25r vs 26f? 48V 15-20Ah battery recommendations?

robocam

robocam

10 kW
Joined
May 29, 2014
Messages
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Based on my search, I've read good things about Ping batteries, but they cost so much ($642 for a 48V 15Ah). Any other suggestions on reputable sellers even if in China? I came across several older battery threads, but I was wondering if anything has changed since then. I saw sunthing mentioned. I've also heard bad things about Vpower, but I wonder if they should still be avoided.

This seems to be the only LiFePO4 eBay seller shipping from the US. What are your thoughts on this $420 battery?

http://www.ebay.com/itm/Lifepo4-Lithium-48V15ah-Portable-Battery-E-Bike-Scooter-Built-in-BMS-Charger-/271889754345?hash=item3f4de468e9:g:Y8EAAOSwBahVLqHD

I'm not opposed to sellers in other countries, but returns would be a huge hassle if even possible, so I'd like to avoid that potential headache.

I am running a 2015 GNG mid drive at stock power levels (22A), so that eBay battery rated at 20A continuous should be ok right?
 
I'd want higher continuous rating for the GNG. At least the 22a GNG rating.
 
Well what country are you in? Read this.
https://endless-sphere.com/forums/viewtopic.php?f=3&t=66302
 
Then put it in your profile. If you don't know how to do that, follow the link I posted earlier.
 
Looks like it has at least 2c capable cells in it. So likely to be similar to ping cells inside. I'd say it will run your 22 amps controller ok. but as always, more will run closer to half the c rate, and last longer usually. But 15 ah should last a few years at least.

If you need service on it, you are still screwed. That guy on ebay likely has no idea what's inside the thing, or how to troubleshoot it. I never heard of him. Ping will help you fix it if you have a problem.

But at 400 bucks, worth it perhaps to take the chance. If nothing else, no customs to sneak an illegally shipped battery through helps.
 
Thanks so much for the suggestion! The prices look great. How safe are those compared to LiFePO4 batteries in terms of starting fires while being charged? The reason I ask is because I've seen people charging their batteries in a BBQ grill, and I'm not too familiar with why they catch on fire, so if these are just as safe as charging a power tool, I'm in.

http://lunacycle.com/batteries/packs/48v-samsung-18650-20ah-ebike-battery/





999zip999 said:
Look at Luna cycle in the usa.
Click to expand...
 
The type of cells typically used in 18650 cell packs are not particularly less safe than lifepo4. It's the RC cells, the lithium cobalt type that have the bad rep for fires.

So why are the hoverboards catching fire? It's hard to say, but I suspect as people learn to ride those things, the board goes flying, and mechanical damage is causing them to short the battery. Any battery can start a fire, if it gets shorted.

So when you get your new battery, don't throw it across a room into the wall. :wink:
 
I was looking at that battery too. At the bottom of the page it says it is not available.
 
Yeah, that's too bad. I'm back to considering the eBay battery or maybe this one. This is getting expensive real fast especially after you add their $80 charger. :shock: I don't know what to do.

http://lunacycle.com/batteries/packs/triangle-52v-samsung-26f-20ah/

It would be nice if it fit my frame perfectly. Any recommended pack builders here? :) Here's what my triangle looks like.

p4pb6509133.jpg


Xray said:
I was looking at that battery too. At the bottom of the page it says it is not available.
Click to expand...
 
I bought a 48v 15ah lifePo on ebay about 3 years ago from the seller sun-thing28 who was getting good reviews at the time. It is still serving me well today, use it about 3 times a week for 7 mile trips. I make sure to leave it charging for hours before and after use so the cells are always balanced. Only problem I've had was the charger it came with started making funny noises after a couple years but all I had to do was oil the fan inside which was'nt hard. It takes nearly 2 months to arrive via boat but by air it would have been $100 more. It looks like sun-thing28 is still in buisness and the feedback rating is good and the prices are even better than 3 years ago $310 shipped. If you can wait it might be the way to go.
 
I'm leaning toward this 52V battery from Luna Cycles. I like the idea of slightly overvolting for a little more performance. The eBay LiFePO4 packs appear to be 44.8V packs (14 cells at 3.2V each), so I'm not too thrilled about that.

Is there anything I should know before committing to it? Is this a good pack?

http://lunacycle.com/batteries/packs/triangle-52v-samsung-26f-20ah/
 
Get some cardboard and make a mock up. A lot smaller at 20ah 12lbs. Cells will not be working as hard with your setup. Plus volts is speed. Lifepo4 is good for cycle life but low c-rate for most Chinese pouches.
If you get there charger and charge to 80% most times till you need all 20ah then full charge and full charge once a month to balance thru bms. This in theory should greatly expand your life cycles on this battery. Time will tell.
So does it fit ?
 
It won't fit in the triangle, so I'll have to put it on the rear rack. These two will fit though, but I'd have to come up with a way to mount it in the triangle using maybe the bottle holder holes, but I'm worried they won't handle the load. I figure I'd rather pay a little more for double the capacity.

http://lunacycle.com/batteries/packs/52v-samsung-26f-10-ah/

http://lunacycle.com/batteries/packs/52v-samsung-29e-11-6ah/

I've been using 4 8Ah SLA batteries, so this should be a huge improvement. I did try to use 4 12Ah SLA batteries once, and it was so heavy it severely affected handling. With the lithium pack at 12 lbs, it will be lighter than having 3 of those 8Ah SLA batteries (my first ebike setup).

This battery seems to be of much higher quality than the eBay LiFePO4s, but it will be costly ($670 with the Lunagizer charger). Which is making me doubt this decision. Is the jump in performance/quality between SLA and eBay LiFePO4 significantly greater than the latter vs. the Samsung 26f battery? I also think I noticed a difference between using the 8Ah and 12Ah SLA batteries. It felt like I had much more torque with the 12Ah batteries, so either my 8Ah batteries were old or they were simply unable to deliver as much current, which also affected the actual available capacity since I was draining them as such a high relative rate, so if I get a 20Ah lithium battery, it might be like having a 50Ah SLA battery or larger.

I really don't care about top speed, so 52V isn't a requirement. I'm mainly concerned about weight, reliability, and capacity. If the eBay LiFePO4 packs really hold 20Ah, that would be a surprise, as most cheap products are typically overrated. I guess in the end, it's only about a $200 difference between eBay and Luna, so I should probably go with Luna to avoid the potential headaches.

999zip999 said:
Get some cardboard and make a mock up. A lot smaller at 20ah 12lbs. Cells will not be working as hard with your setup. Plus volts is speed. Lifepo4 is good for cycle life but low c-rate for most Chinese pouches.
If you get there charger and charge to 80% most times till you need all 20ah then full charge and full charge once a month to balance thru bms. This in theory should greatly expand your life cycles on this battery. Time will tell.
So does it fit ?
Click to expand...
 
Most Luna cycle batteries can easily handle your controller at 22amps. Email Eric ( Luna cycle ) with a pic of your bike and see what he has in mind. It would be great if you can get a battery in the triangle. Lead is dead. Good luck.
 
robocam said:
Yeah, that's too bad. I'm back to considering the eBay battery or maybe this one. This is getting expensive real fast especially after you add their $80 charger. :shock: I don't know what to do.

http://lunacycle.com/batteries/packs/triangle-52v-samsung-26f-20ah/

It would be nice if it fit my frame perfectly. Any recommended pack builders here? :) Here's what my triangle looks like.

Xray said:
I was looking at that battery too. At the bottom of the page it says it is not available.
Click to expand...
Click to expand...

Man that's a tough triangle to work with. Why not on top of the top tube? I have seen fellows mount on the top tube. Or a cased battery on a rear rack?

The trouble with those tight triangles is getting the cased battery in and out of the base. Eric's good but he can't change geometry.
Ya gotta do whatcha gotta do. I wouldn't mount a soft pack on a rear rack.

I have a 13s4p Dolphin on a rear rack. It's not bad at all. I think you just have to make a decision and make it work.

ANY solution beats all that SLA weight.

The cardboard cut out ought to pretty much tell the story. That looks like the Shark might be to tight too.

Do you have a rear rack? I just drilled mounting holes in mine. Done and bob's your uncle. You can fret and try for perfection or just make a decision and live with it. Once you're riding you'll forget about it and smile your way around on your new more powerful efficient lithium powered bike.

All this thinking has to be wearing you out!

What exactly IS the model and brand of bike? Year?

Draw an accurate layout of the frame triangle. I have several Dolphin packs I could measure against it. A buck in postage. But I think the triangle is an exercise in futility.

Rear rack and be done. Dolphin cases are tough. I think the best and sturdiest of the type.
 
A 10" x 3.25" pack can fit. I've included a picture of my frame with a piece of 10" x 4" foam in the triangle.

I don't want to mount it on the top tube because that would increase the standover height. The cased batteries from Luna come with a 30A BMS. The new GNG mid drive has a 31A controller.

http://www.gngebike.com/gng-belt-kit-2016

What do you mean when you say you wouldn't mount a soft pack on the rear rack? I could line the enclosure with some soft material to protect the pack. I don't mind thinking about about it. It's fun actually. I want to be sure I've made the right decision. The Luna Cycle pack appears to be of high quality. I don't think I'd save much by going with an eBay LiFePO4. Most eBay packs are only 14 cell which is a disappointment. People buying those 48V packs are actually getting 44.8V packs! Ping batteries are 16 cell (based on their 51.2V nominal voltage) but the shipping charge is $145, and the 20Ah pack is $658!

http://www.pingbattery.com/servlet/the-2/lifepo4-lithium-ion-phosphate/Detail

The 17.5" frame is a from a Trek HiFi Pro 29 (maybe 2011).

https://www.google.com/search?q=trek+hifi+pro29&ie=utf-8&oe=utf-8

I have a rear rack. That's where I put my SLAs. That's probably where I'm going to have to put the new battery. I'm leaning towards this battery. 52V should be a fun upgrade, and at 12 lbs, it'll feel like air.

http://lunacycle.com/batteries/packs/triangle-52v-samsung-26f-20ah/

tomjasz said:
...Why not on top of the top tube?...Or a cased battery on a rear rack?

...I wouldn't mount a soft pack on a rear rack....

...Do you have a rear rack?

...All this thinking has to be wearing you out!

What exactly IS the model and brand of bike? Year?...
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How about this...I didn't check the measurements, but there are other triangle packs that will work too.

Fellows like SamD can also have custom packs made.



http://lunacycle.com/batteries/packs/52v-triangle-samsung-inr-18650-25r-52v-12-5ah-high-power/

Here's a 7.5 lb solution!
http://lunacycle.com/batteries/packs/52v/rear-rack-52v-samsung-panasonic-sanyo-ebike-pack-11-6-13-5ah-w-charger/

I think you're nearing overthinking this....maybe?
 

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Apparently, I'm not thinking enough, as you have clearly pointed out =) It never occurred to me to even consider that battery since I didn't need the high amperage. I didn't realize it was smaller than their other triangles, so thanks for pointing that out. I'm not too sure I'm happy with the 12.5Ah capacity for that price though.

Another battery I'm considering is this one. I'm going to make a cardboard mock-up to see if I can pedal with a 6" wide pack in the triangle. I still need to come up with a way to mount a pack in the triangle. The only thing I can think of is to buy some sheet metal from the hardware store to make a box that fits the battery and use hose clamps to secure it.

http://lunacycle.com/batteries/packs/52v/52-panasonic-ncr18650b-20ah-power-density-and-performance/

tomjasz said:
How about this...I didn't check the measurements, but there are other triangle packs that will work too.

Fellows like SamD can also have custom packs made.

http://lunacycle.com/batteries/packs/52v-triangle-samsung-inr-18650-25r-52v-12-5ah-high-power/

Here's a 7.5 lb solution!
http://lunacycle.com/batteries/packs/52v/rear-rack-52v-samsung-panasonic-sanyo-ebike-pack-11-6-13-5ah-w-charger/

I think you're nearing overthinking this....maybe?
Click to expand...
 
I run a 11. and a 13.5 pack. I get more than 20 miles with heavy throttle on the 11.5. I'm a big guy, a gimp, 220 pounds on a 65lb bike with a load of groceries. Pretty respectable performance. IMO. Check the same battery pricing elsewhere. OUCH! I think you're going to give up something making a fit that you insist on. Lately I've had a bunch of folks using back packs. Especially single track rider. That way the battery gets none of the transfer of bumps, grinds and vibrations. As Always, YMMV!
 
Ok, so I decided to go with this 26f pack (20.8Ah 52V), but I've learned new information.

http://lunacycle.com/batteries/packs/52v/triangle-52v-samsung-26f-20ah/

At first I thought I wouldn't need the high current handling of the 25r cells. In the 20Ah pack, there are 8 in parallel, so the battery can handle a 160A load (I understand the pack can't actually deliver 160A continuously because of the 50A BMS). The 26f pack also has 8 in parallel, so it should be able to handle a 40A load. Right now I have the 2015 GNG belt-driven mid drive (22A) but I might get the 2016 GNG (31A) or the Cyclone (40A) in the future. Would the relatively lighter load on the 25r pack mean that it would last significantly longer in cycle life? 22A out of a 160A rating is just 14% of its maximum, but 22A out of a 40A rating is 55% of its maximum, so it would seem that the 25rs are just loafing along while the 26fs are working much harder.

Also, because of that, would the actual Ah obtainable be higher in the 25r pack even though the 26f pack has 0.8Ah more capacity? When I think of effective amp hours, I figure that given the same load, a higher capacity battery should be able to provide a higher efficiency. For example, if I discharge a 20Ah battery at 20 amps vs a 2.5Ah battery at 20 amps, I would think that the 20Ah battery would provide closer to its 20Ah rating than the 2.5Ah battery would its 2.5Ah rating. But what I don't know is if the maximum current rating also comes into play if the batteries are of similar capacities. According to this page, the 25r is rated at 20A max continuous and the 26f is rated at 5A max continuous. Does this rating mean that it is safe to draw this current continuously without any damage to the battery, or is it simply telling you that the cell is capable of this current output level?

http://lunacycle.com/blog/18650-cell-ebikes/

The cycle life of the 25r is also rated 50% higher at 600 cycles vs 400 cycles for the 26f. I'm also wondering if the 25r pack will be able to hold a significantly higher voltage under load vs. the 26f pack (with 40A or 22A loads).

See, now I'm beginning to overthink things =)

This is the battery to get now.

http://lunacycle.com/batteries/52v-samsung-inr18650-25r-20ah-high-power/
 
And I've found some data to confirm my suspicions.

If I drain the 20 Ah 26f pack at 40.8 A continuously, its effective capacity will be reduced to 16.32 Ah. The 26f spec sheet states that a 2C drain rate will result in an 80% capacity.

If I drain the 20 Ah 25r pack at 80 A continuously, its effective capacity will be 99.2% of its 0.2C capacity. Basically, the 25r pack's effective capacity is the same as its advertised capacity even at relatively high current levels.

Now of course I'm not going to ride around at 40 A continuously, so I'm sure those differences aren't so great in reality.

https://www.powerstream.com/p/INR18650-25R-datasheet.pdf

http://www.oomipood.ee/kasutusjuhend/ICR18650-26FM.pdf
 
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