Help me choose the best battery!

Hey guys. It's time. It's time for me to stop cheaping out on batteries. I have an ebike (scooter) that shipped with lead batteries. A couple years later I bought the cheapest lipo battery I could on ebay, 3 months later the bms died and I went back to lead.

Right now I have a 56v pack that weighs about 75lbs. I have the money to get a good battery for once
And I don't want to make a mistake.

I have a $500-$700 budget and I was looking at this 52v battery from Luna Cycle. https://lunacycle.com/triangle-52v-panasonic-pf-18650-20ah-pack/

I have seen good deals on eBay but I was burned by ebay before. Does anyone have any thoughts, advice and/or recommendations?

If you're asking if Luna is reputable, I have bought 4 batteries, 3 motor kits, and lots of misc stuff. Once you give up on trying to reach anyone via phone, and just order what you want online or email them a question, I have had great service from them. Highly recommended!

Pinesal said:

I have a $500-$700 budget and I was looking at this 52v battery from Luna Cycle. https://lunacycle.com/triangle-52v-panasonic-pf-18650-20ah-pack/

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There is no one "Best Battery" short of a Star Trek power module which seem to be in short supply.
Be sure to check any special requirement that you may want or is needed by your configuration. Things like power switches, power meters, mounting options, replacement parts (i.e BMS), low voltage for lights or accesories .

Do you know what the maximum battery current is drawn by the scooter?

If you're happy building your own pack, it really is hard to go past both Hobby King LiPo and Genuine high energy density 18650s.

One of the best things about it is that you can customise the build so that you only use the sweet spot of the battery. Vendors rate their battery from full charge to full discharge. I tend to build my batteries one cell larger than the voltage I want, and under charge it. I also build so it never bursts more than half the rated C rate of the cells. The packs last a lot longer that way, at only a small extra cost.

I don't know the maximum draw of the bike. I would want a battery that possibly exceeds. The amp draw of the controller so I could just upgrade or shut mod the controller to get more power.

As far as making my own battery, it's something I've thought lot about and I am not as handy as I'd like and would probably mess something up.

It's important to know how much the motor draws to make sure the battery can handle it. You are right, the battery needs to be rated higher than what the scooter takes.

Do you know how many watts the motor is? And, how big are the stock lead acid batteries?

fechter said:

It's important to know how much the motor draws to make sure the battery can handle it. You are right, the battery needs to be rated higher than what the scooter takes.

Do you know how many watts the motor is? And, how big are the stock lead acid batteries?

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It's a 750 Watt motor and the stock batteries were 14ah but i have 24ah in there now.

Mortor size doesn't matter one bit. The controller is what draws power from the battery, not the motor. But with a 750W motor, it's likely your controller draws no more trhan 30-40A max. Assuming you're going to put at least 20ah in it, any battery capable of 2C would work. When you say you lipo pack bms failed, was that rc lipo, or some other lithium based battery pack? Just use your old lipo pack and bypass or replace the bms. Personally I won't touch an 18650 pack, but as long as you aren't drawing high current, they seem to work ok with enough ah in the pack.

wesnewell said:

Mortor size doesn't matter one bit. The controller is what draws power from the battery, not the motor. But with a 750W motor, it's likely your controller draws no more trhan 30-40A max. Assuming you're going to put at least 20ah in it, any battery capable of 2C would work. When you say you lipo pack bms failed, was that rc lipo, or some other lithium based battery pack? Just use your old lipo pack and bypass or replace the bms. Personally I won't touch an 18650 pack, but as long as you aren't drawing high current, they seem to work ok with enough ah in the pack.

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The old pack was made up of pouches. It was a Sun-thing battery and I left the bms connected for several months which seemed to have caused some of the cells to die. I really just want to start over with a new high quality pack.

Pinesal said:

It's a 750 Watt motor and the stock batteries were 14ah but i have 24ah in there now.

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If you are going to be replacing 24ah of 48 volt SLA batteries then you are going to lose a lot of weight. However you are going to need a somewhat large battery bank if you choose to replace its full capacity. Somewhere close to 100 high capacity 18650 cells.

Pinesal said:

As far as making my own battery, it's something I've thought lot about and I am not as handy as I'd like and would probably mess something up.

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One 18650 DIY option that might be less challenging might be Shawn McCarty's 'bateryBlocs':
[youtube]WvlLtsXK548[/youtube]
http://www.batteryblocs.com/
What his system does NOT inlude is any provisions for a BMS. He is a proponent of using a seperate Balance charger(s). The advantage is that there is very little soldering and NO welding required.

Lots of vendors throughout ES history including:
Ebikekit
Luna
Ebikes.ca
Dillenger
LAebike
Kinaye Motorsports
Ebikes.sf
EM3EV
etc




Sent from my iPhone using Tapatalk

eTrike said:

It seems we had this same conversation a year ago. :wink:

Whatever capacity your lead-batts are, you can halve that with lithium and match/exceed their performance.

Good advice above. I'll PM you a bit more info.

You can also do as Sunder says and rock some LiPo. Hobbyking West warehouse is in Tualatin and you can save the shipping costs and pick up the batteries, harnesses, and monitors in person

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That thread you linked to was for an electric car. I am looking to buy a bike battery now.

Now I am open to the idea of Hobby King Batteries but I think I determined awhile ago that their type of battery is unsafe for unattended charging as I would be charging my bike in an unattached garage.

This whole thread is screwy. First, there is no combination of SLA batteries to produce a 56V pack. Using 12V and 6V batteries, you can have only multiples of 6V. You can't have a 56V pack. So unless you're using single cell lead batteries, some thing wrong. Now what do you really have, and what do you really want? And be specific.

wesnewell said:

This whole thread is screwy. First, there is no combination of SLA batteries to produce a 56V pack. Using 12V and 6V batteries, you can have only multiples of 6V. You can't have a 56V pack. So unless you're using single cell lead batteries, some thing wrong. Now what do you really have, and what do you really want? And be specific.

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You are right. I am dumb. This whole time, I meant to say 54v. 4-12v and 1-6v.

What I want is the safest, longest lasting, most durable, most reliable, and most powerful battery ever made. Or something like that.

I was looking at hobby King and the prices aren't that good. Building a battery at around 52v and 20ah will cost over $600 and that's without a charger or BMS.

On the assumption you have a typical 48V controller with a typical LVC of 42V and a max voltage of 60-63V, a 14s rc lipo pack is the most I'd go with. That's 51.8V nominal and 58.8V fully charged. Minimum of 10C. How fast and how far you want to go at that speed will determine how many AH you'll need. For such a controller, a 12s pack would be the safest. It would never over discharge the battery pack, at the expense of a little top end speed. It would also never overheat your motor under normal conditions, where a more powerful pack could. The last 2 20ah 12s packs I bought cost $180 each. $217 with shipping. Charger would be an extra one time expense from $30 up, depending on how and how fast you want to charge.

Pinesal said:

What I want is the safest, longest lasting, most durable, most reliable, and most powerful battery ever made. Or something like that.

I was looking at hobby King and the prices aren't that good. Building a battery at around 52v and 20ah will cost over $600 and that's without a charger or BMS.

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Taking your list literally, try Lithium Titanate. Density sucks, and be prepared to remortgage your home, but lithium titanate doesn't catch fire, tolerates over charge, under charge and physical damage better than other chemistries. It also has a 10-20,000 cycle life and 10+ year shelf life. And powerful? Try 150C+ and 10C charging.

Back to reality, I just built a 36S 16Ah battery for $500 US from Hobby King packs. How come you can't find the cells for a 14S 20Ah pack for less than $600? Are you picking out unusual battery sizes like 2x7S instead of mixing cheaper, more common cells like 4S + 4S + 6S?

You missed cheapest.

You are asking a lot. Reality requires compromises.

The best power density chemistry is used in 18650 or pouch packaging and generally includes lithium and cobalt. The lithium iron chemistries are lower voltage, lower energy density and greater weight. But still far better than lead.

I've built a lot of packs based on HobbyKing lipo bricks. Some are less expensive than others. Occasionally they have sales. Multistars are good for denser higher capacity packs. Turnigy for lower capacity packs with high power (current) loads. Zippy has not performed as well for me. Lots of connectors and cables are required to make a wiring harness for these bricks. No BMS is provided, so they require a balancing charger occasionally and frequent monitoring. Bulk charging can be used most of the time. Safety is very dependent on the builder/user.

I've also bought a few packs from LunaCycles that are made from 18650s with BMS. The 52V 24AH triangle battery is about what you are looking for. I haven't used mine a great deal, but it has worked well.

The LiFePO4's are good for flat voltage discharge and are slightly less likely to catch fire, and they claim very long life which often doesn't come true. They burn just fine if they get started from a short. Most vendors have moved away from LiFePO4 for ebikes as they are bulky, heavy and expensive. I've used Prismatic, Headway, A123 and Zippy LiFePO4. A123 are expensive and not easy to find (and often counterfeited). Zippy LiFePO4 have all puffed on me though they still work but I only use them for 12V loads. Headway (large cylindrical cells) are still available but are a bit pricey, bulky and the voltage sags (but are still better than lead). Thundersky and other similar prismatics are fairly bulky and expensive, I've used them for 12V packs. LiFePO4 voltages are much better matched to 12V than other chemistries so I use them for that.

Any pack from any vendor that sits around without being tended can develop problems. The BMS or controller can kill the pack over time. The best storage configuration is to charge/discharge to storage level and then disconnect ALL loads, including the BMS. A good BMS will have very small loads on the pack to reduce the problem. Fully disconnection is not provided for in the packs with built in BMS. So they must be periodically fully charged to balance them, and then partially discharged to storage levels. The packs without BMS are a bit easier to "park" since they can be unplugged from all loads, and they provide the connections to monitor the cells.

Sunder said:

Pinesal said:

What I want is the safest, longest lasting, most durable, most reliable, and most powerful battery ever made. Or something like that.

I was looking at hobby King and the prices aren't that good. Building a battery at around 52v and 20ah will cost over $600 and that's without a charger or BMS.

Click to expand...

Taking your list literally, try Lithium Titanate. Density sucks, and be prepared to remortgage your home, but lithium titanate doesn't catch fire, tolerates over charge, under charge and physical damage better than other chemistries. It also has a 10-20,000 cycle life and 10+ year shelf life. And powerful? Try 150C+ and 10C charging.

Back to reality, I just built a 36S 16Ah battery for $500 US from Hobby King packs. How come you can't find the cells for a 14S 20Ah pack for less than $600? Are you picking out unusual battery sizes like 2x7S instead of mixing cheaper, more common cells like 4S + 4S + 6S?

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The reason i can't find them us because I have no idea what I am looking for. You are great help, maybe a link to the cells you are referring to?

wesnewell said:

On the assumption you have a typical 48V controller with a typical LVC of 42V and a max voltage of 60-63V, a 14s rc lipo pack is the most I'd go with. That's 51.8V nominal and 58.8V fully charged. Minimum of 10C. How fast and how far you want to go at that speed will determine how many AH you'll need. For such a controller, a 12s pack would be the safest. It would never over discharge the battery pack, at the expense of a little top end speed. It would also never overheat your motor under normal conditions, where a more powerful pack could. The last 2 20ah 12s packs I bought cost $180 each. $217 with shipping. Charger would be an extra one time expense from $30 up, depending on how and how fast you want to charge.

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I would love to go 25 mph for a least 10 miles with little to no assist.

I guess what I really want out of this thread are hard recommendions with links and prices. Sorry if it's a lot to ask. You guys are awesome.

eTrike said:

Multistar 4S 10Ah packs were pretty cheap a week ago, so you should be able to get a suitable replacement for your lead-pack for near $200.
I only mentioned the earlier thread because it gives the same capacity comparison info I repeated. Do you still have the box of A123s? You sold Zaps, yes?

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I still have the A123 100of them. I think they were like 1.3v 1ah each so I would need a ton of them to make a pack.

I still own one of the Zaps.

eTrike said:

Good news on Zap. They're 3.3V, so you're sitting on ~300Wh of them there. My daily commuter has 400Wh of 8-10 year old A123 cells that I've abused relentlessly, very little balancing, fast charging, etc. They're still near 95% of original capacity after 6+ years of use. Maybe time to put them to use? Did you keep the pink or green?

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I have the green one. It's still drivable.

I am pretty sure my A123 cells aren't 3.3v. I'll take a picture of them when I get home.

Pinesal said:

The reason i can't find them us because I have no idea what I am looking for. You are great help, maybe a link to the cells you are referring to?

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On a phone so I can't link to US West warehouse and USD, but this one is $158AuD, so probably about $120USD?

https://hobbyking.com/en_us/multistar-high-capacity-6s-20000mah-multi-rotor-lipo-pack.html

2 of those will give you a 50v peak, 44v nominal battery, which is what most people will accept for a 48v application. No cutting, no soldering, just buy a $5 series adaptor.

3 of these will give you a 75v peak, 66v nominal pack, which might be too high for your application.

However, I have taken these apart before and the cells are not glued together, and they use standard 60/40 solder so they are very easy to remove and add cells. So you could order 3, cut the last one and go 14S and have 4 spare cells if you do want to be pedantic.

If yoi were brave, you could rebuild it as 2x7S and balance it on a standard LiPo charger instead of getting a BMS. Depends on whether you already have one or not. If not a cheap BMS is more cost effective.

Sunder said:

Pinesal said:

The reason i can't find them us because I have no idea what I am looking for. You are great help, maybe a link to the cells you are referring to?

Click to expand...

On a phone so I can't link to US West warehouse and USD, but this one is $158AuD, so probably about $120USD?

https://hobbyking.com/en_us/multistar-high-capacity-6s-20000mah-multi-rotor-lipo-pack.html

2 of those will give you a 50v peak, 44v nominal battery, which is what most people will accept for a 48v application. No cutting, no soldering, just buy a $5 series adaptor.

3 of these will give you a 75v peak, 66v nominal pack, which might be too high for your application.

However, I have taken these apart before and the cells are not glued together, and they use standard 60/40 solder so they are very easy to remove and add cells. So you could order 3, cut the last one and go 14S and have 4 spare cells if you do want to be pedantic.

If yoi were brave, you could rebuild it as 2x7S and balance it on a standard LiPo charger instead of getting a BMS. Depends on whether you already have one or not. If not a cheap BMS is more cost effective.

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Well. That's cool and cheap. But we are missing something. How would I charge this? Is it safe to leave charging unattended over night?

I am open do this project. I definitely it want at least 52v. Nominal

Does your existing SLAs have a charger? Or did your old blown LiPo have a charger? If so, we can reuse that.

If the voltage isn't perfect though, we will need a BMS to cut charging when it's full.

The lead batteries sag so much that a lithium pack with lower nominal voltage may outperform it.

52V nom is 14 of the 3.7V cells which is not a good number for lipo bricks nor for chargers. 6S is a more common, cost effective value for chargers and bricks.

44V nominal is a more practical value for lipo. You could use 6, 6, and 2S bricks to get 14 if it is really necessary but it will cost a bit more and require more wiring.

For 18650 packs with a BMS and bulk charger, the 14S is not as difficult. Some vendors call these 50V packs while others call them 52V packs, it depends on the manufacturer's cell ratings being 3.6V or 3.7V nominal.