New Battery - E-bike - 36v - Newbie

Hi,
I have recently built my own e-Bike by buying myself a starter kit that included a hub motor (500W) with a 36 V 12 Ah three series-connected battery and a brushless controller (36v).

I however believe that the range isn't enough for me and once I have driven the bike for around 20-30 min the bike can't really output enough speed as it does in the beging of a fully charged battery, I am therefor thinking of getting a new battery possibly a battery which can be serie-connected from examplewise hobbyking, I want as good range as possible that fits and works with my controller and hub motor and that has a good range for atleast 25 miles (40,2 km) and for a reasonable price I would rather not be paying over 150-200$, so does anyone have a recommendation for me?

I appreciate all sorts of responds from you guys, thank you.

- Kevin

You need to up your budget. $300-$600 plus shipping for most 36v Lithium batteries.
http://em3ev.com/store/index.php?route=product/product&path=35&product_id=160
http://www.pingbattery.com/servlet/the-36V-LiFePO4-Battery-Packs/Categories

If you want cheap, and want to add a bunch more weight, buy 3 more 12v 12ah SLA batteries and put them in parallel. Use your same changer, approx. double your range.
http://www.amazon.com/12Ah-Sealed-Battery-250in-Terminals/dp/B001C20T2Y/ref=sr_1_5?ie=UTF8&qid=1401818900&sr=8-5&keywords=12v+12ah

el_walto said:

You need to up your budget. $300-$600 plus shipping for most 36v Lithium batteries.
http://em3ev.com/store/index.php?route=product/product&path=35&product_id=160
http://www.pingbattery.com/servlet/the-36V-LiFePO4-Battery-Packs/Categories

If you want cheap, and want to add a bunch more weight, buy 3 more 12v 12ah SLA batteries and put them in parallel. Use your same changer, approx. double your range.
http://www.amazon.com/12Ah-Sealed-Battery-250in-Terminals/dp/B001C20T2Y/ref=sr_1_5?ie=UTF8&qid=1401818900&sr=8-5&keywords=12v+12ah

Click to expand...

I understand I am aware that lithium batteries are out of my region, but to your second response can I just connect and wont the volt change as my controller is made for 36v will it work, I am totally green in this so I am not sure could you provide some more information?

You can add 3 more 12v batteries in parallel, you will then have a 36v 24Ah battery instead of a 36V 12Ah battery.

You can use your original 36v charger.

10ah of 12s lipo will get you 25 miles if you keep your speed down to 17mph. 6 of these as 12s2p.
http://www.hobbyking.com/hobbyking/store/__18631__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack_USA_Warehouse_.html
And yes your 36V controller will work.

SLA batteries suffer from Peukert's law.
In short, the harder they work, the less capacity they have. On an ebike, it's normal for an SLA to only have 50% to 60% capacity. That means your 36 volt 12 Amp battery will act like a 6 or 7 amp battery.
Switching to a lithium based battery will immediately improve that, as good lithium suffers almost no loss due to Peukert's law. Unfortunately, that also will break your budget.

The other possibility is to add more batteries in parallel. 6 batteries total wired for 36 volts, 24 amps.
It will be heavy as all f#%k but it will do 2 good things. First, it will double the resting capacity of the battery. Second, it will cut the load being placed on each battery by half. since Peukert's law depends on the load, the batteries will suffer less, and perhaps be able to produce 60% to 70%. That means you will more than double your range this way. If you could do 10 miles before, you should be able to do 21-22 miles now.

wesnewell said:

10ah of 12s lipo will get you 25 miles if you keep your speed down to 17mph. 6 of these as 12s2p.
http://www.hobbyking.com/hobbyking/store/__18631__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack_USA_Warehouse_.html
And yes your 36V controller will work.

Click to expand...

I was thinking of these Lipos but the questions is if they are worth it, and how do you parallel connect all of the batteries togheter, is there a guide out there.. and is it just to take the connectors from my old battery and change it with the connectors on the Lipos so it works with my controller?

Also do you know if there is any other lipos that I can use in my case, that is in stock at hobbyking?

Understanding batteries.
http://www.rchelicopterfun.com/rc-lipo-batteries.html
http://scriptasylum.com/rc_speed/lipo.html
http://batteryuniversity.com/learn/article/types_of_lithium_ion
http://endless-sphere.com/forums/viewtopic.php?f=14&t=39666

Yeah, you are just finding out how much the voltage drops as you go when using sla's . The sad reality is, to get the most from sla's, you need to ride about 15 mph max speed. This lowers the peukerts effect, and results in more usable capacity. Charge some, at every opportunity you can find.

My best and cheapest solution, would be to add a 4th 12 ah sla. You will have slightly longer range, if you don't ride faster. You will have a faster speed at the end of the ride, having started out with 5 mph more.

You can not just swap your battery for hobby king lipo. Setup is complex for a newbie, you will need new charger, and a way to monitor the battery etc. If you only have a very basic understanding, and you want to use hobbyking batteries, you have a lot of reading to do.

You either need to buy more SLA, or buy a premade lifepo4 pack. If you ride your bikes lots, you will likely find lifepo4 battery ends up being cheaper than SLA, because SLA has very poor cycle life on an ebike.

Likely you will be replacing your SLA battery after 50 charges, or one year.