morph999 

I was on here last year asking about what bike to buy. I ended up buying a 5303 hub motor and controller from ebikes.ca. I'm very happy with it. Let me say that if you do buy a 5303, make sure you buy a big enough battery for it because it's kind of hard to pedal. Other motors are not quite as hard to pedal as the 5303 but the 5303 has way more acceleration than other motors. Basically, if you don't like to pedal much, the 5303 is great for that.

I just bought a lifepo4 battery from elitepowersolutions.com. I'm very happy with it. The cells are very balanced. I'm not even using a BMS with it. I took a ride on it today. I came back and checked all the cells and they were all at 3.36v. I only went 3.5 miles on it, though because I'm still conditioning the battery. If you only use about 50 % of the battery, you don't need a BMS.

My suggestion for anyone who wants to build a bad ass bike would be to buy a good motor like a 5303 or 5304. Then go to elitepowersolutions and buy 3 or 4 of the 12v40ah packs. Or go to evcomponents.com and buy the Thundersky 40ah cells. That way you got a lot of capcacity that you won't ever run out of it. These days, you can buy so much capacity for cheap that you dont' even need a BMS. Get a black and decker 12v charger, one that tapers like mine does and it will charge all the cells evenly. I got a black and decker 2/10/15 amp automatic charger and it tapers the amps as it closer to filling the cells so that even the weak cells get charged too.

So you'll have a 36v40ah or 48v40ah Thundersky lifepo4 pack. You'll never run out of capacity. You can get a 36v40ah Thundersky lifepo4 for the same price as a pingbattery 36v20ah pack. You can get twice as much with Thundersky cells. It just doesn't make sense to buy from Ping anymore in my opinion. It's up to you. Either you can use 90 % of your ping and kill it in 2 years or use 50 % of a 36v40ah Thundersky and have it last 5 yrs or more. It's up to you.

ambroseliao

Hi Morph999,

Do you have any photos of your ebike?

Ambrose

morph999 

Yes.

geetarboy

Hey Morph, I am thinking about going the same way on my current build - no bms, 48v 20ah thundersky's. I will however control "lvc" with my cycle analyst as well as tracking amp hrs per cycle and try to keep it under 15 ah's. I also won't exceed 1500 watts or 1.5C discharge. So, you have 3 - 12 v 40ah batts in that topeak bag??? Nice looking ebike!!!

morph999 

I'm probably only going to use 10 AH on my pack. 10 AH gets me 15 miles on my 5303. If you have a more efficient motor, which you probably do, you'll probably get 20 miles + out of 10 AH. The guy that I learned this method from only uses 50 - 60 % of his pack and he has been doing it about a year with no problems. You can get a 48v40AH for not too much or 36v 40 AH pack for around $550 from either evcomponents.com or elitepowersolutions.com. I like elitepowersolutions because they send their packs out already hooked up in series and ready to go and they deliver them in a week. Evcomponents sometimes do not get their packs out for 2 months. And these packs from elitepowersolutions are brand new (relatively). Mine was made in July of 2009 and I ordered it in on around Jan 1st of 2010 so it's only a few months old. So it's not like they got stock sitting around for years...this isn't really old stock.

morph999 

No, I have a 36v20ah Thundersky in the Topeak bag. It just barely fits. 48v20ah thundersky will not fit in the topeak bag. I recommend 36v40ah thundersky because you can get crazy distance out of it. I'm short on money so I went with the 36v20ah pack....most people have more money than me. LOL.

morph999 

By the way, don't worry so much about how much amps you pull. It doesn't work that way. As long as you pull less than 3C out of the pack, you'll be fine even if you have major sag. The pack works on how much AH you take out of it. So lets say you go full throttle...you have a 36v20ah pack like mine and it sags to about 32V .... which is 32/12 = 2.6 v per cell. You might think that you are getting dangerously close to kiling the pack but you aren't because you just took off for the ride 10 min ago. As long as you fully charged the pack, it should be okay. It's just voltage sag.

Each pack has a "knee". If you look at the discharge curves, the knee is the point at which if you take anymore out...in 5 seconds, the pack will be ruined. So you want to quit before you reach the knee of any cell in your pack. You can only reach the knee from pulling AH out of the pack...not just amps (voltage sag). As long as you fully charge the pack each time, don't worry about voltage sag. Worry more about how much AH you have pulled out. You can tell a little bit from voltage sag how close you are to hitting the knee, though.

geetarboy

Thanks for the advice Morph, I tried to order today the EB-20-16 and got an e-mail back that they reccomend a balancer. The BL40 @ 8.95 ea, one for each cell - that adds 143.00 to the 571.00 for the batts & charger. I attached the specs on the balancer, they're not listed on their website. I guess the worst thing that could happen without it would be to burn a cell or two, which could happen anyway. It might give you more usable range though, because all your cells would be topped off. The charger they have is 3-stage, the last is a "pulse mode"? I would think that should balance them if you left them on the charger long enough.

morph999 

I'm running mine without a BMS/balancer. I got advice from someone else who bought from elitepowersolutions. He's been using his a year without a BMS with no problems. My 36v20ah lifepo4 cost $384 at elitepowersolutions and $400 with shipping and handling included. I can get 18 miles out of 10 AH which is half the pack so I don't need to use more than 50 % of the pack to be satisfied.

One thing the guy did tell me is that the charger is crap. That's why I use a 12v black and decker charger. The guy told me that the charger that they sent him almost killed the cells because it charged them too high. The charger that they send out is the same one that they sell at batteryspace.com.

This one:
https://www.batteryspace.com/smartcha...amiyaplug.aspx

It's up to you if you want to get a BMS. I just couldn't see paying an extra $150 - $200 or whatever it is to protect $380 battery pack. Think about it. The BMS almost costs as much as a new battery pack costs. That'd be like buying a $300 TV from bestbuy and then insuring it for $150. That's half the cost of the TV.

morph999 

In that form you attached, it says that they want to charge the cells to 4.2v. I think the recommended stop voltage is 3.65v and I've heard that charging Thundersky's to 4.2v repeatedly can damage them. The point of this thread is to tell people that it's possible to use lithium without a BMS. It's up to you to determine what is best for you. I'm willing to take the risk since a new battery pack is only $380 for me and the cost of a BMS which is $100 - $200 is almost the cost of a new battery pack so why would I pay almost the cost of a new battery pack to protect the battery pack? Why not just hang on to that $200 and if something goes wrong, use it to buy a new pack.

I got two chargers. I got a 12 Black and Decker that I use to charge it. This works fine by itself but if my pack gets unbalanced, I have a small 3.2v lifepo4 charger that will balance all the packs for me. I might balance them maybe once every month or once every 6 months. They don't seem to get very unbalanced so I'll rarely use it but I have it just in case.

morph999 

It takes about 4 hours for me to charge all 3 packs. Like I said, doing it without a BMS.

Here is the chargers that I'm using.

https://www.amazon.com/Black-Decker-V...pd_sbs_auto_18

Black and Decker 2/10/15 amp charger

Then I bought 3 of these
https://www.all-battery.com/TenergyLi...rger01300.aspx

3.2v lifepo4 2amp charger...charges to 3.65v which is what you want. If you charge to 4.2v, you could damage the batteries.

The Black and Decker will charge it about 98 % of the way. That's good enough to use but then every now and then I will use the small 3.2v charger to top it off and balance them. I guess I'm still almost spending as much as a charger and balancer. Maybe about $70 less. I just don't trust the BMS's at all. Seems like everyone who has a BMS is killing cells. If the BMS is set for 4.2v, then you are stuck with that and you could be killing cells with it. I chose to go the manual way so at least I know what everything is doing and I know the battery pack won't cut on me prematurely.