Sketchy Battery Pack?

[jetpackjbd]

ALEAIVY 24V 30000mAh Lithium Battery

I need a lithium battery capable of 30A continuous load at 24v that can fit in a 6.8”x8.5”x3.9” space. I haven’t been able to find anything that would fit at this load level outside of SLA batteries. Is this listing legit? I’m not sure how dense lithium batteries have gotten but this seems a bit small for the capacity listed. I don’t really need this much capacity, 12ah is the minimum I would need, but the current is a must. And will this burn my house down within a month if I buy it?

 

[MorbidlyObeseKoala]

I think your title and intuition cover it. Pretty unlikely a $78 battery on Ebay with 400 other copycat versions has high quality enough cells to push 30A for very long. But if you don't mind keeping an eye on it during charging and don't leave it plugged in overnight next to anything flammable, you might get the better range for a while. If you built or modified a battery yourself, you would need to do that too until it proved reliable and didn't overheat

 

[docw009]

The battery is a lie. With the best cells in the world, a 7s3p arrangement will be 10.5Ah. This battery is probably 6-7 AH if you're lucky. If you try to pull 30A out of it, you'll stress the cells and they will die or degrade quixcckly,

A good pack for your space would be a 42cell 7S-6p using LG MH1 cells. It would be 19.2Ah and easily support 30A. However, the cells are $5 each retail, so you're looking at over $200 for just the cells.

They do sell 24V 7S-6P packs on ebay, but not with Samsung or LG cells for around $200, and with more realistic AH claims, Being 6P, they should support 30A bursts too. If they claim 19.2AH, you might get 14AH out of them. Buyer beware though. It's the fire safety that I care about,

 

[calab]

Some will say & claim anything for a sale.

 

[jetpackjbd]

The battery is a lie. With the best cells in the world, a 7s3p arrangement will be 10.5Ah. This battery is probably 6-7 AH if you're lucky. If you try to pull 30A out of it, you'll stress the cells and they will die or degrade quixcckly,

A good pack for your space would be a 42cell 7S-6p using LG MH1 cells. It would be 19.2Ah and easily support 30A. However, the cells are $5 each retail, so you're looking at over $200 for just the cells.

They do sell 24V 7S-6P packs on ebay, but not with Samsung or LG cells for around $200, and with more realistic AH claims, Being 6P, they should support 30A bursts too. If they claim 19.2AH, you might get 14AH out of them. Buyer beware though. It's the fire safety that I care about,

I didn’t look at the pack configuration, thanks for mentioning that. Makes it a lot easier to verify their claimed Ah rating, assuming the configuration is accurate too. I found this, which appears to match what you were saying. Would fit well and claims to be rated at just what I need. Price is a bit expensive, but if it’s suitable for what I need I could justify it. Not super happy to be using li-ion, but LiFePo4 just isn’t energy dense enough to fit in the scooter.

You mention that a 7S6P pack could support 30A bursts, I might use near 30A continous on a 500W brushed motor. Do you still think it could handle it without an early death?

The brand Viset seems somewhat-legit? They sell a lot of batteries for electric bikes, scooters, and hoverboards on multiple platforms and seem to get decent reviews. Never heard of them and can’t find their website though. What do you recommend I should do for safety precautions? I can replace my scooter’s wooden deck with a metal one so nothing else is flammable on the scooter, out of ideas after that.

 

[MorbidlyObeseKoala]

Warning: long post

In general you will often see a peak of burst amperage at start up from stop and then it tapers down when you reach cruising speed because you won't need as many watts to keep your speed (under 25mph, it would be a little different the faster you try to go).

Depending on how hard you push the battery or how often you want to replace it, you could get away with a cheaper pack and unknown cells but it's pretty likely to have the same fate as your lead acids over the period of a few dozen or a few hundred charge cycles or (declining performance, lowering range then trash). Good quality cells will last 1000s of cycles if you treat them properly.

Most of the time this forum encourages new members to ask the vendor what cells they use in their packs, google the cells to fact check the specs and then use them per the manufacturer's guidance (keep them in comfortable temperature range, don't push them well past their current ratings, try to use them 20-80% charged at all times for maximum life). This obviously requires the time to do all that research and oversizing your battery a bit to get the desired range.

I think you could start cheap and see how long it lasts for your use case, then look up the specs and do the research for the replacement when the cheap one dies. Find whatever has the most parallel groups and still fits in your scooter, ideally it will be able to handle the next size up of motor (so like 750w). Your main indicators of battery health will be unusual behavior of the scooter when riding it (stuttering, unusually slow acceleration, sudden power loss, burning smells, etc.) and the heat being given off by the battery. Those behaviors could be the controller or motor too.

Safety recommendations: Find a vendor with real reviews either here or a place with a good return policy, make sure it has a BMS, estimate their advertised numbers are inflated 2 or 3x if they don't have a "continuous discharge amps" listed (and even then assume that is 80% of what you'd need), check the temperature of the battery after a realistic test and a hard test. If you can hold your hand on it for 5-10 seconds, it might be fine. If it is scorching hot or you are seeing discoloration on the sticker/shrink wrap, you are definitely BBQing that pack. Above all with cheap packs: MONITOR IT WHILE CHARGING OR CHARGE IT IN A PLACE YOU DON'T MIND IT CATCHING FIRE LIKE A FIREPLACE OR BBQ PIT. If it is getting very hot to the touch while charging, unplug it and give it a bit to cool down somewhere else.

 

[neptronix]

If you want to know how dense/powerful lithium batteries for ebikes actually are..

See listings on some popular lithium battery vendors:

Ebike Battery in Case | EM3ev <-- this vendor tends to underpromise and underdeliver on specifications a bit. Great battery construction quality.

Batteries - Ebike Parts - Shop <-- this vendor's specifications are typically +/- 1% of the truth, IE, very accurate. Great battery construction quality.

US Stock_American batteries_USA 18650 Ebike Battery-Lithium Battery factory|Manufacturer|supplier-UPPbattery <--this vendor's specifications tend to overpromise/under-deliver, and construction quality is 'good enough, maybe'

I wouldn't price out anything cheaper than what's listed; go too far below this quality threshold and you'll start seeing:
- poor construction quality, which increases the possibility of a fire or early battery death
- no-name cells, of medium to low construction quality; much higher possibility of a random fire than a name brand
- outright lies about specifications, possibly 'second life' cells being sold as new

In short i wouldn't recommend spinning this wheel:

 

[amberwolf]

Your pie chart leaves out the "enjoy your firebomb" option....

(actually the several possible versions of that, some of which youv'e covered in the post text)

 

[Chalo]

Sadly, it is a custom of shady dealers of hokey 18650 packs to claim the sum total Ah of all the cells in the pack. In this case that's 21 cells, so 30Ah = 1.43Ah per cell. Maybe they're nominally 1.5Ah cells, but they truncated it to make a round number.

Anyway, it's not an outright lie; it's just dumb and very deceptive. And 1500mAh is a quite common capacity for junk grade 18650s.

 

[jetpackjbd]

I guess I forgot to give a link to the battery I was considering now, VISET 24V 20000mAh Li-Ion 30A BMS

No reviews on the 20ah version, however the 10ah version has mostly good reviews. I assume the capacity is a bit of a lie, I expect closer to 15ah, but that’s still more than enough for me. Until I change my gearing, it will be drawing close to 30A continuous as full throttle is only about 16MPH. I’ll trying to find out what cells are being used

 

[jetpackjbd]

If you want to know how dense/powerful lithium batteries for ebikes actually are..

See listings on some popular lithium battery vendors:

Ebike Battery in Case | EM3ev <-- this vendor tends to underpromise and underdeliver on specifications a bit. Great battery construction quality.

Batteries - Ebike Parts - Shop <-- this vendor's specifications are typically +/- 1% of the truth, IE, very accurate. Great battery construction quality.

US Stock_American batteries_USA 18650 Ebike Battery-Lithium Battery factory|Manufacturer|supplier-UPPbattery <--this vendor's specifications tend to overpromise/under-deliver, and construction quality is 'good enough, maybe'

I wouldn't price out anything cheaper than what's listed; go too far below this quality threshold and you'll start seeing:
- poor construction quality, which increases the possibility of a fire or early battery death
- no-name cells, of medium to low construction quality; much higher possibility of a random fire than a name brand
- outright lies about specifications, possibly 'second life' cells being sold as new

In short i wouldn't recommend spinning this wheel:

View attachment 343859

The density of the various packs on the links you provided seems on par to some of the more reasonable Amazon listings, although I assume the cells are worse quality and a bit lower capacity than the proven batteries shown. Too bad those sites don’t sell 24V packs; I know it’s more efficient to use a higher voltage battery but the size and typical voltage limitations of SLAs meant 24V is the most common configuration on scooters <1HP.

 

[jetpackjbd]

I think I figured out what the actual aH capacity is of this. I believe they are telling the truth and that it’s a 20aH battery, HOWEVER I noticed the advertised voltage range is 29.4V-20.3V. I may be wrong, but that seems well beyond the safe discharge voltage. If the lowest voltage before degradation of a single lithium cell is 3.2V, and I have a 7S configuration, the cutoff voltage should be 22.4V at the lowest, not 20.3V. The charging voltage seems to be alright though, maybe even a bit low. So I’m guessing the safe capacity is around 15ah, maybe a bit higher. As long as it keep an eye on the voltage while riding, the battery might last quite a while.

 

[Chalo]

HOWEVER I noticed the advertised voltage range is 29.4V-20.3V. I may be wrong, but that seems well beyond the safe discharge voltage. If the lowest voltage before degradation of a single lithium cell is 3.2V, and I have a 7S configuration, the cutoff voltage should be 22.4V at the lowest, not 20.3V.

Well, when manufacturers are rating capacity of a cell, they go from 4.20V (which is also somewhat harmful to the cell) down to 3.0V, 2.85V, or 2.8V depending on the cell. That doesn't mean you have to do that. But it does mean the rated capacity would only be realized if you do it.

 

[eMark]

Being 6P, they should support 30A bursts too. If they claim 19.2AH, you might get 14AH out of them. Buyer beware though. It's the fire safety that I care about,

Can't be stressed enuf (difference between 30A power rating vs 19.2Ah capacity rating when it comes to cycle life. That said it's more about the cells' actual amp energy rating drain than the amp hour capacity rating ... when it comes to potential fire hazard vs prolonging cycle life.

Newbies and not so newbies aren't always certain about a cells' burst rating vs its MCD rating whether no name Chinese cells or LG, Samsung A-grade cells. For exaample how often is intermittent burst and for how long.

No name cells (7s6p) may support short 30A bursts (5-10 seconds for hill climbing) without significantly shortening the cycle life of a battery assuming fresh A-grade dells. However, the difference between intermittent 30A bursts, and a MCD 30A rating is like the difference between day and night. A MCD 30A rating (fake) of questionable quality no name Chinese cells can result in premature (short) cycle life and potential fire hazard ... not able to adequately perform the required task without overheating.

Even with LG or Samsung cells and a MCD 20A rating the cycle life is diminished when cells exceed 100 degrees F.
To be on the safe side figure a cell power rating at 10amps instead of 20amps. Then a 6p MCD rating is 60amps, which is more realistic with a 30A BMS for prolonging battery cycle life.

 

[jetpackjbd]

Can't be stressed enuf (difference between 30A power rating vs 19.2Ah capacity rating when it comes to cycle life. That said it's more about the cells' actual amp energy rating drain than the amp hour capacity rating ... when it comes to potential fire hazard vs prolonging cycle life.

Newbies and not so newbies aren't always certain about a cells' burst rating vs its MCD rating whether no name Chinese cells or LG, Samsung A-grade cells. For exaample how often is intermittent burst and for how long.

No name cells (7s6p) may support short 30A bursts (5-10 seconds for hill climbing) without significantly shortening the cycle life of a battery assuming fresh A-grade dells. However, the difference between intermittent 30A bursts, and a MCD 30A rating is like the difference between day and night. A MCD 30A rating (fake) of questionable quality no name Chinese cells can result in premature (short) cycle life and potential fire hazard ... not able to adequately perform the required task without overheating.

Even with LG or Samsung cells and a MCD 20A rating the cycle life is diminished when cells exceed 100 degrees F.
To be on the safe side figure a cell power rating at 10amps instead of 20amps. Then a 6p MCD rating is 60amps, which is more realistic with a 30A BMS for prolonging battery cycle life.

Good to know, I’ll try to look for something with more parallel batteries. A 7S6P battery is about the most common type that will fit in my scooter. Anything higher is either too big or requires a specialty order from what I’ve seen.

 

[neptronix]

The Parham-Silverman '1/4th rule' states that if you take the continuous C rating of any cell and cut it by 1/4th, then you have the appropriate C rating for long life, low voltage drop, high efficiency, and little to no thermal concerns.

That rule still holds up today after 12 years of battery advancement.

 

[eMark]

Doing a Google search of: Parham-Silverman '1/4th rule' results in the following ...

Parham-Silverman '1/4th rule' - Google Search

The Parham-Silverman '1/4th rule' states that if you take the continuous C rating of any cell and cut it by 1/4th, then you have the appropriate C rating for long life, low voltage drop, high efficiency, and little to no thermal concerns.

That rule still holds up today after 12 years of battery advancement.

If only all manufacturers of lithium Li-Po cells used the same precise industry criteria when it comes to listig the "continuous C rating" of their Li-Po cells. For example a Thunder Power ProLiteX 25C (2800mAh 2S 7.4V) Lipo battery would be good for more cycles using a more realistic 6.25C continuous rating. And a Thunder Power Elite (325mAh 1S 3.7V) 55C LiPo battery with a more realiztic rating of 13.75C.

Is it possible Li-Po manufacturers have advised google not allow any search of: .... Parham-Silverman '1/4th rule' as it would defeat Li-Po manufactureres of their 4 times C marketing strategy?

 

[eMark]

I guess I forgot to give a link to the battery I was considering now, VISET 24V 20000mAh Li-Ion 30A BMS

I expect closer to 15ah, but that’s still more than enough for me. Until I change my gearing, it will be drawing close to 30A continuous as full throttle is only about 16MPH. I’ll trying to find out what cells are being used

IF the cells in a 7s6p have a 10A MCD rating (6P=60A) then a quality 30A BMS will be a good fit. Your brushed motor may only pull 30amps on steeper inclines ... while 15 amps continuously on level/smooth terrain at full throttle. Ideally for battery health keep at 15 amps discharge rate most of the time for prolonging cycle life.

fs your objective to change gearing for more speed with the result pulling 25-30 amps continuously at full throttle on level terrain, but inclines at full throttle may require a 40A BMS. The result more likely than not will result in overheating of the cells and shortening its cycle life. The manufacturer of that 7s6p battery may be tempted to fudge the specs for the same reason as Li-Po manufacturers (TP being just one brand). For one thing there is no way of knowing if those 3333mAh 6p cells (20000mAh) are A-grade with a reliable continuous 10A (or 5A) rating without overheating at full throttle pulling 30amps contnuously. It all depends on the cells' IR.

Li-on like Li-po cycle life is prolonged with cells having a lower internal resistance and not abusing the cells ... thus minimizing overheating of the cells. Discharging that battery at 30A continuously at full throttle with a different gear ratio for more speed could likely shorten it's cycle life dramatically. Depending on cell quality, battery fabrication and realistic demands of your riding application. It's just as likely that the current gear ratio of your scooters brushed motor will pull 30amps to get up an incline at full throttle.

 

[999zip999]

Is this for a stand-up scooter with a handlebar in the battery is underneath the deck ?
Maybe I should just ask what is this battery for ?
Does it have a generous space for the battery ?

 

[eMark]

With its 24V 500W brushed motor might be similar to a Razor Ecosmart Scooter. Would be nice if the motor /controller is good for a 36V upgrade for taking on some inclines with more power/speed.

 

[jetpackjbd]

With its 24V 500W brushed motor might be similar to a Razor Ecosmart Scooter. Would be nice if the motor /controller is good for a 36V upgrade for taking on some inclines with more power/speed.

It’s actually got a Razor motor that I retrofit after struggling to find a direct replacement; an MY1020 meant for a razor dirt bike as well as some other products. I’ve considered overvolting, which I know some people do once they’re bored with whatever they have. I spent $65 on this motor, which isn’t that much, but it’s still enough to make me hesitant about shortening its life. If I went for a 36V battery, I don’t think my controller could handle it. It’s currently drawing a few more amps than intended with this motor that’s 50w more than the stock motor for this scooter, although it doesn’t get warm with this setup so maybe it could. It would probably be best to upgrade the controller to something designed for 36v. There’s another member of the forum who may need this exact controller for their broken scooter, and this controller isn’t available for sale anywhere else.

 

[jetpackjbd]

Is this for a stand-up scooter with a handlebar in the battery is underneath the deck ?
Maybe I should just ask what is this battery for ?
Does it have a generous space for the battery ?

It’s a stand-up scooter with a battery below the deck. A BladeZ XTR 450 SE, with space for two 12v 12 ah SLA batteries in roughly a 6.8”x8.5”x3.9” space. I would expect to fit much more lithium capacity in this space however it seems difficult to find something that takes advantage of these dimensions. I could put the battery elsewhere if I really had to but it would look bad and be easy to steal.

 

[amberwolf]

space for two 12v 12 ah SLA batteries in roughly a 6.8”x8.5”x3.9” space. I would expect to fit much more lithium capacity in this space however it seems difficult to find something that takes advantage of these dimensions

There are direct lithium replacements for various SLA standard sizes. If you look those up you may find one that can handle the current the system needs.

But, as I just wrote in another thread: Keep in mind that the cheaper a battery is for the same capability, the less likely it is that it will work very well or last very long. More expensive isn't necessarily better, but cheaper is usually worse.

 

[jetpackjbd]

There are direct lithium replacements for various SLA standard sizes. If you look those up you may find one that can handle the current the system needs.

But, as I just wrote in another thread: Keep in mind that the cheaper a battery is for the same capability, the less likely it is that it will work very well or last very long. More expensive isn't necessarily better, but cheaper is usually worse.

I’ve seen those batteries before, in fact I was considering them up until recently. I haven’t been able to find any that can handle enough current, and most of them are LiFePO4 and not lithium-ion. I would prefer LiFePO4 but the power density just isn’t great enough for my space.

 

[jetpackjbd]

I’m almost considering LiPO batteries, as I know I can find some that will fit and provide more than enough current. But they last only around 300 cycles, right? That’s about what an SLA should last for. I might sell the scooter at some point and I don’t want the next owner to find the batteries cooked after a few weeks. Literally cooked even, given the volatility of the batteries.