So two tons of batteries to get 1000 added kilowatts … but we need more battery than that, so we’re only using 30% capacity at each stop-start?
40C means the battery can fully discharge in 90 seconds … so if we want 90 seconds of 1000 kW we want 7 tons of battery, so we’re only using 30% of capacity? (I might be making a dumb mistake here.)
The diesel engines in locomotives are decoupled from the vibrations and shocks of the locomotive frame using elastic mounts.
The same can be achieved with the materials available today for battery racks.
RailPower’s Green Goat hybrid locomotive uses a patented suspension system: US Patent 7,661,370 B2 “Design of a large low maintenance battery pack for a hybrid locomotive.”
This patent details a vibration suppression system for the battery rack in yard switcher hybrid locomotives. It protects battery cells from shocks and vibrations up to 0.3 inches peak-to-peak across 1–10,000 Hz, using shock absorbers and isolators for longitudinal, lateral, and vertical movement.
That is one of probably many possibilities.
Regards, Volker
One recharge per day – isn’t this discussion about a 30% discharge at each start, followed by a 30% recharge a few minutes later?
None of the existing battery trains uses “30%” of its battery capacity in a single acceleration.
Look at the current ‘world record’ range for a pure battery train. That involved several stops at the segment endpoints, although there weren’t regular service stops.
I don’t happen to know the exact percentage of regenerative recovery in a given stop and reacceleration. But I’m sure there are people here who will know.
This discussion is about a locomotive like a Prius, isn’t it? Mainly diesel, but with enough battery to store a worthwhile amount of energy as it slows for each stop?
Question is, with X tons of battery, how many kilowatts of boost for how many seconds at each start, and what percentage of that energy can be restored to the battery at each stop.
A mea culpa, it appears that Natron Energy has ceased operations, not sure if anyone will pursue the technology.
Rechecking the website suggests peak specific power on the order of 2MW/ton.
With respect to cycle life of batteries, the lifetime can be very sensitive to the nature of charge discharge cycles, e.g. Li-ion batteries will have a very short life if exposed to greater than 40ºC when 100% charged.
Two examples:
Stadler Flirt class 756: It is a thri-mode multi unit train with diesel engines, batteries and catenary capability. The train can run about 50 miles on batteries alone at 75 mph.https://en.wikipedia.org/wiki/British_Rail_Class_756
Siemens Charger B+AC locomotive: it runs on batteries or under catenary. Instead of catenary there could be a small diesel. The 3.1 MWh batteries allow an operating range of about 100 miles. https://www.railwayage.com/mechanical/locomotives/siemens-charger-bac-new-metro-north-power/
Batteries aren’t used for acceleration boost alone.
Regards, Volker
In other words, no battery-only running, no catenary anywhere. A locomotive for diesel commuter lines in the US, 100% diesel powered when cruising along at 60+ mph. He’s asking, do we have, will we soon have, batteries that would make such a locomotive accelerate better by using the energy stored from braking, and are light enough and cheap enough. I’d say that’s what this thread is about: is there hope for that? Can a five-ton (or whatever-ton) battery absorb a worthwhile amount of energy from the slowing train, and help the train accelerate, and keep doing it for years?
It seems that several proposals have been put forth some already in use.
Not quite - the intent is not to eliminate catenary but provide a way to get straight electric like performance without the need for catenary or third rail where string wire or adding the third would not make economic sense. The other aspect is using batteries to provide most of the accelerating power would allow the prime mover to operate at a constant or slowly varying output to reduce emissions. Perhaps the main reason that manual transmissions are so rare on new cars is that the sudden drop and restoration in power when shifting gears with a manual causes a burst of tailpipe emissions.
One reason for using a hybrid versus a battery MU trainset is the the prime mover can provide copius amounts of heat on cold days without affecting the range.
Yes. I realized that later in the discussion . If you keep a battery in a sweet spot of always mid charge it basically lasts forever. NiCad excluded. Those oddballs needed full discharge to last.