# Newbie needs help

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Luke
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Joined: Wednesday, March 19, 2008 - 20:20
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Newbie needs help

Sorry I know that most of these questions probably have been posed before, but i appreciate any feedback. ( In the process of reading all I can about the ebikes) Thanks again. -- Luke

Luke
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Re: Newbie needs help

One more quick question, how would the x5 hub run with the dewalt batteries? and how many would i need?

andrew
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Re: Newbie needs help

Luke, I can't answer most of your questions, because I'm not an ebiker here. But, I can help give you an idea of power and energy to help you calculate how many dewalts packs to use.
Bicycle Speed and Power Calculator

To average 15 mph, you probably top out at somewhere around 18. For this speed profile, and you pedaling, I have no idea what the power consumption from the batteries would be. But, without pedaling, I can run some calculations.

18 mph cruising yields 206 watts, or 11.4 whrs/mile. This sounds really low to me. Multiply by 1.25 (losses of motor & controller), and that's 14.25 whrs/mile.

The dewalt packs have a nominal voltage around 33v, and 2.3 ahrs. Consider that you might realistically get 90% of the nominal energy at a high rate of discharge or (33 * 2.3 * .9) = 68.3 whrs/pack. Divide that figure by the whrs/mile to get range.

68.3/14.25 = 4.8 miles per dewalt pack. This is without any pedaling, and on the flat at a constant 18 mph with the stock pre-conditions of the calculator above. If you provided half the power, than this would increase to 9.6 miles per pack in range.

I'm not sure about the usefulness of the calculated energy/mile here. Do a search of the board to get some figures of some experienced ebikers. A realistic estimate might be more like around 20+ whrs/mile with real-world factors considered.

[url=/forum-topic/motorcycles-and-large-scooters/587-my-kz750-electric-motorcycle-project]KZ750 Motorcycle Conversion[/url]
[url=/forum-topic/motorcycles-and-large-scooters/588-fixing-my-chinese-scooter]900 watt scooter[/url]
Pic from http://www.electri

Luke
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Last seen: 15 years 10 months ago
Joined: Wednesday, March 19, 2008 - 20:20
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Re: Newbie needs help

So I finally purchased all the parts. I went with the x-5303, with 4 sla 18ah batteries (http://www.poweridestore.com/SLA-Batteries/12Volt-18AH-SLA-Battery) . Ill be running it at 48v untill I get some spare cash to run it at 72. I called and spoke with Earl from www.poweridestore.com, he was very helpful. I will be mounting this on my roadbike. It will be mounted on a 700c rim with the 35A (36-72v) controller. What kind of battery life can I expect with the 18ah batteries at 48v @ full and half throttle and how fast? ( I am awfull with the calculations and you guys make this stuff seem soo easy lol. Ty in advance for any help)

Luke
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Last seen: 15 years 10 months ago
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Re: Newbie needs help

So going off of what you did up there,,,, i will try to caluclate this my slef as I have not gotten any replies,,,

I am using 12v 18ah sla's...

so 12v * 18ah * .9 = 194.4 watt/hours per pack ? ( I have no clue if this is right )

194.4 watt/hours per pack * 4 packs = 777.6 total watt/hours ?

777.6 total watt/hours / (divided by ) 14.25 ( watt hours/ mile ) = 54 miles total ? ( does not sound right to me, but if it is then holy crap lol i can go far at 18 mph unassisted lol, considering I plan on going 25 ),,,

I will have the 35A controller running at 48V for now.. Can soneone please check my math please?

chas_stevenson
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Joined: Wednesday, December 6, 2006 - 17:14
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Re: Newbie needs help

Luke,

There is only one thing wrong with your calculations. You did not take into consideration the Depth of Discharge (DoD). If you are using Lead Acid batteries you should not use more than 50% of the total amp hours they are rated for to keep them healthy. So the last thing to do is multiply the miles by the DoD percentage you plan to use. This will give you the corrected mileage. If you use 50% your final answer is 27 miles. You could use more of the battery but it is not recommended.

Grandpa Chas S.

andrew
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Last seen: 14 years 7 months ago
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Re: Newbie needs help

Luke, there's something else wrong. SLA batteries have a much higher peukert effect than the Dewalt lithium packs. The equation is kind of complex, but a simple rough calculation would be about .6 or 60% for an average EV of the nominal energy. This is one reason why lithium/other technologies offer so much more range than SLA with a smaller battery pack.

12v * 18ah * .6 * 4 batteries = 518.4 whrs/14.25 = 36.4 miles, and you may want to stay within 80% DOD, so 29.1 miles.

Of course, this was for 18 mph on level ground. With the x5, I have no idea what the power requirements will be, and how fast you will be riding under what conditions (like up a 10% hill or something). So there are a lot of unknowns. For instance, try putting the speed up to 25 or 30 mph in the above power calculator I linked, and you'll see what I mean.

[url=/forum-topic/motorcycles-and-large-scooters/587-my-kz750-electric-motorcycle-project]KZ750 Motorcycle Conversion[/url]
[url=/forum-topic/motorcycles-and-large-scooters/588-fixing-my-chinese-scooter]900 watt scooter[/url]
Pic from http://www.electri

Luke
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Last seen: 15 years 10 months ago
Joined: Wednesday, March 19, 2008 - 20:20
Points: 13
Re: Newbie needs help

This is great you guys are awesome!!! I have a total of 30 mile trip that i would like to make at 20-25 mph max with pedaling. If my 80% DoD is at 25-29 mile range w/o pedaling ( and i live in arizona * pretty flat here* ) Then I will be good to go. I cant wait for all the parts to come in,, ill let you guys know how it goes. Thanks again.

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