Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Bogan]

Yeh it is very hard to pick the right battery, simply because it doesnt exist i think! The properties electric vehicals need are, lightweight, high current, high capacity, and cheap. I think you probably need to increase your budget a bit, and try looking at deep cycle flooded lead acid batteries. I know lots bout batteries and electronics cos i finished my robotics engineering degree last year!

Lower Ahrs mean less range, Ahrs are like a cars fuel tank, less is less distance.

[DrumminStewey]

alright then. so i shouold google deep cycle flooded lead acid batteries and find ones with 25 AH ratings but some say 80 AH @ 20 hr should i divide by 20 then to find wat it is at one hour??

http://www.rollsbattery.com/pdf/pdf_rolls/24ht80m.pdf  that is an expensive one almost 200 dollars but looking at its specs i thought it looked good but wat do i kno (it was kinda big and heavy though)  i dont know if that will pass at all.

that degree probably helps a bit in this area haha.

i hate to keep bothering you but most of the things have big graphs and use words i dont know wat they mean and i just get really confused.

[Bogan]

No you cant work out the ahr rate for you application, some give lists like the battery you posted which show the ahr ratings for diffenrent discharge times, the only problem being is you discharge time will be 20min, and not many datasheets have that time.

http://www.electricmotorsport.com/PARTS/parts.htm
has quite few batteries on there, which look pretty good, i checked the specs on the EB50-12 and it looks like it would do the job very well.

[DrumminStewey]

i like that idea and if i purchase it all together i can save on the carbon footprint of shipping it to my house score one for the environment (kinda)

Im sorry it got to the point of you just giving me a battery i didnt mean to take up so much of your time.  You are a very good friend hope your motorcycle turns out better than you hoped. I know mine will with your help. Thank you.

[DrumminStewey]

one final thing is the battery charger what should i know in buying one??

[Bogan]

No trouble at all, most of my replies were done in boring bits of watching tv anyway
Charger, again depends on your needs. Standard car ones will do the job, if you can be bothered with the hassel of 6 sets of clips (you may also have to remove the battery wiring but im not sure about that), and waiting hours for them to be charged. On the other end of the scale is an automatic 3-stage charger which is probably slightly better for the batteries, charges a lot quicker, has only two points to connect, and is probably small enough to fit on you bike so you can charge it almost anywhere, but has the obvious downside of being very expensive.

[DrumminStewey]

yeah true. ill look into it as long its not to far out of my price range. i already have a trickle charger because i leave my lights on a lot soo yeah. but will still look into that kind of a charger thank you again.

[DrumminStewey]

I found one charger its 200 but its still looks nice simple small
http://www.oksolar.com/n_cart/product_details.asp?ProductID=35915&cat=Lighting&subcat=Battery+Chargers

you said i might have to remove the connections to each of the batteries? would i find if i should from the charger or battery supplier?

[DrumminStewey]

http://marine-products.com/boat_parts/accessories/battery_charges_and_guages/minn_kota_battery_charger_portable_10amp.jsp

theres that one too but its mad cheaper so idk if its good enough its for boat batteries but marine batteries are similar to mind right?? they are deep cycle and such

[Bogan]

That would only be the case if you had to charge them with a bunch of 12V chargers, even then most should still be alright, unless the manufacturer has used a common earth which they shouldnt, the worst that will happen is you can blow the charges fuse anyway which is no biggie to replace.

Both chargers do not specify what voltage they charge at, so would assume it is 12v, which means you need to buy 6 of them, or go out and change the clips 6 times to charge(taking 6x as long). Another option is to get a 72V charger which charges all at once, and only requires two clips to be attached.

[dilkes]

I am new to the Forum and looks like this thread has a battery expert..so maybe you can provide me some guidance.

My e-Bike uses 4 x 12V 20ah SLA batteries in series to provide 48V to a 500 watt motor. Charging is with one 48V charger. Some of us were looking at (and have done some testing) on adding an additional battery pack of 4 x 12V 9ah batteries. (We have physical room for these under the seat) connected in parallel with the larger 20ah pack. Preliminary testing indicates a more stable delivery of amps to the motor plus longer range before recharging.
 
One of our group thinks that:

•When the bike is not being used (and the batts are partly discharged), the 2 packs should not remain inter-connected as the larger one will discharge into the smaller one at an uncontrolled rate, potentially damaging the smaller pack. For this reason, he is planning to install some 25A diodes between the two packs to prevent this.

•The two packs need to be disconnected from each other and charged (using the 48V charger) separately and independently as charging through the main pack with both connected will cause the charger to prematurely detect full voltage and shut down early, or perhaps overcharge the smaller pack.


I personally am not convinced either of these concerns is valid, but don't want to destroy any SLA battery packs testing it. Would anyone have an opinion/experience on this?