High Output Alternator for QSB380

Hello Everyone
Well we went into the Lithium battery world with eyes wide open knowing full well that a big tank is great but you still have to fill it.
We changed out our house bank to 5, 100ah Battleborn batteries. This also included a WS500 external regulator etc.
Engine is a QSB 380 Cummins with a 120 amp alternator.
On the maiden voyage we noted that the alternator was running too hot (230degrees ).
We are considering ( only considering if we have to) going to a higher output alternator.
Does anyone out there know of a direct fit replacement that can put out say 240 amps. Without creating a bunch of heat.
Thoughts and experiences would be appreciated.

Brent

You will need a better regulator for your alternator and with a temperature sensor. That’s really important from what I understand to be true. Evidently, it’s pretty easy to fry your alternator. Many people are using the Wakespeed controller that is programable.

http://wakespeed.com

No doubt others will chime in.

Jim

Hi Jim
As mentioned we already have a WakeSpeed 500. I took our existing alternator in and had the internal regulator removed and added the WS500.

Brent

if you search the archives on this topic, there are a number of ways folks have done this.

Cummins does have an adapter for a large frame alternator, assuming you have clearance for the big unit.

then the trail begins..... upsize wiring, upsize terminal blocks, upsize cooling capacities etc etc.

Phase3 said:

Hi Jim
As mentioned we already have a WakeSpeed 500. I took our existing alternator in and had the internal regulator removed and added the WS500.

Brent

Click to expand...

Sorry about that. Early onset I guess!

I presume you have an alternator temperature sensor? I believe the regulator is fully programable, so you should be able to control output.

An expensive way to go is a Balmar high output alternator with their external regulator and temperature sensor. A cheaper way would be to go with a Leece Neville alternator which should fit, but make sure that you get one that is designed for external regulators.

240 amps would be too big IMO. 150 or so would be about right. You should be able to charge at 100 amps continuously with such an alternator.

FWIW the Balmar heat sensor cuts back the charging current by half when it senses an alternator case temperature higher than about 185. As you note 230 is too high. I would keep it down to less than 200.

David

Hi Jim
Yes it is fully programmable. Tech is coming tomorrow to make a straight run with 2/0 cabling from alt to house bank tomorrow morning. We’ll run the engine and take temps to see if they go down. If not we will dial back the demand on the alternator. Not ideal but we knew this could be an issue from the beginning. So far though the batteries are impressive.

If you want to go with a larger alternator you might want to contact Seaboard Marine, sbmar.com. They are experts on Cummins.

Tom

I agree about Seaboard.
www.sbmar.com

BUT Take some photos of the existing alternator in enough detail to show the bracketry in as much detail as you can. There are several different bracket types.
Also find the specific mfgr. name, model number and post it. Cummins has used many different alternators over the years. A clear photo of the name plate would help.
You will need this info if Seaboard or anyone else is to help you.

You do need to use the Wakespeed temperature sensor function or you will burn up your alternator. Most of them are not rated to run continuously over 200 -240 F or so degrees. THere are some that are but if you work them hard enough, long enough even they can be destroyed.

You should NOT need to dial back the demand. THat's the wrong end. Rather use that temperature function. That is what it is for. That way the regulator will cut the alternator output back. As the batteries pick up charge then the heating will be reduced and the regulator will allow the alternator to produce more continually.

I agree with Clectric. Somehow the regulator is not controlling for the temperature.

I looked at the Wakespeed website and watched a video on YouTube. There is a Firmware update and an opportunity to program for the alternator make and model.

Jim

David. Thanks for the input. I think you may be right with 180 vs 240.
Leech Neville does appear to be a more cost effective option. Not really interested in spending $1500.00 on an alternator.
I’ll keep everyone posted tomorrow as the tech is coming back to run the dedicated 2/0 lines.

Fairly sure we are using the WS temp sensor function as that’s likely why the alternator shut down after 5 hours of running at 220 - 230 F????
Will ask the tech about updates tomorrow and let everyone know.
You’re all along for the ride.

We put lithium batteries in our last boat. I used the Balmar 624, I think, regulator. It had an alternator load setting that would essentially let you derate the alternator so it wasn’t trying to output the max current. Never done anything with Wakespeed but they probably have a similar setting.

I had the same problem on my QSB 380. Depending on the vintage of QSB, it will either have a 2" mount or a J180 4" mount. The parts are available from Cummins to change to the J180 if you have the earlier one, however you will have to work for it as the parts are not in distribution or listed in distribution. I can provide the part numbers.

I had the stock Delco 19si, supposed to be 120A I think, but would actually do about 60 once warm.

Once you have the J180 mount (it is an easy bolt on) there are a number of choices. I fit a Delco 28si, available in 160 and 180A specs, J180 short hinge is what you want. These are about $300 online and are designed for continuous bus service. You will need to take it to an alternator shop and get it converted for external regulation (should be about $100). Swap the existing K8 pulley over, they are unique to Cummins. It just barely fits, I had to make a custom top arm. I can get about 120A continuous out of it, limited to 107 deg C. with a Balmar 614. Starts out at about 170 cold but that only lasts a few minutes. The Wakespeed should be similar (I've got a Wakespeed to install but haven't done that yet). Balmar's default of 100C will drop it another 20 or more amps - very sensitive to that setting.

I tried a Balmar alternator they recommended ($1200) and it failed miserably - insufficient output at idle to keep up with engine electronics so I'd get all sorts of alarms at idle. Can't turn the idle up easily (or maybe not at all) on a QSB. I've given up on these expensive aftermarket marine only alternators - very expensive without the added value.

Delco now has a 40si available in a J180 short hinge, up to 320A spec. This looks a little larger than the 28si and might have trouble with the remote oil filter lines. The remote filter is of dubious value in many installations and I'd consider removing it. I'm not sure how much is practical from the K8 belt, I get some belt dust at 120A continuous, not sure how long it would last at say 200A. The 240 and 275A spec 40si are supposed to be rated for 125C continuous (as is the 28si) but it is hard to know where that is measured and what the Wakespeed or Balmar is measuring.

Both the Wakespeed 500 and the later Balmars derate on temp intelligently, hunting until they reach the limit you've set. No reason to derate the field with any of the other facilities (belt load, % field, etc). Just let it run to the temp limit.

How about you alternator belts? If you go to a higher output unit you will need a serpentine or double belt setup.

Dave.
Thank you for the wealth of information. What temp is the Delco 28si running at?

^^ is that a Q for me?

My 28si is set for 107 deg C, and that is what it runs at as reported by the Balmar 614. The temp sensor is fastened to the case, forget exactly where. The Balmar default is 100, Delco spec is 125, measured .... somewhere. With the default setting after the temp stabilized I was getting about 105A to the batteries (everything else draws about and additional 20 while running). I adjusted the temp limit up, even a couple of degrees does something. With it set at 107, I am getting about 120A into the batteries. I don't know how far you could go, surely there is a curve of temp vs. longevity. With a Balmar 614 regulator, you will see the output start at 150 or 160, then derate over the first 10 minutes or so to 80 or 90, then inch back up to 120 as the temperature servo loop captures. Older Balmars just cut the field in half when the temp limit was hit.

When I start the engine cold at idle, I was getting a net -15A from the Balmar alternator. With the Delco 28si, about +90A. Many of the marine rewinds sacrifice low speed amperage for high speed. In my AT34, we run at 1200 - 1300 rpm typically so low speed performance is important. That also runs the alternator cooling fan at a lower speed. The QSB already has a 3:1 ratio on the pulleys which is pretty high, so 1200 is 3600 alternator shaft RPM. One issue with some of the marine rewinds is top speed - Balmar wanted a limit of 7000 shaft, this would be a problem with the QSB at 3000 engine rpm, 9000 alternator. The 28si is rated for 10,000 continuous.

One more thing: the 28si has a grounded frame, the QSB usually has a ground cable from the alternator output to the starter ground or other high current connection. You need to retain this, but will need to fasten to the fixing bolts as there is no ground terminal. I upsized this cable, clamp ammeter readings indicate about 1/2 the current is going through the cable, the other half through the engine block.

Great information once again DDW. The tech is here right now. The decision was made to run a dedicated neg and pos 2/0 lines from the alternator directly to the house batteries so there will be very little impedance.
Is this a concern if we end up going with the 28si?
Sorry DDW. Yes that was a Q for you.
Brent

I put in 2/0 from alternator to the nearest high current bus, serviced by 3/0. There is a couple of tenths drop in the 3 or 4' of 2/0 when charging hard and I kind of wish I'd gone 3/0. They also get slightly warm after awhile. If you have the chance, especially with LFP which will run higher current longer, I'd go 3/0. I don't think 2/0 is dangerous, just not quite optimum. Your remote voltage sense will compensate, so you are just loosing a little efficiency.

Well it’s too late for 3/0. Tech states 2/0 will be fine as the run to the house bank is 10’.

I also have the WS500 (actually bought a 2nd one so I could network both engines/output together)... That being said, it doesn't sound like you have the device configured correctly. If you have BOTH temp sensors (battery/alternator) connected AND have them configured in the setup tool correctly, your alt should never cut out. May be reduced in output, but not cut out completely due to thermal reasons...

Also, if you can find a charge profile of your alternator, that would be very useful as well. Just because you buy a 150, 180, 250a alt, doesn't mean you are going to get anywhere near it's rated output. Even if you do, it will only be for a short time since the output profile declines with the temp...

One of the reasons I bought/networked the 2 engines, was when I started figuring out my burn rates on my engines and found my sweet spots for the RPM's and what time/fuel I was willing to burn on longer trips... What I found out, was that my 1800-1950 RPM's were putting out A LOT less amperage to my batteries and in some cases barely keeping up with battery output. Adding the second alt added in all the "wasted power" after the start battery was full...

Phase3 said:

Fairly sure we are using the WS temp sensor function as that’s likely why the alternator shut down after 5 hours of running at 220 - 230 F????
Will ask the tech about updates tomorrow and let everyone know.
You’re all along for the ride.

Click to expand...

If the alternator was allowed to operate at 240oF for 4 - 5 hrs then either the regulator has NOT been properly set, it is not working properly or the the temp. sensor is not connected or working.

OR unless you already have one of those alt. that can withstand higher temps than most. But even in that case YOU need to find out what that rating is to ensure the regulator is set properly and is working correctly.
That's why you need to find out WHICH alternator you have.

Do not assume here. You can destroy your alternator and maybe cause a fire.

C lectric said:

If the alternator was allowed to operate at 240oF for 4 - 5 hrs then either the regulator has NOT been properly set, it is not working properly or the the temp. sensor is not connected or working.

OR unless you already have one of those alt. that can withstand higher temps than most. But even in that case YOU need to find out what that rating is to ensure the regulator is set properly and is working correctly.
That's why you need to find out WHICH alternator you have.

Do not assume here. You can destroy your alternator and maybe cause a fire.

Click to expand...

So after a few hours we’ve managed to run 2/0 pos and neg directly from alternator to house batteries. We ran the engine at different idle speeds and loads for around 45 minutes. Max temp on alternator reached 220 F.
As temp rose the amperage output decreased which then saw a decrease in alternator temp.
It seems for now that this has potentially helped the heat issue.
All programming was checked with the alternator make model output etc to ensure no mistakes were made.
Maximum output at the alternator was 100 amps at 1500 rpm.
I am also going to try a simple idea and open up the plastic belt cover on the front of the engine info t of the alternator to try and get more air circulation. Will cover with screen for safety.
We have a long run tomorrow of 5 hours and will tell us more then.
As before, I’ll keep folks updated.
Thanks for all the advice.

Brent

I agree with Clectric. I think you should phone Wakespeed and see what their support has to say about the issue. It sounds like the device is fully programable.

Jim

Unless you KNOW what the alternator MAX. safe long time operating temp is you are asking for a meltdown.
220°F seem to high to me for the standard alternators. Another 20° drop would mean a world of difference to the alternator. But find out what that alternator can handle.

I am not an alternator expert but have enough experience to have a pretty decent understanding of these things. FIND OUT or you will cook it.

I won't try again.

Phase, When I repowered with 6bt Cummins, I had the installers upgrade the alternators to 160 amp each with Balmer smart regulators and a Balmer Centerfielder to coordinate them. There were no issues with the alternator mounts that I'm aware of. Send me a pm if you'd like me to get you the specifics from the shop that I used that did the work.

C Lectric. I HEARD you. Capital letters are needed. I will check the parameters again as marine electric tech who deals in WakeSpeed also checked as mentioned before. And yes I trust him.
Thanks Ken. I’ll get some photos and part numbers in the event we need to go that way.
Brent

If the alternator is the original Cummins OEM, it is probably a Delco 19si or 22si. The 22si most easily identified as it has the 4" J180 mount while the 19si is the 2" mount. I believe both of these are rated to 200 deg F. They are intended only to charge a start battery in a car or boat. A house battery is really above their pay grade, not to mention LFP. The 24si is rated at 221 deg F and the 28si at 257 deg F. Delco publishes pretty good specs here, on most HD models you can download complete specs.

The Wakespeed 500 is the most programmable and sophisticated regulator on the market by far.

I took that belt guard off and put it in deep storage. It only gets in the way of every service task. Goes without saying to keep your hands out of the running belt.

Was the alternator putting out 100A when at 220 deg?

Phase3.

I understand you have double checked the parameters so I will leave it there.

Alternator temps and specs are a bit of a shell game, since nothing is clearly specified. From conversations with Prestolite/LN tech support, here's the best I have been able to sort out. It seems to make sense, at least mostly, but it's hardly anything reliable. But it's the best I've been able to deduce.



- Alternator specs as found in data sheets are max allowed ambient temp. This are all in the context of the temperature under the hood of a car, truck, or bus. So a 125C rated alternator is designed to work in a vehicle with an under-the-hood temp up to 125C. But nowhere that I've found does anyone state this explicitly.


- Regulators sense and regulate based on the rectifier temperature. I say this because if you look where all the manufacturer's tell you to install the temperature sensor, it's on the power post of the rectifier. Also note this is at the cooling air INLET, for most alternators. 100C seems to be a common limit. There is an immediate disconnect here if an alternator accepts 125C ambient, yet only 100C rectifier temp. At 125C ambient, the rectifier will ALWAYS be above 100C. But let's not let engineering get in the way.


- I think when most people shoot the temp of their alternator, they are shooting the center of the case. At least that's what I do. That's the stator, and it typically the hottest part of a working alternator, and typically a lot hotter than the rectifier. This is NOT the temperature that a regulator is monitoring or regulating to. I got all concerned with my last boat because I was regularly seeing stator temps in excess of 150C (300F). But after extensive discussions with Prestolite/LN, they convinced me this was fine for the stator. But it wasn't until the question got escalated to engineering that I got a sensible answer. I see the same behavior on my current boat where under extended full load the rectifiers are right around 100C and the stator is 150C. This is under sustained full load for a couple of hours.


So if you want to check for the magic 100C temp limit, be sure to shoot the rectifier, not the stator. Otherwise you will freak out and be sure a meltdown is imminent, as I did when I first encountered it.