bebob recently introduced new Hot Swap Adapters for B-Mount. The B90cineML and B155cineML are two new B-Mount batteries with a buffer function.
We have seen hot swap plates for B-mount before, but at least to my knowledge, the B90cineML and B155cineML are the first hot swap capable dual voltage B-mount batteries on the market.
These batteries are being directly targeted at ALEXA 35 owners and rental houses that stock the camera. They would also be a good choice with the upcoming Blackmagic URSA Cine.
If you happened to own an ARRI Amira, ARRI ALEXA LF, and an ALEXA 35, which is quite common for a rental house, you could use the bebop B-Mount Battery Adapter for ARRI AMIRA or bebob B-Mount Battery Adapter for ARRI ALEXA/LF/65 Cameras so that you could run all of these cameras via B-mount dual voltage batteries.
B90cineML & B155cineML
The B90cineML and the B155cineML have different capacities (86Wh and 156Wh, respectively), but share the same functionality. They can be connected in series with other B-Mount batteries and simultaneously function as dual-voltage high-performance batteries and hot-swap adapters. They automatically take over the power supply to the camera and the D-Tap connection as soon as the connected battery is empty. This guarantees a continuous, uninterrupted power supply during camera operation. Both MLs can be charged either by a plugged-in battery or a B-Mount charger.
The B90cineML and the B155cineML support two different voltages, 14.4V and 28.8V, which means they can be used for 12V and 24V devices. Their continuous power and current output are 450W and 20A, respectively. A five-stage LED display indicates their current charging status. Both batteries are equipped with a Twist D-Tap and a USB-C port.
The digital ID interface of the B-Mount can intelligently identify the voltage (14.4V/28.8V), which means that the dual voltage functionality of the batteries is a good choice for any B-Mount application.
What is important to know is that some B-mount batteries with a low amperage may be overly tasked on the ALEXA 35, especially if the power draw exceeds 150 watts (which is its power output threshold). Early on, ARRI recognized this power issue (mainly because of the original LF) and recommended a minimum of 10A load for HV on B-mount. Since that time, ARRI has softened its stance on B-mount minimum specifications because they need B-mount adoption. The only slight concern with this is that if you don’t use a higher amperage pack, you may end up with a shorter service life for the battery packs since they could be continually overstrained depending on how you are using them.
For this review, I will be looking at the B155cineML.
Key features
- 450W, 20A Maximum Load
- ML-Buffer Battery
- 14.4/28.8V Dual Voltage
- 5-Step LED Fuel Gauge
- Withstands Falls from up to 4.9′
- Twist D-Tap
- USB-C port
- Charge Time: 3.5 Hours in BS2/BS4
- Replaceable Mechanical Components
Build Quality
The shell of the batteries is made out of an impact-resistant, flame-retardant material. They are nicely made and they can survive a drop from 1.2 meters at any angle.
The battery was designed to be strong, reliable, and versatile, and it was built to withstand falls from 4.9′. Its modular design also makes it easy to repair.
What I also like is that bebob batteries are not single-use products. If after years of use, the battery capacity decreases, the cells can be replaced in the bebob factory.
The battery features a built-in protection circuit, as well as high temperature, low temperature, over-voltage, under-voltage, over-current, and short circuit protection. The internal support for the battery is fastened to the core group, and the core and the circuit board and completely isolated. The integrated internal design also means there is no wire welding. All these elements combine to help with reliability and safety.
There is a small button that you press that will illuminate the battery capacity indicator and if you press it twice quickly it will turn on a little inbuilt torch which is handy.
I do wish that bebob would have made the release mechanism out of aluminum. I can’t tell exactly what the mechanism is made out of, but the release pin doesn’t look like it is made out of metal. The locking mechanism is the most likely fail point on a B-mount battery. Because the mount is actually on the battery itself and not on the B-mount plate, the release mechanism needs to be as robust as possible. Now, in saying that, I personally haven’t heard of anyone having one of these release mechanisms ever break on any B-mount bebob battery.
The texture of the batteries is a little slippery for my liking, however, bebob has placed two gripping spots on either side of the battery that makes it reasonably easy to hold.
A lot of operators tend to hold the back of the camera when panning and for that purpose, the batteries work well. B-mount is a super solid mount and it is a lot more robust than any other mount on the market.
What cells are being used?
The battery features Panasonic 18650 lithium-ion cells that offer a 20A maximum draw and a capacity of 156Wh.
Flight Safe
Despite there being quite a few battery solutions on the market for the ALEXA 35, there aren’t actually a lot of flight-safe options. If you travel a lot, then having flight-safe batteries is a must.
The B90cineML and B155cineML batteries are both flight-safe, and on most airlines, an individual can hand carry up to two batteries that have a capacity between 100Wh and 160Wh. There is usually no limit to the number of batteries that are under 100Wh that you can take, although it’s always best to check with the airline you are using.
The only problem with the ALEXA 35 is that it is a pretty power-hungry camera and you would need quite a few smaller capacity batteries to get you through a day.
Charging
The battery can be charged on a Dual Voltage B-Mount charger.
Size & Weight
The bebob B155cineML tips the scales at 2.31 lbs/ 1.04kg. It has physical dimensions of 3.7 x 5.7 x 2.6″ / 9.4 x 14.4 x 6.6cm. So how does this compare to some of the competition?
| WEIGHT | DIMENSIONS | |
| bebob B155cineML | 2.31 lbs/ 1.04kg | 3.7 x 5.7 x 2.6″ 9.4 x 14.4 x 6.6cm |
| SWIT BIVO-160 | 2.42 lbs / 1.1kg | 5.7 x 3.9 x 2.1″ 14.4 x 10 x 5.4cm |
| CORE SWX Helix Max 150 | 2.2 lbs / 1kg | 3.54 x 4.65 x 2.72″ / 8.99 x 11.81 x 6.9cm |
| bebob B155CINE 14.4/28.8V 155Wh | 2.2 lbs / 1kg | 5.7 x 3.7 x 2.3″ / 14.4 x 9.4 x 5.8cm |
Above you can see how the bebob B155cineML compares in size to the CORE SWX Helix Max 150.
Some companies like Core SWX utilize the newer 20700 size cell, instead of the 18650 cells commonly used in other brand packs. While this design creates a deeper build due to the wider cells, the operational functionality of the Helix Max packs is claimed to exceed that of others using 18650 cells in the market.
The batteries fit on the camera nicely and they contour to the shape of the ALEXA 35. This is purely a cosmetic thing, but I personally like having batteries that are the same height as the back of the camera.
The ALEXA 35 balances really nicely on the shoulder, but I do find it helps to have lower-capacity batteries when doing this because you can get better balance when using larger lenses.
Outputs
The bebob B155cineML features a single Twist D-Tap (13.2V max 2.5A) and a USB-C port. These work well, and as always, it is nice to see the bebob Twist P-tap (D-tap) being used where it doesn’t matter which way you plug it in.
The D-tap port is on the top of the battery. I would have preferred to have seen it on the side. While it is nice to have a P-tap port, I personally prefer to power accessories I use with the ALEXA 35 via the Lemo outputs.
It is nice that bebob has incorporated a USB-C output so you can use it to charge or power devices such as your laptop, etc.
Hot Swap
The biggest advantage the bebob B155cineML has over competing batteries is its ability to let you hot-swap another B-mount battery that is placed on the back.
The bebob B155cineML has a B-mount interface on the back of the battery so you can directly attach another B-mount battery.
By utilizing the in-built ML buffer you can facilitate hot swapping with an automatic charge/discharge buffer of 8s. The B155cineML will automatically take over the power supply to the camera and the D-Tap connection as soon as the connected battery is empty. As soon as you place another battery on the back it will start drawing from that battery.
The B155cineML will pass through the other batteries’ capacity information to the camera.
Usability
The bebob B155cineML, while arguably a little niche, is a good solution for the ARRI ALEXA 35. It is solidly made, you can charge it quickly, and it fits the form factor of the camera.
There is no OLED display on the side or the back of the battery like you will find on some competing batteries.
The ability to hot-swap batteries is handy for those instances where you don’t want to power the camera down, change over the battery, and then power the camera back up. By using the B155cineML in conjunction with another B-mount battery you avoid having any down time.
If you own an ALEXA 35 and you are going to be traveling a lot, then you want to be able to utilize batteries you can hand carry on planes. This is where the bebob B155cineML and bebob B90cineML make a lot of sense. You could have two bebob B155cineML batteries and buy a bunch of the B90cineML batteries and then you would be able to travel and shoot all day without any issues. Stacking up a B155cineML and a B90cineML would give you a capacity of 242Wh. You could conversely stack two B155cineML batteries to give you a capacity of 312Wh or two B90cineML to have a capacity of 172Wh.
As I previously mentioned, I also like that bebob has included a USB-C output as this increases the versatility of the battery.
The ALEXA 35 isn’t a huge camera, and the B155cineML is a nice sweet spot for offering decent run times, while not making the camera too heavy. If you do need to go lighter, then the smaller B90cineML is a good option, but you won’t get very long run times, especially if you are powering other accessories off the camera.
Price & Availability
The bebob B155cineML retails for $969 USD which does put it on the expensive side, however, it does things that other B-mount batteries can’t. The smaller bebob B90cineML is only slightly less at $890 USD. Both batteries come with a two-year guarantee on 80% of their capacity and are available immediately from all authorized bebob dealers.
How do these prices compare to the competition? Well, below you can see:
bebob B90cineML
| PRICE | |
| bebob B90cineML | $890 USD |
| SWIT BIVO-98 | $489 USD |
| CORE SWX Helix Max 98 | $569.05 USD |
| bebob B90CINE 14.4/28.8V 86Wh | $689 USD |
bebob B155cineML
| PRICE | |
| bebob B155cineML | $969 USD |
| SWIT BIVO-160 | $579 USD |
| CORE SWX Helix Max 150 | $749 USD |
| bebob B155CINE 14.4/28.8V 155Wh | $798 USD |
Specifications of the B90cineML & B155cineML
- Capacity: 86Wh (B90cineML) or 156Wh (B155cineML)
- Mount: B-Mount
- Dual voltage: 14.4V/4s and 28.8V/8s
- Max continuous load capacity: 450W / 20.0A
- Capacity display: 5-stage LED
- Automatic load switching and charging of the buffer
- Weight: 662g (B90cineML) or 1.04kg (B155cineML)
- Warranty: 2 years
Dimensions (W x H x D):
- 94 x 144 x 47mm (B90cineML)
- 94 x 144 x 66mm (B155cineML)
Outputs:
- USB-C (5.0V max 1.0A)
- D-Tap (13.2V max 2.5A)
Prices & availability
The recommended retail price for the B90cineML is € 769 /$ 849 and for the B155cineML € 879 / $ 969. Both come with a two-year guarantee on 80% of their capacity and are available immediately from all authorized bebob dealers.
