Connecting a hi out put alternator to the invertor bank

I am wanting to connect a high output (150 amp) Balmar alternator to my inverter battery bank and I am not sure of the proper way to do it.

I have a Magnum Energy MS 2800 inverter/charger (w/ temperature sensor & remote) attached to 8 - 6 volt AGM batteries. Presently, I can only charge the bank when I am attached to shore power or run the genny. I am thinking of buying a high output Balmar 6 series 150 amp alternator , they are on sale at Defender, and installing it on one of my Yanmar 4LH-DTE engines.

I have searched all the Magnum Energy publications about but cannot find anything that addresses hooking an alternate DC charging source to the bank. Can I buy the Balmar temperature sensor and external regulator and just attach it to the bank? Would each charging source be protected from the other?

I have not looked at my Calders book yet, it's down at the boat.

Any ideas on this?

Thanks, David

This is really an alternator wiring issue and has nothing to do with the inverter.

Your current alternator output is probably connected to the big starter lug and then to the starting battery. Disconnect that wire and with a new big wire (at least #4 to carry 150 amps of current) connect directly to inverter (house) bank through a 150 A fuse.

Then in order to charge the starting battery with the alternator, install a battery combiner, ACR or Echo Charger so that the alternator will connect to the starting battery when the voltage is above 13.5 volts. That way the house battery will not draw on the starting battery while you are at anchor.

You want the high output alternator connected directly to the house bank because 99% of the alternator output current will go to recharge that bank. Very little is required to keep up a starting battery.

But how is your alternator currently driven. A single 1/2" belt is only good to about 100 amps without excessive belt wear.

David

David,

It sounds from your post that neither of your engine alternators are charging your house bank. That would be unusual so may require some additional inspection to see what is exactly the case. The way start and house banks are typically charged from a single charging source is through an Automatic Charging Relay (ACR) that combines the two banks together for charging purposes when either bank's voltage exceeds a preset amount (e.g. 13.5 volts). That indicates an engine or shore powered charger is charging the battery bank it is connected to.

With two engines and a generator with multiple start batteries (one for each engine and the generator) and a house bank, it gets a little more complicated, but there are a lot of products that are designed to handle that. Here is some of the help at Blue Sea Systems (Systems Gallery - Blue Sea Systems). Magnum Energy also sells products to do this.

One thing I have always been told about high output alternators is that you have to be sure your belt arrangement on the engine can handle the load of the alternator. I think Balmar recommends that anything over 100 amps needs a dual pulley arrangement with 2 v-belts or a single serpentine belt. I currently have a 100 amp Balmar alternator with external regulator on a Perkins. It is tied to my start bank through a Blue Sea ACR to my house bank. When I am at cruise RPM, and the house bank is down, I typically see about 70 to 80 amps going into the house bank on the battery monitor. My inverter is a Xantrex with 100 amp charger connected to the house bank. When plugged into shore power the charge from the Xantrex is sent also to the start bank through the same ACR. The PO had a 50 amp charger tied to the start bank, but I have disconnected that and keep it as a spare. There was no compelling reason to run two chargers on opposite side of an ACR.

Tom

David, this previous discussion may help.
http://www.trawlerforum.com/forums/s4/sterling-charging-voodoo-12712.html

You really don't want to connect your high output alternator directly to your inverter.

Your high output alternator should connect to your house battery bank. Your house battery bank feeds the inverter.

How many Amps do you have in your battery banks?

Thanks, I check the site almost everyday and never noticed the "Sterling Charging voodoo" thread. It's a good one with great info. Also, thanks for your replies. Yes, the 150 amp might prove to be too much for the 1/2" pulley although it has a 1/2" pulley on it from what I see.

No, I did not intend to connect the alternator output to the inverter, I am connecting it to the inverter bank aka house bank. The house bank consist of (8) GC2 East Penn AGM 6 volt batteries. It totals 760 AH at 12 volts.

Good point Dave, I will look into the nicer priced Sterling equipment over Balmar.

I sure would like to find a good marine electrician to lay this out but, they are pretty scarce around here.

It sounds like you have 2 engines David. Do you know the output of the stock alternators? Assuming they are around 80 - 90 amps, this is what I would do in your situation.

Have both alternators converted to external regulation by an alternator shop. Then buy a Balmar Centerfielder device and a 3 stage regulator like the MaxCharge. The Centerfielder will combine the outputs from your 2 alternators into one output. So with 80 amps alternators you could theoretically get 160 amps to the batteries. The 3 stage regulator will give you a much more efficient charging system. You should also get a battery monitor so you can monitor the State Of Charge (SOC) of your house bank.

So now you have lots of amps going to your house bank but you also need to recharge your start battery. This can be done, as was stated in earlier posts, with an ACR that will combined the house and start banks. I would look at Blue Seas for that. Also I noted that on the Balmar site (http://www.balmar.net/) they have a product called the Digital Duo Charge. This appears to be a 3 stage regulator that will also combine the house and start batteries when needed. I would strongly suggest you called Balmar tech support with your problem for their suggestion. They have always been very helpful when I needed help.

Using this system, even if your stock alternators are wimpy, you could get by with two 100 amp alternators so you don't have to deal with double pulleys or serpentine belts. You could probably get something suitable on Ebay for a lot less than the Balmars. Suggestion: Start another topic asking where to get the suitable alternators if you need to replace your stock alternators.

I have had similar systems on my previous 4 boats and it works great. Some people may point out that if you run your stock alternators at max output they will soon die. That's correct, but the 3 stage regulator has a setting that will reduce the output of the alternators to say 80% of their rated output.

Ron

Some people may point out that if you run your stock alternators at max output they will soon die.

Its usually a heat problem , sometimes the cure is to take the alt to a shop and buy a better fan that is designed for the direction the alt rotates , instead of a universal fan.

Thanks, Ron, for the suggestions. Yes, I have twins and I assume that the stock Yanmar alternators put out at least 80 amps.

djmarchand said:

Your current alternator output is probably connected to the big starter lug and then to the starting battery. Disconnect that wire and with a new big wire (at least #4 to carry 150 amps of current) connect directly to inverter (house) bank through a 150 A fuse.

Click to expand...

I would be careful about running the output of an alternator through a fuse. There are, of course, differing opinions on this. However, I have always been advised to avoid this because if you blow a fuse for any other reason than an over-current situation, you risk toasting the alternator completely.

David O said:

Thanks, Ron, for the suggestions. Yes, I have twins and I assume that the stock Yanmar alternators put out at least 80 amps.

Click to expand...

OK, then the setup I suggested would solve your problem and I think you will find the 80 Amp alternators will be enough with the 3 stage regulator. I would suggest you choke the combine output of the alternators down to 100 Amps to see how it works and then raise it if you think you need more. Maybe installed temp sensors on the alternators and batteries. The regulator is designed to accept these values and slow down charging if the parameters are exceeded.

Another source for the components is Ample Power (Ample Power Company Home Page). They also have a lot of tech bulletin's to make you smarter. I think their prices are a bit higher than Balmar but some people think the Ample Power stuff is higher quality. I've used both and had no problems with either of them.

Ron