So I removed my crankcase breather canister on my 695, and made a plate to replace it that mounts both the rectifier/regulator block and one of the coils. That'll give me room to replace my stock Sachs shock with a high zoot factor Showa from a 749.
In addition, the idea of replacing my battery with something made from A123 LiFe cells is intriguing.
So, being an EE by trade, I thought I'd have a look at the charging circuit, to see if it's up to the slightly more demanding charging requirements of four LiFe cells. So far, everything I've seen points to it being a three phase rectifier, followed by a shunt regulator.
Please, please tell me that the box I repositioned contains more than six diodes and a shunt zener... Cos if that's so, it's disgraceful. That's amazingly inefficient.
If that's really the case, then I wouldn't trust it to charge LiFe cells, and would want to make something to replace it. I'm thinking of a rectifier, followed by a non-isolated DC-DC switching converter (like perhaps a couple of Linear Tech LTM8027 umodule regulators in parallel). Only issue with this setup is the 60V max input to the converter, but that could be solved by a simple series pre-regulator (a zener diode and a transistor). Efficiency would be somewhere around 80-90 percent, so it'd dissipate maybe 10W max.
Would anyone be interested in these if I were to make some? Think regulator that's a tiny fraction of the size of the existing one that doesn't get hot, ever, and that has a really tightly controlled charging voltage.
And yes, it probably is that bad. AFAIK, the same regulator that fits your 695 is the same as mine, from 2000. And it would not shock me to learn that it's the same as even older models
Well... people love mods... but what would be the cost on an item like this?
Quote from: yuu on May 05, 2010, 04:57:23 PM
And yes, it probably is that bad. AFAIK, the same regulator that fits your 695 is the same as mine, from 2000. And it would not shock me to learn that it's the same as even older models
Well... people love mods... but what would be the cost on an item like this?
The regulators for the single phase alternators were different.
Your description sounds remarkably similar to the discrete components visible on my 1975 Suzuki. If you are thinking about a LiFePO4 charging system, how about one that could balance charge the cells?
My 2000 750 has eaten two regulators in 8000 miles. I'd certainly be interested.
Sounds good to me. All I could dream up was a better heat sink.
You might have a little problem with the 48 W output you would need 10+ to meet the 520W output (S4R manual states - Alternator Capacity 12 V - 520 W) with the LTM8027. I imagine there are other devices that could be used. Interesting project, I sure would like to see what the alternator actually puts out. Have you characterized it yet?
if you can make a rectifier that replace the stock one that takes up a lot less space and also doesn't need the cooling or does not even get as hot ever, then i'm game.
tell me what the approx price is and just make sure that its safe to use on the bike and won't screw up anything and is plug and play and we have a deal.
I haven't looked at it that closely but it sounds totally feasible. Ducati electrics, especially the regultor, are not known for reliability. There is an aftermarket replacement already, DesmoTimes carries it. Not sure if it's different or just a clone.
Remember the golden rule: Never get an Italian motorcycle wet on purpose ;)
Scott
I'd be interested. [beer]
Good to see some interest. I can't say how much something like this would cost, except to say more than $100 and less than $500 :) It depends, both on what's in the final thing and in how many are made - electronics stuff gets a lot cheaper per unit if you're making twenty or fifty of something than if you're making two.
The idea of adding circuitry to manage cell balancing is a good one, and doesn't preclude using it with lead acid batteries either (you just wouldn't connect those bits). I had a look on my bike last night, and it would be quite easy to re-route the part of the loom that go back to the rectifier/regulator so it goes up to the battery box instead, and would remove more wiring that passes the shock, too. An ideal location for the rectifier/regulator would be in the battery box alongside the LiFe cells.
The 520W alternator spec is in my book, too. I agree that it's a little dubious (the fuse in line with the rectifier/regulator is 30A, so the absolute most we can hope for is 360W before we blow the fuse), and also agree that the 48W from a single little Linear Tech converter won't be enough. An interesting point about a crude shunt regulator is that the more power you pull from it, the cooler it gets (as it has to dissipate the balance between the power in and power out as heat). So perhaps the 520W bit isn't so unrealistic. It's the 50-100W load that would blow them up. The Linear Tech converters can be paralleled for more power - alternatively we could just pick a higher power one.
very interested [drink]
Oh yea, and to make matters worse it s stupidly primitive shunt regulator. So its dumping hundreds of watts right into heat - all the time putting stress on both the regulator and the alternator. The more you rev it the more heat get dumped. But wait, that's not all, if you order today we'll even mount the regulator in the worse place possible that could ever be devised of for cooling - right under the seat away from cooling air flow. Given the state of art for even the simplest devices these days it really amazes me that Ducati is still living in the stone age.
I've often wondered why there isn't some kind of mosfet-switched gizmo in charge of regulating/rectifiying by now. But even Honda, with its legions of engineers, uses a similar arrangement.
There are MOSFET VRs out there. I believe Yamaha has one. Not for 520W though.
I relocated mine and installed a heat sink. I'm fine with it. If something comes along that allows me to use/charge A123 cells reliably, that would interest me.
Any progress on this? [popcorn]
the ducati regulator is also used by many Hondas and has issues with them too just look at VFR forums.
No, none, save a few simulations. I'm sorta tied up playing with suspension (sbk forks) at the moment - I'll probably return to things electrical in a few months.
Don't know how the hell I missed this the first go-around, but heck yeah....I'm interested! [thumbsup]
Definitely a cool project.
mitt
Okay, this is the sort of thing I'm playing with.
(http://farm2.static.flickr.com/1284/4708196254_93c452d095_b.jpg)
The issue with A123 cells (or any LiFe cells) is voltage control and charge current control. According to the datasheet, to get good cycle life, one doesn't want to go above 3.45V float (13.8V for four cells), and shouldn't charge at more than 3A (6A for a 4s2p pack).
The only way I can think of to do that and maintain high current capacity for the rest of the bikes electronics is to have two separate DC-DC converters, one for the battery, and one for the loads. I'm liking the Linear Tech LTC3703 controller, as it's able to drive big MOSFETs and will run to 100V input, plus incorporates current limiting, which is important for setting charge current. The circuit I'm running sims on is the same as the application note circuit, but I'm using Infineon IPD122N10 MOSFETS and Vishay IHLP-6767GZ 10uH inductors, to significantly boost maximum current. I'm using the same circuit (except for the current set resistor) for both battery charge and load supply.
So the principle is as follows. The six diodes on the left rectify the AC from the alternator. The zener/MOSFET across the HV supply is just there to protect the following circuitry from overvoltage - it'll shunt when the HV voltage gets to 90V. Then both DC-DC converters are in parallel. The one charging the battery goes across the battery, with balancing circuits across each cell. The one for the loads goes straight out.
A simple diode from the battery + to the loads allows the loads to function before the bike is started. Also, if the loads draw more than 12A, the charging converter may also source current to the loads via the diode, up to a max of 18A or so.
What are people's thoughts? The only part that'll need heatsinking is the protection circuit, as in the event of overvoltage it may have to dissipate significant power. Otherwise everything is tiny. The inductors are 17mm square, the MOSFETs are TO252 (small), etc. The whole shebang will fit on a circuit board around the same size as the existing rectifier/regulator, but only ~12mm thick.
So, does the ducati alternator not work like a modern car where the regulator adjusts the rotor field current to produce the only power needed?
mitt
Quote from: mitt on June 16, 2010, 06:24:50 PM
So, does the ducati alternator not work like a modern car where the regulator adjusts the rotor field current to produce the only power needed?
mitt
No, the alternator has permanent magnets in the rotor, and three-phase windings in the stator. There's no way to adjust field current - the only thing limiting output power is saturation in the stator.
Quote from: suzyj on June 16, 2010, 06:31:14 PM
No, the alternator has permanent magnets in the rotor, and three-phase windings in the stator. There's no way to adjust field current - the only thing limiting output power is saturation in the stator.
That is crude, but maybe they saved a few pounds by using magnets instead of a rotor winding and claws?
mitt
Quote from: mitt on June 16, 2010, 06:48:06 PM
That is crude, but maybe they saved a few pounds by using magnets instead of a rotor winding and claws?
Yes, it is. In their defence though, the application isn't like that in a car, where there are lots of things turning on and off and drawing current (stereo, fans, headlights, etc.) The load for a motorbike is relatively constant, so you can get away with a much simpler setup.
The rotor and stator also are an integral part of the engine, saving a lot of space and eliminating the need for a drive system. All you really (IMO) loose the low speed efficiency since you cannot control field or run the alternator at higher than engine speed, which would not be a good idea on a sport bike engine anyway.
now you want to use this with a speedcell type battery, how will this setup you are proposing work for a reguarar sealed stock battery that came with the bike? and what if anything can you do to get the packaging even smaller than the stock one?
And will it work for non three phase systems?
It'll work okay with the stock lead acid battery, but it's overkill for that application. You don't really gain anything over the standard circuit (well maybe you'll get a cooler bottom), for quite a bit of effort. The PCB dimensions ended up 102mm long (4") by 65mm wide (2.5"). I designed the board to fit neatly alongside an A123 pack, with the battery connections in convenient places to connect to the cells.
I can't see why it wouldn't work on single phase alternators - I went a little overboard on the rectifier diodes, and used MUR1620s. These come in a TO220 package and are able to pass 16A each, so it will be okay for single phase as well as three.
In any case, after a couple of late nights, here's an image of the PCB (a crappy screen grab from my CAD tools):
(http://farm5.static.flickr.com/4050/4712137763_98ae9b776a_b.jpg)
The rectifiers are down the left hand side - next along is the balancing circuitry, then the two DC-DC regulators. The largest parts on the board are the inductors for the converters. Finally on the right are the pass diode to allow the battery to power the load with the bike not running, and the overvoltage protection FET. The loads connect to the right hand side. The solenoid/starter would bypass this board and connect directly to the battery.
I haven't added up the cost for all the parts yet, but I'm thinking something like $200 per unit in modest quantities.
If anyone wants the PCB and schematic files (I use Protel), shoot me a PM and I'll email them to you.
To answer the first question, yes, the stock regulator sucks. That's why CA-cycleworks doesn't sell it and sells stuff by these guys instead. Ah the memories. Nothing like having your bike catch on fire when the stock voltage regulator fails while riding through rush hour traffic. It's so nice when traffic parts for you even if it is because they're afraid you're bike is going to blow up and you're enveloped in smoke.
http://www.electrosport.com/street/street-models-ducati.php#Anchor-DUCATI-47857 (http://www.electrosport.com/street/street-models-ducati.php#Anchor-DUCATI-47857)
For what its worth, Electrosport is going/has gone under, and is in the process of being sold off. Another source for reliable voltage regulators would be great right now.
http://www.electrosport.com/ (http://www.electrosport.com/)
From the home page:
ElectroSport is operating under new ownership and has moved to a new facility:
ElectroSport
66 Maxwell
Irvine, CA 92618
Phone: (949) 748-6338
Fax: (949) 748-6339
email: info@electrosport.com
We are in the process of launching a brand new website and our existing online ordering system will not be available until the new website launches.
Please call in any orders or tech support questions on (949) 748-6338
We apologize for the inconvenience and we look forward to serving you from our new location!
Happy riding,
The ElectroSport Team
Quote from: accrocker on June 20, 2010, 11:13:26 AM
For what its worth, Electrosport is going/has gone under, and is in the process of being sold off. Another source for reliable voltage regulators would be great right now.
I used a Ricks Regulator on my 96.
Charge light works correctly and everything.
http://www.ricksmotorsportelectrics.com/ (http://www.ricksmotorsportelectrics.com/)
Suzyj
Did you ever build one of these?
Quote from: dbran1949 on September 28, 2010, 02:01:45 PM
Suzyj
Did you ever build one of these?
Not yet. It's on my to-do list, when it comes time to replace my battery.
If you left your headlight on for a few nights we could get this going ;D
There is a great recent post
here (http://www.ducati.ms/forums/80-hall-wisdom/94947-upgrade-fix-no-more-charging-regulator-rectifier-problems.html) on ducati.ms about solving Duc regulator issues by going to a MOSFET unit.
Thread title: "The upgrade fix >> no more charging/regulator/rectifier problems"
from the post:
QuoteThe two biggest benefits provided by mosfet RR's is that they provide improved output and do not get as hot.
Unit chosen is a Yamaha part, from the R1 sport bike, manufactured by Shindengen of Japan.
There is a lot of info there, including how to upgrade connectors and wiring, with links to other relevant posts etc.
May or may not be of help to the OP. But good explanations for a project to fix this generic Ducati deficiency.
Thx f info, moronic! [thumbsup]
Would be great if susyj or someone else knowledgeable could confirm that this fix really works.
And explain why..... ;)
Quote from: greenmonster on October 05, 2010, 05:26:30 PM
Would be great if susyj or someone elde knowledgeable could confirm that this fix really works.
And explain why..... ;)
I can't. Saying a r/r has a mosfet in it is like saying an engine has valves. It's completely meaningless. I could build a r/r with mosfets that would catch fire in minutes. Similarly, I could build one using diodes and a zener that would never fail. It all depends on the ratings of the parts used.
Unfortunately, all these things are gooped up black boxes, so there's absolutely no way of knowing what's inside.
I like your summary. [beer]
suzy
google ripperton battery
he is around on a few forums i read and has been playing with those batteries in a variety of ways for a while
might be a good person to chat with on your ideas
Quote from: suzyj on October 05, 2010, 07:57:31 PM
Unfortunately, all these things are gooped up black boxes, so there's absolutely no way of knowing what's inside.
silly suzy everyone knows they are filled with smoke
Thx, susyj! :)
Quote from: suzyj on October 05, 2010, 07:57:31 PM
I can't. Saying a r/r has a mosfet in it is like saying an engine has valves. It's completely meaningless.
But wouldn't that be true also of saying an engine has titanium valves? Any advantage still depends on how they are used. OTOH, engine builders going to the trouble of using them seem to use them well (for all we know).
I understand your point, which of course is mainly that you can't confirm the Shindengen unit is better than what we already have.
Nevertheless, the author of the post did cite a fair bit of research and linked to posts from other people with different bikes who had done the same mod.
Granted, no clear evidence yet that the new MOSFET regulator lasts longer than what it replaces.
Perhaps I've just unwarranted faith in modern Japanese electronics.
Nevertheless, it still looks to me like a promising avenue, until you get around to your fix for us. :)