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32 volt battery charging circuit http://www.rypn.org/forums/viewtopic.php?f=1&t=42834 |
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Author: | warren032 [ Thu Jan 10, 2019 12:18 am ] |
Post subject: | Re: 32 volt battery charging circuit |
Very interesting reading this thread. The ideas here are amazing. I like the idea of the 600V to 120/240 VAC converter and an automatic battery charger. Safety from overcharging, producing dangerous gas, etc. is important IMO, when you have visitors on the cars. You can even buy an automatic battery charger circuit board 120/240VAC to DC (adjustable) on eBay for a few bucks. Not overly recommending it, but it is possible. [EDIT] Here is a link for an adjustable 12-36VDC battery lo/hi voltage cutoff circuit: https://www.ebay.com/itm/XH-M609-DC-12V ... 3741330175 At $4.99 It should be within anyone's budget :). One important consideration for the Edison batteries - they have a negative temperature coefficient. That is as they charge up their internal resistance decreases. Thus a simple constant voltage charger circuit will "run away" and overload/overcharge them. On the old Waukesha Enginators, they had a separate panel specifically for when Edison batteries were used. ---- I have 4 8V lead acid golf cart batteries that are charged by a Waukesha Enginator (running) or a transformer/rectifier (station power). The car is the old Milwaukee Road Dynamometer car at the Illinois Railway Museum. |
Author: | jayrod [ Thu Jan 10, 2019 10:55 am ] |
Post subject: | Re: 32 volt battery charging circuit |
This is waaaaay out of my league but I'll throw something similar out there that may be workable or get you thinking.... Start with a 600 to 36 volt converter something like: https://absopulse.com/750vdc-high-input-voltage-railway-dc-dc-converters-transit-mining-vehicles/. Much smaller package. This one may/may not have the needed current available, don't know your requirements. No clue on the cost, though. Could be way out of line with your budget. Automatic charging circuits are relatively simple affairs once you get past the initial power supply portion. If you have an electronics guru or technical school that'll take that portion on, you might be cooking with gas. Just a thought... |
Author: | JeffH [ Fri Jan 11, 2019 10:49 pm ] |
Post subject: | Re: 32 volt battery charging circuit |
OK, my two cents, again. If you are a *museum* then part of the mission is to preserve, to the extent possible, the original historic fabric. To me, that also includes preserving the obsolete and inefficient technology of the day. Solutions that involve solid-state converters and other modern electrical components might be the best answer for a transit agency, tourist railway, or "heritage" trolley operation where the primary mission is not historic authenticity. If the original charging system for these cars was M-G, the best practice from a museum standpoint is to either rewind the M-G, or as one poster suggested, get an M-G from a PCC car (there are many of these out there). Then you'll have something which sounds and operates almost like the original. Regarding the resistive charging scheme: if that's not something the cars ever had, I don't advocate for it. But as for the safety aspect if the battery goes open, there is a simple, inexpensive and admittedly anachronistic prophylactic circuit: place a power-rated zener diode in parallel with the battery having a breakdown voltage of say 50V. If you can't easily find zener diodes that can handle the power, then use a "crowbar" circuit with an SCR and a zener diode to bias the gate. In the event of an over-voltage because of an open battery, the crowbar shorts B+ to ground and blows the battery fuse and charger fuse. |
Author: | Tony Pignaloni [ Mon Jan 14, 2019 7:17 am ] |
Post subject: | Re: 32 volt battery charging circuit |
Hard to restore the origninal South Shore MGs when in East Troy case, im sure a couple of the MGs have disappeared over the last 3 decades. I disagree about authenticity. you gotta do what you need to do to keep the cars running. If you run the car once a year, then i suppose being original is ok. but if you run it all the time, id go for the best maintence solution. and a solid state inverte/converter is probaly the best bet for East troy. The riding public is not going to care if the car has an MG or a solid state converter. all they care about is does the car run, and can i ride it. |
Author: | Chuck Richards [ Mon Jan 14, 2019 2:38 pm ] |
Post subject: | Re: 32 volt battery charging circuit |
Tony, you've got that right! I personally believe that the equipment should be preserved as best as possible. That means adhering as much as possible to the original parts and methods. You are correct also, in that 99.99999% of the riding public does not know nor care anything about the details of how it runs, and why it runs, and what it represents historically. Especially with the CSS&SB cars, there is always a balance of these factors to be considered. Given the fact that these cars are rather complex, keeping (6) of them on the active roster is a significant challenge. This situation also provides the opportunity to test a few different concepts for charging the 32 volt batteries. |
Author: | robertmacdowell [ Tue Jan 15, 2019 7:44 pm ] |
Post subject: | Re: 32 volt battery charging circuit |
A South Shore M-G set is a fairly beefish piece of metal, and oriented parallel to the carbody near the outside. It would do a fine job of concealing a digital converter installed behind it or above it. |
Author: | Chuck Richards [ Tue Jan 22, 2019 3:49 pm ] |
Post subject: | Re: 32 volt battery charging circuit |
bump |
Author: | Chuck Richards [ Thu Feb 14, 2019 2:46 pm ] |
Post subject: | Re: 32 volt battery charging circuit |
bump |
Author: | o anderson [ Fri Feb 15, 2019 11:55 am ] |
Post subject: | Re: 32 volt battery charging circuit |
Since it does not seem to be mentioned in this thread, you might approach a motor shop and ask what it would cost to rewind a motor for 600v operation rather than 1200? I think the result would be less windings on the same motor. I had heard of someone doing this on a much smaller motor in different voltages with good results. I have not heard of volunteers rewinding motors, but perhaps it is possible to do that and save on cost that way. |
Author: | RCD [ Fri Feb 15, 2019 2:12 pm ] |
Post subject: | Re: 32 volt battery charging circuit |
If you do ask about convershion there is a motor shop the Shore Line Trolley museume deals with a lot with good results. Unfortunately I can't remember the name of the shop right now. |
Author: | Chuck Richards [ Wed Apr 03, 2019 10:21 am ] |
Post subject: | Re: 32 volt battery charging circuit |
An update on this: Thanks to all of the very helpful suggestions posted here, we have made contact with the design engineer at Absopulse Co. and he has already quoted some prices. With some more time and effort with this company, these solid state units should serve our needs quite well on the CSS&SB cars. Thanks again for all the great suggestions! Updated Update from 11/14/19: Insufficient funds are available at this time for purchasing an Absolulse product. Experimentation is ongoing with the home-made zener diode based charging regulator. This past summer of 2019, the experimental unit was temporarily installed on one of the CSS&SB cars for live testing. So far, these tests have shown the prototype unit proof of concept works rather well. Approximate set points are: Start charging when battery terminal voltage falls below 36 volts. Charge at 26 amps until battery terminal voltage reaches 40 volts. This is a simple regulator which just turns on, or turns off the charging. The car being tested loads the system to about 19 amps max load. With 26 amps charging current that leaves about 7 amps charging when under full load. This setup was tested extensively this past summer. Track tested it 2 round trips so far. Batteries remain cool to the touch throughout these tests. The next testing phase shall be temperature oriented. Must determine how the accuracy of it holds up in low temperatures of late fall and winter, as compared to summertime. So far it seems to be working ok. One additional note of explanation: This is no longer a 32 volt system. It is now nominally a 36 volt system because the original Edison cells got swapped out long ago with 2 strings of 3 each 12 volt lead-acid batteries. These are rated at 150 amp-hour capacity. The resulting string has 300 amp-hour capacity. Chuck |
Author: | Chuck Richards [ Thu Nov 14, 2019 1:38 pm ] |
Post subject: | Re: 32 volt battery charging circuit |
bump. See updated update above. |
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