Battery for heavy duty cycle truck?

what voltage for a cycletruck:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=99952


Now several months later after finnishing my bike and testing my Ah usage with a CycleAnalyst I have to tell the next person searching for this info that a heavy cycletruck needs a very large battery! I have been using more than 50Wh per mile at a very slow speed. I don't like moving so slow, but I have no choice be cause it takes 6Ah to make a round trip to town without climbing any of our steep hills or hauling much cargo. After the first trip to town when I ran out of power a mile from home and I had to pedal with my arthritic knees.

I put a higher gear for the 3% grade into town and use the lowest gear for the steep hills. I need to build a 36Ah LiFePO4 pack. If you have a cycletruck, you need a minimum of 20Ah even if you can pedal most fo the time. And be aware that you can use only half of the capacity if you want the battery to last the longest posible time. That would be an 80% charge and 30% cut off. And that does not tell about the discharge C rate, nor ageing.



Does this chart look reasonabley correct? I really do not know how much amps I will be using but I intend to try to keep the out put down near 1300w, and reconing with the Grintech graphs that is about 1600 batterys amps. And all that is the average worst case senerio on the hills around here. Of course there are worse hills, but I don't intend to be racing up hills as much as my Cyclone 3000w motor could do.

So I was planing to buy a 17.5 ah pack [ 13s (48 volt) Killer Whale Ebike Pack ] from lunacycles soon. My usual route is about 8 to 10 miles round trip with mild hills, but with up to 450bls total combined weight.

How much less amp-hours would the battery have if I charge it to only 4.1v each cell?? Maybe I need to get the next voltage up from 48v.

Should I use the 3amp charger for a slow safer charge? Is the output of the chargers about the same as what they draw from the outlet? Or is there larger loss??

What is the amp draw of the 300w charger? Is there a way to slow charge with it? Yes I realize there is enough resistance in the pack to charge fast, but our solar house power system is not as robust as it should be. That is: the wires to my house are smaller than they should be for a long use of 300watts. As well as the 100watt charger that does my two large deepcycle batterys for off grid lighting etc. (10G 300 foot or more)

“These packs will easily put out 30amps (1500 watts)” and 50amps for 12 second bursts.

Does that mean the battery will “supply” only 1500 watts continulay without any heating over that the battery pack can deal with? What about adding a small dc computer fan? Seems like they would connect on to the BMS.

ok acroding to this page I woulld get a better milage at ahigher voltage if I use a slower accellerator....is that right? lower wattage with less batterys amps....higher voltage. But does that keep the battery cooler? Well it must if there is less amp draw....

Ok so this will be another one that I answer my self, just give me a few days....

http://www.ebikes.ca/learn/power-ratings.html

As far as I can understand, using a higher voltage will take less amperage to climb the same hill at the same speed (13mph on an 8% grade) with the same total combined weight, than a lower voltage, correct? So I am just going to have to spend a little more for a 52volt (57.4V) 14S battery pack.

But what do they mean by “a higher voltage is not as reliable as the lower voltage”???

yet the main thing I need to know is:
*Will I need to reprogram the controller if I use the 52v or 60v pack?
http://www.ebikes.ca/tools/trip-simulator.html

Hugh-Jassman said:

But what do they mean by “a higher voltage is not as reliable as the lower voltage”???

yet the main thing I need to know is:
*Will I need to reprogram the controller if I use the 52v or 60v pack?

Click to expand...

The voltage statement does not really make sense. Sure, if you keep increasing the voltage on a system, eventually something will fail, but if the system was designed for the higher voltage it will be fine.

About programming the controller, what controller are you using? In most cases you may need to change the LVC setting if you want that function to work. You could just skip that if you use a CA or cheap voltmeter and use that to keep you from over discharging the pack.

I will use the controller that came with the cyclone 3000w mid drive kit from luna cycles....

I think the hardest thing to figure is the amount of amp hours I need for a pack charged to only 80%

I was hoping that the new trip simulator would help, but it looks like it is for motor heat only, and I have no idea where to get the data to simulate the cyclone...

fechter said:

Hugh-Jassman said:

But what do they mean by “a higher voltage is not as reliable as the lower voltage”???

yet the main thing I need to know is:
*Will I need to reprogram the controller if I use the 52v or 60v pack?

Click to expand...

The voltage statement does not really make sense. Sure, if you keep increasing the voltage on a system, eventually something will fail, but if the system was designed for the higher voltage it will be fine.

About programming the controller, what controller are you using? In most cases you may need to change the LVC setting if you want that function to work. You could just skip that if you use a CA or cheap voltmeter and use that to keep you from over discharging the pack.

Click to expand...

For 8-10 miles I think a 17.5 Ahr pack will be OK. If you charge to a lower voltage and only 80%, that still gives your 14 Ahr to work with.
It's hard to accurately estimate the total trip energy consumption, but my wild guess is you should be fine. It will depend a lot on how fast you are going and how steep the hills are. If you gear lower, the energy consumption will be less.

Just as a rough estimate, a 52v nominal, 14Ahr pack would be 728 W-hr. My A2B takes about 30Whr/mile at 20mph. It is quite heavy, but maybe 1/2 the weight of yours. Going downhill, the extra weight just makes you go faster. If you run fast, let's say it takes 50Whr/mile. 728Whr would give you 14.5 miles range.

Don't forget that when you use a smaller capacity battery pack you are also reducing it's capability to supply current under high loads without a lot of voltage sag (and stressing the cells).

So make sure you check with the cell specifications and their C-rate, then multiply that by the capacity of the battery pack to see if that's enough current to run your system correctly under the highest loads.

luna cycles does not have a 52v pack at 17.5ah, and they do not tell the C rating.

I may have to settle for the best...52V FLAT FISH PANASONIC PF PACK WITH KEYED IGNITION SWITCH
$799.95

But it will be closer to $950 with charger and shipping...maybe I should look at other sellers. not that I would trust them.

can some one explain this graph?
the big question is do I need the same amount of watts to climb the hills at any voltage? or does the increased volts make it possible to climb at a lower wattage?

or does it show that there just wont be as much wattage with the lowered amps?
in which case there would not be as much advantage as I would like....

Hugh-Jassman said:

the big question is do I need the same amount of watts to climb the hills at any voltage? or does the increased volts make it possible to climb at a lower wattage?

Click to expand...

The amount of watts needed to climb a hill at a particular speed will be the same regardless of the voltage. At a higher voltage the amps will be less but the watts will be the same.

If you gear for a lower speed, then the watts needed will be less.

if this is true then what about discharging a frozen battery?

CRITICAL: Never ever attempt to charge a frozen Li-Ion battery that is under 32 deg F (or 0 deg Celcius) Below freezing permanent damage will occur if you try to charge your battery pack. If your pack is frozen bring it inside your house and let it sit for a few hours till the battery is over 50F (10C)



more interesting info

http://www.ebikes.ca/product-info/battery-kits.html

It looks to me like I would not save much heating of the battery or is that only the motor, by using 52v inplace of 48v.....is that true?? Well no one knows what I am trying to do. So it all gets calculated for speed. and then still no one seems to know, so well have to just guess at it.

luna cycles says: "Yes this battery (20ah) will run cooler as its 7P where the 15.5ah is 5p" looks to me as if the only way to keep a battery cool is have more Ah capacity than needed.

So how do I calculate how much hotter the batterys will get in the same situation?? Maybe I can find it in on of Ron's article.....




1. 17.5amp-hour pack – 20% = 14amp hours at 80 percent charge x 48volts = 672 watt hours.
2. If each mile uses only 20wh ….20 x 20miles = 400wh is needed.

This is a very rough estimation, I probably need more watt hours because of the hills + cargo.

How about 30amp hours per mile? 30 x 20miles = 600watt hours. Still within the range. Obviously the battery pack may loose some mileage over time. But who knows how much if I keep it at an 80% charge only.

1. 20ah – 20% = 16ah at 80% charge x 52v = 832wh – 600wh = 232wh safety margin for $200.

http://www.ebikes.ca/product-info/battery-kits.html#how-to-choose-a-pack

The Amp hour rating is the total power capacity of the pack but has nothing to do with how much power you can draw at any one time. Instead, you have to look at the Peak Amp draw x the pack's P number which gives you a total of usable Amps.

13.5ah, 30a continuous gets you about 20 mins if you're lucky. That goes down as the pack ages.

Power is measured in watts. It's an instantaneous measurement. Energy is in watt-hours.

Run time in hours is energy divided by watts, or average watts. Full throttle = little run time. Mixed ½&½ with coasting gives you more run time.

48voltsx13.5amp-hours=648 watt-hours of energy in the pack. That's a little less than 1 horsepower-hour. Or ½hp for less than 2 hrs. Or ¼hp for about 3 hrs. The pack is then fully discharged.

most of these are confusing:

https://electricbike-blog.com/2017/...ur-ebike-build-ignore-peak-power-bms-ratings/ https://www.electricbike.com/watt-hours/
https://lunacycle.com/blog/18650-cell-ebikes/
https://www.electricbike.com/mounting-e-bike-battery-packs

https://lunacycle.com/52v-panasonic-11-5ah-or-13-5ah-carbon-shark-pack/

https://electricbike-blog.com/2016/...ew-18650-cells-vs-alkalines-ncrb-shark-packs/