help building ebike battery packs!

[jatgm1]

what charger should i use? have you any suggestions? and are you serious about charging them in a bbq grill? is there a high chance i blow it up? and at 5ah isn't that close to no power?

 

[jatgm1]

OK, so here is your charger lable......hummm.....I am beginning to think that your batteries are already toast...Can you give us a discription of where you are in your ride when the batterys stop working? On the flats, the hills, how many miles you have traveled? If the batteries stop working and then you let your bike sit for a little while will it work again for a little while? Give as much detail as you can.

also i have a huge ass hill that i get up ok but towards the top it starts to go slower. also they are new batteries.

 

[DAND214]

How long do you leave the charger hooked up? Till the light changes or longer?
Do you have a voltmeter? If so give us some voltages of the charger and the battery, dead and charged. Might not help but gotta try.
4.4 miles is sick, I also started with 36v12Ah sla's 50amp controller and it would go 10miles or more if I helped it.

At this point in your learning curve, I would not go with any type of LiPo only LiFePo4. Which is the safer one.

have you checked your brakes and make sure they aren't dragging or the wheel? It sure seems like so little range.

Dan

 

[TheBeastie]

I agree with Dogman, just buy a sunthing battery so you get started there is no realistic cheaper way if your hoping to find it you will be looking forever. Even if you went down the HK lipo route you would end up spending more on the charger setup, and it's just not the way to go for a newb.
http://www.ebay.com.au/itm/2013-48v-15ah-LiFePO4-Battery-5A-Charger-BMS-Ebike-Kits-Powerful-7-8-Weeks-/141046282775?pt=AU_Electronics_Batteries_Chargers&hash=item20d7037a17

Any ebike battery nut will tell you that em3 battery packs are worth the money, but having something long lasting battery with great take of discharge rates etc aren't your concern then just start off with a eBay battery.

You can solve any distance problem you could possibly have by going slower... Basically if you go half the speed you can go TWICE the distance, it's all in the laws of physics, drag is exponential!
You can read about the horrible truth here.
http://endless-sphere.com/forums/viewtopic.php?f=2&t=55283&sid=6bcb389baea39ae00ecb7a2398ecef69
The best metaphor I have come up with is this, imagine driving a car at the bottom of the ocean.. The faster you go the more energy it takes to move through the water, and it never gets easier the faster you go it only gets harder and requires even more energy, air is exactly the same it's thicker then most people perceive that's way we can fly 380 ton Boeing 747 aircraft in the skys.

 

[jatgm1]

well the manual for the charger said i didnt need to unplug it as soon as it was done.

 

[jatgm1]

im giving up on the lead acid's and going to some kind of alternitive. im probably going to save up and get a 20ah battery from sunthing. and i never checked if anything was rubbing... thats a good idea.

nope nothing is rubbing. brakes are loose and everything.

 

[e-beach]

well the manual for the charger said i didnt need to unplug it as soon as it was done.

Leaving the SLA's on the charger is the right thing to do. The float charge will keep them topped off. My feeling is that A: you got a bad battery or two (or maybe 3) or your hill is a monster and really drains you batteries..

What street is the hill,(street name) and between what streets are you riding on this hill (what street name on the bottom and what street name on the top of the hill.)

I want to check it out on google earth to try to discern the slope of the hill and distance.

 

[jatgm1]

from spring brook drive mahopac new york to bryant pond road mahopac new york. (10541)

 

[e-beach]

Ok, from the corner of Spring Brook and Secor up the hill to just before Green Acres, you have a .56 mile incline of 4.6% grade. That might be enough to suck some amps out of your SLA's but I still think their is something more going on.....What has the temperature been like when you ride? I forget it is probably cold there.

I was walking around Venice Beach CA today.....it was about 75°F on my beach today. I forget it gets cold in other places....



PS, After you charge your cells next, use your Multi-meter and let us know just what the voltage of each battery is. I am wondering if you got a bad cell or maybe they just aren't fully charged.

 

[jatgm1]

given the fact i dont have any measurement equiptment and the batteries were cheap, im putting this on hold and saving up for a lifepo4 25ah battery pack. sealed lead acid sux....

 

[teslanv]

You will want to have a basic Multimeter for various testing purposes. Even with a "plug & play" battery, this should be in your basic toolbox for an ebike.

Here are a couple inexpensive options:

http://www.hobbyking.com/hobbyking/...70E_Digital_Multimeter_w_Backlit_Display.html

http://www.sears.com/craftsman-digi...p-03482146000P?prdNo=1&blockNo=1&blockType=G1

Or of you really ant to get fancy, here's a great choice.

http://www.amazon.com/Fluke-117-Ele...394481471&sr=8-7&keywords=fluke+77+multimeter

 

[e-beach]

Yep, a muli-meter (DMM) is a requirement. They can be had cheap on places like ebay. If you feel like going to the Harbor Fright at BROOKFIELD, CT #00367
99 FEDERAL ROAD
BROOKFIELD,CT 06804

or another Harbor Fright ,you can find them cheaply as well. Give them a call to make sure they have them in stock, but you should get a multi-meter before you get another battery.

 

[jatgm1]

hey everyone im back, long break, evaluation, comparison, whatnot. decided that 20ah would be fine for me given the fact im light, my bike is light (without the agm batteries) and i dont go too too far. i ordered one because the price was awesome. im aware it says 18 ah, im assuming thats what it is, but i just want to know if anyone can tell me anything about this and if their are any precautions i need to exercise, other than the obvious. i <3 ebay.

http://www.ebay.com/itm/321378851464?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

p.s. i also thought that it may be a wise investment to install an 80cc two cycle gas engine as a backup however im not sure if the weight is that considerable. i thought effectively making it a hybrid would be a good idea.

 

[DAND214]

I like the header "20ah/18Ah" I think that means it was listed as a 20Ah but was proven to be more a 18Ah. So to cover thier tales they made the adjustment.

Before you use it, be sure to charge it overnight. Just because the charger has turned off it doesn't mean it's fully charged.
Using a unbalanced battery will make it much harder to charge it full and destroy the cells!!

Do not just wire it up and ride it! Be sure to chech polarity before connecting!
Just because the colors look right, don't take that they are. Colors don't mean crap over there, they grab what is at thier grasp and use it.

Dan

 

[dnmun]

we try to warn people about buying the Vpower packs. but if you bot it then we will help you fix it.

 

[friendly1uk]

On this rare occasion, I have skip read, so sorry if this has been said.

Good news. Your lead was 10Ah new, and you would only get to use half of that. So you only ever had 5Ah. At 4.5miles I guess you have about 3Ah if that is on level ground.

li-ion batteries don't hold out on you, they give the full capacity. I expect a 3Ah 48v pack would be about equivalent to what you have now. I have a 5Ah 44v pack and it takes me the 7.5miles to gerts house using a little over 3Ah on a good day. Or it will be quite exhausted if I don't pedal at all.


Try and use this post to benchmark what you really need. Your initial 40Ah guess is many many times better than the ~3Ah you have now.


Did I miss your range goal?

 

[2007blueprius]

I must say I'm no expert but those lipos are not such a deal, I got a 48v 20ah shipped to my door for about $500 lifepo4, it was $800 actually for a complete kit charger wheel controller the whole thing, now I haven't extensively tested it to vouch for exact capacity, but is around that 1kw mark, and best I know lifepo4 is not so prone to blowing up I guess

 

[jatgm1]

i got a multimeter, a craftsman pocket multimeter model 17387, how the hell do i tell if the batteries are good and which end is negative and positive using this?
nevermind i got it. for some reason it wont measure amps or anything. well i did for a little then stopped maybe i f***ed it up.

 

[tomtom123]

Here are the Batteries Dogman was referring to. (They are the least expensive way to power your ebike. And also the most dangerous to use.)

http://www.hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack.html

If you wire 3 of them in series it will give you 12S (44.4V) and 5 AH of battery.

These cost About $25 + shipping each. That's probably about $120 shipped.

But as Dogman also mentioned, they are inherently dangerous.

Here is how I charge mine.

what is that? a Barbecue pit? price of one?

 

[teslanv]

Brinkman smoker. $25 at a garage sale.

 

[dnmun]

if you don't know how to use a meter and tried using the amp scale on a live battery it is most probably dead now.

 

[tomtom123]

Brinkman smoker. $25 at a garage sale.

nice it's working well?

I need to get one instead of spending money on expensive steel boxes lol

 

[teslanv]

It has worked so far as providing me a bit of peace and comfort. Never had a fire in it though. The goal is never to.