I think my record for cooking from a 12V 100Ah battery involves using a halogen oven. I am not recommending this for Africa as they are too fragile, but maybe some variant might be suitable. 
With a halogen oven I was able to cook a roast beef dinner complete with roast potatoes, yorkshire puddings , carrots and peas for six adults. All off a 12V 100Ah Lithium battery, not going less than 10V. To be fair, my guests were then late and I did not have enough energy to keep the meal warm while we waited for them – so at that point I cheated and used the mains oven – just to keep it warm.
To be clear though, I recognise that living in the UK the beef was probably a good cut and required less cooking than a tough lower quality cut. And that carrots and peas require very little energy – I just boiled them. And used the water from that for the gravy – so having used batteries for over 2 years now I know how to maximise the energy – and I recognise that that takes time to gain that experience. Nevertheless, I think its pretty cool to be able to say – Roast beef dinner for 6! 🙂
Solar Electric Cooking 