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Old 12-01-09, 11:53 AM   #1
crimsonsnake0
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whitch lipo battery

HI ALL. i have 4 sla batts on my bike at the moment 20ah. these are fine for my needs. 12ah would get me to work and back just but 10ah were a waste of time. my question is i would like to get some lipo batts but whitch ah would cover the same distance as my 20ah sla s ? also is it correct i would get more speed from lipo batts ? REGARDS AND THANKS FOR ANSWERS IN ADVANCE CRIMSONSNAKE0.
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Old 12-01-09, 12:31 PM   #2
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You need to provide more details. You need to remember to look at the BMS (Battery Management System--a computer board that's programmed to protect the battery during charging and discharging) specs, which means you're going to need to know the specs of your controller, especially the maximum Amps it can demand when you hit the throttle. Too many people buy a LIFEPO4 battery without comparing the BMS specs to their controller specs and then are in shock (and disappointed) when the BMS shuts off the battery at times when the controller is demanding peak amperage. Come back with the specs on your controller and then we can give you some recommendations.
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Old 12-01-09, 01:19 PM   #3
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Unless you really know what you are doing, I'd stay away from lipo battery packs. You need a special charger so as not to burn down your house and the max voltage that they are available in is 32V.

I think what you are asking about is lifepo4 batteries. Much safer chemistry. Generally, 10AH of lifepo4 will get you as far as 20Ah of sla. 48V lifepo4 packs are usually 16 cells which means that they are nominally 54V and when hot off the charger ~60V. They also have a much flatter discharge curve and are quite a bit faster than their 48V cousins.
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Old 12-01-09, 02:59 PM   #4
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Originally Posted by nicobie View Post
Unless you really know what you are doing, I'd stay away from lipo battery packs. You need a special charger so as not to burn down your house and the max voltage that they are available in is 32V.

I think what you are asking about is lifepo4 batteries. Much safer chemistry. Generally, 10AH of lifepo4 will get you as far as 20Ah of sla. 48V lifepo4 packs are usually 16 cells which means that they are nominally 54V and when hot off the charger ~60V. They also have a much flatter discharge curve and are quite a bit faster than their 48V cousins.
You're confusing LIFEPO4 with LiPOLY, High-Power Lithium Polymer Battery. They are different chemistries. LiPOLY is much less stable (it has a polymer cathode) and is generally used in RC cars and planes. The LIFEPO4 uses a much safer cathode (Iron Phosphate) than even tradition LiION batteries using ccobalt or manganese oxide that you typically find in cell phones and laptops. LIFEPO4 comes in 48V and 72V and higher (yes, they're used for electric cars). It would be nice if LIFEPO4 could be used in energy intense appliances like laptop computers, but they'd be too big so we're stuck with LiION with cathodes that can be more unstable and more readily subject to catch fire or explode. Traditional LiION can just pack a lot more energy in a small form factor which is required for those appliances.

Here are wikis that explain each battery's technology.
LiPoly--http://en.wikipedia.org/wiki/Lithium...olymer_battery
LIFEPO4--http://en.wikipedia.org/wiki/Lithium...sphate_battery
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Old 12-01-09, 04:12 PM   #5
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Crimsonsnake, as nwmtnbkr said, you may be confusing LiPo batteries with LiFePO4 batteries. LiPo (lithium/polymer) batteries weigh half as much for the power they store, but they are unstable, and have been known to leak toxic material and even catch fire, sometimes for no known reason. From what I've read, LiFePO4 (lithium iron phosphate) batteries don't do those things.

Assuming you really meant LiFePO4, the answers to your question is, Yes, LiFePO4 batteries will usually perform much better than SLA batteries. If you attach a WattsUp meter to your bike, you might find that your 12Ah SLA batteries are running down after they've delivered only 7 Ah of current or so. SLA batteries usually don't like to be deep-discharged, and usually don't like to run at higher discharge rates.

If you discharge a 12V, 12Ah SLA battery at 1 amp, it will usually last 12 hours before it goes dead. If you discharge it at 12 Amps, you might expect it to run for 1 hour, but in fact you might find it lasts maybe 30-40 minutes before going dead. On the other hand, a 12Ah LiFePO4 battery will give you 1 Amp for 12 hours, and will give you 12 Amps for a full 1 hour, not 30-40 minutes like an SLA battery.

If your 12Ah SLA batteries "barely get you to work", you might find that a 12Ah LiFePO4 battery gets you to work and most of the way back home too.

When a battery manufacturer lists their battery's Ah capacity, it's usually along with a discharge rate. And SLA battery might be listed as "12Ah at a 0.1C rate". Meaning, you'll get 12Ah out of it only if you discharge it at 1/10 of its Ah rating, or 1.2 Amps. If you try to discharge it at a higher rate, like at 12 Amps, you'll only get maybe 7Ah out of it before it goes dead.

LiFePO4 batteries usually have higher discharge rates than SLA batteries. An LiFePO4 battery might have a rating of 12Ah at a 1C rate. Meaning, that if you discharge it at 12 amps, it will last 1 full hour before it goes dead. But if you discharge it at, say, 36 Amps, it might last only 10-12 minutes instead of the 20 minutes you expected.

Due to their higher discharge rates, LiFePO4 batteries are better suited to ebike usage, since ebikes regularly discharge their batteries at anywhere from 5 to 20 amps, depending on terrain and other conditions.

BTW, the dreaded LiPo (lithium polymer) batteries have discharge ratings of anywhere from 10C to 50C. They can really pump out the amps, relative to their capacity. So they would be GREAT for ebikes, except for their tendency to go boom in the night. Or worse, they will go boom six inches behind your rear end, on your ebike's rear rack, just as you are trying to scoot through that difficult intersection with heavy traffic, cars honking at you etc.

LiFePO4 batteries (and SLA batteries) won't go boom. They are the way to go. LiFePO4 are nearly ideal, but they are pricey, costing 2 or 3 times what the SLA batteries do. They are also lighter than SLA batteries. You pays your money and you takes your choice.

Last edited by Little-Acorn; 12-01-09 at 04:15 PM.
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Old 12-02-09, 06:16 AM   #6
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hi thanks everyone. sorry i did mean lifepo4 batts from ping for example from china. i think i will get around the 12ah one. any one had any dealings with these china sellers ? all the best and thanks again all for your time regards crimsonsnake0 uk.
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Old 12-02-09, 10:46 AM   #7
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I have gone for 25 miles without a drop in my indicator light. I do pedal all the time, and I don't have any HUGE hills. 36v15ah from Ping will take you a very long way. It's about 7 pounds, fits easily into my Topeak rear bag with the controller. I passed someone who also had an Amped kit; I believe the difference was our batteries. His were SLAs housed in a cooler bolted to the back.
Of course, read the other comments on checking your controller's needs, etc.
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Old 12-02-09, 07:25 PM   #8
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Originally Posted by crimsonsnake0 View Post
hi thanks everyone. sorry i did mean lifepo4 batts from ping for example from china. i think i will get around the 12ah one. any one had any dealings with these china sellers ? all the best and thanks again all for your time regards crimsonsnake0 uk.
Before you decide on amperage, you need to read the specs on your controller. I think amperage in Ping's batteries go from 10 to 15, not 12. Depending on the amperage draw of your controller when you demand peak power from the throttle, you may not be able to use the 10AH version. Again, don't buy anything until you read through your controller's specs. Otherwise, you may find you've bought an expensive battery that will cut out everytime you hit the throttle. Good luck.
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Old 12-03-09, 08:49 AM   #9
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hi is their anyway i can find out amps of controller inside unit as i have no info on controller. all i know is that it is a 48v 1000 watt kit. The contoller has blue things inside that say 62v . regards crimsonsnake0
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Old 12-03-09, 12:48 PM   #10
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hi is their anyway i can find out amps of controller inside unit as i have no info on controller. all i know is that it is a 48v 1000 watt kit. The contoller has blue things inside that say 62v . regards crimsonsnake0
The vendor didn't give you any paperwork? If not, can you contact the vendor to find out what the specs on the controller are? If that's not possible, I'd suggest you post on the Endless Sphere e-bike forums to see if anyone there knows anything about the controller in your particular system. http://endless-sphere.com/forums/ I definitely wouldn't get a battery with a BMS that cuts off at 20A; 30-40A cutoff would be better, given the voltage of your hub motor. Good luck.
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Old 12-03-09, 12:49 PM   #11
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I think amperage in Ping's batteries go from 10 to 15, not 12.
His newest packs are built with 4Ah cells like the V1 was. 12/16/20
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Old 12-03-09, 01:01 PM   #12
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His newest packs are built with 4Ah cells like the V1 was. 12/16/20
He needs to update his site. His site still shows ver. 2.5--10,15,20,30. Are you seeing the updated info on e-bay?
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Old 12-04-09, 12:18 PM   #13
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That's what I told him a while back. He has been selling v3 packs for quite a while now. I guess he is phasing them in slowly.
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Old 12-04-09, 01:09 PM   #14
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That's what I told him a while back. He has been selling v3 packs for quite a while now. I guess he is phasing them in slowly.

Guess he must have a ton of older batteries that he's wanting to use before widely marketing ver. 3.0. I'm more interested in the info on the BMS he's using on ver. 3.0. The controller on my kit can demand high amperage, 35A, so the amp rating of the BMS cutoff protection is very important. It means most of the LIFEPO4 24V with low AH ratings just won't work for me since they tend to use a BMS with cutoff protection at 20A. I'm probably going to go with TS prismatic cells and build my own and use the Battery Space 40A (cutoff) BMS. Although now that Foxx Power has lowered their prices, I'm considering their prismatic cells too.
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Old 12-05-09, 12:15 PM   #15
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As of now Ping won't sell his V3 BMS separately. However, he has said that he will start selling them sometime next year. You might try emailing him for a more accurate date.

Did you know that Hobby King now sells 6s 4.8Ah lifepo4 battery packs?
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Old 12-05-09, 01:37 PM   #16
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nicobie,

Thanks for the info. I wasn't aware of the Hobby King LIFEPO4 batteries. I need to order one of the Turnigy watt meters/power analyzers they're selling for $25.00 (they get pretty good reviews on Endless Sphere). I'll look at the batteries when I'm at the site.
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