Building a large capacity battery for bicycle trailer

[azad]

an actual 100Ah lifepo cell from winston for example tips the scale at 7.2lbs. 16*7.2=115lbs.

if its lighter it probably is not 100Ah....

and i verified the weight. i have a couplr dozen sitting on my bench and floor.

It seems Lifepo4 100Ah cells can be 2.1kg. Does that not beat the whole purpose of using Lipo then?

https://www.aliexpress.com/item/1005001651192097.html

 

[azad]

Anyway, making a multi-kWh pack out of vape pen cells is silly.

tell that to tesla.

you are being dumb. they are not even vape cells.

a 35E cell weighs in at 47 grams and stores 12.5Wh.
a winston 100Ah cell clocks in at 3.3Kg (7.3lbs) and stores 300Wh

5000Wh/12.5Wh=400 cells*47grams=18.8kg=41.44lbs
4800Wh/300Wh=16 cells*3.3Kg=52.8Kg=116lbs

116-41=75lbs difference.

winston $130 per cell * 16 = $2016
samsung 35E ~$4ish a piece in bulk = $1600

ps: energy density for a 35E is (21*47gram=)987g (21*12.5Wh=)262,5Wh

mathz.

might want to get your money back from that US educational system.... :lol:

How about these cells?

https://www.aliexpress.com/item/1005001515275916.html

 

[Chalo]

The OP's question isn't about a bike; it's a trailer.

Yes but it is more like cargo trailer than a camper!
I am intending to carry additional weight on the trailer. Recommended max weight for the trailer is 25kg.

Oh dear. :lol:

There's no way for you to install 48V x 100Ah of any kind of battery and meet your weight limit. Maybe the cells alone, barely, but not a complete battery.

I think you need either a stronger trailer, or a more normal amount of battery capacity. What makes you think you need 5 kilowatt hours?

 

[azad]

The OP's question isn't about a bike; it's a trailer.

Yes but it is more like cargo trailer than a camper!
I am intending to carry additional weight on the trailer. Recommended max weight for the trailer is 25kg.

Oh dear. :lol:

There's no way for you to install 48V x 100Ah of any kind of battery and meet your weight limit. Maybe the cells alone, barely, but not a complete battery.

I think you need either a stronger trailer, or a more normal amount of battery capacity. What makes you think you need 5 kilowatt hours?

I want to travel more than 300-400km on a single charge. Intention is to do ebike touring. I already carry 2 batteries on the bike, total of 45Ah and can do 100km at 40km/h.

 

[Chalo]

Well, keep in mind that dragging a trailer costs energy, so that big expensive mass of batteries won't get you as much extra range as its kWh capacity would otherwise suggest. It's all fine until your batteries give up 50 km from your destination, and you're left pedaling a 120 kg rig.

If the recommended weight limit for your trailer is only 25 kg, it sounds a single wheeled trailer. Those are notorious for wobbling at speed when they're loaded heavily.

I'd spend more time working out a fast charging system and strategy rather than hauling an extra 50 kg on top of my touring gear.

 

[gobi]

The OP's question isn't about a bike; it's a trailer.

Yes but it is more like cargo trailer than a camper!
I am intending to carry additional weight on the trailer. Recommended max weight for the trailer is 25kg.

Op, I live in West MI, we are blessed in paved trails and I was dreaming of ebike solutions to ride atleast 50 miles and then stop and charge, eat a meal and then move on.

Solely for that, I bought Topband 25ah priz cells.

25ah weighs 0.6 kg each.

https://www.topbandbattery.com/Solution/3592.html

I bought mine from BH when they had it by chance.
I can charge these at 1C, so even if I am fully depleted I can take an hour break and recharge them.

Op, do you have access to power on your route?

In MI we have EV charging stations and I plan on buying the EV adapter from TusconEV to use my meanwell HRPG power supply to zap my batt.

 

[flippy]

It seems Lifepo4 100Ah cells can be 2.1kg. Does that not beat the whole purpose of using Lipo then?
https://www.aliexpress.com/item/1005001651192097.html

How about these cells?
https://www.aliexpress.com/item/1005001515275916.html

no, because those cells are still junk.

if you are really running a single wheeled trailer you need to change that yo a dual wheeld one. or better: split the battery in 2 and put them on the bike in place of the saddlebags at the rear.

as you are seriously weight and size restricted you need the highest capacity 18650 cells as i mentioned in the calculations i did with the 35E. that is basically your only choice. lifepo4 is simply too big and too heavy to be a reasonable choice in your restricted setup.

the volume of a lifepo pack that size is 37 Liters (aka: ~10 freedoms) versus the 9.5 Liter (aka: 2.5 freedoms ) you need with 18650 cells. its litteraly 4x smaller and 75 freedoms lighter as previously mentioned.

TLDR: 18650 cells are a stupid amount lighter, a bit cheaper and take up a quarter of the size compared to lifepo.

lifepo is clearly not suitable for use on a bike. not unless the only thing you want to drag along is batteries.

lets be clear, i am not against lifepo. i use them all the time. but for application like this its simply the wrong choice.

 

[Felixaustria]

400 km per day would require to be in the saddle for 10 hrs a day. Is your body up to the job?

A realistic first goal could be: try to make 200 km with the batteries you already have. Ride 100 km and then take a 2-3 hrs break, charge your batteries, eat, drink, relax and regenerate. And then another 100 km. Chose a route you already know well.

I would reduce speed to 30 km/h. This will boost the range you get from the batteries you have. You already have a very big battery.
A fit rider could make 250 km with your battery at 30 km/h

 

[fatty]

Yes but it is more like cargo trailer than a camper!
I am intending to carry additional weight on the trailer. Recommended max weight for the trailer is 25kg.

This is not feasible.
The correct solution, as with all of these extreme range threads, is to buy or build a velomobile.

 

[flippy]

still, just strapping a 360Wh solar panel on the trailer would be a huge boost. as will just stopping more oten to recharger at an outlet and drive a bit slower. all these factors help in reducing the battery siZe wich currently is still comically big.

 

[john61ct]

an actual 100Ah lifepo cell from winston for example tips the scale at 7.2lbs. 16*7.2=115lbs.

if its lighter it probably is not 100Ah....

and i verified the weight. i have a couplr dozen sitting on my bench and floor.

It seems Lifepo4 100Ah cells can be 2.1kg. Does that not beat the whole purpose of using Lipo then?

https://www.aliexpress.com/item/1005001651192097.html

This market is full of outright scammers.

Claimed lower weight higher energy density in the same chemistry family is a huge red flag.

If you can afford to carry a 50lb battery, that is not much to get high range.

otherwise you need a support vehicle coming with to carry spare packs you could swap out

or recharge en route

or go lower weight and accept lower range.

OR, consider a FF motor, petrol has **huge** energy density!

Can't beat physics!

 

[flippy]

OR, consider a FF motor, petrol has **huge** energy density!
Can't beat physics!

does it come with earplugs? listening to a obnoxious 2 stroke for hours upon hours gets really old really fast.

 

[azad]

Op, do you have access to power on your route?

In MI we have EV charging stations and I plan on buying the EV adapter from TusconEV to use my meanwell HRPG power supply to zap my batt.

Yes! but my current chargers are rated at 4A. One battery that I have has 18650 cells and charge rate I don't know but other one is better it consists of 20A EV PHEV cells which can be charged at 0.5C Recommended (10A) and 1C max so technically it should be possible to charge this battery in 2hours. However, I don't have the right charger or the adapter for european EV outlets.

 

[azad]

It seems Lifepo4 100Ah cells can be 2.1kg. Does that not beat the whole purpose of using Lipo then?
https://www.aliexpress.com/item/1005001651192097.html

How about these cells?
https://www.aliexpress.com/item/1005001515275916.html

no, because those cells are still junk.

if you are really running a single wheeled trailer you need to change that yo a dual wheeld one. or better: split the battery in 2 and put them on the bike in place of the saddlebags at the rear.

as you are seriously weight and size restricted you need the highest capacity 18650 cells as i mentioned in the calculations i did with the 35E. that is basically your only choice. lifepo4 is simply too big and too heavy to be a reasonable choice in your restricted setup.

the volume of a lifepo pack that size is 37 Liters (aka: ~10 freedoms) versus the 9.5 Liter (aka: 2.5 freedoms ) you need with 18650 cells. its litteraly 4x smaller and 75 freedoms lighter as previously mentioned.

TLDR: 18650 cells are a stupid amount lighter, a bit cheaper and take up a quarter of the size compared to lifepo.

lifepo is clearly not suitable for use on a bike. not unless the only thing you want to drag along is batteries.

lets be clear, i am not against lifepo. i use them all the time. but for application like this its simply the wrong choice.

It is not a single wheel trailer. It is made of steel however, the flooring is of vinyl and it is little bit different from this picture in that axels are only tied (stuck) from one side while the other side is unattached unlike here in the picture.

 

[azad]

400 km per day would require to be in the saddle for 10 hrs a day. Is your body up to the job?

A realistic first goal could be: try to make 200 km with the batteries you already have. Ride 100 km and then take a 2-3 hrs break, charge your batteries, eat, drink, relax and regenerate. And then another 100 km. Chose a route you already know well.

I would reduce speed to 30 km/h. This will boost the range you get from the batteries you have. You already have a very big battery.
A fit rider could make 250 km with your battery at 30 km/h

I was thinking more on the lines of "No peddling" range and speed I need in order to cover the distance quickly so that I am not an obstacle for the traffic and not too tired as you said.

 

[azad]

still, just strapping a 360Wh solar panel on the trailer would be a huge boost. as will just stopping more oten to recharger at an outlet and drive a bit slower. all these factors help in reducing the battery siZe wich currently is still comically big.

Assuming there is strong sunshine. Here in the nordic parts sun is very rare. It is very sunny these days but it wont last a few more days of summer.

 

[flippy]

It is not a single wheel trailer. It is made of steel however, the flooring is of vinyl and it is little bit different from this picture in that axels are only tied (stuck) from one side while the other side is unattached unlike here in the picture.

great.

with that you can make a flat panel from cells. so a single high pack will be 7cm (2,75591 freedoms) tall and roughly a 40lbs long pack of 70cmx20cm (27,5591 freedoms x 7.87402 freedoms) that you can place in the middle of the cart for optimal weight distribution.

i would replace the vinyl with HPL. its much stronger and durable and you can just bolt stuff to it.

 

[gobi]

azad, can you please post a pic of your charger?

50v @ 10amp = 500w

The meanwells come with NO cables, I just cut of my computer power cables and crimped spade connectors.

The good thing about meanwells is that the input voltage goes all the way to 240v,

My priz cells can take 25a max charge current, most 18650s take 1C also, but both will get warm at the charge rate from my experience.

 

[azad]

azad, can you please post a pic of your charger?

50v @ 10amp = 500w

The meanwells come with NO cables, I just cut of my computer power cables and crimped spade connectors.

The good thing about meanwells is that the input voltage goes all the way to 240v,

My priz cells can take 25a max charge current, most 18650s take 1C also, but both will get warm at the charge rate from my experience.

It is just an inexpensive 4A charger that I bought from ebay. I tried to find 20A charger from aliexpress but realized they are more than 1000$ and also very hard to find. I want to charge fast but don't want to destroy batteries though.

 

[flippy]

you can charge a 20S20P pack of samsung 35e with 35A and still remain witin full spec. thats basically 3kW of charging power....

 

[azad]

It is not a single wheel trailer. It is made of steel however, the flooring is of vinyl and it is little bit different from this picture in that axels are only tied (stuck) from one side while the other side is unattached unlike here in the picture.

great.

with that you can make a flat panel from cells. so a single high pack will be 7cm (2,75591 freedoms) tall and roughly a 40lbs long pack of 70cmx20cm (27,5591 freedoms x 7.87402 freedoms) that you can place in the middle of the cart for optimal weight distribution.

i would replace the vinyl with HPL. its much stronger and durable and you can just bolt stuff to it.

How many amps? 40lbs? ( nearly 20Kg) wouldn't it be too much for those wheels? They are 19" wheels but as I said axel is such that it inserted from one side while other side remains free.

 

[azad]

you can charge a 20S20P pack of samsung 35e with 35A and still remain witin full spec. thats basically 3kW of charging power....

I have 13S8P 25A and it is Chinese battery, not samusung, maybe liitokala but I am not sure, I haven't torn it apart and now it is burried in my bike.

 

[Felixaustria]

I was thinking more on the lines of "No peddling" range and speed I need in order to cover the distance quickly so that I am not an obstacle for the traffic and not too tired as you said.

Your current horizon covers 2 hrs in moped mode at 40 km/h. You cannot scale that up and assume, that with more energy on board you could do that all day long. If you have no experience in endurance sports, you will encounter mental, physical and material limits soon. F.e. he cheap trailer you suggest, is not suited for 40 km/h all day, with 50 kg of batteries on board, it will not even survive a single day.

Try to start with something realistic you can do right now without buying additional stuff. You cannot buy physical and mental physical fitness, you have to aquire it by training.
Try to make 200 km in two 100 km stages, charging your 13s8p battery at halftime.
Then you have an idea, how long you can sit on the bike, and if you ENJOY it.

 

[TrotterBob]

Just saw that BatteryHookup has those 25ah lifepo4 cells back in stock. But they're only selling them in packs of 24. Maybe you could get those and sell off the extras at a slight markup.

 

[flippy]

Just saw that BatteryHookup has those 25ah lifepo4 cells back in stock. But they're only selling them in packs of 24. Maybe you could get those and sell off the extras at a slight markup.

still too big and heavy to be useful on a bike.