Greenpower

Hello,
my first thread here, i just got the ebike bug and i have some questions:
- I am going to install a front hub 350 watt/ 36 volt kit without batteries on my bike, i want to use 3 X 12v batteries, what is the best A/H rating to choose? so far i found 7A/H 10A/H and 12A/H.
-Another question, can i operate the bicycle while the batteries are charging?

nwmtnbkr

Welcome. First, determine whether your fork is aluminum or steel. If it's aluminum, you'll need to replace it with steel or install a rear hub wheel; aluminum drop outs can fail without warning and cause serious injuries. Secondly, make sure to get torque arms, regardless of whether it's a front or rear hub wheel. Third, if you can afford it, lithium batteries will perform better and have a longer life, if cared for properly (2,000 charges vice the approximately 600 of SLAs). I have two batteries, my original 24V 10AH SLA and the 24V 20AH LIFEPO4 pack that I built this spring. I would urge you to consider 20AH, although if you're looking at SLAs, that would be very heavy so you might have to settle for 36V 12AH. You definitely want higher AHs since the battery will pack more power with more AHs. You shouldn't have problems operating the bike as a pedal bike when the batteries are off it, charging. Good luck.

dumbass 

Go with the biggest batteries you can afford and carry. You can never have enough AHs. Trust us you will wish you had more no matter how big you get. And without question if you can afford it make the jump to lifepo4 packs........

Greenpower

I wish i can afford Lifepo4 packs, for now i am going with the SLA as this is my first ebike ever. from your comments i will try to find batteries with higher A/H rating.
The second question i asked before is if a can operate the bike with the batteries attached and charging while going down the hill, it is just an idea like when you drive your car with A/C, wipers on...and the alternator charging the battery at the same time.
edit: the fork i have in this bike is steel with suspension.

dumbass 

You should be able to charge the batteries on or off the bike. You should also be able to ride the bike with the batteries off the bike and charging. the one thing you can not do is ride the bike with the batteries on it and charging. If you ride the bike without the batteries there will be a slight drag caused by the motor. In fact you will always fell a slight drag caused by the motor unless you are actually powering the motor. I hope this answers your question.

Greenpower

That is exactly what i want to know, Thanks. and would explain why the car battery can be charged while operating wiper motor, and the bicycle battery can not?
Thanks again

yopappamon

It's very difficult to find a power cord that long.

If you are referring to using a regen controller to charge the battery going down hill, yes you can do that.

Greenpower

So regen controller will make the motor to act as a generator when going down the hill?
what i want to know is if i can charge the batteries using (some kind of charger not the hub motor itself) while the bike in motion. is that going to damage the controller,batteries, the motor...?

dumbass 

this is of course true however, I'm guessing that he actually was thinking that he could recharge on the down hill the amount he consumed on the up hill. As we all know regeneration on a bike has proven to not do all that much for you. For the most part it's a waste of time and money because regeneration consumes power in terms of lost momentum weather going down hill or just coasting. This is one of the biggest reason the better regen systems have an off switch because most of the time you lose more then you gain.

Greenpower

I see, what you said make sense.

seanreit

Yes, you can charge the batteries while operating the bike with the batteries. Say, with an additional 12 volt battery on board with a dc to ac converter, and then attaching your charger to the ac port you just created, you would be effectively adding ah and voltage at a lesser rate than you are consuming likely though. Range extending vs hassle, might be a little upside down.

dumbass 

Yeah, wouldn't it be great if it really worked that way? But as you point out the usage is much higher then the charge. Consider the fact that all dc to ac inverters are very poor effiency. I don't remember how bad they are but it's somewhere between 60 and 80%. Not the mention the added weight of this additional battery will reduce the eff. of the packs the bike is running on. No offence but the only proven way to charge while riding is with a mini gas generator. Some guys have mounted them to the back of their bikes or on pull carts. Some of the people have reported very good results. But lets fact the fact that if you are willing to deal with a gas generator motor then why not just have a gas bike?

If you want to ride while charging get a second set of batteries or get bigger batteries in the first place.

Greenpower

Udate:
Still waiting on the kit, but i got the batteries,they are 3X 12v SLA with 11A/H rating, they are 6.5 Lbs each.
What wire gauge is needed to connect batteries together? from your experience,What is the best location to put them in?
My bike is GMC topkick 7000 series.
Thanks

mrdarklight

Basically it's a tradeoff between size and range. The bigger batteries will give you more range, but they weigh more.

I have two sets of batteries, a set of 7ah and a set of 10ah. I only did this because due to a special when I bought the batteries I basically got the 7ah set for free. Anyway, the 7ah set can get me to work and back easily, and weighs about 2/3rds what the 10ah batteries do.

dougmc

Do we all know that?

How is it typically implemented, anyways?

However it's implemented, yes, it's going to make you go slower while it's charging your battery. I can't imagine wanting to use it while you're cruising (unless you don't mind going slower now so you can go faster/further later, but it's not going to be that efficient), but you may want to use it when you've got extra speed -- in particular, when you're going downhill and when you're stopping/slowing anyways.

To me, the best implementation would seem to add a third brake lever right next to the brake lever for whatever wheel that the motor is on, so you can squeeze that brake lever or the standard brake lever. If you squeeze the new one, it brakes using the motor, charging the battery. If you squeeze the original lever, then it uses the normal brake and charges nothing. You could remove the original brake entirely, but I'm not sure I'd trust that. And you could make something smart that uses the regenerative braking for small brake activations, but for larger ones it starts to engage the standard brake, but that might be tricky to work out.

dumbass 

OK, I'll rephrase my comment for those of us who don't know. "As many or most of us know". How's that? On hybrid cars the regeneration is commonly used during braking from the electric motor being forced to act as a generator. As you press the brake pedal it activates the regeneration. The harder you brake the more regeneration. If extream braking is needed the car uses both regen and actual wheel braking. On my hybrid is seams to work very well but it in no way regenerates near the amount of power that was consumed by driving. While actually driving the regeneration is 100% turnned off. Having it opperating would be counter productive because it would consume more power then it could generate. Hense the reason it is used primarily when braking.

Here's an explantion from Bionx bike on how their system works. Note they allow for selecting from 4 modes of opperation.

Regenerative Anti-Lock Braking
Bionx offers four levels of power braking regeneration. In addition to 4 generative modes (G button on console) and regenerative braking also activates when the rear handbrake is used. When in use, the Generation Mode recharges the battery but also makes it harder to pedal so its often used to recapture energy when going downhill. Please note that the generative mode does not replace the existing brakes, but considerably increases braking quality especially on extended downhill runs and steep, off-road surfaces

alfonsopilato

lifepo4, super great, you get a steady performance throughout the trip

get the most ah you can afford, you won't regret it and something you need to consider is: the less you tax your battery pack, the longer it will live.. which means.. the more AH you have, the less likely you are to fully deplete your pack _ not fully depleting your pack and always keeping it fully charged is very good for the packs longevity

example. ("uh oh. here he goes again... ") when i went from 48 12ah to 72 volt 12ah setup, i noticed that my battery pack was less taxed, my range increased, performance increased and i had power to spare at the end of my trip. i realise we're talking ah here and not voltage, but trust me, it plays the same way

dumbass 

AL, You might want to re-read what you said. I think you ment to say the LESS AHs you have the more likely you are to fully deplete your pack..

alfonsopilato

thanks dumbass () for picking up on that ... i have made the necessary changes

Greenpower

Thanks everyone for your help. i'll post some pictures when the kit arrive.

Greenpower

I got the kit, now I am looking for the torque arms, I don't know where to get the ones that can fit my bicycle. any help?

Greenpower

Here is a picture of the bike almost done: waiting on front brakes to arrive and still looking where to buy torque arms.

rezkiy

It already looks fast. Now paint it yellow, and it will gain 50 watts!!!

Greenpower

I am not looking for speed, just a daily commuter to work. I hope someone can tell me where to buy torque arms as I am still newbie here and couldn't find them on ebay.
Peace.

rezkiy

THere was no war in the first place. Maybe my sense of humor wronged me:-).