I’m currently gathering ideas whether or not will be able to do anything with them anytime soon. My interest in the “hybrid” is not necessarily to be able to run either way but to have track power for recharging batteries. How about a “refueling” station that is a hot track section? The wiring, devices, and circuit logic on board the locomotive would direct the power for charging the onboard batteries.
Also if large stretches (or all) of track were hot might the power continually recharge batteries, but the drive power would always be from the battery?
May I surjest that you read some railway mags on recharging of batts. All I have seen say recharge 2-3 hours via a proper chager in a charging bay think how are rechargeable razer works. Hope this helps
All of my electric locos use Sealed Lead Acid (SLA) gel cells of 6Volts 4.5Amp Hour rating. The charger for this is a plug in unit and it takes 90 minutes to completely recharge one of them. The SLA must be in the upright position to do this. I think that your idea for a charging section of rail is impractical. This is not because of the technical aspects, it would be very easy to do, but rather the needless duplication of the equipment required. You would have to have one regulator and charger sensor per locomotive, then rig external power feeds and circuit breakers. What I do is a simply lift the lid, drop one in and then play for about 3 hours per SLA battery pack -total changeover time around 10 seconds. While I am doing this another one is charging -or trickle charging in its slot in my shed. I have a total of 10 of these batteries at a grand cost of £25. All of my track is electrically “dead”. Why make life more complex? regards ralph
Thanks for the feed back. I can see that it’s kind of like having a bunch of batteries for battery powered tools… put in a freshly charged one and stick the discharged one on the charger. Will think on this a while and try to grock the difference between my idea vs the simplicity you describe.
OK, since I too have often been accused of coming from Mars… Let me aid you with a few thoughts “Water Brother”. Your loco is going to have to continually detect the voltage state of your on board battery pack (BP) and then reference this with the supply voltage (SV) from your track. How do you intend to do this while the battery is discharging through the motor and simultaniously being charged from the rails -unless your system fast switches between two sets of on board BPs(?) Remember you are dealing with a chemical reaction that takes a finate amount of time to occur. The train will also need a bridge rectifier to enable it to supply the BP with voltage of the correct polarity regardless of the direction or position of the train. The wheels will require insulating from the track and the chassis and the current pickup shoe to the SV will need to make good contact with the rail. The BP will only charge up at around 10% of the discharge rate -unless they are specifically designed to do so (mine are, they are computer UPS batteries). If you are going to use your track to charge your batteries in the locos with them -your best bet might be to use mid frequency AC at about 1Khz. Most simple KT88 AB1 ultralinear amplifier circuits work fine at this level… Always remember K.I.S.S. regards ralph
The technology exists to drive the load continuously from the battery, and recharge the battery whenever incoming power is available: it is called an “Uninterruptible Power Supply” and was very fashionable for computer power packs about 10 years ago. I don’t know the details, but it should be searchable on the web. Whether you can buy or build one of the right size for this use is another matter, of course.
You could always set up a maintance(a round house or a siding) area where the crew could park the loco on the powered section of track and do their “maintance” for a few hours, just long enough for the batteries to charge.
I think most people have tried to charge the batteries from the rails by trying to maintian the voltage at the power supply. Correct me if I’m wrong. If so, this is fundamentally flawed and won’t work.
Has anyone tried to mount the charging / voltage regulation circuitry in the engine, and float charge the batteries by monitoring their voltage locally? You’d run the track voltage, at lets say 18 volts, and regulate the voltage at the proper 13.7 volts across the batteries. It would be failry easy to create the circuit to do so that would maintain the same voltage accross the batteries when idle or at full load. Only when the track power disappears would the battery be called upon to run the locomotive. No over-charging could occur.
I’m an HO modeler that has toyed with going to G for the yard. I’m also an EE in the power industry, so we run into this sort of thing all the time but at MUCH different scales.
It’s my understanding that an uninterruptible power supply such as those for a computer do not draw their power from the battery until there is a power failure. The batteries are trickle-charged by the mains power, and a fast-switching circuit draws from the batteries only if the mains power is interrupted or the voltage drops below a certain threshhold.
There are basically two types of UPS. In the constant draw type the mains is rectified fed to the batteries and the the batteries run the inverter -thus they are NEVER out of circuit. This EATS batteries and is normally reserved only for extreme emergency equipment (baby monitors and ICU equipment in hospitals for example). The normal standby type uses a charged bank of batteries with a detector that flips the circuit to the inverter and normal power is resumed (there may be a delay of 1/120th to 1/100th of a second before it operates fully)…
It is incorrect that this type of a system, if properly designed, eats batteries. Any wear and tear on the batteries is caused by poor charger design.
Communications systems all over the world operate on float-charged DC systems, where the load is powered from the batteries directly, and a charger continuously maintains the proper voltage across the battery bank. The result is that virtually no current goes into the batteris, and almost all of the current is used to serve the load. Flooded lead acid batteries on such a system routinely operate for 40 years with nothing more than routine maintenance.
It is a similar system that I propose to operate within a garden locomotive.
To provide the desired protection, UPS units must be properly maintained. Sealed lead/acid batteries have a useful lifetime of 3–5 years. In determining when to replace batteries, it is important to remember that the batteries can be completely bad after 3–5 years and lose their ability to hold a charge gradually over that time. If a UPS started with 1 hour of runtime for the connected load, after 1 year, it may only provide 45 minutes and after 2 years, it may only provide 20 minutes. Some UPS units have user replaceable batteries, but some require a qualified technician or electrician to replace the batteries.
Battery failure can also be caused by temperatures exceeding 25 °C
regards
ralph
Post Scriptumn: I normally recommend in my designs that the client replace their battries on a six monthly cycle and keep their standby diesel generators running while this is happening. I standardise on the Chloride 60Volt 600 Ah battery for my designs -which is very common in the EU. Most of my clients have systems that are charged from 3 phase delta star -which the computers run on. All of my designs (that are still running) can be sat on a commercial floor loading of 18 metric tonnes per square metre.
The sealed UPS batteries that you use have several strikes against them:
UPS systems have an agreesive re-charge program in order to quickly recover from any momentary outage. Often the batteries are operated at the equalize voltage, and not at the proscribed float voltage. (Higher than optimum float voltage) This causes a higher amount of gassing of the battery and a resultant water loss. In order to have a satisfactory battery life this must be adjusted for a proper float voltage for the batteries.
Sealed batteries are unable to have their water reserves replenished easily. It CAN be done, but you have to know what you’re doing AND it’s usually not cost effective from a commercial perspective.
If a battery is exercised often, it’s happiest being exercised around the 50% level of charge. The top 10% of charge creates by far the most wear and tear (and gassing) on a battery.
Virtually all of the sealed battery banks I’ve run into commercially I’ve had torn out and replaced by flooded cell units. The ongoing replacements and questionable reliability of them has rendered them virtually worthless in my industry. The lessons learned though in making a flooded cell battery live a very long time can be carried over.
To have good reliability with sealed Pb batteries, they must be operated at the correct float voltage, and not at the equalize voltage. In order to set this you must know if they are a lead-alcium or lead-antimony alloy. Most likely to be lead-calcium, as this gasses less, but costs more.
Another thing it to not be so anal for having the batteries “topped off” before running them. It takes +24 hours to fully charge a battery at the float voltage, but less than 8 to get to 90% of capacity.
If the on-board charging circuit maintains the battery at float, the battery should be happy, even if it is not kept at 10
I am sure that you are very happy with your wet cells…
However you must ask yourself the following questions…
1: Why in the Decade that I have been designing Liquid Cooled Computer Systems for Banks, Building Societies, Hospitals and Scientific Institutions, (all over the EU) -have I ever seen a customer with a wet cell system?
2: Why was the last wet cell system I saw -was as a boy in Rhodesia (circa 1971)?
3: Why do my computer designs start at £3.5million pounds to £9 million pounds?
4: What do all the letters mean after my name?
regards
Rheinhart Manfred ben Brades B.Ed B.Sc M.Sc M.I.A.A.P. Ph.D
Post Scriptumn: I will continue to use SLA packs in my designs because they are simple, easy to replace, and the customers are happy with their SLA and diesels. End of story.
It shouldn’t matter what type of battery that is used, just be sure you have a charger that can handle the type of battery or cells that you are using.
If you want to run battery, You do not want track power. You have a charging station. You are using batteries to eliminate track power.
I you want continous running. You use unlimited track power. If you are looking to over come drity spot drop outs. You run feeders from other pick ups to your power units.
If you are just looking for very short power loses feeding your onboard electronic speed and direction control. Place a couple of very large filter capacitors. They will help to jump the gaps in track power.
By combining the batteries with a continuous charging circuit in the locomotive you end up with the best of both worlds.
You install the batteries so you can run continuously and not worry about the track conditions.
You power the rails so you don’t have to change batteries, but then have to keep the track clean.
In combined operation you install the batteries, charge the rails, operate as a battery system, and don’t sweat cleaning the track.
Lets say the rails only make electrical contact with the locomotive 50% of the time (highly unlikely). While you have contact, you’re charging the batteries while you run. While you’ve lost contact, you’re running off the batteries. On a purely battery system you’d have to change out the batteries fairly often. On a hybrid system you may NEVER have to change out the batteries, but you’d enjoy all of the benefits of a battery system without the headaches.
Lets face it, the batteries are there to carry you though those areas where you’ve lots electrical contact, or maybe are tired of trying to maintain electrical contact, right? By aknowledging the uncertainty of the track power, but by being willing to make use of it whenever it decides to grace us with its presence, we still can put it to good use keeping us moving down the track.
Mark in Utah
P.S. Just because you’re running on batteries does not necessarily mean that you’d have no use for power on the track.
Mark, have you actually built and tested such a system?
If so, would you be so kind as to show us old fellers, who have been designing and building battery R/C systems for 20 odd years, how to do it with anything other than lead acid Gel cells.
We would be particularly interested in knowing how you overcame the never ending intrusion of nature which will ultimately make 100% of the track dirty, without any cleaning. Also, how you maintained continuity in the track without having expensive clamps on each joint.
How also do you prevent the sudden inrush current the batteries demand when the loco passes from an extended dirty section into an area where track pick up is possible again? How do you regulate the current required for the differing battery chemistries and capacities?
I have not built such a system, but it follows some tried and true princples that I’ve used on many other systems for years. Right now I’m using a variation of it to regulate the voltage for my tortoise switch machines for my indoor HO layout. Simplicity is the key. Here’s what you need:
Full-wave bridge rectifier - Takes power from the rails and corrects the polarity no matter which direction you place the locomotive on the rails, or even if You have AC running on the rails. It costs under $2, is a black platic square with 4 leads on it.
Adjustable Voltage Regulator - Feeds the batteries the precise voltage they need for float charging. Float charging is the voltage that you can keep the batteries at forever without boiling them dry. For lead-acid batteries it’s 2.25 volts per cell, or 13.5 volts for a 12V battery. They’re self current limiting. You want to limit the current to approximately double the current draw of the locomotive. For example, if the locomotive draws 1.5 amps, you want a 3 amp limit. This is not a hard and fast rule, but gives you a starting point. You may need to add a power transistor to give the regulator a boost in capacity. You’ll need to mount them both on a heat sink, as it’ll dissipate 18 watts of heat worst case. The last regulator I bought cost $0.50 and had a 1/2 amp output. A power transistor to boost it up would cost around $2. A few resistors are pennies apiece. The heat sink is the big ticket item, for around $5.
Power Supply - For a 13.5 VDC battery system, you need 13.5 + 1.2 (rectifier drop) + 3 (regulator drop) + 2 or 3 for voltage drop on the rails. This puts you at a 19.7 to a 20.7 VDC supply. The only problem you get from a higher voltage supply is more heat to be disipated by the on-board voltage regulator for the batteries. You also need to have enough “poop” to feed the maximu
My “Annie” runs on 14.4v batteries for well over 3 hours…with my MAHA charger it takes about the same time to get a good charge back into them…
I have a HLW Mack that has run for over 6 hours continous on 9.6v NiMH on my Main Loop…and still has some juice left in it…no telling how long that dude will run?
Straight Battery made more sense to me…and I have been pleased…NO track wiring needed or wanted…
With my kids and the RR construction in process, 3+ hours seems to be more than enough for me…if I were to need more, I could hook up my AMS Stock Car with the 18v NiCad pack inside…