New Battery choice, 48v or 52v

[RoyL]

Looking for a battery replacement

These two options are similarly priced, both using the Sanyo NCR18650GA 3.7V 3450mAh 10A cells.

I see in the U.S. the 52v setup is more popular with the BBSHD mid drive setups, i`ll be using it presently with my BBS02 and probably later with the HD version. But i notice one has 65 cells (48v) and the other (52v) item has only 56??

Any advice on which would be strongest/most suitable? I would have thought the extra 9 cells would have been the one to go for ... but maybe not?

13Series 5Parallels 13S5P = 48v

14Series 4Parallels 14S4P = 52v

 

[Cameron Newland]

I always recommend 48V batteries for two reasons:

1) Both the display's battery charge state indicator and the battery pack's battery charge state indicator LEDs (if it has them) will work properly
2) The pack likely includes the standard pack stencils/cell dividers, which help to ensure that your pack doesn't short out (which can happen if it's just a brick of cells glued together)

I happen to own 52V Shark packs from both Lunacycle and EbikeOutpost, and though they're both great packs, they lack the standard pack stencils/cell dividers that come with 48V packs, and this compromises their safety with regards to internal shorts that can occur when battery cells without stencils/dividers between them make accidental contact. On both packs, the builder went the extra mile and added some insulators around the top of the positive terminal, however, these thin insulating strips could come loose, and any contact between cells could cause a potentially dangerous short circuit. That's why most packs use pack stencils/cell dividers. The 52V packs also generally weigh 5-8% more than their 48V equivalents, although on the packs you mention here, the opposite is true because the 48V pack is a 5P pack and the 52V is a 4P pack.

The only benefit of the 52V packs is that you get up to 8% more power, however, above 20 or 25MPH, that extra power just gets eaten up by aerodynamic drag, so your top speed most definitely won't be 8% higher than using a 48V pack. There could be a slight, barely noticeable improvement in hill climbing with a 52V battery, too, I guess.

Anyways, it depends on whether you value safety/reliability or raw power. I recommend the 48V battery, but I understand why some folks buy the 52V versions.

 

[RoyL]

Interesting you mention the lack of pack stencils/cell dividers, do you also not think there would be a heat issue with the cells being glued together?

 

[Cameron Newland]

Interesting you mention the lack of pack stencils/cell dividers, do you also not think there would be a heat issue with the cells being glued together?

I used to wonder about that myself, however, I learned recently that with the 18650 battery cells glued together, they actually function as a sort of heatsink in that they radiate heat outward as a single unit, whereas using pack stencils, there is a ~1mm air gap between each cell that actually serves to reduce the ability of the pack to get rid of heat effectively.

 

[harryS]

If range is a consideration, figure the watt-hours. Those batteries are rated 13.8 and 17.2 AH respectively? Multiply the AH by battery voltage to get 717 and 825. The bigger battery has 15% more watt-hr and thus 15% more range.

Having a BBS02 myself , I would estimate that extra 108 watt-hours is good for about 6-8 mile at 14-16 mph. Probably 4 miles at top speed.

When I had this choice a year ago for a rack battery for my BBS02, I chose 48 volts to save $40 on the battery and $40 for the charger (already had a 48V chargers). Didn't care about the higher speed. If I was starting fresh, I think I'd pick 52.

 

[RoyL]

some interesting info from Karl Gesslein about the two battery options,,,

https://electricbike-blog.com/2016/...ve-system-with-a-52-volt-battery-master-yoda/

"Do you really feel a difference when riding with a 52v battery instead of a 48v battery? I have spent hundreds of hours riding the BBS02 & the BBSHD with both 52v and 48v batteries from a variety of vendors. Honestly, right off the charger both the 48v and the 52v batteries feel about the same even though the 52v battery is about 4v more. I have not noticed any difference in the top RPM range of the unit, although it might be slightly higher with a 52v pack. The real differences come when your ride is about 1/2 over. With a 48v battery, once your battery is about half depleted you can feel the power drop off slightly. As the battery gets down to about 1/4 of its charge left, the difference becomes even more noticeable with both throttle lag and a noticeable lack of power. With a 52v battery this never really happens as the voltage never sags into the ‘ho-hum’ zone. With a 52v battery the BBSxx drive units run quite powerfully right up until the battery BMS cuts out."

 

[tomjasz]

48V will mean an accurate, or as accurate as the display gets, battery level reading. My 52V 20Ah is 2 MPH faster than the 48V 20Ah at full charge. Doesn't last long. More cells less sag. I'll always take the pack with more cells. 14s5p would be great! Empowered and some resellers are actually lowering BBSHD controllers to 20A from the 30A max. Matt thinks the motor will last much longer. Others have a very very different approach, believing the BBSHD will run problem free at 40A so 30A is absolutely no problem. Pick your expert.
I'm a street rider that wants maximum value and least amount of problems. NOT IMPLYING 52V will be a problem. I have both. I also use a GA pack on a 36V system and only draw 18A. It's all about how fast you want to ride. I'm the old guy that's happy below 25MPH. I find that at higher speeds car drivers misjudge my speed and make more left turns in front of me, on busy streets. It was fun seeing what the BBSHD could do. But 32MPH with V brakes wasn't my cuppa. I'd go 13s5p. Some would say the GA will last longer with that configuration. Others call bunk. Next packs for me will be 30Q and I've come to like soft packs in battery bags where they fit. Now that I've muddied the water... Whatever you do, you'll have a good pack. I'm with Cameron.

 

[wjs]

More cells more power.

It doesn’t matter how you stack them (series/parallel),, the more cells (of the same type), results in more power. Put them all in series, and a DC motor may spin faster, but not for as long.

The main advantage of higher voltages is that currents can be reduced which then permits lighter gauge wiring. There is a tradeoff however when the barrier between low, and high voltage circuits is crossed (UL or CSA). Some electrical codes suggest that 48V is quite safe, while 49V is not.

 

[tomjasz]

48V (54.6V)and a wedding ring can do this. The ring was partially melted.

 

[harryS]

I've recently compared three batteries on a 350W hubmotor bike. Rough top speeds: 36V 17-18 mph, 48V 20-21 mph, 52V 22-23 mph.

I was glad to see it go a little faster on 52V.

Stories circulate in auto shops about mechanics reaching around an oil pan and getting their wedding ring onto the two exposed nuts on the starter that carry +12 volts, Supposedly, ring fingers have been burned off.

 

[tomjasz]

Several severe burns have been posted on Endless_sphere.