Balancing transformer help needed

[mbryner]

@Tom:  

Are there any good reasons not to go this way?

the 120 vac taps on the secondary winding should have 60 vac and having gone through the transformer might be clean enough to rectify and send to an MX60?

Nope, that's what I do.   You'll need a bigger transformer, though.   Mine's a just a surplus 5kva 2:1 transformer.   Price to ship was more than what it cost me on ebay, but I couldn't find one locally.   You'll also need to put the rectified power through a big choke to smooth out the ripple before feeding it into a MX60/MX80.   There are a couple threads on this when I was building it last year and spring this year.

@gregger2k:

If anyone knows of a source for a big 48VDC alternator, or one that can be modded to 48V I would also be interested.

ha, I just asked that same question a few minutes ago on a different thread.

[mbryner]

And gregger2k, with that rectifier you linked, the output is 48 V regulated.   How do you charge a battery bank w/ 48 V?   You have to get it up to 60V.   Also, what Brett just wrote...

[gregger2k]

bschwartz: here is a link to the data sheet of that particular unit:
http://www.alldatasheet.com/datasheet-pdf/pdf/408744/LINEAGEPOWER/CAR3010L1NH-1A.html
Look it over and let's see if we can figure this thing out.

mbryner: the output is adjustable by pot to 43.2 to 58.2 volts. Some of the other other rectifiers in this family type
http://www.datasheetking.com/DSA00383318-datasheet.html have a 'V Program' terminal to set the output to between 40 to 58 volts" One might even to program a micro-controller to make a 3-stage charger out of it!

'For -48 V version, output voltage is -40 V with 2 V applied to Pin 10 WRT Pin 14. For each additional 1 V applied to Pin 10 the output voltage
increases by -2.375 V.'

Not high enough for equalize though. I don't know how much the voltage sense pin can compensate. You might be able to drop the sense voltage by a volt or 2 to get a boost on the output.

-Greg

[Tom Reed]

Found a data sheet on that but alas it says "Output Voltage Range • +43.2 to +52.8 VDC via trim pot" which is not even enough for floating the batts.

[gregger2k]

Looks like DC into a charge controller is your best bet. Or the elusive 48VDC alternator.

[mike90045]

http://otherpower.com/listeraxialflux.shtml
  and
http://www.microcogen.info/index.php?topic=50.0

[Lloyd]

hi all,

There are a number of alternator builder that build a 48v alternator on the Leece Neville 4900 carcus, the problem is i don't know any one who makes a 3-step regulator for the beast.

I think there are a couple of options, but they would need to be tested.

1. 48v alternator(as mentioned here), and a Balmar 624(24v) regulator, using a voltage divider on the bat sense wire, and a 48 to 24v  2-1 linear dc dc power supply on the field wire.

2. using 2 Leece Neville 24 volt alternator with isolated ground, then either series the outputs or use each alternator to charge half each of the 48 bank at 24v, using the Balmar 624 bat. sense off the middle 24 volt of the bank.

I think it might be done...but BobG...would have a better handle...on the alligators of such a convoluted rig.

The next best thing to do might just be to call/email Balmar tech support, and ask if they could serve the market in any way.

Lloyd

[mobile_bob]

i am a bit late to the party fella's so bare with me if i repeat something already stated

yes leece neville makes at least 2 units capable of 48volt nominal, however one is designed to do
48volts at 85amps continuous and not really made to be a battery charger, the other is a 54volt AC
unit 3 phase with AC outputs made to drive a special inverter for service trucks.

to my knowledge they are both hard to get, and/or discontinued by leece neville, and when available are very expensive
often well over a grand each.

i have one of each in my collection, and in my opinion neither is capable of the efficiency we need
both being connected star in the stator leads to higher resistance, and being built on the fat core leece
neville means there already is too much copper to keep the resistance down even connected in wye.

my white paper describes running the 555 jho prestolite at 24volts using a mc612balmar which is a 12volt regulator
there is now reason that the 555 could not be pressed into doing 48 volts charging using the same scheme
however one would need to turn the alternator upwards of 6500rpm to do so.  efficiency should exceed 80% and longevity should
be pretty good if you limit to less than 100amps max output.

now before anyone starts moaning about 12volt excitation for a 48volt alternator, bare in mind that both of the leece neville alternators
(48 and 54volt) versions use 12volt rotors!  so there is no reason we can't do the same.

before the move i have been working with a leece neville doing 48volt nominal charging running at 57.6volts dc and 100amps, the machine had to be fitted with a water cooled stator (designed, built and installed by me) in order to run at that level for protracted periods of time. while it works it is too complex for general use in my opinion.

sometime this winter i hope to do more work using the 555 on a 48volt system, which is something i need for my exceltech 48volt inverters anyway.  i will be building and testing using the r175 changfa which is about 6hp so it should be close to what a 6/1 listeroid could do.

bob g

[bschwartz]

Gregger2k THANKS!!!! I don't know what it means, but that is more information than I've seen before.
If anyone knows what any of that means, please let me know.  ie.... put 240v AC across pins X and Y, and you will get DC voltage from pins Z and J.  Put Q resistance across pins D and F for output of L.......

That was fun... 

[gregger2k]

let me digest the datasheet a while and I'll get back to you..

[DanG]

If anyone knows of a source for a big 48VDC alternator

Define big? Direct drive?

[Tom Reed]

This looks like a viable solution http://www.alten-dc.com/products/item/142-48-volt-100-amp.html. All that it will take is $$$.

[mbryner]

Note how that website says "call for price".    $$$$$    Muuuhhhaaaahhaaaaahaaaa.     (Evil laugh.)   

[vdubnut62]

RCAvictim has talked about having a big old honking 50 some odd volt dc generator head. IIRC he spoke about being willing to maybe part with it?

[yellowhead]

Greg, if you find that info, ill buy you a bunch of beer!!!!
I bought one of those a year ago, and never got it working.
The seller was no help.

I've been using a couple of these for a year now. I have a PDF spec. sheet if it helps which I'm happy to share. Pins 1-4 are +V1, pins 5-8 are V1 RETURN for the DC output and to get the unit to turn on I've jumpered pin 12 (module enable) to pin 16 (another V1 RETURN).

I forget the sense of +V1 and V1 RETURN but I have a recollection that its is reversed; a quick check with a meter will sort that out.

In case it is of interest, I have 2 of these with the DC outputs wired in series (since they appear to be floating). This gives me 96V to feed to my charge controller; handy if you need to get the voltage up there to do more than a bulk charge. The spec. sheet suggests the trim pot can bump the output to ~53V but that's not enough for me to absorb/equalize.