Obtaining 24V battery from 12V

I need 24V 12AHr battery within weight limit of 6Kg. I tried to go for connecting two 12V lead acid batteries in series(of the 12AHr) but the weight limit is getting exceeded. I have Lithium Ion batteries of 12V 6AHr. So I am thinking of connecting two of them in parallel and this in series with another parallel combination. Is there any wrong in this? Also,Li-Ion batteries have much less weight.

traditional lithium ion is finicky about being charged, discharged and even looked at the wrong way. consider these as alternatives, both well under your weight limit, but you pay for that lightness.

250wH LiFePO4 pack:
https://www.batteryspace.com/lifepo426650battery256v102ah26112wh40aratewithpcm.aspx

240wH NiMH pack:
https://www.batteryspace.com/nimhbatterypack24v10ahforelectricbikeandscooter3r767.aspx

justDIY said:

traditional lithium ion is finicky about being charged, discharged and even looked at the wrong way. consider these as alternatives, both well under your weight limit, but you pay for that lightness.

250wH LiFePO4 pack:
https://www.batteryspace.com/lifepo426650battery256v102ah26112wh40aratewithpcm.aspx

240wH NiMH pack:
https://www.batteryspace.com/nimhbatterypack24v10ahforelectricbikeandscooter3r767.aspx

Click to expand...

But considering cost, they are not affordable to me. Is there any other option?

LiFe and LiIon are about equal on costs, NiMH is a lot less expensive, so I'm not sure what your statement of affordability means. If you can purchase 280 watt-hours of lithium-ion, you certainly can afford the same in NiMH, or close in LiFe.

Chose any two:
1. Inexpensive
2. Light weight
3. High capacity

justDIY said:

LiFe and LiIon are about equal on costs, NiMH is a lot less expensive, so I'm not sure what your statement of affordability means. If you can purchase 280 watt-hours of lithium-ion, you certainly can afford the same in NiMH, or close in LiFe.

Chose any two:
1. Inexpensive
2. Light weight
3. High capacity

Click to expand...

See the motors for which I need battery consumes 9 T0 10A of current continuously at 24V. My battery should last for half an hour. So what AHr rating should I prefer? At the same time, the battery should be inexpensive and light weight.

well, that rules out lead acid... unless you get very expensive high-rate SLA batteries, most lead acid are rated for 10-20 hour discharge curves.

inexpensive and high capacity: NiCad or NiMH
lightweight and high capacity: LiFe or LiIon

make sure you are shopping for batteries rated at high rate discharge ... 10a run current probably means a lot more starting current.