Is 5 Ah enough ?

[StudEbiker]

I don't read every thread on this forum

That comes as a shock to me as I thought you posted on every thread on the forum. I honestly can't remember a single thread of late you haven't posted on.

[blissisebike]

For me, it usually is, but I can see how it would not be sufficient for other needs.

My round trips are normally right around 13 to 15 miles and my 7 ah pack is generally only depleted about 50% by those trips. When I need to go much longer distances, I have a second pack that I also carry. For me, that is a much better solution than carrying a 14 ah worth of batterypack all the time.

Ebike used: Yamaha Easy Super (bottom bracket drive motor) 235 watts

[RVD]

To get a little back on topic,

I have a small 14s1p (5ah) pack that I use for really quick trips to the bank ATM, supermarket, etc. My packs are turnigy 6s 5ah 20C packs. I always thought that since they are 20C, they should be good for up to 100 amps draw. Even if we only take 50% of that, I should be good up to 50 amps right?

I actually use around 35 amps at WOT and although there is some voltage sag, I haven't noticed it being *that* bad...maybe 2-3 volts?

Am I doing some harm to by batteries by riding them this way? It's very convenient because the pack fits easily on the top of my rear rack panniers and I don't need to use the side panniers.

Regarding range...it's it all a bit of hogwash anyway? I can pedal 99% of the time and say that I get 100 miles range out of my 5ah can't I?

[neptronix]

Studebiker: yeah ok you got me
Been paying less attention though lately ( now i have work to do )

RVD: I find that turnigy's take the abuse far better than zippy 20C. If they are getting warm, you are taxing them some. 35 amps isn't *too* bad, but for max battery life ( and watt-hours! thus longer range ) you want to run these bad boys at as low of a C rating as possible. 10ah would be better if you can squeeze it in, or maybe 8ah.

Besides, it is nice to have some fluff room in your pack for spontaneous trips.

[RVD]

I'll try it out. I don't use the pack that often and my pack is enclosed in a plastic container so I never actually feel if they are hot. I don't think so though but I'll check sometime.

It's also 35 amps peak...usually it does that briefly and then heads down to more like 20-25 amps.

[neptronix]

Ah.
Yeah ido constant hillclimbs so my advice is going to be overly cautious.

With a constant 4C-5C load, these packs do fine.

[el_walto]

It takes me 13 minutes and 5ah 48v to get to work. If i had a plug and play quick charger, that would be the most I really needed.

What i have is 30Ah 48V. It works good also, but heavy.

- Walt

[neptronix]

I started out with 5AH but got nervous because the lipos would get kinda hot on me, plus i didn't like being so close to LVC in the middle of nowhere. This bike really does replace a car and the idea of being out of gas is unsettlin'.

I ran with 20ah for a moment but realized that it was a bit too much to haul up a flight of stairs each day. Been trying to get the bike weight down.. pound here.. pound there, adds up..
Now i have 15ah + a rear rack that can plugin another 15ah if i want to do a 60+ mile run ( once it stops raining here )

[RVD]

I generally use about 10-11ah each way on my commute if I pedal almost zero and go pretty much top speed as much as possible. I only charge my lipo up to 85% (4.11v/cell) though so even with my 14s3p pack, I'm usually down to around 3.7v/cell (15-20%?).

I bring my charger to work and have an extra power supply that I leave at work so I charge at work and for my ride home. My rear panniers are removed when I get to work for charging and it is dang heavy. I don't know how you walk around with 20ah...

I would love to reduce my pack to 10ah and I probably can if I charge up to 4.2v/cell and I pedal some more or conserve a little bit. I have made it at 9ah each way many times. I'm just too scared of lipo charging...

[Ziggurat]

...I only measured the Ah on one ride so far, and that was at 10S. Used about 2.3 Ah used over 13.5 km, so about 6.5 Wh/km on a mostly flat route with one short steep hill. I was pedaling a lot along with throttle, and there was very little stop and go.
...

OK; that's 8.3 miles on 2.3ah, which would translate to him getting maybe 20 miles on 5AH while 'pedaling a lot'.
Seems like a stretch, but if you are pedaling really hard, i'll believe it since i got 14 miles out of mine with stop and go.

Well, since you were talking about me ...
At the time, I had only one measurement, now I have many, and still getting 6.5 to 7 Wh/km. I've been riding to work daily for weeks, 17 km round trip, fair amount of stop and go, 150 foot elevation change. Charging to 4.15 V/cell and coming home with about 3.8 V. That's from 90% charge to about 30-35% -- nice comfortable range to keep my batteries happy and give them a nice long life.

Gravimetric/volumetric info : 5' 8.5", 160 pounds.

So 5 Ah is just about perfect for my commute. I do pedal along, but I'd guess the motor is giving about 60% of the power to accelerate from stops and more than that for climbing big hills.

[amberwolf]

It would be enough for my work commute on CrazyBike2 (actually probably enough for two days' worth), if the cells used had a high-enough C-rate (to give me at least a safe low-sag 60A peak and 30-40A short-term high, with average long-term of 5-10A).

On the lighter DayGlo Avenger, with the smaller Fusin motor and slower speeds, I expect I could get 3 days of commuting on that, or nearly so, assuming 100% DOD.

[darkshirikens]

Nah i like speed and distance too much and then i try to beat my old records getting to different places and also ..... I'm FAT and i need a new crank with like a 53t on it so i can pedal with the motor.

[kevo]

Nope. Even for minimal friction drive assist, I like to bring at least 10Ah. Worry about draining batteries too low otherwise.