This past summer I had the opportunity to stop at the Battleborn factory in Reno, NV on my way back from 3 nights of astrophotography at a northern CA dark site. The folks at Battleborn were nice enough to give me a factory tour and answer many of my questions about their batteries. I decided to visit because I became impressed with the company and their lithium batteries from my prior research. At my request, they sent one of their 100Ah batteries to me to try out as a power source for my astronomy equipment on my next trips out into the field.
Battleborn makes a line of different capacity LiFePO4 batteries which they sell under the parent company name Dragonfly Energy to OEMS like RV manufacturers. They sell the same batteries to the public with a different color casing under the brand name Battleborn. They are a US company which designs, assembles and tests their batteries here in the US. While many of the components are sourced from outside the US, including the lithium cells inside which are only made in Asia at this point, the components are built to their own particular specifications. Unlike most of the Chinese batteries found on line, the folks at Battleborn can be easily reached on the telephone for technical support and service. And, you can even stop by the factory I did if you are passing through the Reno area, but call ahead first.
The 100Ah battery I received weights 31lbs and is sized similarly to any 100Ah lead acid battery weighing more than twice as much. Because this is a lithium battery with a battery management system (BMS) inside it is capable of supply the full 100Ah capacity for 3000 - 5000 full discharge cycles. This compares to the typical 100Ah lead acid battery which is only capable of suppling 50Ah without damage to the internal cells for up to 450 cycles. The Battleborn battery is designed and warranted for a 10 year service life.
As discussed in previous blogs, the BMS is an internal controller whose function is to protect the cells inside from unsafe operating conditions which includes:
1. High/Low Voltage Protection
2. Short Circuit Protection
3. High/Low Temperature Protection
4. Cold Charging Protection
5. Automatic Cell Balancing
This battery can be used to supply power at low and high temperatures given its discharge temperature range of -4°F (-20°C) to 135°F (57.2°C) Like all lithium batteries, it cannot be recharged at a temperature much below freezing given its charge temperature range of 25°F (-3°C) to 135°F (57.2°C). The battery has internal temperature sensors so that the BMS will prevent charge or discharging outside of the allowable range.
Inside a Battleborn Battery
It is worth looking inside any battery that you would consider buying to understand both the quality of components and build process. Unfortunately, this is not something we can typically do but there are YouTube videos showing the teardown of the Battleborn battery and some of the others as well. Here is one from Will Prowse from which I was able to grab a few images for this blog. In this video you can see the excellent build quality and components which can be contrasted with another vendor which is not of very high quality.
Looking inside the Battleborn one can see that it uses cyclindrical cells which are the most common cell type found in lithium batteries at this point since they are more amenable to automated manufacturing processes. This makes them less expensive and provides for consistent build quality from cell to cell. You can also see that the cells are arranged in 4 groups in series of 30 cells each in parallel for a total of 120 individual cells. The cells in parallel provide the voltage ( 4 x 3.2 to 3.3V = 12.8 to 13.2 V). The 30 cells in series provides the overall capacity (30 x ~3.4 to 3.5Ah = 102 to 105Ah ).
Capacity and Discharge Voltage Tests
I performed extensive testing of the Battleborn 100Ah battery both at home and in the field on two different dark site trips. The results of these tests are summarized here. The first test was a capacity test to see if the battery delivers its rated Ah. Three full discharge cycles were performed using a 90W, 60W and 60W load. A typical astronomy setup might use between 30W and 60W with 90W being a very high power case. Regardless, these loads are very small compared to the battery's 100A maximum current capacity so, not surprisingly, the measured capacity remained constant within 1Ah across all three tests with an average capacity of 110.5Ah. Considering that the voltage drops, especially during the last 10% of capacity, a more relevant number is the capacity at 12.0V which was 105.5Ah. This is in line with the fact that Battleborn overbuilds their batteries using cells packs measured during test and assembly to be between 104 and 108Ah. I was actually able to see the capacity markings on the sides of the cell packs before final assembly which are used to balance the final capacity within their manufacturing tolerance of 104 to 108Ah.
Next, is the voltage drop off with the state of charge (SOC). Since LiFePO4 cells have a voltage of 3.2 to 3.3V and are combined with 4 packs in series, the initial voltage of a fully charged battery will be between 12.8V and 13.2V. The discharge curve which I measured below shows that the initial voltage under load was 12.9V and that the voltage remained above 12.0V until 96% of the total capacity was consumed which is the 105.5Ah number stated above. The voltage curve was the same for a 60W load as it was for a 90W load. In contrast, a typical lead acid voltage curve also shown indicates that the voltage drops below 12.06V at 50% SOC which is the minimum SOC to avoid damage to the cells. For comparison only, a lead acid battery drops below 12.0V at ~44% SOC.
I was able to take the battery with me to the Calstar star party in California for 4 nights under the stars. It was nice to only have to carry a single 31lb battery rather than my usual 63lb lead acid battery, or even 2 of those if I could not recharge during the day. My setup included a Software Bisque MyT mount, an ASI1600MC uncooled imaging camera, an ASI224MC guide camera, a Celestron Motorized focuser, a Pegasus Pocket PowerBox Advanced Power/USB Hub, a Beelink Mini-PC, a GL-iNET GL-AR750S-EXT wireless router and a Dell 15.4" laptop. Power was supplied directly to the Pegasus which then powered the MyT and the Beelink. The cameras and focuser drew power from the MyT while the router drew power from the Beelink. Because my Dell laptop can only use AC power from its AC adapter, I used a 300W Inverter attached to the Battleborn to provide the AC power to the laptop.
The Pegasus Powerbox Advanced has an internal power meter which allowed me to monitor the power to everything except the laptop. I used an in-line power meter to keep track of the power consumed by the inverter/laptop. The net power for everything was 63.2W with 41.6W going to the Pegasus and 21.6W going to the inverter. The Beelink ran The Sky X which controlled everything (cameras, focuser, imaging) while the laptop was used as a remote control by connecting to the Beelink through the router using Team Viewer. This explains the low power consumption by the laptop.
The first night I did my TPoint model, Polar Alignment and imaged, running for a total of 7 hours using 32.85Ah (432Wh), or 31% of the Battleborn's 105.5Ah measured 12.0V or higher capacity. On the second night I imaged for 5hrs and 20min before turning in and used an additional 25.9Ah for a net of 56% of the total capacity. The third night was a bust due to high winds, but I was able to image for 6 hrs and 20min on the fourth night using another 31.48Ah. Adding these up, I ran for a total of 18.5hrs and consumed 86% of the battery capacity which indicates that the maximum run time is 21.5hrs for a 63W load without a need for a recharge.
Everyone's power consumption will be different from mine so I put together a table with three different power ranges to provide estimates of run times with the Battleborn 100Ah battery. Because one can use the full capacity of this battery, it provides seriously long run times without a re-charge and obviously longer with a re-charge in the field.
While I was able to run my setup for three nights without a re-charge, there will be times when I am imaging for longer periods each night, running a heavier load or spending more nights under the stars. In those cases I will want to re-charge the battery during the day.
If one has access to AC power during the day, an AC charger designed for lithium batteries can be used to top off the battery. I used this 10A charger from Bioenno Power to recharge from a complete discharge to fully charged in 11 hours. The nice thing about lithium batteries is that they can take a higher charge current than a lead acid battery. The Battleborn spec indicates 0.5C or 50A maximum. Even a 20A lithium charger like this one would recharge the battery fully in 5hrs. Also, it is unlikely that one could fully discharge the battery in one night anyway so a 20A charger is probably more than sufficient to top off the energy used during the previous night.
In most cases, we do not have access to AC power during the day which is why we carry a battery with us in the first place. For this situation solar panels along with a solar charge controller are required. You will have to add a pair of wires to connect from the solar panel to the charge controller and from the charge controller to the battery. Always connect the battery first and the solar panel last. In my case, I used these pre-made Power Pole Adapters from Bioenno, but you can make your own cables with Power Pole connectors, a crimper and zip cord from West Mountain Radio. You can get all of the components needed from any number of suppliers on Amazon for less, but I have found that the genuine Anderson Power Poles work best.
In the first solar recharge test I used a 100W Bioenno solar panel along with a Bioenno charge controller with full sun. This setup recharged the battery from fully discharged to fully charged in 20hrs as the average current supplied to the battery was a little over 5A. The math works as it should (5A x 20hrs = 100 Ah). Obviously, we do not get 20hrs of sunshine during the day but since it is unlikely that one would have to fully recharge the battery after a single night's use a 100W solar panel should provide at least 6hrs of re-charge time or roughly 30Ah which would have topped off the battery after one of my typical nights usage.
Clearly more solar panels will re-charge the battery faster, so in the second test I used two 100W Jackery Solar Panels in parallel along with the same Bioenno charge controller to recharge the battery. With two panels supplying 11.3A of charging current, I was able to fully recharge the Battleborn in 9.75hrs. So, if you want to be certain to have sufficient charging power to fully recharge the battery if you are using more than ~30Ah a night, a second 100W panel will be necessary.
The Battleborn 100Ah LiFePO4 battery met all of my expectations and even exceeded its capacity spec by 5%. This battery packs a lot of energy into a small light weight design and can easily supply power for most astronomy setups for multiple nights on a single charge. For larger power requirements you will need to invest in solar charging equipment to re-charge during the day or have access to AC power to use one of the lithium based AC chargers.
What I like about the Battleborn 100Ah Battery:
1. Designed and manufactured in the US
2. US sales and technical support
3. Delivers 105% of its rated capacity at 12.0V or higher
4. Uses cyclindrical cells
4. Unheard of 10 year warranty
What I do not like:
1. At $799 from the factory the Battleborn battery is still one of the most expensive LiFePO4 batteries compared to some of the Chinese brands like Ampertime, Chins and Zooms who all use prismatic cells instead of cyclindrical cells. And, all three of those based upon tear down videos look like they are built in the same Chinese factory although they are sold under different brand names.
So it comes down to whether or not you are looking for the cheapest option, or a good battery with US support that is easy to reach if you need it.
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