Here in North America, these are the batteries people seem to like a lot:
- Optima. Spiral wound gel-cel. Not cheap. Wal-Mart has them. Tolerates deep discharge better than conventional lead-acid batteries.
- Interstate. They seem to be everywhere. Some will say "short lived".
- Autozone battery made by Johnson Controls.
- Exide.
Group 49 seems to the most commonly seen size of battery
for most older Mercedes.
No matter who makes it, it will last longer the less you drain it. Always put the electricity back and try not to use too much. If you're a chronic battery drainer you should have two of them at all times. Keep the other one someplace warm, and always keep it charged.
You'll need big booster cables with a diesel too. The skinny ones jut won't work. Good booster cables are HEAVY and the best ones are home made from 00 gauge arc welding cables.