DIY Battery Box Systems - What You Need To Know

A lot of people are looking for a way to build a battery box for use either as a portable power system OR for use with a small solar power system. We're happy to say that we've already done it. It's called the ArkPak, and it's a great device for anyone looking for a portable power storage battery system.

ArkPak powering multiple devices

Still, if you're not convinced that the ArkPak is better than a DIY battery box, here's how the ArkPak stands up to DIY battery boxes, at least according to us. We've tried to be as neutral as we can be here , so that hopefully anyone considering a DIY battery box will consider what we have to say.

The Trouble With DIY Battery Boxes

Campers, overlanders, and owners of small solar energy systems sometimes take it upon themselves to build a battery box, the thinking being that a DIY battery box is easy and affordable. Indeed, many of the websites selling DIY battery box supplies and/or selling plans talk about how much money they saved over buying a dedicated battery box system.

While we're obviously a bit biased here, we'd argue that there are some problems with DIY battery boxes , problems which the ArkPak solves readily. Here are the problems we think most DIY battery box plans don't account for:

1. What charging options will you have when plan A fails? Most of the people building a battery box are planning to use it with a solar system, a vehicle, etc. But what happens if you've got a battery box that's almost completely discharged, and charging plan A has failed?

If plan “B” is to charge from your vehicle, you'll want a dedicated 12VDC charger to do that efficiently. Will you charge from an 110VAC outlet, either on a portable generator or in your garage? If so, you'll need a standard battery charger...and if you want to recharge your battery box quickly, you'll want a battery charger that puts out 5+ amps, so that it doesn't take more than a full day to completely charge a 100ah battery. The ArkPak bundle comes with a 12VDC car charger AND a 6 amp*, 7 stage smart charger that runs off 110VAC. These chargers are valuable because they're "smart" and because they're cleanly and carefully integrated into the ArkPak's case.

2. How will you know when your battery is running empty or nearly full? It's one thing to measure the voltage output of your battery box, it's quite another to get an hour estimate of charge time remaining. If you own a solar power system and you want to know how much longer until your battery is charged, most of the simple solar battery charging systems tell you very little. Likewise, if you want to know how much power you have left in your battery, a simple voltmeter isn't accurate enough to help you determine that. All ArkPaks have a built-in LCD that displays the battery's current capacity using our advanced battery conditioning and charging system.

3. How will you make sure your battery box stays at the right temperature? Extreme temperatures lead to performance issues - if things get too hot, battery charger performance is (effectively) reduced. You need to run a cooling fan that keeps air circulating around the battery charger and inverter inside the box. The ArkPak has a built-in fan to circulate air, one that's designed to last for years. The Arkpak also has several temperature sensors to monitor the temperature of key components including the battery. Most DIY battery box plans do not have any sort of cooling fan or battery temperature sensing.

4. How portable will your battery box really be relative to its capacity? Portable power is a big deal. Most DIY battery boxes offer varying degrees of portability and capacity. Some very clever power packs can fit inside a small case, but these only offer a few amp hours of capacity. Other battery boxes are designed for solar installations and not at all portable. The ArkPak is the perfect compromise between size and power: It's about the same size as a small toolbox, yet it offers up to 130ah of energy capacity.

ArkPak black box

5. What kind of battery are you going to use, and what happens if you change it? A lot of people like the Sears brand “Platinum” deep-cycle AGM batteries, which can be had in a Group 31 size, and are basically the same as the more expensive Odyssey brand batteries. They're zero maintenance, they've got a great warranty, and they last. But what happens if you need a new battery and you opt for a Gel battery rather than an AGM? Will your charger(s) still be compatible? What happens if you go to a wet cell? The Arkpak is capable of determining the type of battery you have and adjusting. Not every charging system can do that.

The Costs of Building a DIY Battery Box

Setting aside the fact that most DIY battery boxes don't offer the ArkPak's combination of portability, reliability, and adaptability, let's talk about the costs of a DIY battery box. Specifically, we'll look at the costs of a DIY system that can offer the same 100+ amp hours of capacity:

  • Investing in a quality 6amp charger that runs off AC or DC power and that reliably indicates battery charge level: ~$150
  • Investing in a battery box, a cooling fan, and all the associated hardware (USB charging points, 12VDC charging points, Anderson plugs, internal wiring, fuses, isolator switch etc.): ~$100, depending on quality
  • An inverter : $25-$50, depending on quality and output

You're looking at $300 worth of parts. Can you go cheaper? Sure. You can buy a 500ma battery charger that will require days to charge your 100ah battery (and which doesn't tell you anything about battery capacity) for $25, and you can skip the cooling fan, the DC charging system (which allows you to charge from your vehicle), the inverter, and most of the hardware. You'll "save" a lot of money, but you'll lose a lot of functionality in the process...especially in an emergency when your battery is dead).

Finally, let's not forget that there are three other factors here to consider in addition to parts cost:

  • Time to assemble the box : Even the 'easiest' DIY battery box is going to require an hour or two of work.
  • Portability: Is the final battery box going to be easy to throw into the back of your truck or SUV and haul around without worrying about something breaking or shaking apart?
  • Reliability: Is your DIY box going to stand up to the same level of abuse as a purpose-built system that's been field tested in Australia's outback for years?

Again, we're obviously biased here, but even the most ardent DIY battery box fan has got to admit that there are benefits to going with a purpose-built product.

Don't Get Us Wrong - DIY Projects Are Fun

Building cool gear yourself can be a ton of fun, and a simple battery box project is something that most people can manage regardless of skill or experience.

However, if you're looking for a battery box that will store 100+ amp hours of power, that will be useful in nearly any situation, that will be easy to haul around, and that will be reliable, the ArkPak is the way to go. When you do the math and add up the value of all our components and our packaging, we think you'll agree that we've got the best portable battery box on the market at a very reasonable price.

 *Specs on newer versions vary. Check them out here.

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