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  1. #1
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    Looking for battery recommendations

    Hi all, another newby here.

    Great resource here. I think you all helped me avoid being too cheap and not getting a good system.

    I just ordered an Amped rear geared kit. Now I'm looking for a battery. The controller is 36v and says 20-25amps. I was looking at this elite power package
    http://elitepowersolutions.com/produ...roducts_id=123
    My questions are, would I be better off buying a kit like this or piecing the battery, charger and BMS seperately?
    I'll be riding 4 miles to work and 4 miles back. Pretty much flat city streets with one highway overpass hill.
    Any advice or other sources you can point me to for the battery would be really appreciated.

    Doug

  2. #2
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    Well, I bought the same batteries but I didn't buy the balancers. When I bought them, I don't think the balancers were available but I didn't feel like I needed one anyway. Some want them, some don't. Most people want a BMS because they want to be able to use 90 % of their battery. I'm happy using 50 % of it since it's more than enough for my needs.

    The questions are: how much of the battery do you want to use? If you are planning on only using 50 % and you don't mind manually balancing them every 4 or 5 uses, then you could get away without a BMS and probably save about $100 if you don't buy that package and instead buy the chargers separate. If you want to really easy setup and don't want to hassle with balancing them, then you are better off buying the package deal which includes the BMS. I think most people are probably better off buying the package deal. I have lots of time on my hands and I don't mind balancing mine. ALso, I already had the 12v charger at home so all I had to buy was the batteries and then a little 3.2v lifepo4 charger to balance them. I saved probably $150 not buying the package deal. If you have a 12v charger at home already with a 6 amp option then you might be better off going without the BMS, too. Just remember that if you use a 12v charger, and you use 10 AH of the battery, you'll need at least a 4 - 6 amp charge current to charge them unless you want to take like 15 hours to recharge the whole battery. I use a 10 amp charge current and it takes about 3 hours to charge a half completed battery.

    On just 50 % of those batteries, you'll still get 20 miles range. I typically get about 2 miles for each 1 AH so about 10 AH will get you 20 miles. That's more than enough for what you are using them for. Also, make sure you measure the batteries and think about where on the bike you will put them. They are a little big. They are still very lightweight, though but a little bigger than other lifepo4 batteries. They are still half of the weight of SLA batteries.

    You have several other places to choose from....I like Thundersky batteries and I like elitepowersolutions.com and I think they are a fantastic value. You are getting like $1000 worth of batteries for basically half price. But you have other choices:

    pingbattery.com (you pay about $100 - $150 on shipping cost so you need to add that in to whatever price it shows because he ships from China )
    cycle9.com
    ebikes.ca
    evcomponents.com
    itselectric.ca
    batteryspace.com

    Those are a few more places where people buy there batteries. Also, there is lipo from hobbyking.com but those are pretty dangerous batteries and I don't recommend them unless you have experience with them.
    Last edited by morph999; 03-25-10 at 01:38 PM.

  3. #3
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    Here is a picture of my setup:


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    I cut the corners off the top so I could easily take the top off without removing the wires. Here is a picture:


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    Thanks for the comments.

    I'll probably put the batteries up front in a basket (which I already have). My bike is a Giant Suede comfort bike. It carries a lot of the weight in the back already and has aluminum forks, so I was forced to use a rear wheel motor. I'll start with that and see how it does.


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    So after thinking about what you said, a couple new questions come to mind.

    How often would the batteries need to be balanced?

    At 20 miles a charge, that would get me 2 - 3 days. Would it be acceptable to use a 12v charger and charge a different 12v cell each day? The batteries would be way out of balance all the time, but if I didn't drain them below 50% would that really matter?

    Can you use an automotive style charger (12v)? Like the Black and Decker that someone posted a link for in another thread.

  7. #7
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    Definitely charge them after each use. So basically you go to work, then you come back home. Charge them that night. Also, get a watt meter. Definitely a necessity with lithium batteries.

    My suggestion would be either to buy this one:

    http://www.hobbyking.com/hobbyking/s...dProduct=10080

    for $24

    or this one....I think this one is better but I can't vouch whether or not this is a good website to buy from. I can vouch that hobbyking is good, though because I bought from them before. I like this Trakker watt meter better because it doesn't scroll through the data. It shows data on screen at all times. The turnigy is annoying because it scrolls through the data so you have to wait about 5 seconds for it to show the AH used.
    Both are basically the same price. I have a Turnigy watt meter but I wish I would have bought the one below. I think it's the same price in dollars as the Turnigy.

    http://www.plus2city.com/plus2rchobb...onkj1lhafqh362

    You absolutely have to charge all the batteries at the same time and charge them to full or almost full. That's very important because of how lithium works. Lithium batteries have a "knee" and when you hit that "knee" in the discharge curve, it only takes about 5 seconds for the battery to be destroyed. Since it sounds like you will only use 50 % of the battery, you don't have to worry about this as long as you charge all the batteries to full and balance them once every 5 to 10 times. If you buy 3 or 4 of those small chargers that I suggested (the 3.2v lifepo4 charger from all-battery.com), you can balance them very quickly...maybe in an hour. I own 3 of them. The good part about manually balancing them is that you don't have to rely on a circuit board (BMS) that will probably break in a year or two. Also, since you are manually balancing them, you'll know that they are all charged to full capacity rather than relying on a microchip to do the job for you. If you don't think you want the hassle of doing that, then get the balancers, though.

    If you want to manually balance them like I'm doing then I would suggest buying these two chargers:
    http://www.amazon.com/Black-Decker-V...pd_sbs_auto_14

    That one has a 2/6/10 amp charge setting. 6 amp is the recommended current to charge. I use a 10 amp charge and it's okay. I have the same brand of charger but it's the 2/10/15 amp one.

    Then buying one or two or even 4 of these. If you buy 3 or 4, then you can get them balanced much faster since you would be able to balance (fully charge) 4 at a time. When I say "balance" I mean just basically charging them to full capacity. That's called "top balancing" the cells. The idea is that when you top balance them, you prevent them from overcharging one of the cells. That's why I do it so when I use the black and decker, none of the cells are more full than any of the others, that way all of the cells reach full or near full at the same time. (so you don't ruin any of the cells). That's why it's important to charge all the cells.
    http://www.all-battery.com/TenergyLi...rger01300.aspx
    Last edited by morph999; 03-25-10 at 03:46 PM.

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    The watt meter is important because once you hit 10AH - 12 AH, time to stop using the battery. You'll likely never use that much but if you ever want to go joy riding through the neighborhoods, then you'll need a watt meter to observe how much battery you have used and know when it's time to go back home or stop using the battery.

    I go joy riding on mine so when I've used about 5 - 6 AH, I know it's time to come home because it will take another 5 to 6 AH on the way back so when I get home, I've used about 10 AH which is 50 % of the battery.

    Like I said, though, if you want to use more than 10 - 12 AH of the battery, you'll need a BMS for it. You'd only need a BMS if you wanted to go further than 20 miles though. Most people don't need to go that far anyway. That's a pretty long ride.

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    So would you recommmend using a 36v charger or a 12v charger? My goal is to charge them at work (and use their electic bill).

    Those watt meters are neat. Do they connect to the 12v cell or to the individual 3.2v cells?

    The more we talk about it I think I could get away without the BMS and manually balance them each week.

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    The BMS's have a low end shut off too, don't they?

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    Here is the discharge curve of lithium....notice the "knee" at the very far right when it begins to bend. See how quickly it drops off....If you only use about 50 % of the battery, you'll never get to the knee. People who use BMS's, they use them for the reason that they want to know when they reach the knee, and so the BMS alerts them to when they've used so much of the battery that they've hit that part. I avoid using a BMS by just not ever using that much battery. (ignore the bottom values..this is for a very large lithium battery)

    Last edited by morph999; 03-25-10 at 04:08 PM.

  12. #12
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    If it's only 4 miles to work, you won't even need to charge at work. You'll have 20 miles that you can go before you need to charge but I would charge after each ride....(one ride being to work and back).

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    Quote Originally Posted by yopappamon View Post
    The BMS's have a low end shut off too, don't they?
    Right. I think Elitepowersolutions just provides balancers, not a true BMS. I'd personally buy a 12v charger and manually balance them. That way, you only spend $330 on the batteries and since your usage will be so small....a BMS for you would be a waste of money.

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    Quote Originally Posted by morph999 View Post
    If it's only 4 miles to work, you won't even need to charge at work. You'll have 20 miles that you can go before you need to charge but I would charge after each ride....(one ride being to work and back).
    But I want to use their electricity! lol

    Can you charge the 12v cells in parallel off the same charger? I know it would require rewiring from the running configuration, but was just wondering.

    So right now I'm thinking just get the 3 cells, a 12v charger or two, and a couple of the 3.2 cell charger.

  15. #15
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    Quote Originally Posted by yopappamon View Post
    So would you recommmend using a 36v charger or a 12v charger? My goal is to charge them at work (and use their electic bill).

    Those watt meters are neat. Do they connect to the 12v cell or to the individual 3.2v cells?

    The more we talk about it I think I could get away without the BMS and manually balance them each week.
    The watt meter just goes between your batteries and your controller. For this setup, you'll need some 10 gauge wire and some ring terminals. It doesn't cost much, though. The ring terminals are about $1.50 - $3 for a whole pack of them. You can get the wire at a department store. To crimp, them I used a pair of pliers but it's better if you have a crimp tool but you don't need to buy one if you don't want to. I got by without it. Keep in mind that this is a project so you'll have to do some stuff yourself but you have a forum here that can help you. I had never done this either and I figured it out with help on the internet. See how I wired my batteries up in that picture?

  16. #16
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    Quote Originally Posted by yopappamon View Post
    But I want to use their electricity! lol

    Can you charge the 12v cells in parallel off the same charger? I know it would require rewiring from the running configuration, but was just wondering.

    So right now I'm thinking just get the 3 cells, a 12v charger or two, and a couple of the 3.2 cell charger.
    You can but trust me, you wont' want to rewire those batteries. I try to keep from screwing and unscrew the terminal bolts as much as possible. That's why I cut the corners off the battery tops so I can just take the tops off really easy without unscrewing the bolts. Also, you probably won't want to take the charger with you to work. It's kind of a hassle.

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    No, I wouldn't want to rewire everything. But I work in industrial electrical controls and have a lot of relays and contactors laying around. If I get ambitious I might would rig up a wiring harness that I could flip a switch and go from series wired going to the bike controller, to parallel wired going to the charger. Just a thought for now though.

  18. #18
    Senior Member CowtownPeddler's Avatar
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    I just picked up the same set, but I also got the 36v 6a charger. See my thread http://www.bikeforums.net/showthread...my-first-eBike for lessons learned. I have a lot of hardware hacking experience and Morph did provide some good advice. I didn't get the balancers because my plan was to use an RC Balancing Charger designed to charge 4 banks of LiFePO4 cells (6 hooked in series per bank). I did otherwise and pulled the packs apart and rewired them to make the batteries of 6 cells each. I then used Anderson 30A connector cables I got with my kit to make a wiring harness to put the two batteries in series to bring it up to 36v. The 6 cell count is because the RC charger will balance 6 cells at a time per bank.

    Again, I'm "learning as I go", so I'll be updating the thread....

    Balancers (as I understand it) act to equalize the cell voltages within each pack whereas a BMS will prevent a cell from discharging below 2.8v and cut the cell off from charging when it hits 3.85v.... Balancing would still be required for a BMS-equipped system (again, I may be wrong.)

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    Quote Originally Posted by CowtownPeddler View Post
    I just picked up the same set, but I also got the 36v 6a charger. See my thread http://www.bikeforums.net/showthread...my-first-eBike for lessons learned. I have a lot of hardware hacking experience and Morph did provide some good advice. I didn't get the balancers because my plan was to use an RC Balancing Charger designed to charge 4 banks of LiFePO4 cells (6 hooked in series per bank). I did otherwise and pulled the packs apart and rewired them to make the batteries of 6 cells each. I then used Anderson 30A connector cables I got with my kit to make a wiring harness to put the two batteries in series to bring it up to 36v. The 6 cell count is because the RC charger will balance 6 cells at a time per bank.

    Again, I'm "learning as I go", so I'll be updating the thread....

    Balancers (as I understand it) act to equalize the cell voltages within each pack whereas a BMS will prevent a cell from discharging below 2.8v and cut the cell off from charging when it hits 3.85v.... Balancing would still be required for a BMS-equipped system (again, I may be wrong.)

    I read it once already, very helpful. I'll go back and read it again now that I have an idea what everyone is talking about.

  20. #20
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    Quote Originally Posted by yopappamon View Post
    No, I wouldn't want to rewire everything. But I work in industrial electrical controls and have a lot of relays and contactors laying around. If I get ambitious I might would rig up a wiring harness that I could flip a switch and go from series wired going to the bike controller, to parallel wired going to the charger. Just a thought for now though.
    You're probably a lot more electrically inclined that I am. Yeah, I've heard of people doing that. I think it's best to use a 12v charger because charging 4 cells at a time is better because you get less variance between the cells. Keeps the cells more balanced that way.

    One more thing, if you plan on getting the black and decker 12v charger, the alligator clips were too big to put on the terminal bolts. The bolts were too low and the top case was interfering with getting the clips on. It was a minor problem and I fixed it by putting a nut on the bolts so that they would sit higher up. I like that black and decker charger because it tapers off the current once it gets close to full charge. It will automatically select the right charge setting but I manually use the "Gel" and either a 2 or 10 amp charge depending on how depleted the battery is.

    BTW, the watt meter connects to the entire battery pack so you'll connect it to the full 36v pack. So when you hook up the watt meter, it'll probably say something like 42v or 41.7v and the reason we use a watt meter is because when it gets around 36v, that's when you enter danger zone and need to stop using the battery. Because at 36v, that means each cell is around 12 cells x 3.0 = 36v ...each cell is around 3.0 v . The cells cannot go below around 2.5v . You only need to know about it. I don't really even look at the watt meter anymore because I know roughly how far it can go and I check it every maybe 30 min just to see how depleted the battery is. It's more about how depleted the battery is more than how low the voltage is. You've only got a 20 or 25 amp controller so you are well below the maximum C rating for the battery.
    Last edited by morph999; 03-25-10 at 05:31 PM.

  21. #21
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    you'll love your e-bike, though. In the 1980s and 90s when gas was cheap, we could ride where ever we wanted for cheap. Well, these e-bikes allow us to do that again. I go joy riding all the time.

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    Quote Originally Posted by morph999 View Post
    you'll love your e-bike, though. In the 1980s and 90s when gas was cheap, we could ride where ever we wanted for cheap. Well, these e-bikes allow us to do that again. I go joy riding all the time.

    I can't wait. I'm in southern California so I can ride year round. I've made the trip pedaling a few times, but am not in good enough shape to do it all the time and still have enough left to perform at work. I'm hoping this will let me ride most every day and not walk in to work sweating.

    It should pay for itself in gas savings in a little over a year if I ride most days.

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    Just ordered the batteries. No charge for shipping on online orders! Awesome.

    How long does it take Elite to ship, anyone know?

  24. #24
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    yopappamon,

    The no charge for shipping only applies when you buy a battery "package," i.e., battery and charger. If you only ordered batteries, you'll get an e-mail indicating what you owe for shipping (it's reasonable--my shipping fee was only $15). I would suggest that you get the CellLog 8 to monitor discharge and charging (in lieu of a BMS). I have one and it's amazing how much information it provides. http://epbuddy.com/index.php?main_pa...5vqe6vl4v2jdn2 (Clearly, if you have more than a 24V (8 cell) battery you may need more than 1 CellLog since it can only monitor 8 cells.) You can get a pre-made connector off ebay for $14. http://cgi.ebay.com/Chargery-Power-D...item3ef9488a10
    With the Chargery cable, you could actually use an iCharger 1010B or 208B to charge your battery since the Charger cable is 100% compatible with those Lithium smart chargers.

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    Quote Originally Posted by yopappamon View Post
    Just ordered the batteries. No charge for shipping on online orders! Awesome.

    How long does it take Elite to ship, anyone know?

    No charge for shipping? Did you get the package deal? I've always gotten my batteries in just 3 to 5 days from them and I've on the otherside of the USA. She gets them shipped immediately from my experience. Very fast.

    When you get your batteries, I recommend monitoring your batteries closely on the first charge. Use a multi-meter or just some way of measuring the voltage and make sure none of the batteries go above about 3.7v per cell. And get them topped off with the 3.2v charger and then after that you can use the 12v charger by itself and just top them off every now and then. Maybe check them periodically to see how out of balance they are. If they are only about .05v or .1v out of balance, that's not a big deal. The usable range for lithium batteries is 2.5v - 4.2v. Don't want any cells going below 2.5v or over 4.2v. The single cell charger that I recommended takes them up to 3.65v so aim for about 3.65v on your cells. The black and decker usually takes them up to about 3.65v. I've seen cells go up to about 3.76v on mine but as long as you stay under 4.2v, it should be okay.

    The celllog monitors are even cheaper now. Only $15. Damn. You don't really need one but if you want to buy an individual cell monitor, that's what I'd get. http://www.hobbyking.com/hobbyking/s...dProduct=10952

    The monitors still don't tell you your used AH, though. I like knowing how much AH I've used. These just tell individual voltages. It's up to you. You could either buy a watt meter or buy two of those celllog monitors and put them on each of your cells. It's about the same price. The celllog monitor would keep track of all your individual cell voltages and that's pretty good. Or you could go with a watt meter and only use 50 % of the battery. These cell log monitor's were about $40 when I bought my turnigy watt meter but if they were $15, I might have bought these instead. Of course, if you got the celllog monitor, you'd still need one of those adapters that nwmtnbkr suggested so that's an extra $10 so it might be a little more expensive to do that. about $50 total. The cellog monitor would be your BMS basically. It would do everything that a BMS would do. It would show you when any of your cells got to 2.5v or below. Most people stop their use when their cells get to about 3.0v , though.
    Last edited by morph999; 03-25-10 at 09:56 PM.

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