130 vs 160 amp alternator?

[BDofMSP]

On our trip across the country I purchased a replacement alternator for my Cummins 6CTA 450. I just got around to swapping it out recently. Looking closely at the original Delco Remy (PN 4003445) it's a 130 amp alternator. The one that I was sold as a replacement (Wai 8560N) is a 160 amp version.

It seems to be working great since the install. I was intending to get the Delco Remy rebuilt and replace the port side alt with the rebuild (just to get them both "new" at the same time) and then rebuild that port one as a spare.

So:

1. Is having a 160 amp version as a replacement a problem?
2. If not, should I replace the port with a 160 amp version so that they match?
3. Is there something in the rebuild process that could convert it to 160?

Thanks,
BD

 

[DavidM]

The difference between 130 and 160 amp alternators is not significant. Maybe heavier diodes, heavier fan, heavier windings or maybe just a label change. Don't worry about it.

Perhaps a more significant question is do you need high rates of charge for several hours? Stock alternators due to their fixed voltage settings don't put out anywhere near rated current unless the batteries are near dead. So if you anchor out a lot and would like to charge up your batteries in a few hours rather than all day, consider a high output alternator with an external regulator that will push more amps into your batteries quickly.

David

 

[BDofMSP]

Thanks David,

We anchor out but currently only generally overnight or two. Work requirements and all...

We run the gen for heating water, microwave, occasional A/C, etc and add the battery charger whenever we do that. So far that's kept us going fine, although I get that I'm not probably really getting my bank charged to 100% by doing that. They do get back to 100% when we return to the dock, so it's just for a couple days.

I guess if I'd had time to plan the whole thing out before I bought the new alternator, I may have considered doing it differently. But now that it's bought and installed, I'm not excited about crawling back there again. Fortunately the port alternator is simple to access. Given that that amp difference is not significant, I'll move ahead as planned and get the rebuild done. I'll have 160 on one side and 130 on the other.

Thanks for the input.
BD

 

[Comodave]

Are the wiring and fuses big enough for the larger alternator? What type of belt is driving the alternator?

 

[BDofMSP]

Are the wiring and fuses big enough for the larger alternator?

I don't know the answer to that. That's sort of why I asked the question - to find out if there's anything problematic with replacing with the 160 vs the original 130. Is that a concern? The wiring as far as I can tell is the wire from the alternator to the starter, which then of course has the huge wire to the battery. There's no fuse between the alternator and the starter that I saw.

As a side note I asked the same question when I just dropped the old one off for rebuild. The guy said that the new alternator would likely never be demanded to output anywhere near it's maximum capacity and that I shouldn't worry about it.

What type of belt is driving the alternator?

The stock Cummins serpentine belt. It was just replaced prior to replacing the alternator in hopes that was the problem (it was not).

Thanks
BD

 

[Comodave]

If it is going to the starter and then to the start batteries the wiring is probably big enough. A serpentine belt should handle the 160. How are you charging the house bank if the alternators are going to the starters and not the house bank?

 

[BDofMSP]

I don't have a separate house bank. I have 3 group 31's on each side that provide both starting and house power. And a separate battery to start the gen.

 

[Comodave]

Ok, if you don’t anchor out much that will work, but the start batteries don’t work as well as true deep cycles for house usage. But it would be a lot of work to add a house bank.

 

[rslifkin]

I had a similar setup where house loads were split between the 2 engine banks. Ultimately, I split it off to a separate house bank. Basically, changes were as follows:

• Delete generator start battery
• Add house bank with on/off switch
• 3 bank charger (charges start 1, start 2, house)
• Engine and generator battery switches configured to select between start 1 and start 2 (normally port uses 1, stbd and gen use 2)
• Move panel mains and other house loads to house bank
• Move engine ignition breakers from panel to separate breakers drawing from each engine's battery switch
• Add ACR on each engine to connect to house bank for charging (these are ignition interlocked on my setup, so charging is independent on shore or generator power, but engines charge the house bank when running), alternators still feed to engine batteries

All told, it wasn't too bad to do. Batteries used in my setup are a group 27 for each start bank (you'd need at least a G31 with diesels) and 2x L16 6v to make a 400ah house bank.

 

[Comodave]

The only things on my start batteries are the engines. Everything else goes to the house bank which right now is 2 6 volt golf cart batteries and may change that to 6 6 volt GC batteries this winter.

 

[rslifkin]

The only things on my start batteries are the engines. Everything else goes to the house bank which right now is 2 6 volt golf cart batteries and may change that to 6 6 volt GC batteries this winter.

That's how my setup works after the re-configuration. If it's not directly controlled by an engine key switch (or the generator start toggle), it doesn't draw from a start battery.

 

[BDofMSP]

I have thought about this change for awhile while sitting down there trying to figure out how everything is set up. My problem, like most folks, is space. I do have one space on the port side where I could add batteries. They wouldn't be super accessible but I could use AGMs. My problem is that I ALREADY have a slight list to port due to the location of the dinghy engine end. Adding a bunch of batteries won't help that much.

Sounds like I problem I should solve when it actually starts to become a problem. Or maybe when I renew the battery bank.
BD

 

[Comodave]

My 6 volt bank is a PITA to get to. It also causes a list to starboard but loading equipment takes care of that now. If I expand the bank the list will be more of a problem. In order to do that I have to get a new A/C and go from a split system to a stand-alone A/C. So it will cost me about $3K to do it. Not sure if it is worth it or not.

 

[BDofMSP]

I'm glad you brought this up. I say it's a problem that I should solve later, but what I really mean is it's a problem that I should PLAN a solution for now and solve when the right opportunity emerges. If I don't have the plan, I may be stuck just replacing what I have because it's urgent vs because I decided to.

Thanks
BD

 

[BDofMSP]

Basically, changes were as follows:

• Delete generator start battery

Why the deletion BTW? Just for space saving purposes? Or did you think it became unnecessary?

BD

 

[Comodave]

I actually don’t have a dedicated generator start battery, I use the house bank. I don’t have the room for one. But just in case all three banks go dead I carry a jumper pack that will start the diesels or the gendet.

 

[Swfla]

I have thought about this change for awhile while sitting down there trying to figure out how everything is set up. My problem, like most folks, is space. I do have one space on the port side where I could add batteries. They wouldn't be super accessible but I could use AGMs. My problem is that I ALREADY have a slight list to port due to the location of the dinghy engine end. Adding a bunch of batteries won't help that much.

Sounds like I problem I should solve when it actually starts to become a problem. Or maybe when I renew the battery bank.
BD

That makes a great deal of sense. The way you use your boat, it's unlikely you'll have any issues. Once you start thinking about starting batteries vs deep cycle and agm vs wet cells, then you want to separate them and set up your charging system with isolators and all the other things. I'm sure you'll be able to work out the list to port at that time too.

 

[rslifkin]

Why the deletion BTW? Just for space saving purposes? Or did you think it became unnecessary?

I deleted it for a few reasons. Freed up a little space on the board you climb down onto to get into the engine room, saved some weight, and kept the charging and starting battery selection switching simpler. And I figured that with 2 independent start banks, there wasn't any need or benefit to having a separate generator start battery vs just sharing with one of the engines.

Both engines and the generator each have their own 1-2-both-off switch, so any of them can be started from either start bank if something happens to one of them.

 

[Swfla]

Let me make one amendment. If one cell in a battery goes bad, the whole battery is bad. If all batteries are in parallel, one bad cell in one battery will strain them all.

 

[FF]

"I have 3 group 31's on each side that provide both starting and house power."


If the gp 31 are all house (deep cycle) batts thats fine , but starts do not take kindly to deep cycling.

 

[Bacchus]

"I have 3 group 31's on each side that provide both starting and house power."


If the gp 31 are all house (deep cycle) batts thats fine , but starts do not take kindly to deep cycling.

"I have 3 group 31's on each side that provide both starting and house power."


If the gp 31 are all house (deep cycle) batts thats fine , but starts do not take kindly to deep cycling.

Above true for FLA battys.
I'v been developing a batty replacement plan (no more 8Ds) and have contacted East Penn. They confirmed for their AGMs plate design is the same and no difference in start vs deep cycle performance / preference between GC2s and GP 31s (other than spec values). So it appears AGMs are a much better dual purpose batty than FLAs.
What prompted the inquiry was I noticed both AGM GC2s and GP31s listed both CCA and AH specs which are not typical for FLAs.

 

[DavidM]

Don:

Thanks for checking that question of deep cycle vs starting AGM batteries with East Penn. That has always been my suspicion too but never confirmed it with a battery manufacturer. The only AGM battery manufacturer that I am aware of that builds separate batteries for deep cycle and starting is Optima and the only difference may just be the color of the tops .

David

 

[Swfla]

There are combination start/deep cycle batteries. I had them in my flats skiff(many years ago) with electric trolling motor but only used them for trolling. They lasted about 6 years. I'd say true deep cycles would have lasted longer. So, using those for a trawler would likely kill them in 6 years. Way too soon.