Best battery to pair with the BBSHD?

[Marc]

Hi, I recently purchased an HD and I'm looking for the best options for a battery to use with it.

I'll be using it more on road, but off road as well.
There will be a lot of hills involved.
I'm opting for 52v
I'm in the UK, so the Luna Cycle batteries aren't an option unfortunately, but I'm in contact with someone locally who sells/builds ebike batteries. They have recommended higher amp-hour NMC chemistry (25Ah) or Boston Power cells, although lower capacity Samsung cells are also an option.

The battery seller is of the opinion that the higher amp-hour battery is more suitable for a high wattage motor. And that, when a battery ages, its capacity reduces and if you start with a fairly low amp-hour battery then it is useless as its runtime is greatly reduced. However, with a larger capacity battery, even with a reduced capacity, it would still have usable amount of capacity with a decent runtime.

But I have read that 25Ah is overkill and could reduce life cycle.

Obviously that's contradictory to what the battery maker is saying, but I'm new to all this & I don't have experience with EBike batteries, so I'm looking for some sage advice, please.

[eDavid]

Consider several HobbyKing battery packs and chargers
They are available in the UK and I have seen Endless Sphere postings from the UK where other ebike riders are using HobbyKing LiPo's

http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=66481

[rs4race]

52v will give better performance over 48v, but the battery meter on your display will be worthless, it will read full all the time. Also you will almost never get a straight answer about sizing a battery pack. It takes a little bit of work to get a good estimation.

You could start by checking out the cells used in your pack. For example I have the 52V 11.5Ah bottle battery from lunacycle.com. It uses NCR18650pf cells. Check the data sheet, it has some useful information.

http://industrial.panasonic.com/cdbs...A4000CE240.pdf

I started off trying to estimate my energy consumption. I found bikecalculator.com, google maps, and some local resources pretty helpful. With google maps I was able to map my route and check the distances for the flat portions and hills of my ride, and used some local resources to figure out the grades of the hills. Using the bike calculator you can get the power for a given speed and grade. Power/Speed = Watt*Hour/distance. You can then multiply this number by the distance of that portion of your ride. For example lets say I have 15 miles of flat and the calculator gives me 15Wh/mi, thats 15Wh/mi * 15mi = 225Wh. Then I also have a hill that's 1 mile, and bike calculator gives me 60Wh/mi, again 60Wh/mi * 1mi = 60Wh. My total estimated power consumption is 225Wh+60Wh = 285Wh. Now my pack is 52V * 11.5Ah = 598Wh. So I'm using appx 47% of the packs capacity.

The other consideration is that whichever pack you choose can sustain the power draw the HD will use. In other words make sure it can do 1kW constant, with a 52V pack that is 17A-23A depending on voltage. It's also 30A peak which in reality might go a bit higher than that. The NCR18650pf cells are rated at 10A continuous, my pack is 14s4p thats 14cells in series x 4 cells in parallel. This will give 4cells(parallel) x 10A = 40A continuous. In reality the BMS on this pack limits it to 30A. Either way this pack meets the power requirements the BBSHD has, and most likely you wont be drawing 1kW constant.

As for battery life, it will depend on how you use the pack. If you look at that data sheet you will drop from 2750mAh to 2200mAh over 500 cycles if you fully discharge at 2.1A continuous (8.4A for 14s4p). If you are a bit nicer and don't charge and discharge fully, and your typical discharge current is lower you will get better life. What this is I'm not sure, I haven't looked into it.

So to sum this all up, you can estimate your energy requirements, keep in mind the power requirements of the BBSHD, and use this information to make an educated decision on your pack size. If your nice to your pack it will last a long time. This is also not considering pedal assist, which will add quite a bit of range, and either boost your speed, or lower the power requirements of the electric system.

I hope this helps!

[spinningmagnets]

The volts stay the same no matter what you are doing with the throttle, the amps are the part that is varied to get acceleration, and then maintain cruise speed. The more volts you use, the less amps you need to use, to accomplish the performance you are demanding from your system by how much you twist the throttle. 52V is not a huge upgrade over 48V, but every little bit helps.

The less amps you have to draw from the battery pack, the cooler the pack is, the cooler the controller is, and the cooler the motor is. Plus, lower amp-draw means you will get slightly more range from your pack, and the cycle life will be slightly longer for the higher-voltage/lower-amps method.

If moving up to 52V is good, isn't 60V even better? (the next step up). I could run an external controller on my BBSHD to use 60V, but the stock controller runs fine from the factory on 52V (14S). Plus, a 60V battery would be physically larger, and 52V/60V is the dividing line in skin penetration for shocks. High amps can burn skin at any voltage (even just 12V), but if you plan to use at least 48V, then 52V does not create any additional dangers.

Nothing wrong with 48V, especially if you have to try to fit a pack in a small frame triangle due to using a full-suspension frame. But...I can afford to buy anything I want, and I have a 52V pack (I'm a simple street ebike commuter)

[Marc]

Thanks for the knowledge. Not sure I'm any wiser though. (:

[Louis]

Yeah. Just get a nice 48V or 52V PF pack for riding hard and putting it up wet. A nice NCRB packs for commuting and general use.
52V will make your battery meter wonky, but it's already not a great monitor. I have both 48V and 52V. You won't be disappointed either way.

Iy you want to charge outside in the BBQ there's the Hobby King packs. But that aren't suitable for most of our customers.

[BikeB4Drive]

Buy the biggest Ah pack in 48V or 52V that you can. The less amperage each parallel string needs to contribute to the total current the better. Use the pack between 80%-20% as your self imposed limitation and it will last a long time I'm told. I don't think there are negative or contradictory statements by battery manufacturer. Bigger battery takes longer to charge the deeper you discharge it. I wouldn't consider a shrink wrapped battery to be safe, make sure you protect it. Obviously check that bms is solid also, no worries about Luna Cycle bms, we are lucky in US.
I bought just enough battery 11.5Ah 52V PF dolphin pack it discharges on my commute from 56.5V to 49V and I average 24 mph over 13 mi with giant 6% grade for 30% of commute. I wish I had a 14S5P, that would ensure I have room for degradation as pack ages. I think I'm hard on this pack, I hit 30A routinely but it is holding up probably because of recovery on downhill.

[spinningmagnets]

Since we are talking about which pack to get, choose 48V or 52V. Then...

you need a pack that can safely provide 30A. For the PF cell, 3P is the minimum size, but definitely get 4P or larger. The GA cell is popular right now, and it can theoretically provide 30A with 4P. I recommend 5P to help the pack live a much longer life, because the larger it is, the fewer amps you are drawing from each cell, and the cooler they run...the 30Q is a beast, it can produce 30A with 2P, but more range is always better...