I know this is going to sound like an ad, but this really is actual news, and it’s very good news for street ebike commuters.
Ebike builders who want to add a kit to their bicycle really seem the love the hardcases. The first example of this is how many customers opted to get the now-famous “dolphin” hard case, instead of a soft-sided battery pack in a battery bag. These last few years, any major North American retailer of ebike battery packs had 18650-cell battery packs that were covered in a heavy shrink-wrap, and most customers put these in a heavy-cloth bag that attaches into the central frame triangle of their bike.
The popular “Dolphin” hard case, filled with 18650-format cells
However, a growing number of experienced ebikers discovered that…if they charged their battery pack every night, then they didn’t really need to have as large of a pack. So…when the old one wore out, a large portion of the “second wave” ebikers bought the hard cased “dolphin” pack. This last year, cells with a higher energy density have become readily available, and that fact has breathed new life into hard-case dolphin pack sales, making them a viable option to a much wider customer base. Without changing the size of the dolphin pack, it could now be had with longer range cells inside.
This is a dolphin pack in a common “diamond” frame bicycle. Some frames have enough room in them to add another row of cells to the pack (for the absolute maximum capacity, you can see here why I like the triangle-shaped packs so much)
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Off-Road or Street?
The trend for off-road bicycles is to have a smaller frame triangle on the hardtails, and most of the full-suspension designs put the rear shock absorber right in the middle of what little space was there. This means you will rarely see a hard-case dolphin pack on an off-roader, however…for the street, hard cases have proven to be VERY popular.
One of the most popular street commuter frames is the Electra Townie. The standout features that enthusiasts like are that its frame is very strong while still being made from light aluminum, it has a comfortable upright “feet forward” posture, it will accept “plush ride” 2.5-inch wide tires, and it has very large frame triangle (for centrally mounting a battery).
Here is an Electra Townie “Go!” ebike using a slim “Shark” pack. you can see here that a much larger hard case will easily fit.
My personal street commuter is an Electra Lux fat cruiser. The Townie can be found for roughly $400 at most retailers, and the “Lux” stretch cruiser that I have is more expensive. Both are great candidates for a street commuter whether you want a rear hubmotor, or any one of the popular mid drives.
Take a quick look at the “chopper” section of our “Bicycle Style” article, and you can see that there are many street frames that will easily allow a much larger hard case to be fitted.
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Enter the “Killer Whale”…
The dolphin hard cases, and the “similar but slimmer” shark hard-cases have been around for quite a while, and many retailers carry them. However, many builders would like a hard case that is “plug and play” like the dolphin case, but maybe larger?…This really is a new thing, and it’s something that I expect to become very popular for those builders who have a bicycle frame with a large enough central triangle space on their bike.
So…how much bigger is it?
Why is he smiling? he wants you to come in the tank for a swim! This looks like a killer whale, but it’s actually a very rare vegetarian “snuggle” whale…
The quantity of cells inside is dependant on several factors. If the pack configuration was using five cells per paralleled group (5P), then…to go from 13S to 14S (48V to 52V), the manufacturer would have to cram-in five more cells. Also, the amount of current a pack can put out affects which BMS (Battery Management System) appropriate. A 5P pack of Panasonic GA cells can put out 50A peaks (5 cells per “P” group, 10A per cell). So…in order to take full advantage of the performance of these cells, the BMS is rated for 30A continuous, and 50A temporary peaks. A BMS like that is larger than the common BMS’s found in “average current” packs, which might only see occasional peaks of 30A. Remember, volts and amps both add power, but…amps also add heat. More amp-heat means a larger BMS.
All the dimensions are almost identical to the now-common dolphin pack (the width is identical), except it is bigger enough to add 13 more cells inside. It is 5-inches tall (128mm). It easily fits in an Electra Townie frame, but if you have anything other bike than one of those, draw out a template with the dimensions shown below to make sure it will fit, before ordering one of these.
MAKE SURE TO ADD ONE INCH TO THE HEIGHT TO COMPENSATE FOR THE SLIDE-IN CRADLE!
The Killer Whale hard case
For these reasons (among others), Luna has decided that their first order of Killer Whale packs that they are stocking will be 13S / 48V, and they will use the Panasonic GA cell (10A peaks per cell, 3500-mAh per cell). In an average sized pack, this cell would be considered an “average current” pack, with “maximum range” capacity. However, in a pack this physically large, with a 5P configuration (compared to the average 4P or 3P pack), it actually also has pretty fantastic current capability.
The Killer Whale has 13S X 5P = 65 cells inside. Luna’s popular 48V Dolphin pack has 52 cells (13S X 4P = 52)
The common Dolphin case.
The dolphin pack is listed as having a height of 5-inches at its tallest point (the same as the Killer Whale), but…the dolphin is sloped down on its top (towards the nose), and it’s also sloped on the front and the rear of the case. These sloped portions help it fit into more frames that have the common triangle-shape in the center of the frame. The Killer Whale is more “rectangular” shaped, so…those extra 13 cells that got crammed inside? they might not fit in as many bicycle frames as the dolphin.
But, what if it would fit yours?…
Someone started calling these a “dolphin” case when they first came out, and the name stuck. Is the dorsal fin on the right from a dolphin or a shark? Look at the face when it pops out of the water. If it makes you smile and want to jump in the water for a swim, it’s a happy dolphin. If the face has cold, dead eyes…and you can tell it wants to consume what little life you have left, it’s either a shark, or…my ex-wife.
If you have a direct-drive hub (DD), and you live where there are long and steep hills, you can get this battery and the motor hot from constant high-amp draws. However…if you live where your commute is relatively flat, you will only experience high-amp loads for a few seconds during acceleration, and then you will enter a “cruise phase” where the motor, controller, and battery have a chance to cool off.
If you have a mid drive, they typically provide very good hill-climbing performance, while staying relatively cool, and also providing decent range-per-Watt Hour (WH) of battery capacity (as long as you shift your bike into the proper gear), so…the Killer Whale (if it will fit your bike) will provide longer range between charges. However, the shark or dolphin may still be a viable choice for a system that only draws 25A or 30A max (like the BBS02 or BBSHD).
One of the key features of this pack [using this cell, and in this configuration]… is that you can now get a 17.5-Ah’s (Amp hours) worth of range in a hard case, plus…you can use this on a hot rod direct drive rear hub that draws 50A peaks. If raw performance is all you want, then you should research packs that use the Samsung 25R cell, or the 30Q cell, but…if all you need is occasional 50A peaks, then this hard case pack will provide that, along with more range than the 25R and 30Q “performance” cells I mentioned.
More range for mid drives, or…now there’s a hard case that can be used on a 50A DD hub that still need 17.5-Ah’s of range.
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Here’s the feature list from Luna’s website
- USB Charge port for your phone etc. built into pack (can also be used to power lights)
- Can be used as the best phone bank charger ever
- On-off switch
- 4-LED battery meter built into pack
- Spring quick-release rack with anti-theft key lock
- Hard plastic case to protect your pack
- 850 watt hours means incredible range in small package
- 13S / 5p = 65 Genuine name-brand grade-A Panasonic GA 18650 cells
- 30A continuous / 50A maximum BMS
- 9 pounds = incredible energy density
- Life Span: 400-1000 charges
- See images for dimensional drawing
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Written by Ron/spinningmagnets, August 2016
