When an engine reaches maximum revolution under load, there are a few things to consider depending on how quick you lose power. These are the following... a clogged air filter, an inefficient fuel pump, a clogged fuel filter or oil at low level. As for the battery light to come on, there is something fish on that. Maybe when the accelerator is depressed to the floor it could make contact with an electrical wire and upon rubbing against it, the plastic protective cover of the wire may have worn out and scraping against the accelerator cable or metal components of the accelerator, resulting in a light coming on or resulting on shorting the wire running to the distributor, hence the loss of power. Try backing off a little, see if you can feel the power of the engine picking up. I had a similar problem in my Valiant years ago and remember this from that experience. Whenever the windscreen wipers were on - the engine was losing power on each sweep. Upon inspection, I found that one of the wiper arm under the dashboard had been rubbing with a wire leading to the ignition resistor and causing a short. Although I don't think your problem is related but I do think that something is causing a similar problem. If you can't find the fault and fix it, have it checked it with an electrician.
Now, a clogged air filter could be the culprit. It depends on how quick you lose engine power. If you accelerate to full throttle under load and it slowly stops gaining power at a point in revolution, then it's probably a clogged air filter. Air filters filter the air of impurities, and in dusty roads, or in group driving close behind each others, if you're behind another vehicle your air filter is actually getting more dust than the vehicle in front. So, backing up a fair distance is the only option if you want to run the engine at high revolution without loss of power. To test, try taking the air filter out of the housing and put the engine on high revs on load (on load means do not rev the engine only but run your vehicle on a highway with or without a trailer or caravan, etc.), accelerate hard to see if the engine still loses power at the speed you first noticed before removing the air filter. If there is no loss in power after exceeding that speed, then you don't need to accelerate more and risk a speeding ticket, because you now know that it was a clogged air filter the culprit of your dilemma.
If however, the problem is not resolved, you need to look at the next possible scenario, a clogged fuel filter. If it is full , it is okay but if it has bubbles then it is not. That indicates the fuel pump has a broken or leaky diaphragm and should either changed over or, in a more delicate job, fixed. Although it's hard to see if the fuel filter is clogged but it can be connected to a gauge by using a bypass (you need to be a mechanic to do this or have this gauge. Or I will tell you how it's done my way, since it is an F250, I used to own an F100. Acquire (buy) a gauge that is able to measure fuel pressure, connect a length of fuel line (rubber hose) about 2 meter long to the gauge with a bleeder valve as close to the gauge to expel all the air trapped in the hose. Connect the other end of the hose anywhere near the fuel filter (if you connect it with a T-connector, before the filter, you are measuring the pressure from the fuel pump. If you are connecting after the filter you are measuring the pressure from the filter, as the pump may be straining to pump as much fuel as it can but is restricted by a clogged filter), or wherever you see the fuel line leading to the carbie. If you are able to disconnect the line between the fuel filter and the carburettor and then connect a 1/4 inch T fitting, available at a plumbing supplier or speed shop, brass is preferred, then attach the hose line of the test gauge the filter in the third part of the T fitting, as shown in a diagram that I have made for you to facilitate easy understanding on how it is done. If you are able to do this, you must first make sure that each connection has a screw type clamp also purchased at a speed shop for fuel hoses, etc.
You must be aware that, unless you're an mechanic or have the right experience of doing this, you shouldn't attempt to go ahead. But if you insist, then note carefully when doing these two tests. Always have the gauge facing the side door window in case the hose slips and disconnects from the gauge and sprays fuel in your face. First thing first, make sure the hoses are connected and clamped properly with no chance of slipping off the T fitting or the gauge. If it does happen during the test, immediately put the gears in neutral and kill the engine. If you leave it into gear while the car is running at high speed, it will still keep the engine into revs and that means the pump is also operative until the engine or the car stops. Just remember to disengage the gear first and immediately kill the engine. For that reason I suggested you hold the gauge by the hose and have it near the open window, not closed. if in case it bursts at the connection, you only have to aim the hose outside the window. Then disengage the gears and stop the engine. Note that without engine power you have limited braking until the brake booster runs out of pressure, So brake one and wait till the car stops. if you don't, your brake pedal becomes harder and difficult to stop in an emergency. That's why you have to conduct this test in an open road with minimal traffic and bushes, with plenty of room along it to stop without panicking.
Now if the pressure drops at high revolution, it could be that the filter is the wrong one, especially if you have a V8. V8's suck a lot of fuel and a different or smaller fuel filter cannot pass out an exact amount of fuel per minute. Maybe for a Toyota Corolla, yes. But not for a V8, so, this is why you have to do this test first. If you're unsure, change the filter first before you do any tests because the first test can also check if the fuel pump delivers the right amount of fuel per minute, plus more. Check if the new fuel filter is genuine Ford product for the F250. Once done, then do the test and see if the pump can deliver the right pressure and maintain it within its range at all speeds. If the gauge starts to lose pressure or is not gaining more at high speed under load (not just revving the engine), then the pump is faulty, probably a leak or cracked diaphragm. It's common that after 10 years some diaphragm fail to perform. next. If you wish to do the pump removal and repair, there are quite a few video clips on this, but to do the repair of the diaphragm, that is a bit of a delicate job and if you don't have the time and patience, I'd suggest you purchase a new or rebuilt one.
Good luck. I hope you'll succeed in this test. I once used to do a lot of car repairs and I admit, I sometimes couldn't do some repairs to the component, so I ended up buying a rebuilt or new one, and that made me happy to have done the impossible. Those were my days. Cheers
