At the risk of overcomplicating this....is there electrical power available reasonably near to where you will be mixing?
If there is, you can buy or hire the cheaper electrical Belle mixers. If not, you have to get the petrol ones (usually Honda but there are other options) which are more expensive. The 130 litre DIY mixer is electric only
You can run the electric mixers off an extension lead. I've even seen multiple extension leads chained together but that isn't such a good idea