DIY SOLAR BATTERY BANK
For those who are interested in getting into solar, there are many avenues available for any of the parts required. Here I will cover the requirements for the battery, more specifically, a DIY one.
Battery- What’s Required
In order for a solar generator to work properly, you need the 4 basic items stated before. For the battery, it requires a specific function that can be substituted with many products. The battery needs to be able to hold a significant amount of electricity compared to the system. Where certain systems will only require the amount of energy produced by the panels and no excess, like a flashing streetlight, most systems require a storage with increased amounts to fit the bill for increased usage, such the draw of certain tools or equipment. In order for the latter to work, you will need to put a significant amount of energy storage compared to the energy draw.
For what I built I used the following:
2x VRUZEND Battery Building Kits
2x Battery BMS from VRUZEND
1x 5.5 mm Nut Driver
100x “18650” Li-ion Battery Cells
4x Power connectors (I repurposed some from a Harbor Freight Solar Connector Kit.)
1x Soldering Iron
1x Solder, flux preferred
1x Size appropriate Heat Shrink/ Kapton Tape (I was a little creative here, and used some Proto-Putty, idea from ‘The King of Random’.
Order the kits and BMS from VRUZEND, they take a week or so for shipping. Get the ‘18650’s from EBay or Ali express, whatever you find the best deal. At the time I got mine from EBay, 100 for about $59.00. A tool that’s fairly rare, is the 5.5mm Nut driver, can be bought from VRUZEND as well, but I had mine already (surprisingly). Power connectors is dealers choice, whatever you feel comfortable with, and can solder well enough.
How to Build it
Now to the “How To”. There is a couple videos on YouTube for this, So I can provide a link to those.
The simple overview is pretty basic. Research how you need the batteries to be stacked, i.e. Series/Parallel. This will be figured by finding the required voltage/amperage for your system, and will be reflected in your battery. The math isn’t all that complicated. In series, Voltage is added, where Current or Amps are constant. In parallel, Voltage is constant, where Current or Amps are added. So if you need a 12 V battery, you could have 4Seriesx 3v 2amp cells, at 12V 2amps, or 4Seriesx4Parallel 3v 2amp equal 12v 8amp. There are resources out that can direct you on how best to calculate the requirements. Make sure whatever you end up of with, that your wires and connectors are properly rated for the amps and voltages.
So you found out your build, not before your start putting it together, you need to verify the status of the batteries in regards to voltage, current, and continuity. Switch your Multimeter to DC Voltage, and connect either side. If you get a reading approximate to what the battery is rated for, it’s good to go, if it’s significantly lower, considering charging it before putting it into place, if it doesn’t read at all, make sure nothing is preventing conduction, i.e. paint, rust, etc. If there isn’t any continuity, you may have received a faulty battery Cell, and you should consider returning it.
Once you have tested all the batteries, you can start building. With your now tested good, charged Battery Cells, you can start placing them into the layout for your Series/Parallel build. Your VRUZEND Kit will have 2 colored caps, with a bag of bars or buses, and a bag of nuts. As compared to other ways of doing this, this way is easier in my opinion. No spot welding/soldering here. Goes together like Legos. Connect the Caps is the form you decided earlier, keeping note which side of the batteries are positive and negative. Slip the cell into the caps, keeping note of which way the clips are facing so that they can interconnect properly. Tricky, but not overly difficult. Once you have this set up how you decided earlier, you are going to want to make to press the caps together pretty good, to make sure they are conducting the battery. I just put some gloves on, and used my hands. You can use hand clamps, or a block of wood if you want. After that, check again with your mulitmeter to ensure that battery cells are properly connected the caps. Now, you should ready to lay the bars out on the grid of caps. Make sure not to create any shorts, by putting the bars in the wrong layout. Once the bars are laid out in the proper configuration, you can fasten them with the nuts and 5.5mm nut driver.
Whoo-hoo!, you got a battery.
I recommend putting Battery Management System in place, to prevent fires, and to get the most out of your battery. Each BMS is different to suit the Battery Layout. My BMS had 10 red leads with one black lead, as I had a 10P setup, each row got 1 Red lead on the Pos+ side, and 1 Black lead on the first Neg- Side. All you have to do is hook the lead onto the post on the respective row under the busbar and tighten. Then glue it on a safe spot on the battery, and voila.
After you get the BMS in place, now you connect the power connectors. A little of solder will go a long way here. You will be using the BMS leads for this. Using the Charge lead from the BMS, and the Pos+ Side of the Battery, solder to leads to a power connector, and do the same for the Power lead. After this is all done, throw on some Kapton to hold all the cables in place, or whatever floats your boat, and should be good to go. There are plenty of videos out there that can provide guidance on this as well, and I can answer any questions that may arise.
This can be used in many ways. From making a portable power bank for your phone, to making a massive Battery Bank for your house, this kit is very versatile. I plan on using mine to make a portable Solar Generator for my car, as it is Ford C max Energi, and I believe I can extend my “20 Mile” range with this battery and a solar panel. Still working on the Kinks but I’ll keep you guys posted as to what happens.
So let me know what you guys think, give it a whirl. This should lead to a few interesting projects for you guys.