One of the problems that we have in the man portable field communications world, is a lack of lightweight Portable Power Solutions, which can be simultaneously charged/discharged in the field, from solar panels. Solutions do exist, but they are costly one size fits all, and rarely fit amateur radio emergency comms requirements. What I’m proposing is we, put our heads together and come up with a as few adaptable solutions to this problem.
What we want
Of course what we’re trying to achieve is putting together a flexible and adaptable battery pack system for man portable field communications. It’s not that commercial solutions are bad, in fact more so than ever, we have many more commercial options. However in regards to emergency communications it is often the case that a bespoke solution adapted specifically for your operating requirement, can better achieve the requirements of field operators over one-size-fits-all solutions.
The basic requirements for a battery pack (ordered from most to least important)
- Based on LiFePO4 technology
- 12~15v output voltage
- ~3.5-20A (to meet operator requirements)
- Dual fused Anderson powerpole ports for outpup
- Separate charge and load ports
- Integrated charge controller
- Direct PowerFilm 10, 20, 30, 60 watt panel connection
- Single Anderson Powerpole charging port
- Voltage remaining meter
- Amperage load meter
- Weight 1. 5kg or less
- 2A fused USB port
- Load disconnect switch
- Workout all the kinks
- Come up with seveeal feasible solutions
- Create a parts list for each configuration
- Built a working solution
- Document and share the knowledge from various builds.
By the end of the project will have at least one portable power pack for emergency field communications which can be adapted for QRP to 20 watts radios.
Latest Update (14 July 2016)
I changed the name of the project to QRP Power Project. The Open Power Project wa too general a name, gettin lost in the ocean of google search results. The project documentation is no good, if operators cant find it.
QPP UltraPack Parts started arriving.
Again I want to thanks Jim K7JLJ for continuously kicking me in the butt on this project. From a preparedness perspective, we always want to make the most of our batteries.This means we want to use them in a variety of projects, not limiting their use to a specific application. So the QPP UltraPack proof of concept is born.
Olight 3.6V 3.4A 18650 batteries in 4S configuration will power the this prototype. A BMS will balance the cells during charge and provide charge/discharge leads.
Output will be fused (5A) with 30A powerpoles in input and output.
I’m still wpring on the power level meter.
The entire system will be enclosed in a plastic project box. This makes changing out batteries easy enough.
The next version may use dual 18650 4S2P, or a single set of 26650 batteries. Lets see how it goes.
Update (05 July 2016)
Once again my friend Jim K7JLJ has inspired me to update the project. This time around we are taking a look at the QPP UltraPack using 4S2P 18650 batteries.
18650 battereis are a popular choice in the survival community. They power flashlights, optics, reticles and other equipment. Naturally, if 18650 batteries are in your strategy, you would like to stick with them wherever possible.
As with the other prototypes, the requirements remain the same. We want a battery pack wich can be charge and discharged simalteneuosly! In teh perfect world, we would do that without the need for voltage regulation on the output, but we reserve the ability to add it if nrequired.
We are going to wire this pack up in 4S2P, which means 4x 18650 in series, the another 4x 18650 in series, then wire the completed packs inputs and outputs, in parallel.
Some users may wish to build this pack using 18650 removeable trays. I suppose thats possible, but from experience, don’t use cheap molded chinese made trays as they will not handle the heat generated from this 4.5A pack.
I’ve decided to use the expandible battery holders and tabbed 18650 to simplify for my build. My battery packs are always dedicated to purpose, with additional random cells around for odd power jobs.
Its aaso possible to build the pack using other trypes of cells. 26650, rectangular, flat, … Lets see if later on we try those others as well.
Previous 15 June 2016
So taking a moment to write a brief description about this project. Originally shared it on my Instagram account but I think it’s better served here.
Reviving an old project. I’m calling this the”Open Power Project”. It’s a series of #LiFePO4 battery packs which can be simultaneously charged and recharged in the field with a solar panel. A small battery pack like this is certainly useful to the #disaster #survival #emcomm and #QRP Field operator communities. I’m sure some of our prepper brethren will be interested in this as well.
Its design goals are to be a cost effective DIY alternative to:
– Goal Zero Sherpa series.
– QRP Ranger by Hardened Power Systems.
– Anker Pro series 12v packs.
– China made car jump starter packs.
The prototype pack (OPP ManPack10A) is made from 4x 3.2 volt, 10 amp lithium iron phosphate cells, and a 10A BMS for protecting the cells from overcharge, over discharge, and balancing. When it’s complete I’ll pack the whole thing inside a very small Pelican case, with voltage and amp displaysas, as well as Anderson power pole connectors for charging and discharging.
So far it looks like the 10A version can be built for $150-180USD in components.
This is the first variation of the pack. I’m calling it the OPP ManPack10A. As the project continues I’ll order the components and create the parts list. Then once the parts are here will create a how to video, schematic, and put them all together.
In the picture above, you see that the configuration uses 4x 3.2 volt, 10A, lithium iron phosphate cells in series. It also uses a low-cost battery management system which protects against over-charging, overdischarging-, and balances the individual cells in the circuit. Anyone with a steady hand and a multimeter can put the cells and battery management system together. It’s not complicated, but it does require a little care.
Why these cells?
The reason for choosing these particular lithium iron phosphate cells is for the ability to mount them flat! Most of the solutions that are available right now basically come in the form factor of a brick. The ability to mount these lithium iron phosphate cells in a flat configuration will make it easier to pack, when it’s necessary to hike to your operating location. This is also one of the problems that we talked about earlier with the slab batteries. A heavy brick in a backpack is not a reasonable trade-off for their ease of use.
The easiest way to protect the LiFePO4 cells making up the pack is using a battery management board. This SBM is connected between the battery pack cells, the load, and the charger/controller. There are also connections between the individual cells to the BMS to monitor the state of each cell for balancing.
For the ManPack10A I’m using the SBM04 (4S) 10Amp. This is a protection and balancing circuit for LiFePO4 cells – for 4 cells in series, the total nominal voltage of 12,8 V, the balancing voltage 3.6V.
Charge Controller & Voltage Regulation
Since we are using Powerfilm solar panels to sustain Our man portable field operations we will need to regulate the voltage coming from those Powerfilm panels, into the ManPack10A. One of my subscribers and content contributors (GreekPreparedness) suggested using the buddipole charge controller for the open power project. Well with that said I don’t see any reason why not to use it. I think we can even use it for the smaller UltraPack5A as well.
Thinkmof the OPP UltraPack5A as a direct replacement for tThe Goal Zero Sherpa 50. This will be a 4-6A pocket-sized battery pack, based on the A123, or 18x 8650 packs in 4S2P configuration, and 2x integrated BMS per 4S cells.
The OPP Basecamp20A is a larper battery pack meant to sustain field Communications for higher power radios over longer periods of time. Cobleskill portable in nature Detroit controller for this system will be the Genisun Lithium Charge controller
Brainstorming and abstract rambling
06 June 2016
One of the problems that we have in the man portable emergency field communications world, is a lack of lightweight Portable Power Solutions that can be recharged in the field, from solar panels. Solutions do exist, but they are costly and rarely fit amateur radio emergency comms requirements. What I’m proposing is we, put our heads together and come up with a solution to this problem.
The recommend SLABs as a solution. Perhaps that’s a solution for someone who never intended to operate or deploy on foot. In my experiences, one has only to carry a SLAB around with him in a backpack for a day, to understand that it’s not a practical solution! I have to say as K7JLJ pointed out, slabs might be a solution in an TEOTWAWKI scenario. I’m more concerned with the man portable Emergency Field operators EMCOMM work during or after Hurricanes, earthquakes, flooding, tornadoes, nor’easter, …
Other operators have found solutions in the RC Community to solve the problem. They’re using LiPO or LiFePO4 battery packs from HobbyKing, to power their radios and gear for an afternoon in the field. These batteries are lightweight but they lack the ability to be easily recharged in the field. The upside is they have provided extended operating times for field communications. The downside is balance maintenance needs to be done after the fact.
Another solution are the slab replacement LiFePO4 batteries. So far these have been the best solution, but their size and shape make them impractical for Man portable field use. There are lithium iron phosphate batteries from Tracer and A123, which are basically sealed lead-acid backup battery replacements. This means they’re also shaped exactly like a big brick sealed lead acid battery. Many of them also have battery Management Systems built-in so you don’t need any special type of charger to maintain them.
01 June 2016
So the problem I’ve been having with the lithium and lithium iron phosphate is compatibility with the solar charge controllers. There’s also the problem of having to carry an external charger when using LiPo or LiFePO4 batteries without integrated BMS. We already know that lithium and lithium iron phosphate are the right solution for Man portable radio communications. What we haven’t had until recently was a cost-effective solution allowing us to directly charge these batteries with a solar panels without overcharging them, or damaging them with under-voltage. Certainly you agree if we can solve that problem we would use them!?