36v batteries in series? And 800w front hub.

[lotrwiz]

So, I am able to purchase these two items around christmas:
http://www.ebay.co.uk/itm/Front-36V-800W-e-bike-Electric-Engine-Conversion-Kit-wheel-Motor-Hub-thumb-26-/221294822188?pt=LH_DefaultDomain_0&hash=item338633032c

http://www.ebay.co.uk/itm/New-36v-36-volt-9ah-water-bottle-type-lithium-Li-ion-electric-bike-battery-/141096612277?pt=UK_Bikes_GL&hash=item20da0371b5

For one, the battery will mainly be used for range =, so I can just slot in the other battery as I already have one of those.

But, do you think it would be possible to wire the two n series to get 72v?

If so, how could i get it to run on the motor that I've linked, as it has to be able to operate on 36v for those times when I really need the range.

Sorry if I haven't made this very clear, and thanks in advance!

Edit: The items I've linked are the best prices I can find, as one of them is from the UK (so am i) so I don't have to pay the outrageous customs fees on one of them. If anyone can beat the prices from UK based dealers though, I'd love to be linked to it!

 

[dnmun]

you can use batteries in series but that controller and voltage monitor may not work at the 90V it will charge up to.

 

[lotrwiz]

you can use batteries in series but that controller and voltage monitor may not work at the 90V it will charge up to.

Okay, what controller would I be able to use that could take that power, and the 36v when I need it? Like, one with a limiter in it or something?

 

[dogman dan]

Your plan is not a good one. You can't have all you want with those batteries.

IMO, that kit will be straining just one of those batteries pretty hard. Not that it's impossible to ride slow enough to not do that, but you have a kit with a 20 amps controller, and a battery just barely, "on paper" able to handle that. It's best paired with a 200-400w kit.

What you need to do is parallel those batteries when you want to climb steep hills, or do a ride with tons of stop signs. Then you have the 20 amps without hammering your battery to death. 10 amps per battery when they share the load by running them in parallel.

It's a horrible choice for series connecting for a real 72v bike. But if you can find a low enough amps 72v controller, you could do it. Mostly, controllers able to do 72v have higher amps, but you could buy one and snip one of the shunts.

Then you'd have the lowest performing 72v ebike on earth. Sorry if I'm sounding really harsh, but I truly think you have a bad plan there buddy. What will work is to use just one battery for the truly easy trips. Such as a 10 mile round trip where you ride just 15 mph on flat ground, and have only a few stops on the way. Parallel the batteries for more amps if you will ride into a stiff headwind, or climb some hills.

Get yourself a controller that handles a wide voltage range later, such as 36-72v. Grin has them, and so do others. Or more economically, get a 72v controller from ebay cheap later on. But make getting a much better battery part of the plan for then.

 

[lotrwiz]

Your plan is not a good one. You can't have all you want with those batteries.

IMO, that kit will be straining just one of those batteries pretty hard. Not that it's impossible to ride slow enough to not do that, but you have a kit with a 20 amps controller, and a battery just barely, "on paper" able to handle that. It's best paired with a 200-400w kit.

What you need to do is parallel those batteries when you want to climb steep hills, or do a ride with tons of stop signs. Then you have the 20 amps without hammering your battery to death. 10 amps per battery when they share the load by running them in parallel.

It's a horrible choice for series connecting for a real 72v bike. But if you can find a low enough amps 72v controller, you could do it. Mostly, controllers able to do 72v have higher amps, but you could buy one and snip one of the shunts.

Then you'd have the lowest performing 72v ebike on earth. Sorry if I'm sounding really harsh, but I truly think you have a bad plan there buddy. What will work is to use just one battery for the truly easy trips. Such as a 10 mile round trip where you ride just 15 mph on flat ground, and have only a few stops on the way. Parallel the batteries for more amps if you will ride into a stiff headwind, or climb some hills.

Get yourself a controller that handles a wide voltage range later, such as 36-72v. Grin has them, and so do others. Or more economically, get a 72v controller from ebay cheap later on. But make getting a much better battery part of the plan for then.

Thankyou, I wasn't een sure if it was possible, so thankyou for telling me!