9C came alive on 48 volts!

[willfcc]

A few months ago, I bought a 2805 9C in 20" wheel kit from Grin Technology, and mounted it on my recumbent bike. Being my first foray into e-bikes, I wanted to start with SLA to keep the cost down. So, I bought three 12v14ah batteries and went riding!

On 36 volts, the bike maxed out at 22mph. The legal limit for e-power only in Oregon is 20mph, so this worked out pretty well. On a 22 mile ride, pedalling lightly the whole time, I averaged about 13 wh/mile and 18mph.

This past weekend, I added a fourth battery to get up to 48 volts. The main reason for adding the battery was increasing range. But, I had to try a max speed run just to see what it could do. I was only expecting a couple mph boost, but damn, it topped out at over 29mph!

I still need to do some range testing, with and without pedalling, but, the lithium dreams have begun since I'm carrying almost 40lbs of lead. When I was riding with 36v, I only got about 8ah out of the batteries. Can I expect the same at 48v? If so, it looks like a 44.4v/10ah pack of lipo will be an excellent replacement.

 

[Eujangles]

According to ebikes.ca:

"Because of the Peukert effect, the 7Ah gel cell usually delivers about 4 amp-hours of actual capacity, while the 12Ah lead acid packs will deliver approximately 8 amp-hours. So keep this in mind when comparing a lead acid pack to one of the NiCd, NiMH, or lithium replacements."

So you should get the full Ah advertised by a lithium pack if you convert

 

[jmygann]

"On a 22 mile ride, pedalling lightly the whole time, I averaged about 13 wh/mile and 18mph."


9c on 48 volts ,same route, does ??

 

[veloman]

On a rolling, small hill route, with a stop every couple miles, light pedaling, on my mtn bike build with MY1018 motor Stokemonkey style, I average 20-21mph and draw 13 wh/mile.

I would expect the 9c to be about as efficient, but maybe it's not?

Is this 9c a DD or geared?

 

[dogman dan]

10 ah of lipo, since it's 15c discharge rate or better, will easily give you the range.

I found 14s a really good 48v pack, since I thought 15s was really too close to the max on the caps in the typical 48v controller. But you might want to try 12s lipo.

It's a voltage right in the middle between 36v and 48v, giving you more speed than 36v, but not so close to the danger zone for the controller. Best of all, two 6s lipo bricks makes 12s, so you can get a 12s lipo pack of 10 ah size using just 4 blocks of 6s 5ah lipo. That makes all the wiring and charging pretty easy to handle. 12x 4.2v = a 50.4v battery. For more range later, easy as pie to add 2 more bricks to the pack.

 

[knoxie]

Hi

Yes I agree with Dogman, I run 4 of 6S batteries, 2 series 2 parallel and they rock and roll, I use simple buzzers on each pack for LVC (finally got a batch that don't blow) and have had nothing but great fun since June.

I got a 4 channel charger to charge and monitor each pack individually at cell level along with a high quality PSU to feed it as much as 30A if need be, I can charge these packs from totally flat (don't go that low though!!) to full in an hour, 50.3V hot off the charger, they only sag 1.5V under load so that's 48.5V under load at 40A continuous! now show me a lead acid or NIMH battery for the same size and weight that can do that!

If you thought 48V of lead was fun then your going to love lipo, if you are only on a short run you could even just use 2 bricks instead, you wont even know that they are there in comparison to the lead, and as the Dog says you can add in extra packs of any voltage (better to keep the same AH rating though) in series to pep things up a little if you want more speed or range or both.

This is the beauty of Lipo, weight, price, performance, size, adaptability, redundancy (being able to swap out bad packs) etc etc, don't let the safety issues cloud your judgment on this, charge them safely and be sensible, watch your voltages and fit buzzers or even better cell level monitors like the BM6 and you will have no troubles.

Once you get really hooked then you can get bigger packs, bulk charge, parallel the packs at the taps and the discharge leads etc, there is a ton of information on here, some of us like to configure our cells differently others like the cells to stay paralleled whilst other like the flexibility of running different voltages and capacity in their cells as mentioned.

Hobbyking is your friend!! go and invest you will be happy, lose the lead its only good for lining roof tops and making bullets. :wink:

Knoxie

 

[icecube57]

I give my 4 Turnigy Packs hell on 44v 10AH. Its going to cost about $250 shipped. Might as well even it out to $300 for other little trinkets. One thing i love about lipo is even the above average user wont max out the C rating on the packs. They deliver every ounce of power without complaining. I get 10AH if i go to 40.5v and they stay balanced. Thats the safe zone. I can get 10.3 if I take it down to 3.0v which is a No No! You get your money worth and its not a shot in the dark like other ebay packs. You could always go ping. I want one oft hos 48/30 but its gonna be a heavy one compared to lipo.

 

[willfcc]

@jmygann: Haven't ridden the same route on 48v, yet. Hopefully this coming Saturday.

@veloman: Hub is DD. Probably made more stops than you. Perhaps I should count them?

@Eujangles: About 60% useable capacity is what I expected. Going from 48v14ah lead to 44v10ah lipo might lose about 10% range (if discharged to 80%), but I also lose 30 pounds. If I discharge to 90%, lipo is right there with the lead.

My wishlist is 4x 6s5000mah lipo batteries, along with the Turnigy 4x charger, an 8s cellog and some buzzers. Start with a 2s2p pack, and add another 2p if range doesn't meet my needs.

 

[torker]

The extra battery will get you more range but only if you can keep the speed down That will be really hard to do. Upping the speed will use more wh so if you use all that speed you may actually have less range. IF you have good self control it should improve a little. 9c on 48v is just too damn fun though.

 

[willfcc]

The extra battery will get you more range but only if you can keep the speed down That will be really hard to do. Upping the speed will use more wh so if you use all that speed you may actually have less range. IF you have good self control it should improve a little. 9c on 48v is just too damn fun though.

Yes, it is fun!! But, I'll probably set the CA to 25mph max, and will feather the throttle to keep my average speeds around 20. I'm a little leery of doing 29-30mph with no suspension and 40lbs of battery.

 

[dogman dan]

I bet you do max speed at about 25 mph on 12s lipo. So that ought to be the perfect voltage for you if that's the speed you like.

 

[will_newton]

My wishlist is 4x 6s5000mah lipo batteries, along with the Turnigy 4x charger, an 8s cellog and some buzzers. Start with a 2s2p pack, and add another 2p if range doesn't meet my needs.

You could just use a 2x charger and charge the parallel packs as a 10ah battery. Much easier to hook up and charge and also prevent series/parallel mixups when reconnecting. Always treat the pack as two batteries, if you can. 5ah, 10ah, 15ah, 20ah when paralleled but still just a 6s battery to the charger and the paralleled packs will help keep each other balanced.

I recommend a cycle analyst first, then the lipo batteries. You will see in minutes why your SLA's are no match for lipo of the same voltage. It's a little thing called voltage sag. A CA is a seriously important addition for the e-biker.

 

[willfcc]

@dogman: Good point, I didn't think about the speed REDUCTION going from 48 to 44.4.

You could just use a 2x charger and charge the parallel packs as a 10ah battery. Much easier to hook up and charge and also prevent series/parallel mixups when reconnecting. Always treat the pack as two batteries, if you can. 5ah, 10ah, 15ah, 20ah when paralleled but still just a 6s battery to the charger and the paralleled packs will help keep each other balanced.

I'll have to look at chargers more, didn't realize this was possible. It's actually how I'm running the SLAs.

I used a 36v Soneil charger, and when I went to 48v I started looking for deals on 48v chargers. What I ended up finding, on ebay, was two 24v Soneils at half the cost of a single 48. So, I made two 24v packs, connected in series with a 30 amp fuse, and charge them individually.

 

[dogman dan]

For the full 60v, you can use two 5s and one 4s lipos for a 14s pack. I felt that 3 5s packs at 63.4v was just too close to the max on the caps in my controller. So that is what I do for 48v, 14s lipo. And for 36v 10s.

But then you have three batteries to charge. 12s is kinda nice, since then you just have two sets of paralelled blocks of batteries to charge using 6s packs.

If you go 12s for convenience, adding two more 2s packs for speed when you need it is not hard or expensive.

 

[chroot]

No, You could just set LiPo charger as "Li-Ion" and they typically set to 4.1v each cells

15S x 4.1 = 61.5v will be fine with stock Ebikekit controller or non 4110 fets controllers as long
it's under 63v max.

15S has better choice using parallel charging than 7S (2x of 7S (14S)) unless your charger offer 8S or 10S can
do charge 7S in series via charger's balancer board.

I was going build 7S LiPo using 3S + 4S (14s2p) in series for my 2nd IZip uses Bafang geared hub motor
with upgrade ebikekit controller or bang buck controller.

For the full 60v, you can use two 5s and one 4s lipos for a 14s pack. I felt that 3 5s packs at 63.4v was just too close to the max on the caps in my controller. So that is what I do for 48v, 14s lipo. And for 36v 10s.

 

[BIG BEAM]

What is the life expectancy of Li Po batteries? We don't use no where near the c rating so will this help with how long they last?I have 2-5mah turnigy 20c batts and 44v is fun with a 9c.But I use my 36v headway pack a lot more.Maybe I'll sell the Li Po.
DON

 

[chroot]

LiPo usually last 500 cycles. LiPo blow LiFepo4 in ampere and LiFepo4 beats LiPo last long time cycles.

 

[veloman]

From what I heard, some here will tell you they are getting 1000 or more cycles from LiPo when used/charged correctly.

 

[dogman dan]

Yes, it's said that lipo can last longer than 500 cycles. I think using them at 1/2 the c rate they claim helps, but can't actually prove it.

Others say they have proof that charging to 4.1v instead of 4.2 v helps, and it is well known that keeping depth of discharge below 80% helps all chemistries of batteries.

Doing all three of these things should get you 1000 cycles or so. But I suspect that if you follow the same kind of pattern, slight undercharge, reasonable c rate, and less than 80% depth of discharge, you'd see 2-3000 cycles out of good quality lifepo4.

This is why my commuter runs on a heavier ping lifepo4. For ease of charging at work, long range, and should last many years. But for performance, it's the lipo on my race bike, and when I want my dirt bike to be lighter.

 

[chroot]

My commuter runs LiPo batteries everyday!

my theory for the LiPo more Ah = more longer cycles. I mean 10Ah vs 20Ah so 10Ah usually faster cycles more often charge and faster dying when it reach 500 cycles by time the 20Ah probably at 250 cycles.

 

[dogman dan]

Yes, lower depth of discharge = more cycles. So 500 100% cycles = at least 1000 50% cycles. If I had a short commute, I'd be more likely to use lipo, but I have a long one, so carrying 15 ah, a ping is just simpler to charge.

Here's a pic of my 5 ah 12s lipo pack. With a short commute, one of these would be dandy. For me it's more like a reserve tank I occasionally carry. The pencil box from wallmart fits it like it was made for it. It caught my eye in the store, and I thought hmm, that's about lipo size.