Been riding at night on the Tandem once a week for a couple of months now, so time for an update.
First of all it is an offroad Tandem and this causes a few problems with regard to lights. On the road you want to be seen and if there are no street lights about, a good light is required. When we do go on the road we use the LCD lights, a Cateye EL500 and a n EL310. The 500 is more powerful so is used as the distance lamp and the 310 has a wider spread of beam so is used set up a bit lower. These two lights are completely adequate for road use, and we couple this with two rear lamps, just in case one may fail.
However off road, we need more powerful lights so have gone to a System that has a 2.5 watt, wide spread lamp and a 10watt distance lamp. We still use the LCD's at the same time to give us ground coverage, and this is a good setup for us. However -- Better lights are available if you have enough money, but the main problem is battery life. The LCD's work on ordinary batteries and have a life of 25-30 hours to a set. Good enough for a few weeks rides and the batteries are cheap. However the main more powerful lights have a rechargable battery that fits in the water bottle carrier, but only have a life of 2-3 hours. Not enough for a long ride, and spare batteries are expensive. Still long enough for our night rides, but not for a few allnighters that we intend to do.
The big problem we have found is that we have no perception of how tricky the track is. Shadows cast mean that we cannot tell if the rut is 2" deeep or 6" deep. We cannot tell how slippery the trail is, just by looking at it, that we can do in daylight. We cannot tell how deep the mud is untill we are going through it, and the bike has suddenly slowed. We have to take it slower downhill, and we are finding that uphills are trickier to find the route with grip. Even on the flat, we have started take the "Safe" line as we have had a few offs completely unexpectedly through finding slippy patches on the normal trail.
Night riding is a challenge- but it is another way that we can actually get out on the bike on those dark winter evenings. It is going to cost us money for better lights eventually, but they will be worth it. It is also going to cost us a fortune in clothing, as those winter nights are cold, and the extra winter Polar type tops and leggings are not going to be cheap. Big factor is are we enjoying it? You bet we are, but My wife has now decided that a New Washing machine is on the cards as you ought to see the state we come home in after a 3 hour ride on the Winter mud.