

 

 

[besharp]

Very nice. But what is the -56 VDC about?? The label suggest there is +56 and -56 available... so that would make 112V in between.

The lithium-ion electric bike battery pack is a "13P5S" pack. In electric bike battery talk, this means it has 13 cells in series, with 5 of those sets in parallel (or, 13 x 5 = 65 individual 18650 cells).

A lithium-ion cell's nominal charging voltage is 4.2 volts. 13 cells in series x 4.2 Volts = battery pack charging voltage of 54.6 volts.

I use a Satiator electric bike battery charger, widely regarded as the best in the world (and made where I live, in Vancouver, BC, Canada!)https://ebikes.ca/shop/electric-bicycle-parts/chargers/satiator-standard-model-8a.html

The Satiator's output is a 3-pin XLR connector, commonly used in pro audio, because it is sturdy, and can pass up to 16 Amps of current (unless they're fake Chinese copies!) The square rubber weather seal flips down to reveal the 3-pin XLR charging port:
https://ebikes.ca/shop/electric-bicycle-parts/connectors/xlr-panel.html

So the label of 54.6 volts just identifies which pin of the three in the XLR connector is positive, and which one is negative. Total voltage is still only 54.6 volts.