Reroute Alternator Output...?

[salty_dog_68]

I am updating the electrical system in my sailboat. I have removed the noisy old dinosaur(4kw Genset) and plan on replacing it with an inverter. I also would like to separate, and effectively isolate, the starting battery circuit from the house battery circuit. What I intend to do is remove the alternator output from the house battery circuit(panel) and connect it directly to the battery isolation switch that controls the two starting batteries. It seems simple and straightforward enough. So, my question is this. What then do I do with the field and sense wires to maintain voltage on my starting batteries? I have posted a simple wiring diagram to illustrate what I plan on doing. I appreciate any input, suggestions, concerns, or knowledge you may have to share. Thanks.

[DeepFrz]

The current (pun intended) thinking is to run your alternator directly to your house bank with the echo charger then supplying charge to your start batteries as needed. This works best because your start batteries generally only need a small top up, whereas your house bank may be significantly discharged.

[salty_dog_68]

That is a good idea. I would be a little nervous about depending on only an echo charger to charge the starting batteries. But in a worse case scenario, if I understand this correctly, I could run jumper cables from the house battery to a starting battery in an emergency?

[salty_dog_68]

That scenario would certainly simplify the wiring I would need to do. I think I would just have to disconnect the alternator output from the starting battery isolator switch and connect to positive terminal on the house battery.

[cal40john]

The Echo Charger limits its output current to 15 amps. It is specifically designed to charge a start battery, not a house bank.

page 9:
http://www.xantrex.com/documents/Acc...204-01-01).pdf

[Fuss]

Starter batteries should only be used for one purpose- to start the engine

They should then only be charged using some form of echo charger

Dedicating an alternator to charge a dedicated starter battery is a complete waste of a resource

Alternators should be used to charge house banks and they should be big and externally regulated

A further advantage of the echo charge design is that if you have solar charging the house bank then the start bank also gets charged

[arisatx]

SD:

Mainesail's posts are worth a read re: electrical systems:

here

You planning on installing a house bank monitor?

[Capt Hugh Wilde]

A Balmar Digital Duo Charger will do what you want to charge the start batteries off the house.
If you have 2 start batteries isolated from each other by a switch, you could use one on each battery to keep everything fully charged at all times.

No matter what charging source you house it on, alternator, solar, or inverter charger, your starting batteries are being maintained.

They are adjustable to charge all types of batteries and I have installed them on a new construction we are in the process of finishing.

Attached is a picture of mine installed.

[smac999]

why do you have 2 start batterys? ditch the 2nd one, and put the house battery on number 2 of that swtich. the house is the backup starting battery, and now you can jumper between house and start if ever needed for charging or starting.

the neg of the start battery(s) need to be joined to the neg of the house battery.

you need a battery switch between the house battery and house panel, and should have a main fuse as well.

you need a battery swtich between the house battery and charger / inverter, and also a class t fuse.

the ac wiring is totally wrong for a charger / inverter.

one, you don't need a transfer swtich for most charger / inverters (any good one anyways)

2 you don't power the entire boat or ac panel from an inverter. it needs to be split up into inverter and non inverter loads

and 3. you certainly don't power the charger / inverter from the inverter... which your picture is doing. it is going to try to power itself.

don't screw around with ac if you don't know what you're doing.

[salty_dog_68]

"why do you have 2 start batterys? ditch the 2nd one, and put the house battery on number 2 of that swtich. the house is the backup starting battery, and now you can jumper between house and start if ever needed for charging or starting."

If I were just bee-bopping around the coast all the time I would not bother with another starting battery. But, I spend a significant amount of time every year in the 50-100 mile offshore range, in remote areas, and in third world countries where there is not a west marine in every costal town...why wouldn't I want an "Option C" to start my engine(especially when I have plenty of room for another battery).

"you need a battery switch between the house battery and house panel, and should have a main fuse as well."

already in place I just didnt include it on my diagram

"you need a battery swtich between the house battery and charger / inverter, and also a class t fuse."

I am planning on having the fuse spliced into the battery cables when I have them made. I wasnt planning on adding another battery switch but I think it is a good idea. Thank you.

"the ac wiring is totally wrong for a charger / inverter."

it is just a rudimentary illustration not a schematic. That is not, litterally, how the inverter is wired. Are you referring to the common ground wire that i did not include?

"one, you don't need a transfer swtich for most charger / inverters (any good one anyways)"

The transfer switch is already in place for the 4kw genset I removed. I am just taking advantage of what is already in place. The inverter does have "pass-thru".

"you don't power the entire boat or ac panel from an inverter. it needs to be split up into inverter and non inverter loads"

what then do you do with a/c loads that you want to be able to run off both inverter and shore power? Like the water heater for example? When I am at the dock (with shore power)and want to take a hot shower I dont want to strain the house battery and inverter.

"you certainly don't power the charger / inverter from the inverter"

Yes, I am aware of that possibility. Having a big boat and playing with all these complicated toys is no place for ametures and idiots.

"don't screw around with ac if you don't know what you're doing."

I am not a marine electrician but I did stay at a Holiday Inn Express Last nite...in all seriousness. I am not an idiot. I hired a marine electrician to: 1. inspect my wiring and clean up any problems and 2) do all the significant and complicated wiring and installations. I am just trying to educate myself so I don't do something stupid and dangerous...like try to charge the house battery...with the house battery. Thanks for you input!

Capt. Eric