Need input - buying batteries

[metaneuralnetwork]

So I've budgeted $600 for investment in upgrading battery capacity. I'm running 48v 1kw hub motor on MTB that sometimes pulls an aluminum trailer. I currently have 2x 48v 14ah batteries.

My main goal here is range. I'm not even that concerned about weight. So, with money in my pocket I went shopping and that's when my ideas about what I might purchase completely broke down.

For one, I've looked into building my own packs and given that I'm not doing 72v (or higher) or something specialized or super high end cells or something, I've found it's not cost effective whatsoever to be making my own batteries in this budget range. By the time it's done, I will have spent the same or less on a new and assembled battery. With a warranty.

Perhaps I'm looking in the wrong places, but unless I'm willing to invest several thousand in aliexpress, I see little gain in building my own. I'd have to be in business it seems for it to be worth that.

I've looked at other places and it's always something. For example, Battery Clearing House looked great, but I hope they know they're getting hammered on shipping. They'd honestly get all of my money if not for the non-competitive shipping rates. I mean is it really $30 to mail a tire? $150 to mail a few flat packs?

So my request is this - what should I get and where? 48v or 52v, range desired, weight not a priority. $600.

 

[neowizard]

BatteryHookup are my go-to source for batteries. These guys are super reliable, very competitive on pricing and provide excellent shipping services (I live an ocean away, and they've shipped multiple kW to me quickly and with reasonable prices on several orders)

You didn't specify chemistry/cell-type, so here are a few options for > 48V 1300W (all well below 600$ to leave lots of room for shipping and whatever else you may need):

1. New 35Ah LiFePO4 pouch cells. 70$/4cells, 280$ for nominal 51.2V (16s), totaling a little under 1800w
2. New 3.8Ah LiFePO4 cylindrical cells. 228/120cells and a nominal 48V (15s), totaling a little over 1450w
4. Like-new used 8Ah Lion pouch with holders, bars and screws. 8.5$/2cells. 221$ for nominal 48.1V (13s), totaling a little over 1500w
3. Like-new used 39-41Ah Lion cylindrical cells. 125$/6cells. 250$ for nominal 48V (12s), totaling a little under 1900w

I'm not affiliated with BatteryHookup an any way, just a huge fan.

 

[metaneuralnetwork]

Very awesome my friend, thank you! I will pour over the links you've shared, down to the fine details. I shall return!

 

[SafeDiscDancing]

Here are really nice, compact 44.4v 10ah 444wh modules. These would be perfect for an Ebike. You will have to cut around the lid with a dremel or heat up the glue to pull the lid off. These are made up of 12x 3.7v 10ah cells. They were removed from EV modules that were cycled only a few times. We check for voltage of each module so every module will be good to go. Just add your BMS and you're all set. These can easily handle a 3c discharge as well so they are power modules.

Dimensions: 13" x 7" x 3.5"

Weight: 12 lbs.

$59.99

https://batteryhookup.com/products/samsung-ev-battery-44-4v-10ah-444wh

I have plenty of working batteries right now, but at $60 this looks like an absolute steal.

Probably very durable too once you get it properly set up.

The only "glitch" is you need an ebike with the right place for it.

 

[metaneuralnetwork]

I like this. I like it a lot. Thanks. Still looking at everything. A lot to consider.

location won't be much of a problem with my trailer. If it's starts to get heavy I'll add 20" hub motor to it. Let's be honest I'm gonna end up doing that anyway.

edit-best use for that item would be to remove the 12 cells. So looking at it that way, it's $5/ea used but they are 10AH.

 

[metaneuralnetwork]

Ok looking at the other options so far, and not including BMS or other materials for any of these -

1. Ok this looks fab - > $350shipped for 35AH. What is the caveat to this build? What does this need outside of a BMS and a box to go in? What am I missing with this?

2. This comes out to about $10/AH not including other hardware. Seriously considering these. Plus good to have several for other smaller aplications.

3. This is $143 shipped for 16AH. Lets say 32AH for >$300. This is a bargain!

4. These would need to be 14s meaning 3 lots of 6 for $375 for 41AH. This is a very good deal as well. I like the smaller total number of cells.

Well, I haven't decided 100% yet, but I'm strongly leaning toward #2

 

[99t4]

If you can be patient, you will find they are constantly rolling out "new" merchandise. If you monitor their site you may find something near perfect for your needs requiring minimal mods. Be ready to buy right away because the really good ones sell out quickly.

 

[metaneuralnetwork]

Thanks for that. Already I see so many options beyond what I was looking at.

You guys need a tip jar on here.

edit - can I just throw this on the bike trailer? Would that be all right? :lol:

 

[SafeDiscDancing]

edit - can I just throw this on the bike trailer? Would that be all right? :lol:

Why not? The price is great. The power is insane.. You will never need that much burst potential and I own those pouch cells in a 12S configuration and can say they will last practically forever.

As long as you properly manage the battery and don't do something really stupid it will last a decade or two.

All the crap you buy that claims to be an ebike battery and they include some cheap Battery Murdering System that destroys your pack in a few months due to extreme retardation in design is all "planned obsolescence".

If you can use your brain to manage the cells manually that's the best way.

All these cells have easy access. You can directly measure and adjust each cell in the series.

If you "Bottom Balanced" once and then set your charger to cut off at 4.1 volts you might literally go years without a problem and never need a Battery Murdering System.

And what you want to do is never allow the cells below 3.2 volts or so and only hit 4.1 volts just before you ride it.

Leave it resting around 3.7 volts most of the time. (all voltage references were "per cell")

 

[SafeDiscDancing]

https://batteryhookup.com/products/samsung-ev-lithium-ion-12s-44-4v-47ah-2-07kwh-module

In my opinion these are an even better deal if you are going for a trailer battery.

About the same price, but each cell is the full capacity (47 ah) and it's all welded up perfectly so nothing is ever going to get loose over time.

Again you can easily access each cell and manage it.

2 kWh is simply insanely huge for an ebike.

My guess is you could do a hundred miles on a charge pretty easily... enough to be exhausted afterwards.

26 lbs.

 

[metaneuralnetwork]

https://batteryhookup.com/products/samsung-ev-lithium-ion-12s-44-4v-47ah-2-07kwh-module

I saw this one as well and like it a lot BUT it's 44v.

Would take some real tinkering and reorganizing to break it all up (bus bars and all) to rearrange it for 48v.

edit - or wait it's 1p so I'd need 2 of them?

 

[SafeDiscDancing]

I saw this one as well and like it a lot BUT it's 44v.

The convention is ## "S" and ## "P".

Series... Parallel.

So this is 12S1P.

Which means since it is Li-ion that:

12 * 4.2 volts = 50.4 volts "peak".

Empty is 12 * 3.0 volts or about 36 volts.

Sometimes they recommend that you don't hit the full 4.2 volts when charging in order to increase battery life.

Most of the time a 12S Li-ion will hang around 44.4 volts as that is 12 * 3.7 volts the "nominal rating".

Occasionally people do 13S (or 14S) just so they exactly center around 48 volts but it's not necessary because all these motors and controllers can tolerate a wide range of input variability.

Voltage sag alone can be several volts.

Also... 50 volts is generally seen as the point when electrocution gets serious. Stay below and it's not likely to kill you if you do something stupid.

I'd say stick to 12S as your maximum.

---------------------------

These modules are beautiful and built like tanks. These were overstock modules not put into vehicles. Each module can easily push 3c or 150a continuous. You have easy access to the busbars to make your BMS balance lead connections. Check out the 2nd and 3rd photos. This is one of the best built batteries we have ever seen. Perfect compression and just built like a tank. Perfect for forklift or golf cart projects. At this price it even makes sense to make a powerwall out of them. Imagine buying 7 modules for over 14kWh powerwall and using one module to add 2 cells to each 12s module. Making 6x 14s 48v modules.

Dimensions: 14" x 6" x 4.5"

Weight: 26 lbs

 

[metaneuralnetwork]

I saw this one as well and like it a lot BUT it's 44v.

Occasionally people do 13S (or 14S) just so they exactly center around 48 volts but it's not necessary because all these motors and controllers can tolerate a wide range of input variability.

Voltage sag alone can be several volts.

Right, so running this means undervolting, and it also means using a controller that won't cut off at 42v.

Now if I were running 2x 48v hub motors, that might change things. But as it stands, I think there are some other options that might be more suited to my particular application (which I haven't bothered to explain).

 

[SafeDiscDancing]

Right, so running this means undervolting, and it also means using a controller that won't cut off at 42v.

I basically disabled my low voltage cutoff.

Why?

Because it will not protect your battery "at all" from a low cell and this is most true doing "top balancing".

I have destroyed many cells that way in the past.

This is why wisdom helps in this stuff.

--------------------------

The best way to never have problems ever... ever... ever... is you "bottom balance" once then when you charge you halt the charge when the weakest cell peaks.

All I'm saying is you seem to be chasing things I remember chasing long, long ago.

Remember... 12S is actually 50.4 volts if you charged it fully.

44.4 volts will be your midpoint.

48 volts will be your top 10%.

36 volts will be empty, but with bottom balancing it will NOT cause any damage.

What I'm saying is a bottom balanced battery really cannot be destroyed. And so you don't need or want the controller to cut power at any time because it's another example of bad logic.

When a bottom balanced battery nears empty it pretty much stops delivering power and you "know" it's empty.

The top balanced battery with the cheap Chinese low voltage cutoff is just going to murder your weakest cells.

It's the first of a series of horrific Battery Murdering System problems that get introduced.

 

[metaneuralnetwork]

Call it a matter of preference.

I want 48v.

Matter of fact, I prefer 52v. I'm settling on 48v.

 

[SafeDiscDancing]

Matter of fact, I prefer 52v. I'm settling on 48v.

Well just be aware of all the traps I'm "trying" to warn you about.

I have been at this hobby for nearly 20 years and am trying to steer you towards wisdom.

You are entering a kind of minefield of failures and it's still happening.

Higher voltage is always better efficiency wise, so the direction is not bad.

But these 12S packs are probably the best anywhere.

Voltage mostly determines top speed so you must be seeking higher speed?

 

[metaneuralnetwork]

So by wanting a 48v battery I'm walking into a minefield of failures?

Ok.

 

[SafeDiscDancing]

So by wanting a 48v battery I'm walking into a minefield of failures?

Ok.

No. I'm saying "Why" do you want that?

Everything at 12S is very ordinary and common.

Once you get beyond 12S you start needing more rare equipment.

If you are pulling a trailer it seems "odd" that you are obsessed with higher top speed.

How fast are you going to go?

Do you see the contradiction here?

High Voltage ---> High Top Speed

Trailer ----> Low Top Speed

 

[metaneuralnetwork]

Well for reasons sort of already explained.

You know, I didn't realize that trolling was a thing here. I thought the other day someone threw some shade at me for nothing but then they kind of explained it as meaning something else.

Now I got a guy that wants to bust my balls over me wanting a 48v battery. Tells me I'm making all these failures, basically derailing my thread with some ridiculous take.

It's like this man - it's my money. I'm not buying the 44v battery. Get over it.

 

[SafeDiscDancing]

It's like this man - it's my money. I'm not buying the 44v battery. Get over it.

Do you see the contradiction?

Fast Bike... High Voltage... Trailer?

 

[metaneuralnetwork]

Get a life, man.

 

[Chalo]

I saw this one as well and like it a lot BUT it's 44v.

Would take some real tinkering and reorganizing to break it all up (bus bars and all) to rearrange it for 48v.

edit - or wait it's 1p so I'd need 2 of them?

Ignore the P count; all that matters to you is the Ah rating.

If your main concern is range, 44V rather than 48V or 52V is actually a good thing. It means your bike will consume less power at cruise speed than if you used higher voltage. I don't know what controller you have, but KT displays let you lower the LVC voltage by up to 2V-- so a 48V controller could be set to LVC at 38V, or 3.17V/cell. Nothing good comes of going lower than that. Even 40V cutoff is 3.33V/cell, which is pretty low.

I use 12S on one of my bikes, and I just received one of those Samsung modules. Haven't cut into it to install the balancer yet. It's a nice compact shape, but quite heavy for its size.

 

[metaneuralnetwork]

Range with 48v or 52v batteries. Not high peak discharge, not number of cycles. Not based on kw/kg.
Range.


I have more than one setup. Much of my arrangement is modular. I want range with 48v or 52v. I never intended to make this a thread about how a turtle can go a thousand miles, and then optimize around that. That's what it got derailed into. I don't know why the topic can't be about 48v and 52v batteries. I didn't come here to talk about changing up my whole setup for something else.

1. New 35Ah LiFePO4 pouch cells. 70$/4cells, 280$ for nominal 51.2V (16s), totaling a little under 1800w
2. New 3.8Ah LiFePO4 cylindrical cells. 228/120cells and a nominal 48V (15s), totaling a little over 1450w
4. Like-new used 8Ah Lion pouch with holders, bars and screws. 8.5$/2cells. 221$ for nominal 48.1V (13s), totaling a little over 1500w
3. Like-new used 39-41Ah Lion cylindrical cells. 125$/6cells. 250$ for nominal 48V (12s), totaling a little under 1900w

I'm not affiliated with BatteryHookup an any way, just a huge fan.

Thanks for that I'm going with option #2. Also going to get about 50lbs of their parts that should be fun to pick through and have some extra for other things... maybe a longboard next.

 

[neowizard]

Just keep in mind that if you're pairing this new battery with your existing one, a different chemistry (or any different properties, really) require more planning.

For instance, LiFePO4 have a VERY stable voltage across most of the charge curve compared with Cobalt Lion. So if you try to power a single motor with two packs the draw characteristics on each pack will not be consistent.

Even if you have to LiFePO4 packs you need to consider their specific characteristics. You want the higher capacity battery to also have higher discharge capacity since at some point the lower-capacity battery will run out and only the second battery will keep on pushing. You might know all this already, but I don't know you, so not assuming anything

Basically, what I'm saying, if you're setting up with two packs, let's discuss the specifics of those packs, BMSs and motor(s).

 

[999zip999]

Tell us more about the battery that you already have so we can match a new battery do your existing battery to keep the voltage issues to a minimum and lvc to match. I have those spaim08 cells at 20s 72v great cell big and heavy should last long time. I Just bulk charge and check with cycle analysis or the C.A. I have balance wires and a cheap cell meter for checking voltage. You can feel when your battery is getting low as it has less and less power just don't go below 3.0 volt.