Safe Battery pack for 1200w motor?
11-13-19, 12:03 AM
#1
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Safe Battery pack for 1200w motor?
Hello folks,
I have a question regarding the battery pack for my 1200w electric scooter. It is currently running on 60v 20AH lead acid battery pack, and I have tested it on 72v where it performs quite well. Now I was about to buy a Li-Ion battery pack for it, and I searched different stores online. Most of them told me that 60v20AH can be operated safely with 1200w motor. However, a couple of store keepers told me that 20AH is not sufficient, and I need to buy at least 40-50AH lithium battery packs. Now I am confused that whether they are right, or they are just trying to earn more money from me. One of the store keeper had some confusing math about it, which says:
"It is better to discharge lithium battery at 0.5C, 1200w/60v=20A, which is the highest working voltage. If you buy a 20AH lithium battery, it is 1C discharge. Only atleast 40AH battery just discharges at 0.5c. The lead acid batteries doesn't need protection circuit, so thats fine to used any AH of those lead-acid packs."
I need opinion from you guys. Please share your thoughts..
Thanks a lot
I have a question regarding the battery pack for my 1200w electric scooter. It is currently running on 60v 20AH lead acid battery pack, and I have tested it on 72v where it performs quite well. Now I was about to buy a Li-Ion battery pack for it, and I searched different stores online. Most of them told me that 60v20AH can be operated safely with 1200w motor. However, a couple of store keepers told me that 20AH is not sufficient, and I need to buy at least 40-50AH lithium battery packs. Now I am confused that whether they are right, or they are just trying to earn more money from me. One of the store keeper had some confusing math about it, which says:
"It is better to discharge lithium battery at 0.5C, 1200w/60v=20A, which is the highest working voltage. If you buy a 20AH lithium battery, it is 1C discharge. Only atleast 40AH battery just discharges at 0.5c. The lead acid batteries doesn't need protection circuit, so thats fine to used any AH of those lead-acid packs."
I need opinion from you guys. Please share your thoughts..
Thanks a lot
11-13-19, 04:51 AM
#2
Cycleway town
60v 20AH should be able to put out a stable 40A without issue. A 1200w motor is not using more than 30A at 60v so I really don't see an issue.
I'm at 2,000w and whilst I have 30AH it's only at 48v, and that's proven sufficient for two years of daily use - I can run 15AH but the battery management cuts power if I use full power (over 1500w) and that's all that will happen if your battery isn't up to the job.
I'm at 2,000w and whilst I have 30AH it's only at 48v, and that's proven sufficient for two years of daily use - I can run 15AH but the battery management cuts power if I use full power (over 1500w) and that's all that will happen if your battery isn't up to the job.
11-13-19, 10:43 PM
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Originally Posted by MikeyMK
60v 20AH should be able to put out a stable 40A without issue. A 1200w motor is not using more than 30A at 60v so I really don't see an issue.
I'm at 2,000w and whilst I have 30AH it's only at 48v, and that's proven sufficient for two years of daily use - I can run 15AH but the battery management cuts power if I use full power (over 1500w) and that's all that will happen if your battery isn't up to the job.
I'm at 2,000w and whilst I have 30AH it's only at 48v, and that's proven sufficient for two years of daily use - I can run 15AH but the battery management cuts power if I use full power (over 1500w) and that's all that will happen if your battery isn't up to the job.
11-23-19, 04:47 PM
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I think his math should be: 1200 watt-hours/60v = 20 Amps-hours, full discharge in one hour (which is 1C). Leaving out the "hour" is confusing.
I'm not a battery expert by any means, but a discharge rate of "1C" is recommended by lithium ion battery manufacturers and driver circuits have built-in limiters for over 1C discharging. I hadn't previously heard of a requirement for a .5C discharge rate, unless you need it for more than an hour I guess. I could be wrong on this - does anyone know where store got that "requires .5C discharge" rule?
I'm not a battery expert by any means, but a discharge rate of "1C" is recommended by lithium ion battery manufacturers and driver circuits have built-in limiters for over 1C discharging. I hadn't previously heard of a requirement for a .5C discharge rate, unless you need it for more than an hour I guess. I could be wrong on this - does anyone know where store got that "requires .5C discharge" rule?
11-24-19, 05:40 PM
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Cycleway town
Tbh nobody's using 1200w for an hour solid. I'll scramble across town at a good rate and only average half that.
11-24-19, 09:01 PM
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Originally Posted by wphamilton
I think his math should be: 1200 watt-hours/60v = 20 Amps-hours, full discharge in one hour (which is 1C). Leaving out the "hour" is confusing.
I'm not a battery expert by any means, but a discharge rate of "1C" is recommended by lithium ion battery manufacturers and driver circuits have built-in limiters for over 1C discharging. I hadn't previously heard of a requirement for a .5C discharge rate, unless you need it for more than an hour I guess. I could be wrong on this - does anyone know where store got that "requires .5C discharge" rule?
I'm not a battery expert by any means, but a discharge rate of "1C" is recommended by lithium ion battery manufacturers and driver circuits have built-in limiters for over 1C discharging. I hadn't previously heard of a requirement for a .5C discharge rate, unless you need it for more than an hour I guess. I could be wrong on this - does anyone know where store got that "requires .5C discharge" rule?
