Comments on Proposed new DC System

[millennium]

Hello all.

Just joined here, great forum. We have had MILLENNIUM 11 years, a twin engine Mainship 390. Summer on Lake Champlain, winter in St Augustine.

I will be replacing the stock 55 amp internally regulated*alternators and single 8d house battery with the following.* We spend many nights anchored, need good battery capacity and quick charging. (12 volt system). I would like to be able to go up to 36 hours with minimal generator use. Inverter,*frig*and other dc loads average 10 to 20 amps/hr.

*Any experience with these components or suggestions would be appreciated.

1. Two Balmar110 amp*alternators each with mc614 regulators.****

2. Balmar Centerfielder

3. 8 six volt*golf cart batteries(210amp), probably Trojans. Some type of box to contain them. (840 amp capacity?)

4. 2 Xantrex Echo Chargers(15 amp)*to charge 2-31 series starting batteries.*********

Upgrade wiring*for higher loads.****

Thanks- Bill*****************************

*



-- Edited by millennium on Wednesday 18th of May 2011 10:13:41 AM


-- Edited by millennium on Wednesday 18th of May 2011 10:46:23 AM

 

[Phil Fill]

With out knowing the amp volts and/or Watts of each item its difficult to reply. The standard electrical formula is** Amps X Volts = Watts.* If you did not increase the demand and/or amps draw, you may not have to change the wiring and* you might be spend a lot of money with no net benefit/change?

 

[millennium]

Thanks Phil, Info added to origional post.
Bill

 

[FlyWright]

I would confirm that the alternator output wire size is sufficient to handle the higher amperage of the Balmars. Balmar suggests 2 gage for round-trip runs of 15 feet.
http://www.balmar.net/PDF/2009-12V-alternator-manual-web.pdf

Here's another good read before starting the job. http://www.pkys.com/alternator_installation.htm

What battery charger do you have for your new house bank? If those Xantrex chargers are 15A, they'd be undersized for the 900AH house bank. (That's a nice, big*house bank!)* Have you considered one charger for the starts with an Automatic Charging Relay (ACR)?* http://bluesea.com/category/2/productline/overview/387(BillyIII has convinced me that BlueSea ACRs are best.)

Here's what Balmar says about Alternator-to-Battery ratios:

"In order to achieve optimal performance from your charging system, it is essential to determine the capacity your charging system is capable of supporting. In general, the size rating of the alternator should mirror the acceptance rate of the batteries being charged. Differing battery technologies will vary in terms of their acceptance rates. For example, a deep-cycle flooded battery is typically capable of accepting roughly 25 percent of its available capacity at any given time. As a result, we want our alternators rated output to equal the acceptance rate of the battery being charged when it reaches its full discharge rate. In other words, a deeply discharged 400 amp hour deep cycle flooded battery would require an alternator rated at 25 percent of 400 amps, or 100 amps to support that bank.

In simpler terms, a deep-cycle flooded battery bank will require 25 amps of alternator output for every 100 amp-hours of battery rating. Some newer battery technologies, such as AGMs and spiral wound batteries can accept up to 40 percent of their available capacities, as such, alternator output should be increased to reflect the optimal ratio between alternator and battery capacity.

Failure to meet recommended alternator-to-battery ratios will commonly result in slower charge times, increased alternator heat and wear, and reduced alternator life."

My system with a 660AH house bank does not meet this ratio standard, either.** Due to belt size, I am limited to about 100A alternators.* I will be installing a Balmar 125 (regulated to 100A) and also a MC-614 regulator.* I'll be following your posts for advice and results.

Welcome to the forum!

Al


-- Edited by FlyWright on Wednesday 18th of May 2011 10:51:22 AM

 

[windmist]

Your list looks good to me except the shore power battery charger. I would look for a bigger one and one that has multiple outputs. Most of them can charge 3 different battery banks from one unit and make sure it is capably of 3 stage charging. And as long as I am spending your money, I would suggust you get a DC energy meter that will monitor your DC usage while at anchor. BEP Marine and Newmar make these. They give you SOC (state of charge). You can go down 50% without harming your house bank.

Also, I didn't notice an inverter. Do you need 120 VAC while off shore power? If so, you can combine a charger with the inverter and eliminate the charger mentioned above. I suggust Magnum for this unit.

Ron

 

[millennium]

Al/Ron

Thanks for the reply.

Main battery charger is a Xantrex 3 bank 50 amp 3 stage. The little 15 amp chargers are for the two starting batteries(twin engine boat) which will be their only source of charge. The generator also has its own battery.

Inverter is also Xantrex, 1800 watt unit, pass through, power outlets and microwave only

220 amps of charging from two alternators should be ok with 840 amp bank using 4/1 rule. I am limited also to a 1/2 inch belt.

All new batteries will be AGM.

Bill

 

[Per]

since you have a flat fixed FB cover, i would consider installing a couple or 3 solar panels.
you can easily harvest 100 amphours daily from the sun.. i did it recently and am very happy with the results.
the system i installed included a battery monitor, informing of AH used etc.
btw, i have the bluesea acr switch, works well.

what is the thought on using 6 V golfcart batteries?
I have 4 AGM's in mine, all shared only when starting/cranking are the battery banks isolated.

 

[FlyWright]

The start batteries won't receive a charge from the alternators? Are all 3 banks of the 50 A charger already used by house, inverter and genset?

Rather than add another charger or two, consider the ACRs as a way to share the charge to the start batts from another bank (house or genset or inverter) after that primary bank has reached sufficient voltage (i.e. 13.2V +/-). This charge can come from an onboard charger or from the alternators or from the genset. You'll have greater flexibility for keeping your start batts topped off.

Just a thought, but if you're using AGMs, Balmar suggests 40% charging capacity vs. 25%. Probably not feasible though with an 840AH bank and 1/2 inch belts.

 

[millennium]

Per: I have never looked at solar, always thought it was a sailboat thing, putting out milliamps. I will check them out.
I havn't settled yet on CG bats, looking for opinions. I still may try 6 group 31 agm's instead.

FlyWright: Start Bats charged from echo chargers only. They will always be receiving power from the house bank. I believe an echo charger does the same thing as a ACR.
I talk to tech at Balmar, you are correct regarding agm's requiring more charging capacity then flooded. 110 amp alternator is max with1/2 inch belt.

Bill

 

[bshanafelt]

Like the initial poster, I also wanted the ability to be at anchor for up to 4-5 days if desired.

We use 120 amp/hrs in a 24hour period on average, during the summer.* In addition to normal loads, I run a*12v freezer on the cockpit deck.*

I use 12ea 6v 225AH (golf cart) batteries in series parallel for a 1350AH capacity.* Batteries are AGM.* Start battery is a grp 31, recharged via Balmar digital duo.

I monitor the bank & charging via a Link 10 monitor.

My math shows I could draw the bank down to 60% SOC and not have to initiate a recharge cycle for up to 6 days.* In reality, it is more typical for 2-3 day (250-300AH) depletion which is around 80% SOC, before we start up and move to a different anchorage.

Recharging is via a large frame Penntex 200A alternator with a Balmar ARS-5 regulator - I have puposely 'dumbed' the regulator down so the most the alternator will put out is 175A.* Both the battery bank and the alternator are temp sensored.

When on shore power I use an IOTA 75A charger with multi-step regulation.* This unit will put out a full 75A for a very long bulk cycle if necessary and seems to be quite adequate in amperage despite the size of the bank - of course when cruising the engine alternator will usually keep us fairly close to a full SOC, so the shore charger normally doesnt have to work too hard.

I am away from the boat for up to 30 days during the off-season, and since we do not cruise very often in the winter, I will isolate the bank entirely from any loads(via a disconnect switch).* Any 12v loads needed at the dock are supplied by the IOTA, which is rated as a power supply as well as a smart charger.

Since the batteries are AGM, they will hold the charge for many months and I prefer to leave the bank isolated instead of risking short cycling if the charger should see a load and initiate a charging cylce.

*

I have a DC charging schematic, but it is in Powerpoint which this site will not show - if you want a copy let me know and I will email it.

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[sunchaser]

Bill

You are on the right track. Lay it all out on paper and clean up old wiring if you have the time. Ask a good marine electrician to comment and reveiw install as you prgress.

I*am a lead acid fan, my 8 Trojan 105s lasted 8 years with nary a problem and I just bought 8 more. I*see no need for 2X or more the expense of AGMs, although I have two for my bow thruster to minimize gassing in the forward bilge area. I have a Newmar (very highly rated) charger for the 3 engine start batteries and Xantrex Prosine for the house.

Since my boat is in the water, my charger is on all the time - for bilge pumps if ever needed. My 90 amp Prestolite alternators do a great job of charging the batteries when I'm cruising.

 

[FF]

"AGMs and spiral wound batteries can accept up to 40 percent of their available capacities, "

If you are willing to pay for silence , the fancy batts with higher acceptance will work better, for 2 reasons.

The faster acceptance is great , but the fact that they die less at NOT being fully charged is also a help.

On a noisemaker most cruising folks bounce between SOC of 85% down to 50% on wet batts..35% of the rated capacity is useful.

The better battrs can go to 40% SOC , so 85% down to 40% is 45% of rated as useful. Almost 1/4 more energy to use.

And the bottom is easier/faster to fill than the top , last 15%.

Mostly a dockside charger will be given loads of time to pump that slow filling top 15% into the set to finally get to 100% full.

So it does not have to be very large , bur SMART is a bonus.

Install a SOC meter , if not aboard , before the old batts are removed.

Then you can learn on garbage the compromises to keep up the house set.

 

[David O]

Bill,

I have a 98 350 Trawler with twin Yanmars, pretty much the same boat. Last year I did a similar project.

Being concerned about the weigh, I put (8) 6 volt Penn AGM batteries (75 lbs each) in a fiberglassed box (2 wide x 4 long), with lid, in the center of the boat in the hold in front of the engine compartment. I cut the panel between the hold and cutty bedroom for full access to port side of the batteries. I put some pretty chrome hasps on the panel to hold it in place.

I installed a Magnum Energy 2500 watt inverter/charger with the battery monitor and remote display, good stuff. I installed the remote below the breaker panel, looks good. I installed the inverter on the overhead of the front hold, to starboard of the battery bank and to port of the lower helm wheel. I installed the T fuses and disconnect on the forward bulkhead below the inverter.

I attached the inverter to the (3) port outlets, so that would take care of the TV, stereo, microwave, coffeemaker and plug at the sink (toaster). I also ran cables back to hookup the battery bank so that it can serve as the house bank too. I connected everything with custom made 4/0 cables from Genuinedealz, good folks, great prices.

I can anchor 3 days, run the genny 2 hours a day and never discharge the bank more than 80%. I have the ability to switch the house over to a set of starting batteries if needed. I left the OEM Charles charger on the genny and both engine battery sets (twin 27s each). I did not add the larger alternators. I would probably consider solar panels before alternators, the price has come down low enough to made them a better deal than the alternators (you don't have to run the engines). Plus the Magnum inverter/charger will accomodate them.

My only problem came up when the inverter kicks in on a load and the autopilot is on, it will throw it off momentarily and I have to reset it. The fluxgate is mounted to the over side on the bulkhead under the steps, about 2' away from the inverter. I don't know what I'm going to do about it, if anything.

David

 

[Per]

if anyone needs info on solar panels feel free to im me.
i get 60-90 AHS / 24 hr from 2x85 watt panels. the complete set up cost me roughly $1000.
havent had a chance yet to to anchoring but this summer should be plenty chances, by my estimates i figure only need to run the genset for an hour or so, probably in the early evening when we cook and use electric stove.

 

[sunchaser]

Per -- Question, any info on panels working efficiency*in the PNW?

 

[Per]

a few days after my installation it was a cloudy day all day in so cal, but we still got good output from the panels. here is a cavot though, most charge controllers will only accept the power when the volt is between a min and a max voltage, say 12.5 - 18, for the panels to produce current in this range you need fairly good conditions.

However, there is something called a MPPT charge controller.

Basically this unit takes any volt/amp combination and spit out what the batteries need.

that means even when cloudy or there is a shadow on the panels, you still get to harvest sun energy...

i am not an expert so i recommend some research, not only on solar for boats but rather just solar, thats where i found most of the data i researched.

this website holds lots of information and the experts there will reply to you in a heart beat..

http://www.wind-sun.com/ForumVB/index.php

*

 

[millennium]

Dave O

Thanks for your input, sounds like I am doing pretty much the same you did. Any more details on that fiberglassed battery box? Homemade? That's a lot of weight to contain.

I plan on installing a vac u flush system where you put the 8 batteries. My batteries will go in the engine room where the stock holding tank was between the motors. This is one of the reasons I am chosing agm's. Thoughts from anyone regarding agm's in the engine room?

I will check out the 4/0 cables from Genuinedealz, thanks for that.

You are using the stock alternators for that big battery bank or the charger off the gen? Are you combining their output? Must take a while to charge the house bank.

Bill
MILLENNIUM
2000 Mainship 390

 

[David O]

Bill,

I made the box from 1/2" plywood and had the fiberglass guy glass the whole thing and the lid. I installed it on top of the welded aluminum water tank in hold in front of the engines.

I just installed a Raritan Marine Elegance freah water flush toilet. In my opinion, it's far better than the Vacuflush (been there) and a lot cheaper ($640.00). I just had to notch the fiberglass to allow it to receded back 2" on the footprint. It was a very easy installation (thank you Dremel Osolating saw). It's the new generation of toilets, check out the reviews prior to purchasing all the Vacuflush equipment. The fresh water flush version with the Smartflush control is "maintenance free" and uses very little water, just my experience.

I used the East Penn AGM batteries because of the low/no gassing in an unventilated space. The hotter the battery, i.e. the ER, the less AH capacity. Go here, http://www.dekabatteries.com/default.aspx?pageid=468 , and check out the technical brochure on the AGM/Gel batteries.

The Magnum Energy 2800 inverter/charger, http://www.magnumenergy.com/Mobilepower.htm , charges the house bank. You enter the battery type, manufacturer, battery AH, total bank AH and the charger automatically ajusts the various levels of charge required via the battery monitor option. It monitors the temperature of the batteries, the AHs they have produced and a bunch of other stuff. You need to get the monitor and remote panel options to get all this. At 80%, the bank is back to float charge in 2 to 3 hours of charging.

Bill, where did you put the holding tank?

 

[millennium]

Dave:

I will investigate the Raritan head. Thanks.

I considered putting the new batteries where you did, above the forward fresh water tank. I was concerned about all that weight on the tank. This is where I planned on putting the vacu flush holding tank, which they claim can be smaller due to less flush water. I will loose that little storage area off the small bedroom.

Good point about the heat in the engine room effect on battery performance.

So you can only charge your house bank when AC power is available, shore or gen? I want to be able to charge underway, hence the Balmar alternators.

Bill

 

[David O]

Bill,

I removed that (worthless) storage box and took the back of the box and covered the hole with it. Then I made the whole panel removable.

The water tank handles the weigh with no problem. I had to made the box in 2 pieces in order to get in. I also extend the front edge and trailing edge of the box down about 3" to slide down in front and back of tank. I fastened the side down with an aluminum angle anchored into the floor and into the side of the box.

I can only charge the house bank via the genny or shore power. I figured I'm going to be hooked to one or the other everyday at some point. Plus I would prefer to run the genny with a good load on it when it is on.

It works for me right now, YMMV.

David