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

When I was looking for this battery, there was a similar one that came with a connector. It has very similar specs except it says BMS+ in the description and has slightly different dimensions. I wonder if they gave me this one instead. But the webpage says it’s out of stock.

Heat84

I contacted the manufacturer through Amazon and they got back to me in 71 minutes:

Dear customer
Hello, thank you for your letter
Our battery is indeed 24V 30Ah, and we assure you that its capacity and size are not related. Our product is a bestseller in the store, with excellent quality, and you deserve to have it.
Looking forward to your purchase
Best wishes

Not a very helpful response, but at least it isn’t AI.

Somewhat-Reticent

Heat84 What was your question to the maker?
( And what load(s) is it designed for? )

MacLeech

Heat84 There are a few other options besides battery chemistry that affect battery size and output ability. The old battery probably contains cylindrical cells, and the new one might be prismatic or pouch cells. There are also tabbed vs tabless batteries. These are ways the cordless power tool industry gets more power output with smaller batteries.

real_aurgathor

If you have a DMM. you can hook up 2 small 12V light bulbs (license plate light) in series, hook them up to the battery, take a current reading every 30 mins or so until the battery is nearly (about ¾) discharged, and you can approximate the capacity from the runtime and current readings.

As I’ve mentioned before, you do not want to fully discharge the battery, and except in cases of emergency, try to stay above 10%. (if there is a reliable battery gauge, that is)

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

The battery is defective and I have to return it. On a fully charged battery, the battery died after 4 miles of riding. I’m in Florida so no hills or mountains. Then a couple days later, with a fully charged battery, I rode the bike 2 miles with no problem and didn’t charge it over night. The next day, I went to use the bike and the battery was dead. But the battery should’ve been 80% full.

Also, I ordered a battery WITHOUT a connector but they sent me one WITH a connector. I cut the connector off so I can connect the wires with wire nuts. Could that void the return policy eventhough it was their fault?

I started a return process with the reseller. They want me to take a picture of the problem. How do you take a picture of a battery not holding a charge?😕😂: `

Thank you for bringing this matter to our attention. We sincerely apologize for the inconvenience and are committed to resolving this issue promptly. To ensure we provide the best solution, we kindly request your assistance with the following: What We Need from You Please share 3-5 clear photos showing: 1️⃣ Full product overview (showing packaging if available) 2️⃣ Specific issue area (damage/defect/function problem) Photo Guidelines: Use natural lighting & avoid blur Capture multiple angles Next Steps After Submission We'll review within 24 business hours Propose solutions: Replacement/Refund/Partial compensation Thank you for helping us serve you better. Best regards

Maybe they’ll let me bring it to a recycling center instead of shipping it back to them.

real_aurgathor

Heat84

Size and *weight* are often good indicators of the capacity among batteries using the same technology, and given that it was half size of the original, I don’t find this unexpected at all.

It won’t help you much, but I’m planning on creating a universal battery tester, partly for my own use.

Heat84 I started a return process with the reseller. They want me to take a picture of the problem. How do you take a picture of a battery not holding a charge?

Hook up a voltmeter to it and make a picture showing that it’s discharged.

As an aside, I purchased more than one laptop batteries from eBay, and never had any problem with them.

Dks01

Heat84 Could that void the return policy eventhough it was their fault?

Yes. They would have a solid argument to refuse the return as “Not in Original Condition”.

Heat84

real_aurgathor How did you determine that?

I already explained it earlier in the thread:

Heat84 On a fully charged battery, the battery died after 4 miles of riding. I’m in Florida so no hills or mountains. Then a couple days later, with a fully charged battery, I rode the bike 2 miles with no problem and didn’t charge it over night. The next day, I went to use the bike and the battery was dead. But the battery should’ve been 80% full.

Somewhat-Reticent

Amps or Amp-Hours ? i.e. Current or Capacity ?

Heat84

Somewhat-Reticent

Somewhat-Reticent Amps or Amp-Hours ? i.e. Current or Capacity ?

Capacity.

Heat84

Dks01

So I should’ve exchanged it for one without a connector(which would’ve taken 1.5 to 2 months since the company is in China or there abouts) instead? I would have done that if I knew there was a problem with the battery. Obviously I didn’t know that yet.

Heat84

I went looking for a different replacement in case I decide not to get a replacement from the reseller. To my shock, there’s tons on EBay(of the same make, model, and size) from different sellers that weren’t there when I was looking 2 months ago. And there’s actually 100Ah batteries🤯. Is there any way it’s not BS? But it won’t work for my bike because it’s 20 amps and my bike is 8 amps, right?

Here’s the description for the 30Ah. It should work with my bike right? What does the second # 3 and 4 mean? 60 and 45 what?: `Rated voltage: 24 V

Input voltage: 29.4v

Output voltage: 21 V ₂₉.4v

Battery capacity: 30Ah

Mesh size: 1305868mm

Battery weight: about 1 kg

With protection circuit: charge and discharge, over-current, short circuit protection function, and so on. D.

Packaging: blue PVC

Battery requirements:

1: you LI-ION battery chargers; DC DC;

2: charging voltage: 29.4 v

3: Charging current: 4 or less

Batteries discharge requirements:

1: Out of 18 lines, 150 mm long, red and black

2: results in line 2.1 socket, 150 mm long

3: Maximum instantaneous current: 60

4: The maximum operating current: 45`

There’s actually an AleAivy store in EBay.

Dks01

Heat84 Correct. They can deny your claim otherwise.

real_aurgathor

Don’t worry too much about the maximum instantaneous and operating current as long they are bigger, or in the same ballpark as your old battery. The specs you need to watch for:

operating voltage – should be within +/- 1V
termination (connector) – you preferably want a match
battery type – Lithium Iron Phosphate, Lithium Cobalt Oxide, Lithium Manganese Oxide, Lithium Nickel Manganese Cobalt Oxide, etc.
size – should be roughly the same (fit)
weight – should be roughly the same – can be heavier, but a significantly lighter pack should be a red flag
capacity – should be same or better, but it is often fudged and the indicated capacity is significantly greater than the real capacity

Heat84

real_aurgathor Don’t worry too much about the maximum instantaneous and operating current as long they are bigger, or in the same ballpark as your old battery.

I wasn’t worried about it. I don’t know what those numbers mean. Are they voltages?

And in my case the connector is wire nuts, which means I need no connector. I don’t understand why these batteries come with connectors if they’re not sold for any particular make, model, or type of battery powered device.

Heat84

real_aurgathor weight – should be roughly the same – can be heavier, but a significantly lighter pack should be a red flag

The one I started this thread to replace weighs 6 pounds. The one I need to return weighs 2 or 3 pounds. I really hope these newer batteries weigh alot less just because they’re using newer technology that has a better weight to capacity ratio. Those batteries I linked to on EBay weigh 2-2.5 pounds.

px_eliezer_

Dks01 Correct. They can deny your claim otherwise.

They’ll probably deny it in any event.

The detailed requirements are just to cause hassle, delay, frustration, and discouragement.

As was said in the movie “Shapespeare in Love”, this whole saga was going to end in “tears and a journey”.
https://www.imdb.com/title/tt0138097/quotes/

real_aurgathor

Heat84

Current is what needed to perform work since power = voltage * current. In some respects, it’s analogous to “torque”

Heat84

It doesn’t look like that battery I need to return is being sold anymore. I just get 404 not found. I love that Amazon has dogs on their 404 not found pages. Websites should be more creative with their 404 not found pages. Some are, most aren’t.

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?

Sparkchaser

Heat84 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).

It can read the battery voltage anywhere as long as it is just connected to the battery. The wire size doesn’t come in to play since the current to read the battery is very low.

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