48V gas powered charger

[Mad_Labs]

Hey Folks,

So, I thought I'd start a thread rather than hijack the others. Here is my situation:

I live off grid. Currently I have a 12V system, but I am just about to make a major purchase and upgrade to 48V. I have a Honda 5000S generator that I replaced the usual gen head with a LN 110-555. It's a direct drive set up and it came out nice, looks just like a regular generator. I was very, very naughty and didn't even use a lovejoy, I just made an adapter to connect the two drive shafts together, figured out some mounting for a couple of bolts and voila. I know this isn't recommended, I don't endorse the idea but it has indeed worked fine for several hundred hours and still sounds great. The bummer is that it is way too much motor for the alt and fuel economy sucks. Charges the bank up pretty quick though and shuts itself off when done. I am in the process of making a new controller, this one has a fuel sensor that will track volume consumed and a few other fun features.

Anyhoo, with the upgrade to 48V, my battery bank will be eight golf cart batteries in series, for a 10.5kWH bank. I'd like to be able to charge it between C/10 and C/15, so say 80 amps would be nice. Eventually, I will need to charge a 31.6kWH bank with it, within a couple to 5 years. So my ideal would be to make something that could handle the larger load, but I may settle for just being able to charge the current bank. Of course I would like to be able to equalize, but could use my solar for that, my charge controller has that capability. So I could charge the bank up in the AM with the genny, then let solar do the EQ.

I just remembered I have a Leece-Neville model A0014864JB. It's used and untested. If I could strap that to the Honda 5000S frame and use it to charge a 48V bank, I'd be very happy. However, since this upgrade is bleeding me dry cash-wise and is going to be a black hole of time, if I could just modify the 555 to charge for 48V in the current direct drive set up then I could at least do that. While my new inverter will have a charger built in, I just feel naked without a second charging source. I make my own controllers, so no overcharge issues with large alts or anything like that.

Ultimately, I have a new, never run China diesel 8kW generator that I will be using. At that point I want to capture waste heat etc. But I have to build a permanent shed and I am still having to deal with the building dept. and don't want to get them *too* interested.

So bent, I may need those alt frames or not, depending on what the verdict is.

[bentcrafter]

Jonathan,

Is the motor a GX270 (9hp)?

Your coupling has me concerned. If you mounted the alternator with both front & rear alternator bearings intact, your coupling alignment has to be near perfect. By perfect, I mean well below .003" runout between the engine PTO & the alternator input shaft. If not, you'll eventually lose the alternator's front bearing, and quite possibly the alternator's front housing - especially if the alternator is rigidly mounted. Higher RPM & heavier loading will exacerbate the pending failure. LoveJoys allow for a slight misalignment - and if misaligned bad enough, will only wear out the replaceable, neoprene insulator (a.k.a. star). What is your zip?

I have two separate 24v gen projects in progress - Honda GX240 (8hp) W/LN 110-555 (shown) - and the second is tandem coupled (2) GX160's;



       

[Mad_Labs]

Bent,

The motor is a GX340. I do plan to add a lovejoy in this newest version. Basically I just hung the alt on the motor shaft and then gently bolted it in place. It runs quiet and sounds good through a stethoscope. But I know it's bad and I will add the lovejoy. My zip is 95410, I live about 5 miles outside the teaming metropolis of Albion, CA, poulation 399.

So, from what I have gathered, I could rewire either the 555 or the A014864JB from delta to wye configuration but then I would need to run at 5000 rpm. The Honda runs at 3600 RPM. The only way to get 48V (nominal) at 3600 rpm would be to rewind.

So it looks like choosing between totally modifying my current platfrom to allow for pullys to up the RPMs or re-wind the stator. Is that about right?

And how much of a bugger is it going to be to rewind? Doesn't seem fun, but then niether is building a new platform.

Thanks Gents!

Jonathan

[bentcrafter]

Interesting dilemma,  Jonathan

Before I offer a another possible solution, I need to ask;

I'm all in favor of 48v, wish I could. But are you setup for 48v charging with your PV's?... but more importantly, are you setup to 'use' 48v (.i.e inverter, lights, ect). If not, can you make-do with S/P the batteries for 24v instead?   

[mobile_bob]

having rewound many stators, for my own projects, i can tell you it gets more difficult
the more wire you try to stuff in the stator slots. bare in mind the ends of each coil must clear the inside of each end housing.

rewinding a 555 for 48vdc nominal wouldn't be too bad, but again what is the goal here?

if the goal is simply to get to a useful 48volt machine at a specific rpm, without regard to efficiency, then go for it.

if on the other hand you are also concerned with efficiency, you might want to consider a belt drive.

in these machines, stator resistance is the dominate factor limiting efficiency in my opinion.  far more so than air gaps, iron losses, friction and windage, field current, all combined.

also, if you have problems with carpel tunnel or arthritis, you will certainly pay dearly rewinding one of these stators.

fwiw, if you are going to do it, go to a motor rewind shop, and beg/buy/trade for or whatever you have to do to get some slot paper, and top strips, and use the highest temperature rated wire you can get.  don't take short cuts because you will have a few hours invested and having a short or failure later due to not using the proper materials is going to really piss you off.

there is a lot you can do with one of these machines, when rewinding

i came across one a rewound back in the mid 90's, an old leece 2700jb series
it will make 120vac single phase at 600rpm, conversely it will also make 480vac single phase at 2400rpm with 12volt excitation. bloody dangerous machine in my opinion. i built it to see what is possible, the machine is limited to about 7amps due to small gauge stator wire needed to get enough turns in there.  it will remain on my shelf as an example of one of my old projects, but i will likely never use it because it is a frightening thing if you forget what it is capable of.

at some point i will destroy it, because i don't want sometime after i am gone to have someone buy it at auction thinking it is a 12volt alternator and get himself killed!

bob g

[Mad_Labs]

Brent, Bob,

I am set up to use my PV's for 48V. Actually, I will be running the panels at around 90V and the the charge controller (Midnite Classic 150) will charge at 48V. Nice thing about this is that it allows me to run 4320 watts of panels at the best part of the controller's power curve, for total power processed, charge efficiency and maximum MPPT boost. Plus smallest possible wire guage. So yeah, I'm going 48V.

Efficiency. Well, in the end I need to wind up as efficient as possible. I don't HAVE to, but I want to. Might not be right now though. As I mentioned, I have a diesel gen waiting in the wings. It comes down to how much work and time to do a good job on the gas powered version as to which way I go. I am leaning towards using pullys, but rewinding would just be so slick... And the gen set frame I am using doesn't lend it self well to pullys, from the physical layout point of view.

Thanks, you are both reallly helping me.

Jonathan

[bentcrafter]

Pictured below is a comparison between a 12v (1920w rated) stator, and a 24v (2860w rated) stator. A simple drop-in for the LN 555. I have the 24v stator installed, but I'm still a ways from efficiency testing.

I should point-out here, that I'm NOT using the OEM rectifier or regulator - I'm pulling AC directly off the converted 555 and feeding an external rectifier.

[bentcrafter]

And here's a shot of the naked 'business end' W/24v stator. Suffice to say, stator cooling shouldn't be much of an issue. (The field wires weren't yet installed when this pic was taken.) I'm using the OEM 12v rotor.

[mobile_bob]

Bent

is the 24v stator wye connected?  or delta

i am betting it is wye connected?

btw. where did that spec chart you posted come from?
what alternator was used for the chart?

thanks
bob g

[bentcrafter]

Bent

is the 24v stator wye connected?  or delta

i am betting it is wye connected?

You tell me...

[mobile_bob]

it appears to be delta wound like the 12volt version, however it also looks to have maybe twice the turn count per coil?

i just can't tell for sure, looks well made though which one would expect

thanks
bob g

[Lloyd]

Bent

is the 24v stator wye connected?  or delta

i am betting it is wye connected?

You tell me...

It appears to be a Motorola 8MR, originally a marine alternator, one of the few CG approved alts for a gas engine, by the CG.

This one certainly would not be CG approved, due to the modifications and open brush holders.

Of interest to also note is it is an isolated ground...or was in it's factory form. The largest 8MR was only 120 amp cold @12 volt.

So if this alt is/was rated at  12v (1920w rated) stator, and a 24v (2860w rated) stator, it's not by Motorola/Leece.

I also don't think it's a drop in for the triple nickle, as it is /was a different form factor.

Lloyd

http://www.prestolite.com/pgs_products/specs.php?item_detail_id=897&item=8MR2070TA&product=ALTERNATOR#

[Lloyd]

Now I'm thinking an elder Prestolite except most of those housings weren't round, but it def come from the merger somewhere. They had some larger amp models that weren't Marine related, bu used the same/similar housing

Lloyd

[SteveU.]

Hey Mr bentcrafter
Do NOT use the 12 volt  stator pictured. It has a leg shorted or grounded out some where as evidenced by the overheated, blackened flaking insulation.

A wye wound three phase stator will somw where have a common lead pigtail connector. A delta wound/connected never have this. Have to see a picture of the complete stator to say for sure if delta or wye.  Two leads to each flag end not a 100% reliable indicator of delta due to parallel lead windings possible on some.

Regards
Steve Unruh

[mobile_bob]

i am going with the delta connected 555 style stator made to fit the 24volt counterpart

reason being, in order for the thing to cutin somewhere near as low as the 12volt counterpart i would need about twice the turn count as evidenced in the picture

there would therefore be no need to connect it in wye that i an see if you have the already low enough cut in.

of the 24 volt stators i am aware of the only wye connected ones were single in hand wound and were wye connected, having about 5 turns if i recall correctly, they were rated at about 70-80 amps

the other series i know of is delta connected, wound two in hand, having about 9 turns and were rated at around 160-180amps

there is another series that i have seen, but not taken apart, it is rated at 24 volts @ 240 amps, i can assume  it to be wound three in hand, possibly 4 in hand,  definitely delta connected.  that would be an interesting stator to take a look at.

also RE electric (seattle tacoma) bought a large rewind shop down in socal about 5 years ago now, i was told that they would rewind any stator to my specification provided it was a possible project. the  price would be something between an aftermarket stock stator and a new oem stock stator, which i thought to be quite acceptable.

that would open up some interesting possibilities.

if i were to spec a stator for my purposes, i would probably go for 4 in hand, 6 turns per pole connected in delta. this would get me a 48volt nominal output (~60v charging) in the 5-5500 rpm range. which would work out very well for my needs, a nice compromise between reliability, cooling, output, efficiency and rpm.  i might also want it pigtailed for connection as wye or delta, that way i would use switch gear to get usable charging at ~ 3500-4000rpm wye connected albeit at lower efficiency.

in any event, i have long been a strong proponent of the 555 type alternator.

my first hands on connection with the grandaddy of this unit was in '82 while working in a truck shop, one came in dead on a truck and got swapped for an 1100080 delco..
it was the motorola Steve and Lloyd talk about, but not a marine version. it was very heavy because of a cast iron case, even though thin wall cast it was very heavy compared to the modern 555.  i knew when i first got my hands on it, that it would be a great alternator for low rpm ranges or rewind to other voltages. it having 16 poles, externally accessible brush holder and low iron stator made it very desirable, just not very available and bloody expensive to experiment with back in the day.

when i first saw the loadhandler by prestolite i immediately knew where it came from, they bought the rights from motorola and i was thrilled to see it available for such a low price.

as far as i am concerned it is the best thing since sliced bread for diy battery charging uses.

bob g