Battery advice wanted A123 pouch cells or 18650 cells

[Justin.Clements]

Hi,

I wasn't sure which forum to post this on but as my bike is a conversion this seemed the best place.

I've been running my bike for nearly 5 years and use it for an 8 mile commute over the south downs. I bought 2 kits and 2 batteries from cellman. The batteries were 16 cell A123 cells 20ah type. One of the batteries was used occassionally on my partners bike and lasted 3 years, this was then replaced with an 18650 cell type battery also from cellman, using 22P cells arranged as 14Series 9Parrallel. I started using this battery myself for the daily ride occassionally using my old battery which has since started to show signs of puffing it is now nearly 5 years old. The new battery after 18 months has now lost capacity and doesn't quite get me home so needs replacing.

Although I had lots of problems with the A123 pouch cell batteries with the connections to the BMS breaking off my experience of the battery made up with 18650 cells is that it just doesn't last nearly as long, is that what other people have experienced?

I still have the BMS from the old battery that puffed up and died so am thinking of buying some A123 pouch cells and rebuilding it. Does anyone have any advice where I could buy some from. There's a few on ebay none that I can find on aliexpress, they seem hard to find!

All advice welcome. Or offers of ready made batteries for that matter.

Thanks,

Justin

 

[Deleted member 4366]

LiFePO4 batteries last 4 times as long, but weigh at least twice as much. Take your pick!

 

[Justin.Clements]

LiFePO4 batteries last 4 times as long, but weigh at least twice as much. Take your pick!

A definitive answer, thank you

 

[DouglasXK]

and 3 times the volume!

 

[Justin.Clements]

and 3 times the volume!

I'd say my original LiFePO4 battery was a bit less than twice the volume of the 18650 type replacement tbh and prob less than twice the weight as well. It certainly lasted more than twice as long, cost about the same, gave slightly less speed as it was 52 volts instead of 54 volts but had at least a third more range comparing both when new.

As d8veh says you take your pick, but size and weight are less important to me than how long a battery will keep going for. I can't afford to be shelling out £500 on a new battery every 18 months.

 

[DouglasXK]

OK, did one of the 20ah A123 batteries only last 3 years and the pack made with Samsung 22p cells lasted only 18 months of 16 miles daily commute and cost £500? In your position I would be very disappointed. Something is wrong here, the dodgiest Chinese cells would almost be better.

 

[anotherkiwi]

Hi,

I wasn't sure which forum to post this on but as my bike is a conversion this seemed the best place.

I've been running my bike for nearly 5 years and use it for an 8 mile commute over the south downs. I bought 2 kits and 2 batteries from cellman. The batteries were 16 cell A123 cells 20ah type. One of the batteries was used occassionally on my partners bike and lasted 3 years, this was then replaced with an 18650 cell type battery also from cellman, using 22P cells arranged as 14Series 9Parrallel. I started using this battery myself for the daily ride occassionally using my old battery which has since started to show signs of puffing it is now nearly 5 years old. The new battery after 18 months has now lost capacity and doesn't quite get me home so needs replacing.

Although I had lots of problems with the A123 pouch cell batteries with the connections to the BMS breaking off my experience of the battery made up with 18650 cells is that it just doesn't last nearly as long, is that what other people have experienced?

I still have the BMS from the old battery that puffed up and died so am thinking of buying some A123 pouch cells and rebuilding it. Does anyone have any advice where I could buy some from. There's a few on ebay none that I can find on aliexpress, they seem hard to find!

All advice welcome. Or offers of ready made batteries for that matter.

Thanks,

Justin

OK so tell us about your motor and controller, let me guess a 1000 W motor and a 35 A controller?

9P Samsung 22F cells is 90 Amps, if you wore that out in 18 months you are drawing some serious current.

 

[Deleted member 4366]

20Ah 48v A123 LiFePO4 battery = 9.5kg
21Ah 48v Li-ion battery with Panasonic GA cells = 4kg

That's a massive difference. Nothing spoils an electric bicycle more than weight.

 

[Nealh]

As AK said which kit and controller ?

The Samsung 22P is reasonable 10amp cell with low mah and agree that you must have given it some serious stick as they should be 90a rated in a 9P config.

My crappy 4.4a 22F cells in 5P gave me 18 months good use unrestricted with 30- 45 mile range.

 

[Justin.Clements]

OK, did one of the 20ah A123 batteries only last 3 years and the pack made with Samsung 22p cells lasted only 18 months of 16 miles daily commute and cost £500? In your position I would be very disappointed. Something is wrong here, the dodgiest Chinese cells would almost be better.

Hi Douglas, thanks for your post, errrm....well I wasn't dissapointed as I'd been given to believe that you could only expect 2 years out of a battery, so I was actually thinking I'd done quite well. The 22p cell battery is still going but I'm only getting about 17/18 miles out of it. I've not used the original A123 type battery for a few months as it was showing signs of puffing, maybe it's still got life in it. I'll post a picture of the other one that puffed. .

 

[Justin.Clements]

OK so tell us about your motor and controller, let me guess a 1000 W motor and a 35 A controller?

9P Samsung 22F cells is 90 Amps, if you wore that out in 18 months you are drawing some serious current.

The motor and controller were bought from Em3ev, the controller is a 9 fet 3077 I'm not sure how that transcribes into amps, the motor is a MAC motor, Paul used to describes them as 500w/1000w I think the 1000w being peak power.

 

[Justin.Clements]

I do often carry a lot of weight on the bike, could that be the issue?

 

[anotherkiwi]

Those are 30 A peak controllers.

Lots of weight and agressive use of a throttle with a very powerful direct drive motor won't help battery life. I think 18 months isn't too bad considering.

 

[Justin.Clements]

Those are 30 A peak controllers.

Lots of weight and agressive use of a throttle with a very powerful direct drive motor won't help battery life. I think 18 months isn't too bad considering.

Using 30a on a 20ah battery would surely mean the battery was flat after 40 mins? When new the both batteries would last for hours and I'm still getting close to an hour from the newer battery. So I don't think I'm pulling that much current.
But going back to the original question I can still expect years more service out of a lifepo4 over the 18650 cell battery?

 

[anotherkiwi]

Using 30a on a 20ah battery would surely mean the battery was flat after 40 mins? When new the both batteries would last for hours and I'm still getting close to an hour from the newer battery. So I don't think I'm pulling that much current.
But going back to the original question I can still expect years more service out of a lifepo4 over the 18650 cell battery?

A 20 Ah 52v battery holds 1040 Wh (nominative). How long it lasts depends on how many Wh/km you are using.

You are getting 25 km if I read correctly above so that is 41.6 Wh/km. If you do a search (https://electricbike.com/forum/forum/main-forum/general-discussions/7891-what-is-your-efficiency-watt-hours-per-mile-with-your-ebike) you will find that this is a common range for a MAC, Mxus, Magic Pie motor or similar. Interesting to note that BBSHD bikes with similar power and 52v batteries can get up to twice that range. When ridden carefully

I can go over 140 km on 1040 Wh on my bike. At an average speed of about 27 km/h that is over 5 hours. I haven't tested real world range at higher speeds yet but it will be a lot less. Sorry to convert every thing into kilometers but miles went away when I was a wee lad in NZ...

 

[Justin.Clements]

A 20 Ah 52v battery holds 1040 Wh (nominative). How long it lasts depends on how many Wh/km you are using.

You are getting 25 km if I read correctly above so that is 41.6 Wh/km. If you do a search (https://electricbike.com/forum/forum/main-forum/general-discussions/7891-what-is-your-efficiency-watt-hours-per-mile-with-your-ebike) you will find that this is a common range for a MAC, Mxus, Magic Pie motor or similar. Interesting to note that BBSHD bikes with similar power and 52v batteries can get up to twice that range. When ridden carefully

I can go over 140 km on 1040 Wh on my bike. At an average speed of about 27 km/h that is over 5 hours. I haven't tested real world range at higher speeds yet but it will be a lot less. Sorry to convert every thing into kilometers but miles went away when I was a wee lad in NZ...

Hi, anotherkiwi, I can see the misunderstanding now. 17m(27km) is what I'm getting now. We never did a proper miles test on the new battery but I think the most we got out of it was 30m. The A123 batteries did 40 - 45m when new. It doesn't hold anything like 20ah now.
I've been looking at some A123 cells that have been in storage for 18 months. I've never built a battery before but if as you say 18 months is quite reasonable for 18650 cells I think I'd sooner go back to these even if they are bulkier and heavier.

Sent from my LG-D855 using Tapatalk

 

[anotherkiwi]

The americans have dropped the A123 cells with the arrival of more powerful 18650 cells. I myself have used up a battery that wasn't fit for purpose in 18 months, it still works out cheaper than buying bus tickets! Now I use a battery that is capable of the output I need - it can be as simple as wiring a couple of batteries in parallel.