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Discussion Starter · #1 ·
Before i ask this keep in mind that I’ve never built custom battery packs before and have a limited understanding of whats required for different types of batteries. So I have 3 spare black and decker 18v battery packs which consist of 15 Sanyo KR-1500 batteries each, making a total of 45 individual cells. To my understanding these are NiCd batteries, and they dont seem to have any sort of chips or bms in them.

I am trying to add it to my e bike which currently has a 36v 20ah lipo battery, however it needs more capacity. Is there any way i could make a custom battery out of these packs?

Can i just get a black and decker charger and wire them in where it doesnt go above 36v or should i try to make a custom battery out of the three packs and get a charger that could charge the battery.

Again I’m new to batteries and stuff but i think i could add the batteries for extra capacity. Any information would be greatly appreciated
 

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What's your poison? Mine is 40:1
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I dont have a lot if experience building them either. BUT, you cannot mix lithium and NiCd at all. Bad things happen. You would need more of whatever cells are in your pack. Its possible the BMS in the pack would need to be upgraded too.
 

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Discussion Starter · #3 ·
I had a feeling that you wouldn’t be able to mix the two batteries. I have a second controller and motor that i was planning on slapping on.

I was thinking of having dual batteries, motors, and controllers. That way there would be basically two separate systems with the same inputs for throttle and power. I feel like this is the best way to get around them not being able to mix.

All i need is another 36v battery with around or more than 20ah.

I currently have a battery from a rental scooter that is rated for 36v 350w and i have been using that as a make shift “back up battery” however the LVC kicks in after about 15 seconds of throttle and wont turn back until a minute or so

Sorry if it all sounds confusing, at the end of the day i just need more battery capacity so its either 1) add to my existing battery by bypassing the LVC on the rental scooter battery. Or 2) add the NiCd battery by combining the three in a separate motor and controller set up.

Hope that makes any since lol.
 

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Your BMS trips because your pack can't deliver enough amps and the BMS is preventing the pack from venting and catching on fire if you circumvent the feature you're more than likely will be talking to the fire department very soon.

You can not mix li ion or lipo with any other battery type or together period at all it will catch on fire 🚒 ( in fact it is so dangerous any threads talking about mixing lithium battery types together will be closed and deleted immediately)

You could build two separate systems like you are saying and run one system on lipo and one system on ni/m as they are separated and isolated with two motors two speed controls but I see this as terribly inefficient you'll lose almost 40%.

Honestly your best bet is going to be to build that ni/m pack and see if it can hold as a standalone unit if not you may need to purchase more of those ni/m cells.

Members have reported that those Chinese e-bike battery packs sold and available on eBay are okay. Make sure you get one with at least a 50 amp BMS.
 

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Discussion Starter · #5 ·
Okay I was thinking i could potentially get more run time with combining the three NiCd packs compared to the 36v 20ah lipo battery. The issues i would have is combining all the NiCd packs together and charging them.

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Here’s a picture of two of the bare packs and what I’m kind of working with.

Each pack has 15 KR-1500s, so a total of 45 cells, what sort of AH could i get out of combining the three packs together not exceeding 36v?

Thank you guys for the responses so far, if this seems like a waste of time or not an upgrade then i might just use the batteries for the headlight. I currently have the headlight wired up to a dewalt battery and is completely independent from the rest of the system just in case the thing dies at night ill still have a light for people to see me.
 

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I honestly don't think the nickel pack is worth it. At 18v, you need 2 in series to get the 36v, then wod need to run the 2 36v packs in parallel to only double the storage. I dont see enough to be bigger than the 20ah pack you are currently running.
 

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Discussion Starter · #7 ·
Okay i appreciate the insight I’m just going to use the batteries to run the headlight so I dont have to use my good dewalt batteries. Looks like my best option is to just get an identical battery to teh one I’m running now and run them in parallel.
 
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