Crazy Battery Chargers

[GJH]

Angela, get yourself a copy of Nigel Calder's "Boat Owner's Mechanical and Electrical Manual", right now. You will love it. It will explain everything you want to know about this subject (batteries, inverters, chargers, alternators etc. etc.) in plain English and in detail. If you had it, you would not be asking these questions here.

Personally, I am out on the idea of using GC batteries as a house bank; haven't you already had some explode on you? One of the secrets to Sky's success is that he uses the big bad Rolls 8HHGs for his battery bank. They will crank the engines and provide 275 amp hours (AH) at 32 volts. That's like 365 AH at 24 or 730 at 12 volts.

I went to a separate 24 volt bank for my inverter system because we planned to, and did, live on moorings full time in winter (Marathon) and summer (Westport, MA). I just didn't feel comfortable running one of the main banks down all the time, and I had new, much lower AH (about 190) Interstates on the boat already via the PO. I also liked Magnum's integrate-able inverter, automatic generator start and battery monitor system (the new ones are even way slicker than mine). Additionally I had plenty of room to install 4 L16 deep cycle batteries delivering 410 AH at 24 volts in the generator room. They have the same footprint as a GC but are taller.

My primary goal was to have a system that would power our giant household Sub Zero side-by-side reefer, along with two beverage coolers, overnight, along with the rest of the upper deck. We ended up running the genny about 6-8 hours a day anyway for cooking, dish and clothes washing so that worked out fine. Now that we have settled in North Carolina for a couple of years, the generator is used much more for heating and cooling.

The flaw in my system that I have not corrected yet is that the inverter bank does not get charged off an alternator, so it gets run down more while underway. Someday I may hang a 24volt alternator off one of the engines, which is doable though somewhat expensive. I only have selected circuits on the inverter and someday may add more. Given where the different AC panels are, that will be a bit of a PITA.

While I have been delighted with my system for the last 3 1/2 years, if I had to do it all over again, I would probably install a second, smaller and quiet modern "night generator" of about 10 KW (my boat is wired for one) and MAYBE hang an Outback or NewMar on the 32v house bank, which is now made up of the same Rolls batteries Sky has. Current long term plan is to get the 2nd generator which may well mean giving up my beloved Magnum system. I would run that way awhile before deciding if an inverter was needed.

Remember, inverter power is not all "free". You are going to buy the energy to recharge that bank from somewhere: your engines, the genset, or FPL. Eventually, the batteries have to be replaced. To me, the main benefit of the inverter is the quiet, and secondarily not putting out exhaust fumes and water all night.

[MikeP]

IMO you don't really need separate batt banks. I have both oem banks combined and charged with the Outback inverter/charger. It works beautifully.

THe Calder book mentioned earlier describes that one large batt bank is more efficient than two smaller banks so overall you are better off with one bank instead of two as far as battery life and efficiency are concerned.

HOWEVER, I will readily admit that it is theoretically possible to run down this large batt bank far enough so that you cannot start the engines. I say it's theoretically possible because I have never been able to actually do that but it could happen if you sat at anchor for several days and never ran the mains or genny. But I can promise that for at least 24 hours of batt/inverter use, our 8v71TIs will start instantly. We have cheapo Dekka Batts; I'd imagine that with Rolls batts you'd be talking about at least 36+ hours with no trouble if they started out fully charged.

[Angela]

I have Calder's book - I've had it since I got the boat five years ago. I've begun reading it over and over, but I just don't get it. I end up reading on through it, but not quite understanding it, still, and the further into it I get, the more lost I am. That's my problem - I have some sort of mental block for all that electricity stuff.

[SKYCHENEY]

As George noted, most of the new inverter/chargers have all kinds of special functions. The Outback will start your genset at a predetermined battery voltage if you have the Mate. It also will equalize and all of the charging voltages and times are programmable (Absorb, float, refloat, etc). Additionally, if you add the Flexnet, you will be able to keep track of total amp/hours in, out, and remaining.

I know there are other good units, but if you want one in 32v, I think Outback is one of the only choices.

[GJH]

Angela, if the Calder book is difficult for you, then hire someone like Ward's to do the install for you. You can't get this explained in plainer English and pictures than Calder uses. Coming to a forum for advice will likely at best end up confusing you and at worst lead to some bad mistakes.

Sky, the Outback's method of accomplishing generator starting is rather convoluted, whereas Magnum's networked module (I have a three wire system) is quite elegant and easy to use.

http://www.outbackpower.com/pdf/tech...ator_start.pdf

[SKYCHENEY]

Sky, the Outback's method of accomplishing generator starting is rather convoluted, whereas Magnum's networked module (I have a three wire system) is quite elegant and easy to use.

http://www.outbackpower.com/pdf/tech...ator_start.pdf

I don't have mine hooked up to start the genset. I'd rather start it myself as I don't like that automatic stuff. I want to know that the generator is pumping cooling water, etc.

But, if I did want to do this, I think I could simply run the wire from the Mate to to the Norpro Aux start input and I'd be good to go. I don't have the standard Norpro panel. I have the optional digital control so it looks like that would support this without the need for any additional relay.

[GJH]

I had somewhat mixed feelings about the AGS for the reasons you do, Sky, but it has turned out to work well for us. I only have it on when we are on the boat, and it virtually always comes on when I am awake, or it awakens us. What typically happens is one of us will get up in the morning and start the microwave for tea and/or the coffee maker, and the voltage draw down will trigger the gen start. You definitely know when the genset starts. I like it because you don't have to keep minding the volt level of the batteries or worry about the inverter kicking off due to low voltage. Since we spend so much time living aboard away from shore power, this has been a very nice convenience. As a side benefit, it is also there to spring on if and when dock power fails. Also, my generator cuts off very quickly if temps get high as I learned when we had a bad heat exchanger. I use a daily checklist to confirm oil and coolant levels as well when we are moored or anchored for more than one day.

The Magnum system is highly and easily adjustable for start voltage and run time hours, the new ones are even more sophisticated in integrating with the Battery Monitor System. My old Onan requires glow plug activation for a set period of time, as well as the starter being engaged for a certain period of time and engaging the stop solenoid for X amount of time to ensure proper shutdown. You program the Magnum AGS to your genset's profile and it executes perfect starts and stops every time.

[spcoolin]

I'd add the NewMars to your 12 volt list. American made and great customer service. NewMar makes a very expensive and well made 32V inverter, I think the Outback may be a better value. Newmar shows a 32v charger in their catalog, But I think it is a made-to-order unit.

Sentry still makes 32v chargers as well. Steve Pooler (SPcoolin on here) is an expert and evangelist for those; I have had issues with mine which seem to have got better with a new control board. Nice thing about them is they are field serviceable and getting parts for my old unit was easy. Most (if not all) authorized Cruiseair techs are also trained in Sentry. I decided to go with a separate 24v bank for my inverter set up and highly recommend Magnum for 12 or 24v inverters.

Wow George LOL...I've been called a lot of things in my life but "Evangelist" ???
Guess that's one I'll have to add to the list...Though I never much cared for the Bakers...

Angela...Yes the Sentry will reliably do what you want...It's just not as fast at recharging deeply discharged (inverter depleted) batteries as the newer multi stage chargers are...But it's also field repairable (as mentioned by George) as opposed to sending it out for complete board change outs like happens with most newer multi stage chargers...The only thing in those to replace is the board, which is the main cost of the charger...When they quit...They usually quit altogether...
The Sentry will almost always work, or even have a work around inside till you can get service....That's part of why they get some bad hype...Most have had someone into them doing a work around that never got fixed properly, but it still works (for many years) so folks leave it be not knowing the difference...

Sentry "Evangelist"
Steve~

[SKYCHENEY]

Newmar lists 32v chargers in several sizes but in reality they only make the little one(10amp, I think). If you call them they will tell you that there wasn't enough demand.

[GJH]

OOps, I was referring to NewMar's "smart" charger. They still make a ferro AFAIK.