Battery Too Good To Be True?

Heat84 · 2025-02-08T21:39:48+00:00

I wanted to put this in the electronics section here, but that doesn’t exist here. I have an electric bicycle and the current battery is 24V and 24Ah. I rode it for at least 5 more miles than I should’ve a week ago and discharged the battery too much and it won’t recharge anymore. I get enough of a charge to go about a quarter Mile😭. I found a new one. But it seems too good to be true. Its 30Ah and it costs about half of what I paid for the 24Ah battery that I have now and it’s physically smaller than the one I have now. Does it make sense that the newest electric bicycle batteries would have more Ah capacity but are physically smaller and cheaper than the previous ones? Another question I have is about the heat from extra Ah causing the metal part of wire nuts and wire couplers to brittle-ize. The stock battery was 8Ah. There’s nothing wrong with the wire itself. I’m not having this problem any more since I replaced 2 stock wire couplers on the controller wiring with crimp on connectors and replaced 4 wire nuts(2 by the controller and the 2 for connecting the battery). Why would more battery capacity create more heat? It’s not like it’s more volts. Doesn’t more voltage create more heat? As for the brand name, Duracell and Energizer or the car battery brands don’t make electric bicycle batteries, so you have to go with the weird unknown brands. But this is the weirdest brand name I’ve ever seen. It’s not even a name. It’s more like an acronym. It’s sold by Amazon(and only Amazon apparently). That has to be a good sign right?

Heat84

px_eliezer_

Wow!🤯

Somewhat-Reticent

Heat84 voltage … 24 … higher … ?

Only look for higher-voltage parts if shopping for a replacement bike.
Higher voltage allows using more energy into a smaller package.
Possible advantages - more power, moving more load, faster acceleration.
Possible downsides - more heat stress in failure point(s), empty battery faster.
( Design Engineers feel free to chime in )

Heat84

Somewhat-Reticent Only look for higher-voltage parts if shopping for a replacement bike.

I wasn't planning on upping the voltage, although maybe I could if I got a controller for a 36 or 48v bike. But of course if I did that, I would also have to get a 36 or 48v motor. So it would make no sense or cents to get a 36 or 48v battery.

real_aurgathor

Somewhat-Reticent Higher voltage allows using more energy into a smaller package.

In general, that is not necessarily true unless the size of the battery packs are also different. For example, let assume there are ten 3.6V nominal Li-ion cells. With those, one can build either a 36V battery pack or a 18V battery pack when using all cells. And while the 36V pack will have twice the voltage, the 18V pack should be able to supply twice the current -- and power = voltage * current in this case.

Now, if one makes battery packs with 8 batteries and 12 batteries using the same cells, then obviously the latter one can provide 50% more power, but it will also be about 50% heavier and bigger.

For kicks, I measured 3 power tool battery packs, shown with their official specs:
18V 1500 mAh NiCd: weight: 783g, no-load out: 19.9V (no usage since charging it a few days ago)
20V 1.5 Ah Li-ion: weight: 373g, no-load output: 20,0V (some usage after charging a few days ago)
20V 5 Ah Li-ion: weight: 676g, no load output: 20.5V (no usage since charging it a few days ago)

The above Li-on packs most likely contain 6 or some multiple of 6 LFP (Lithium Iron Phosphate) cells.
The NiCd pack probably contains 16 cells, and not only it's a bit heavier, but it is also a bit larger than the 5 Ah Li-on pack.

HooRU

Voltage is like force, the greater the voltage, the greater the force, but also the greater the hazards to some extent. It's important to match the voltage and equal the current rating. I don't know bikes at all, but it sounds like you have a serious challenge. I'd look into battery dealers, I'd avoid Amazon. But that's just an opinion.

Splitpair

HooRU It's important to match the voltage and equal the current rating.

Not true, voltage and current are seldom matched.

You have 120 volt appliances in your home, how many of the run on 120 amps?

Splitpair

Heat84 Does the garage count as indoors? That's where I charge mine.

Yes.

Heat84

Should I get the warranty for the battery I’m thinking of buying? Would it cover my stupidity(See above😭), or just a failure caused by a manufacturing defect?

real_aurgathor

Heat84

Heat84 Should I get the warranty for the battery I’m thinking of buying? Would it cover my stupidity(See above😭), or just a failure caused by a manufacturing defect?

Read the terms including all the fine print. Sometimes they cover “operator errors”, other times they don’t.

Heat84

I wanna get a battery level indicator. I found this one. Can I just put it in series with the battery, or is it more complicated than that? Maybe someone has a better one? But that one has everything I need.

real_aurgathor

Heat84

Heat84 I wanna get a battery level indicator. I found this one. Can I just put it in series with the battery, or is it more complicated than that? Maybe someone has a better one? But that one has everything I need.

I’m fairly certain that it would need to be installed in parallel with the battery.

Because of differing chemistries and slightly different voltage levels it may not be 100% accurate, but it should be better than nothing.

Heat84

Heat84 I wanna get a battery level indicator. I found this one. Can I just put it in series with the battery, or is it more complicated than that? Maybe someone has a better one? But that one has everything I need.

I can’t use this because it appears to read voltage telemetry from the controller and not voltage directly from the battery(judging by the tiny size of the wires). I don’t know what do with it. I waited to long to try to return it. There’s a few of the exact one I have on E-Bay, not to mention other ones. And If I sold it by some miracle, I’m not gonna make any money if I have to pay for shipping, I don’t think, since the item only cost me $7.60. Although there are 3 different sellers on EBay selling the exact indicator that I have for $16 and something cents. But I’ll bet those sellers have had them in their store for years. Do any of you guys want it?

Heat84

real_aurgathor Read the terms including all the fine print. Sometimes they cover “operator errors”, other times they don’t.

I think it just says Malfunctions covered after the manufacturer’s warranty. That means no operator error.

Heat84

real_aurgathor Heat84

Heat84 I wanna get

After looking at the battery level indicator, I noticed that the 2 wires for it are about a MM in diameter. Wire that small wouldn’t cope with the current, would it? That indicator was likely designed to read voltage telemetry from a controller and not voltage directly. Is there anyway to tell if a battery voltage indicator reads voltage telemetry or voltage directly besides looking at how thick the wires are before you buy it? I thought it read voltage directly since it only jas 2 wires. I guess I’ll just have to figure out the battery level with math using Amps & Amp Hours and how long I’ve been riding the bike. Somebody asked what the load was. My bike’s manufacturer doesn’t sell it anymore, or the stock batteries. I had use the Wayback Machine to get the specs for my bike from their website from 8 years ago:

Watts: 300 Watts
Amps: 8 Amp Circuit (7 Batteries at 10 Amps Each)
Volts: 24 Volts (Each Battery is 3.6 Volts)
Batteries: 7 Lightweight Lithium LiFePo4 Batteries in a Sealed Removable Pack
Speed: 20 MPH*
*depends on rider weight & terrain

Hopefully I’ll be able to return it. The 30 day return period expired a few days ago, but if you buy something directly from Amazon and ask nicely, apparently they’ll let you return something after 30 days.
real_aurgathor

Heat84

I went ahead and bought the new battery. The one on the left is the new one. How could it be less than half the size of the old one and have a 6Ah higher capacity? Is there any chance I didn’t get tricked? Is it possible the new battery is made with new technology that’s capable of having the same or better specs in a much smaller battery pack? And for half the price.

Guy54435

Heat84 Heat84 I would not touch the new one you found, why
About this item
1.Life expectancy is two times that of lead-acid batteries. The weight is more lighter.
2.No memory effect and rechargeable. the battery life is more longer.
3.Safer and more environmentally friendly, No heavy metals and hazardous substances.
4.Built-in IC chip will prevent battery pack over charge, over discharge, over-current, over-heat, short circuit.
5.Avoiding mechanical accidents caused by vibration.

They already lied in the description with #3. No identifiable information can be seen on battery or charger, It just seems like danger to me. Go with what came with the bike.

Do lithium batteries contain hazardous materials?
Lithium batteries are hazardous materials and are subject to DOT’s Hazardous Materials Regulations (HMR; 49 CFR Parts 171–180).Mar 20, 2024
It is possible it is legit, Other than it actually being a battery, I really have high doubts it is what they say it is.

real_aurgathor

Heat84 The one on the left is the new one. How could it be less than half the size of the old one and have a 6Ah higher capacity? Is there any chance I didn’t get tricked? Is it possible the new battery is made with new technology that’s capable of having the same or better specs in a much smaller battery pack? And for half the price.

Possible, but not very likely, to say the least. There are quite a few Li-ion chemistries (though only 2 - 3 are common) and some can have more capacity in less space, though a more likely explanation is that the new battery’s spec have been *enlarged*. Accurately measuring the capacity of a battery pack requires either an instrument, or some knowledge of electronics, so it’s not something customers can easily verify.

Heat84

This thread belongs in the Electronics section(Which didn’t exist until after the previous post). But this section is busier which is better for me.

Heat84

Guy54435 Go with what came with the bike.

But the stock batteries are only 8Ah and I don’t know how much longer I’ll be able to get them since the company that makes my bicycle stopped selling it years ago.

Heat84

Guy54435 About this item
1.Life expectancy is two times that of lead-acid batteries. The weight is more lighter.

The old battery is Lithium ION.

Guy54435 They already lied in the description with #3

What is #3?

Guy54435

Heat84 They Lie about #3 3.Safer and more environmentally friendly, No heavy metals and hazardous substances. That aside the gauge of the wire on the new battery looks tiny compared to the old battery.

Heat84

Guy54435 That aside the gauge of the wire on the new battery looks tiny compared to the old battery.

The wires on the old battery are at least twice as thick as the ones on the new battery. The wires on the new battery have a connector. I would’ve preferred them not to. Although I guess can get the matching male connector and put it on the other wires instead of cutting the female connector off.

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