Need help building a 48V pack from the cells... How many P/S needed?

[Klauts]

https://hobbyking.com/en_us/turnigy...D=78415&indexName=hbk_live_products_analytics

I'm looking to use these cells to create a battery for my ebike, they seem to be exactly what I need I'm just unsure how many I'd need to run in series/parallel to achieve a 48v output and 15-25Ah?

Any help would be greatly appreciated... My amateur calculations say I'd need a minimum of 3 packs?

Thanks a ton!

 

[tomjasz]

Why? When there are much safer easier managed batteries?
https://endless-sphere.com/forums/viewtopic.php?f=14&t=52240

 

[Klauts]

I don't understand what is unsafe about these turning batteries vs the blue turnigy? I was considering using these based on how high the capacity is for the price...

 

[tomjasz]

Read about the dangers of these batteries. There’s LOTS of information here.

 

[Klauts]

After reading through that thread it seems like this would be a safer option??

https://hobbyking.com/en_us/zippy-compact-4500mah-4s-35c-lipo-pack.html?queryID=9f4cb9c1cfe5da91d8b9b506cc213968&objectID=24755&indexName=hbk_live_products_analytics

If I'm understanding correctly I should be able to achieve 48v and a decent capacity using 4 of these packs?

 

[999zip999]

51.8v 35ah 1.77/1.84kWh 14s Lithium Ion Module
Regular price$275.00
Just rip out the old BMS and put a new Bluetooth BMS in its place.
Professionally made automotive grade battery good to go.
EZ.
The majority of this people here on ES no enough to not use these in a place where you can't store the bike in a cement bunker.
Or take the battery off each and every time and put it in a barbecue for charging and storage then you'll be safe and sane.

 

[Klauts]

Where did you find a 35Ah battery for that price?

 

[Klauts]

51.8v 35ah 1.77/1.84kWh 14s Lithium Ion Module
Regular price$275.00
Just rip out the old BMS and put a new Bluetooth BMS in its place.
Professionally made automotive grade battery good to go.
EZ.
The majority of this people here on ES no enough to not use these in a place where you can't store the bike in a cement bunker.
Or take the battery off each and every time and put it in a barbecue for charging and storage then you'll be safe and sane.

https://batteryhookup.com/collections/whats-new/products/51-8v-35ah-1-84kwh-14s-lithium-ion-module

Is this the battery you were mentioning? That price is insane I didn't realize you could get Li-ion for that cheap... Do you know of a guide for installing charging/discharging ports on that style of battery? Wiring the BMS I'm confident I can do without guidance but how to connect xt60/Anderson plugs etc doesn't seem clear cut to me...

Thanks a ton for your help!

 

[tomjasz]

Or take the battery off each and every time and put it in a barbecue for charging and storage then you'll be safe and sane.

All well and good if you live in a temperate climate... Too hot, danger, too cold danger, undercharged danger, overcharged, danger.
Not a good choice for a n00b!

 

[Klauts]

I shall take your warnings to heart and stick with Li-ion i think I'll probably just grab that 35Ah EV battery and wire a BMS to it if I can figure out how to install discharge/charging ports....

 

[From-A-To-B]

https://windynationstore.com/products/8-gauge-cable-lugs

Crimp or solder heavy duty copper cable lugs onto the end of whatever hefty wire you’re using. 10AWG is fine for most ebike loads (30amps, cable run of a foot or two). Linked is an example.

Bonus points for matching the diameter of the lug to the diameter of the terminal post on the battery. Remember to use a washer on TOP of the lug, between the nut, but not underneath.

 

[Klauts]

https://windynationstore.com/products/8-gauge-cable-lugs

Crimp or solder heavy duty copper cable lugs onto the end of whatever hefty wire you’re using. 10AWG is fine for most ebike loads (30amps, cable run of a foot or two). Linked is an example.

Bonus points for matching the diameter of the lug to the diameter of the terminal post on the battery. Remember to use a washer on TOP of the lug, between the nut, but not underneath.

Thank you! This is really helpful! Would the charging and discharging happen through the same terminals in an EV style battery like this?

Just trying to figure out exactly what parts I'm going to need to get the pack running before I start

From what I gather so far, I can just attach copper lugs to the terminals and use those to attach 8-12G copper wire with an Xt60 connector at the other end?

The BMS would be wired to the individual cell groups and from there to the other end of the +/-battery terminals?

I'm thinking to use this BMS for the project...

https://vruzend.com/product/52v-14s-battery-management-system-bms/

 

[From-A-To-B]

https://windynationstore.com/products/8-gauge-cable-lugs

Crimp or solder heavy duty copper cable lugs onto the end of whatever hefty wire you’re using. 10AWG is fine for most ebike loads (30amps, cable run of a foot or two). Linked is an example.

Bonus points for matching the diameter of the lug to the diameter of the terminal post on the battery. Remember to use a washer on TOP of the lug, between the nut, but not underneath.

Thank you! This is really helpful! Would the charging and discharging happen through the same terminals in an EV style battery like this?

Just trying to figure out exactly what parts I'm going to need to get the pack running before I start

From what I gather so far, I can just attach copper lugs to the terminals and use those to attach 8-12G copper wire with an Xt60 connector at the other end?

The BMS would be wired to the individual cell groups and from there to the other end of the +/-battery terminals?

I'm thinking to use this BMS for the project...

https://vruzend.com/product/52v-14s-battery-management-system-bms/

Charging happens through the main +\- for most Batteries. Note that your BMS will be hooked up to the negative terminal, and your charge / discharge negative lead will go through the BMS.

There are many good discussions and how-tos about BMS wiring on this forum. Find a wiring diagram for your particular BMS if this is your first DIY battery. Most of them go on the same, but have the one for your BMS alongside for reference.

Note that there are Common Port and Separate Port BMSs— common ports have the charge and discharge through one lead, separate ports have a charge lead and a separate discharge lead.

12awg is easy to solder on an xt60, 10awg gets hard, and I wouldn’t bother trying with 8awg. YMMV.

 

[docw009]

4 x 6 inch cross-section, 19 inches long and 27 pounds. That's going to look pretty gross on an ebike.

 

[Klauts]

4 x 6 inch cross-section, 19 inches long and 27 pounds. That's going to look pretty gross on an ebike.

I honestly don't care what It looks like so long as I can afford it and make it work my bikes stock Silverfish battery weighs 15 pounds, 14.5" long and is only 15.6Ah so I don't really see a problem?

 

[docw009]

A silverfish is 3"x4.5". This won't fit in the same space. And you have to put a cover over it and find a way to clamp it to the bike. 30 pounds on a rear rack makes for a lot of weight too.

Buy a 48V15AH Hailong and run it with a diode box to the silverfish,

 

[Klauts]

A silverfish is 3"x4.5". This won't fit in the same space. And you have to put a cover over it and find a way to clamp it to the bike. 30 pounds on a rear rack makes for a lot of weight too.

Buy a 48V15AH Hailong and run it with a diode box to the silverfish,

I was aware it wouldn't fit in the same space intended to mount it to the wrack, it's a really sturdy fat bike I can easily carry 100 pounds of cargo on the back wrack

 

[Klauts]

Ive got one more question... Would 4 of these lifepo4 in parallel do the trick if I were to charge them seperately? I'm pretty sure that would give me 40A continuous discharge and 32Ah capacity?

https://www.amazon.ca/ECO-WORTHY-Rechargeable-Phosphate-Protection-Fishfinder/dp/B092PR8QFQ/ref=mp_s_a_1_16?content-id=amzn1.sym.abdf4ed6-c663-4e24-a631-7acbfbd655f1%3Aamzn1.sym.abdf4ed6-c663-4e24-a631-7acbfbd655f1&keywords=48v+battery&pd_rd_r=b4878a13-9fd3-4fff-b0b4-c1a8e997c48c&pd_rd_w=jZg9J&pd_rd_wg=ugvnL&pf_rd_p=abdf4ed6-c663-4e24-a631-7acbfbd655f1&pf_rd_r=Y6P5WQ161THDDB6WA3EQ&qid=1668145944&qu=eyJxc2MiOiI2LjA3IiwicXNhIjoiNS40MyIsInFzcCI6IjMuMTgifQ%3D%3D&refinements=p_85%3A5690392011&refresh=1&rnid=5690384011&rps=1&sr=8-16

 

[From-A-To-B]

I don’t see the discharge specs of those lifepo4 batteries. But 4 in parallel would give you 32Ah at 12V. You’d need 16 of them to get 32Ah at 48V.

FWIW: I would also steer you towards a hailong-style pack that can be mounted in the center triangle. Some people find that a lot of weight mounted on the rear rack degrades bike handling.

That EV pack is a kickass battery— it’s also large, heavy, and not easily mounted or tucked away.

 

[Klauts]

I don’t see the discharge specs of those lifepo4 batteries. But 4 in parallel would give you 32Ah at 12V. You’d need 16 of them to get 32Ah at 48V.

FWIW: I would also steer you towards a hailong-style pack that can be mounted in the center triangle. Some people find that a lot of weight mounted on the rear rack degrades bike handling.

That EV pack is a kickass battery— it’s also large, heavy, and not easily mounted or tucked away.

Here's the link to the lifepo4 pack info from the manufacturer, the BMS they have supposedly supports having up to 4 cells in series and unlimited cells in parallel...

https://ca.eco-worthy.com/collections/lithium-batteries/products/lifepo4-12v-8ah-10ah-20ah-lithium-iron-phosphate-battery

I'm having a hard time wrapping my head around the combined capacity of battery packs...

I was under the impression that if you put four 12V packs in series you'd end up with 48v output and that adding more cells in parallel just increases the capacity without affecting voltage?


Where is my understanding going wrong?
Relooking at things I think I just misunderstood the total Ah of a 4S1P setup using these packs?

Shouldn't a 4S1P setup with these packs result in 48V and 8.2 Ah?

Thanks again for all your help

 

[999zip999]

No not those lifepo4. Sorry for not linking battery hookup
What size soldering iron do you have ?
12ga ? 10ga better what amp is your controller ?
Almost all BMS most - would have 15 wires first one to neg as number one cell and next to number 1 cell post. Then number 2 post next number 3 pos. ECT. Always check with multi meter.
I like my Bluetooth BMS the one with the little blue elephant . Can't spell the name but do read up first
Plus that battery is 35ah or 50 miles
How about a picture of your bike ?
Most battery fires in my neighborhood are from RC lipo toy batteries and then cheap e-bikes with a s***** junk battery packs easy to buy from China junk.
Answer all questions please

 

[Klauts]

No not those lifepo4. Sorry for not linking battery hookup
What size soldering iron do you have ?
12ga ? 10ga better what amp is your controller ?
A BMS most - would have 15 wires first one to neg as number one and next to number 1 cell post. Then number 2 post next number 3 pos. ECT. Always check with multi meter.
I like my Bluetooth BMS the one with the little blue elephant . Can't spell the name but do read up first
Plus that battery is 35ah or 50 miles
How about a picture of your bike ?
Most battery fires in my neighborhood are from RC lipo toy batteries and then cheap e-bikes with a s***** junk battery packs easy to buy from China junk.
Answer all questions please

I've got soldering tips for 8ga - 12 ga,

Here's a picture of my bike:

The controller is max 25A with 12.5A constant.

Also what is wrong with those lifepo4 cells? The wiring diagram they provide indicates it would work and they come with a BMS designed to be run in series and parallel?

 

[Klauts]

Ooooh dang I just found what looks like the perfect option for my situation...

https://www.evwest.com/catalog/product_info.php?products_id=488&osCsid=dd25bdbdaed25e68040b1652d9153abc

From what I can tell these packs would be ready to go as soon as a BMS was installed and they already have the capacity and voltage I'm looking for...

If I were to get a BMS that supports additional parallel packs would I be able to wire 2 of those 48v 505Wh packs together in parallel for 48V 1010Wh?

 

[From-A-To-B]

Ooooh dang I just found what looks like the perfect option for my situation...

https://www.evwest.com/catalog/product_info.php?products_id=488&osCsid=dd25bdbdaed25e68040b1652d9153abc

From what I can tell these packs would be ready to go as soon as a BMS was installed and they already have the capacity and voltage I'm looking for...

If I were to get a BMS that supports additional parallel packs would I be able to wire 2 of those 48v 505Wh packs together in parallel for 48V 1010Wh?

You could wire two of those in parallel, yes. The main positive and negative would come off in parallel, and then every parallel group in the two pack needs to be correctly paralleled. Voltage of the two packs must match beforehand. At that point, you’ve joined the two batteries into one, and a single BMS will handle the job.

 

[From-A-To-B]

Where is my understanding going wrong?
Relooking at things I think I just misunderstood the total Ah of a 4S1P setup using these packs?

Shouldn't a 4S1P setup with these packs result in 48V and 8.2 Ah?

Thanks again for all your help

You got it right. 4s1p is 48V 8ah. 4s4p is 48V 32AH, which requires 16 modules.