4788 house bank recharge-gctid383191

[ksanders]

On our 4788 we have a 840 AH house bank that is charged by a Balmar alternator.

The challenge is that at low engine RPM settings, 1500 RPM for example I'm not getting enough charge current to actually recharge the batteries very effectively.

This is probably a common problem.

Ways to fix this would be to:

Use both engines to charge the house bank.

Decrease the pully size on the alternator, thus speeding it up.

Buy an alternator with better low RPM capability

Quit fussing over it. Use the generator to charge the batteries quickly and be happy.

BTW, its amazing the power it takes to run this size boat. At rest we're drawing between 30 and 50 amps DC all the time.

I've palyed with ways to minimize that, but with the inverter running the satcom link, and all the other stuff that makes life comfortable like the ice maker, etc... it just seems to take a bunch of power.

I can save about 10 amps off of that at anchor by shutting down one of the Furuno displays, and dimming the other one, but I've never ever seen the boat draw less than 20 amps.

[mmichellich]

ksanders wrote:
On our 4788 we have a 840 AH house bank that is charged by a Balmar alternator.

The challenge is that at low engine RPM settings, 1500 RPM for example I'm not getting enough charge current to actually recharge the batteries very effectively.

This is probably a common problem.

Ways to fix this would be to:

Use both engines to charge the house bank.

Decrease the pully size on the alternator, thus speeding it up.

Buy an alternator with better low RPM capability

Quit fussing over it. Use the generator to charge the batteries quickly and be happy.

BTW, its amazing the power it takes to run this size boat. At rest we're drawing between 30 and 50 amps DC all the time.

I've palyed with ways to minimize that, but with the inverter running the satcom link, and all the other stuff that makes life comfortable like the ice maker, etc... it just seems to take a bunch of power.

I found the ice maker draws an unbelievable amount of power, but lifting the bale so it it is not making ice all the time and the power load decreases a lot but keeps cubes frozen. Our two freezers draw a lot of power, so only run them twice per day, morning and evening while engine or gen set running for an hour or so and everything keeps frozen solid. We also switch one freezer to propane for a lot of the time, especially if we are freezing a lot of new stuff, like fish. In the evenings with lights, laptop and TV we usually run only 10-15 amps DC in our 47 If our batteries are especially low and we are going to run for a couple of hours, I switch the crossover on and tie all the batteries together with two alternators working. On the stbd side I use a very large truck Delco alternator that brings things up pretty fast.

[Guest]

How about adding an external(smart) regulator to the alternator. I had a Bosch alternator that did not like to charge at low RPM so I disconnected the internal regualtor and added a Xantrex regulator which resolved the problem. You could potentally add a second alternator onto one engine for housebank charging only.

[Guest]

My experience with this issue just drove me to run the generator more of the time. When I lost my inverter the "first time" I lost all electrical power to circuits serviced by the Xantrex inverter. I had to rewire the power panel to get power to the circuits until I could repair the inverter. So unless your constantly on the move you are going to be running the generator at some point to recharge those batteries. In my case that was at least as long as I ran the inverter. So why not just run the generator. So on the Hatteras I set up the inverter to run my tv, stereo, home style refrigerator, coffee maker. The inverter charges the house bank and starting bank. And the rest of the time I start one of the generators. With a all electric kitchen and hot water heater your going to be running it anyway. The likely hood of wearing out a generator in the period you own this boat is next to nil. You should get at least 8000 hrs out of that Northern lights, if not more. If I would have thought out my system better on the 4788 I would have built a better sound box to keep the noise to a minimum. When I added 4-L16 batteries to the 2-8D's and the 12kw Generator I had to raise the water line and the cockpit drains really should have had ball valves on them as they were at water line. This also effected how much plate I needed to hold plane. In my case I was better off just listening to the generator. A easy fix would be to upgrade your alternator to one of the 200 amp or larger units. On my 47 with the 4-L16 6v batteries I just made it through the night as it was without recharging the batteries. In the AM [I] would just have enough juice left to make coffee without discharging the batteries below half way. There are a lot of electrical needs on the 47, one light switch seldom turns on one light , electric toilets, you know the drill.

[Guest]

ksanders wrote:


I can save about 10 amps off of that at anchor by shutting down one of the Furuno displays, and dimming the other one, but I've never ever seen the boat draw less than 20 amps.

Do you leave your plotters on so you can track your position as ou swing? I shut down my displays, sounders and GPS antennaes after I'm convinced my anchor set is good. Only the radio stays on. Killing 2 displays, the depth transducer and 2 GPS pucks gives me back 20A.

I do the same as Micky does wrt the ice maker. Refilling the ice maker repeatedly with warm water keeps the compressor running on a high duty cycle, and the ice tray heaters draw a high current (briefly) on each cycle. make only as much ice as you'll need, and then kep it cold. Flip the bail down when you run engines or genny.

You can also dial up the temperature n the fridge and freezer, with care, to reduce run ime and frequency.

I probably don't need to mention ths one, because it's such a biggie, but.... Run the genny instead of drawing on the inverter for any large load that will be hard to replace (recharge). For me, examples are the admirals blow drier, the microwave, bread maker when it's on bake cycle, the large coffee percolator.

[mmichellich]

Any large draw item like a 1200 watt use like a hair drier will require a gen set or shore power run as long as the inverter useage, unless you are charging well over 100 amps when on the gen set. Plus you are using up battery life. As a result we never even hooked up the microwave, galley, hot water tank, heaters, or head outlets to our inverter. Mostly use 2500 watt inverter to run laptop, TVs, sat dish, low draw AC lights, ice maker, freezers, etc.

[Papa_Charlie]

I too need to get a handle on the loads our boat pulls. My inverter runs far too many items. When the old Trace went out several weeks ago and I replaced it with the Magnum 2850 pure sine wave. I had a chance to check out all of the loads that PO's had put on it. Unbelievable, the amount of stuff. I created a matrix of all the loads on the inverter and also the AC loads so that I can try and rearrange them.

I have 12-6V GC batteries supporting the house and there is just too much load on them. Also because so much of the load has been put onto the inverter it has unbalanced the load for the three 30 amp main circuits on the boat. I want to get it so that one of the 30 amp lines on the boat is dedicated to the inverter and its loads. The rest will be for non inverted loads. Right now I have 16 items on the inverter. I need to get it to 9 then I can use the main to feed the inverter.

Refrigerator

Ice Maker

Salon Recept

Galley Recept

State Room Recept

Master St Rm Recept

Head Recept

Microwave

P/H Recept

OH Lights #1

OH Lights #2

OH Lights #3

OH Lights #4

Stereo / TV

Fresh Water Pump

Engine Rm Lights

I have an auxiliary AC panel that someone installed I think I am going to combine all the lighting loads to it so there will be only one breaker dedicated to feed that panel. That will combine 5 of the loads into 1. The Microwave and Ice maker are two more I could take off the inverter too.

What I really need to do is to measure these loads so that I can re-balance the three systems.

Long way to a short response to your post is have you laid out your circuits and evaluated them to see what is on them and what they are pulling. You may only need to rearrange loads instead of spending a lot of money on new equipment. If you find you still need it, at least you will know what you need to address.

[mmichellich]

Papa Charlie wrote:
I too need to get a handle on the loads our boat pulls. My inverter runs far too many items. When the old Trace went out several weeks ago and I replaced it with the Magnum 2850 pure sine wave. I had a chance to check out all of the loads that PO's had put on it. Unbelievable, the amount of stuff. I created a matrix of all the loads on the inverter and also the AC loads so that I can try and rearrange them.

I have 12-6V GC batteries supporting the house and there is just too much load on them. Also because so much of the load has been put onto the inverter it has unbalanced the load for the three 30 amp main circuits on the boat. I want to get it so that one of the 30 amp lines on the boat is dedicated to the inverter and its loads. The rest will be for non inverted loads. Right now I have 16 items on the inverter. I need to get it to 9 then I can use the main to feed the inverter.

Refrigerator

Ice Maker

Salon Recept

Galley Recept

State Room Recept

Master St Rm Recept

Head Recept

Microwave

P/H Recept

OH Lights #1

OH Lights #2

OH Lights #3

OH Lights #4

Stereo / TV

Fresh Water Pump

Engine Rm Lights

I have an auxiliary AC panel that someone installed I think I am going to combine all the lighting loads to it so there will be only one breaker dedicated to feed that panel. That will combine 5 of the loads into 1. The Microwave and Ice maker are two more I could take off the inverter too.

What I really need to do is to measure these loads so that I can re-balance the three systems.

Long way to a short response to your post is have you laid out your circuits and evaluated them to see what is on them and what they are pulling. You may only need to rearrange loads instead of spending a lot of money on new equipment. If you find you still need it, at least you will know what you need to address.

Some of those would appear to be 12 volt loads and not fed by the inverter?

[dmcb]

I switch the crossover on and tie all the batteries together with two alternators working. On the stbd side I use a very large truck Delco alternator that brings things up pretty fast.

I do this also. Both alternators will contribute.

I probably don't need to mention ths one, because it's such a biggie, but.... Run the genny instead of drawing on the inverter for any large load that will be hard to replace (recharge). For me, examples are the admirals blow drier, the microwave, bread maker when it's on bake cycle, the large coffee percolator

Yup. In many cases the draw will exceed the charger capacity so you will run the genny longer to replace it than it took to do the job.

If you are keeping your plotters on to check for drift, most small plotters will have a drift alarm. I have a small Humminbird plotter/sounder that takes very little power and works perfect as a drift alarm.

Doug

[ksanders]

Thanks for all the responses guys!

as far as load management I'm happy with what I've got on inverter. I like the convience of the inverter.

I leave one furuno display on all the time for anchor drag and depth alarm. Those things draw allot of current.

Im probably going to play with the voltage regulator since its a Balmar smart unit to see if I can get a little more low rpm current.

Other than that I have a great new northern lights generator so it's not an issue to run the generator. It's very quiet.

[Papa_Charlie]

mmichellich wrote:
Some of those would appear to be 12 volt loads and not fed by the inverter?

No they are all 120V loads. The lights are all 120 V Fluorescent lights. My fresh water pressure pump is a 1/4 hp 120 Volt AC pump.

[ksanders]

Papa Charlie wrote:
No they are all 120V loads. The lights are all 120 V Fluorescent lights. My fresh water pressure pump is a 1/4 hp 120 Volt AC pump.

It looks like your boat has been converted to be a liveaboard with all the 120 volt stuff.

Thats a little risky for a non liveaboard.

Its one thing to want 120v power, quite another to need it.

You know, I wrote that and now I'm thinking why not?