Long story but looking for battery.

[hubcaps219]

EVT Bravo 4000e scooter, lithium conversion. Long story but i think i blew out a battery so if that's the case then i only have 3 of 4. Does anyone know where i can get a 48v 18 amp hour battery? these ones are 54v at full charge but labeled as 48v. I am seeing all sorts of 18ah batteries online but anything under a couple hundred bucks is sketchy stuff from alibaba or dhgate that has me suspicious. The ones i have are in a black case with a 12x7 configuration of 18650 batteries. I'm debating if it's more effective and safer than replacing the bms myself (which i am not comfortable with, i don't have experience with that yet).

 

[neptronix]

How old are these lithium batteries? You might have some problems as a result of 1/4th of your pack being new and the other part being significantly old.

The best configuration is a big single battery.. if your 3/4ths of the pack is really old... that's the direction i'd go in.

 

[E-HP]

EVT Bravo 4000e scooter, lithium conversion. i only have 3 of 4. these ones are 54v at full charge but labeled as 48v. The ones i have are in a black case with a 12x7 configuration of 18650 batteries.

What type of lithium conversion? If the original batteries were a group of 4 12v lead acid in series, frequently people would convert to 4 12v LIFePO4 lithium iron phosphate batteries in series; a straight swap. What you are describing would be 4 packs in parallel.
Lithium ion 48v packs will be 13 cells in series, with as many parallel groups to make the desired capacity. Those packs would be 48v nominal, and 4.2x13=54.6v fully charged. 12 cells would be 50.4v
The math doesn’t jive. Do yo have a pic you can share of one of the batteries, and any markings or labels?
You can’t replace the battery until you know what you need to replace it with. LIFePO4 is forgiving, safety-wise, while lithium ion could be dangerous placed in series or parallel, with your other batteries during charging, or even during use.
If they actually are lithium ion, I’d replace them all.

 

[hubcaps219]

Oops - you're right, it's 4 lithiums in parallel and yes they're 13 lines. Any ideas on a good lithium battery or alternatively what are the specs for the size of battery I'd need if i was to get an entire battery?

 

[hubcaps219]

Here's the pics i have on my phone right now I'm not home

 

[hubcaps219]

How old are these lithium batteries? You might have some problems as a result of 1/4th of your pack being new and the other part being significantly old.

The best configuration is a big single battery.. if your 3/4ths of the pack is really old... that's the direction i'd go in.

it's not old it's 2022 i believe but what size do i need? it's gonna be expensive

 

[E-HP]

I think I’ll defer to other battery experts on the forum. I’m comfortable running packs in parallel, but I’m super paranoid, never leave them unattended when charging, and have a strict charging routine, but wouldn’t advise others on doing it.
If you are currently charging the packs all at once, then they likely have their own single port BMSs to protect each pack individually when charging and discharging. You would need to verify the new pack has the same at minimum.
Anyway, others will likely chime in now that you’ve established what you are working with. Neptronix initial caution is something to keep in mind. Age is one thing, but how they were used is another, and figuring out why one pack failed may be a critical first step.

 

[neptronix]

These are all paralelled? that's kinda weird.

What is the maximum amp draw of your controller? this will determine what kind of battery would be ideal.

I agree with e-hp about.. what state are the other batteries in.. i wonder if they were underspecified for the job.. cycle testing them ( so that you know their capacity is right ) would be extremely helpful before making the choice on whether to replace part of the pack or the entire thing.

To determine what kind of battery you need next.. you need to know what the maximum amp draw of the controller is first so that you can buy a battery that can supply that, plus some overhead.

 

[hubcaps219]

These are all paralelled? that's kinda weird.

What is the maximum amp draw of your controller? this will determine what kind of battery would be ideal.

I agree with e-hp about.. what state are the other batteries in.. i wonder if they were underspecified for the job.. cycle testing them ( so that you know their capacity is right ) would be extremely helpful before making the choice on whether to replace part of the pack or the entire thing.

To determine what kind of battery you need next.. you need to know what the maximum amp draw of the controller is first so that you can buy a battery that can supply that, plus some overhead.

i think it pulls 130 amps? he's sold several others exactly like mine but they're working fine for those customers.

 

[Stealth_Chopper]

EVT Bravo 4000e scooter, lithium conversion. Long story but i think i blew out a battery so if that's the case then i only have 3 of 4. Does anyone know where i can get a 48v 18 amp hour battery? these ones are 54v at full charge but labeled as 48v. I am seeing all sorts of 18ah batteries online but anything under a couple hundred bucks is sketchy stuff from alibaba or dhgate that has me suspicious. The ones i have are in a black case with a 12x7 configuration of 18650 batteries. I'm debating if it's more effective and safer than replacing the bms myself (which i am not comfortable with, i don't have experience with that yet).

Hi - consider viewing, and calling, this Utah business with a good reputation that builds battery packs, perhaps bespoke. Good Luck

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