grounding 12 v system

[Quique]

hello, i have some free time in my hands so i decided to organize a bit my rats nest.
i noticed my batteries are not grounded. do they needto be grounded to the engine?
i also have an inverter that when in use i get current on the helm/pedestal.should i ground that and where to?

[btrayfors]

Grounding

Also, if you have (AC?) current on the pedestal when you use the inverter, you have serious problems which can be FATAL.

Suggest you engage a marine electrician to have a look.

Bill

[Quique]

its not ac. the inverter is attached below the cockpit. the bolt go through the deck in the cockpit to the inverter below. i think the slight shock i get might come from the inverter itself through the bolts and with the floor wet i feel the slight shock when i touch the helm.
i removed it and will install it somewhere else.
no money for a marine electrician.

[barnakiel]

Our house battery has common negative rail but our 12 Volt equipment is not grounded.

I think I am going to make a split ground 12 Volt system here next.

b.

[hellosailor]

Are your batteries scattered about the boat? Or are the negative cables from them all connected together, to a common point or busbar or daisychained?

[boatpoker]

You say your batteries are not grounded ! this statement shows you are absolutely lost with electricity.

How do you know the shock you are getting is AC and not DC. Your inverter is an AC/DC appliance !

Betcha $10.00 your inverter case is not grounded and I'd make damn sure that the AC neutral and ground are not bonded.

You most definetly need a qualified marine electrician, preferably ABYC certified.
He will be cheaper than the cost of your funeral.

[Maine Sail]

If your engine starts the batteries are connected to the engine. Can't start an engine without the batteries being connected to it.

[osirissail]

Originally Posted by Quique

. . . I noticed my batteries are not grounded. do they needto be grounded to the engine?. . .

I agree, there is some basic 12VDC background needed here. The "The 12 Volt Boater's Handbook" can probably be found in used boat parts stores or libraries.

Direct current works by electrical energy, commonly stored in batteries, leaving one terminal of the battery and going to the "load/motor/whatever" and then back again to the battery's other terminal. As was stated by MaineSail if your engine starter operates your battery (at least the engine starting battery) is connected (grounded) to the engine block. The only exception to this would be if your engine starter had two (2) thick battery cables attached to it, one black, one red - instead of the normal one red cable.

Same thing goes for the engine alternator which makes DC power from the rotation of engine and sends it via one red cable to charge your battery. It normally does not have a separate black (negative) cable attached so it is using the engine block as the negative (ground).

If you have more than one battery bank then it is normal practice for all the negative cables from the various battery banks to be hooked together usually at a "amp-hour" meter shunt and then the other end of the shunt is connected to the engine block and/or the boat's negative battery bus terminal.

So by definition everything in the boat's DC system is "grounded" to a common point usually the engine. There was another discussion awhile back about using seawater grounding plates for the DC system. Normally this is taken care of by the engine being connected metal to metal with the transmission and the transmission connected to the propeller shaft and propeller which is "in the water."

Some instruments or lighting fixtures that have metal cases or frames should have internal or external connections from the DC negative system to the metal case or frame. This is done more to protect from an electrical short and fire than human electrical shock hazards. 12VDC and 24VDC systems really don't have enough energy to "shock" a normal human. However, AC system do have enough to give your anywhere from a tingle to a heart stopping zap. So making sure the "safety ground" system on the boat's AC systems is in good condition and each AC load and generation item has a safety ground unless it is rated as "double insulated."

[Quique]

my batteries are not scattered. i have 2 deep cycle as houe and a separate starting from the engine.
i inhereted a rast nest. iam in the pocess of making things better.
my research through the internet bring the doubt of how to ground the batteries. the book i have as reference says to ground to.the engine but i have read diferent opinions specially if shaft is sealed, i beleive mine is. i have read 12 v is does not need to be grounded yet many people have cabpe from the bus to the engine block. thats why i bring the ? here.
with the invereter i think the shock come from.the.case.
it doesnt have a ground wire. so iam hoping a relocation might fix the problem.

[Quique]

Originally Posted by boatpoker

You say your batteries are not grounded ! this statement shows you are absolutely lost with electricity.

How do you know the shock you are getting is AC and not DC. Your inverter is an AC/DC appliance !

Betcha $10.00 your inverter case is not grounded and I'd make damn sure that the AC neutral and ground are not bonded.

You most definetly need a qualified marine electrician, preferably ABYC certified.
He will be cheaper than the cost of your funeral.

give me your address and ill send you the 10 dollars.
my funeral be free for me.
caseof the inverter is not grounded, only has - &+ cables which went to battery.
how should i ground it. attach cable to the case and lead it where? - on battery, engine?
you are right. i have no idea if shock come from ac or dc. guess iam just lucky it was just a tingle and not a SHOCK.
thanks for your concern!

[Quique]

Originally Posted by osirissail

I agree, there is some basic 12VDC background needed here. The "The 12 Volt Boater's Handbook" can probably be found in used boat parts stores or libraries.

Direct current works by electrical energy, commonly stored in batteries, leaving one terminal of the battery and going to the "load/motor/whatever" and then back again to the battery's other terminal. As was stated by MaineSail if your engine starter operates your battery (at least the engine starting battery) is connected (grounded) to the engine block. The only exception to this would be if your engine starter had two (2) thick battery cables attached to it, one black, one red - instead of the normal one red cable.

Same thing goes for the engine alternator which makes DC power from the rotation of engine and sends it via one red cable to charge your battery. It normally does not have a separate black (negative) cable attached so it is using the engine block as the negative (grou

If you have more than one battery bank then it is normal practice for all the negative cables from the various battery banks to be hooked together usually at a "amp-hour" meter shunt and then the other end of the shunt is connected to the engine block and/or the boat's negative battery bus terminal.

So by definition everything in the boat's DC system is "grounded" to a common point usually the engine. There was another discussion awhile back about using seawater grounding plates for the DC system. Normally this is taken care of by the engine being connected metal to metal with the transmission and the transmission connected to the propeller shaft and propeller which is "in the water."

Some instruments or lighting fixtures that have metal cases or frames should have internal or external connections from the DC negative system to the metal case or frame. This is done more to protect from an electrical short and fire than human electrical shock hazards. 12VDC and 24VDC systems really don't have enough energy to "shock" a normal human. However, AC system do have enough to give your anywhere from a tingle to a heart stopping zap. So making sure the "safety ground" system on the boat's AC systems is in good condition and each AC load and generation item has a safety ground unless it is rated as "double insulated."

nd).

thanks,
you mention the amp meter.
in the boat was a heart interface link 2000 made by xantex.
i got the shunt and installed it. right now shunt only has the meter wires on it like the manual says. or i think it said. should i connect the - wires to the grounded sidw of the shunt? right now the go from bus to the - terminal of the battery

[osirissail]

I might suggest you be a bit more exact in your descriptions so we can better understand what you are asking. Maybe there is some problem if you are translating from a language other than English as your use of the word "ground" in reference to a DC (direct current) system is unusual.

If you do not have the Link 2000 manuals you can get them by Google them. Simply wire up the system as it is shown and described in the manuals and things will be fine.

Basically speaking, all the negative battery cables are routed to the battery negative terminal on the amp-hour shunt - if - you want to monitor amp-hours of your whole DC system.

However, if your Link 2000 has a dual section shunt (2 Battery-side terminals and a common Load-side terminal) then you would connect the negative (ground) cable from the house battery to one of the shunt's battery-side terminal and the negative (ground) cable from the other battery to the "second" battery-side terminal on the shunt.

From the shunt's "Load-side" terminal you would connect a cable to the engine block and another cable to the boat's DC negative (ground) buss system. The only exception to this is if your engine starter draws in excess of 500 amps in which case the "starter-battery" negative cable would be connected to the "Load-side" of the shunt to prevent damage to the shunt.

The Link 2000 is no longer in production so getting the installation manuals may be challenging. It might be advisable to find somebody with the same type of setup and simply copy what they did - assuming their system works.

- - - - - -
For those interested in installing an Amp-hour meter system without spending "big-bucks" I found this interesting link to a US$60 unit.
RV & Marine Battery Monitor

[ozskipper]

This is getting scary! No one here wants you dead or wants your boat burnt to the keel. Please get an electrician to look at it. Or even a technician- heck even a mechanic. But someone technical. You say you have no money for it. How about using the money you would spend on the next two cartons of beer you were going to drink on the boat instead. In the long run you will be much better off.

[Quique]

i got xantrex working right. the manual didnt have the info i needed but the manual for the link 20 had a goos diagram. so thats fixed.
removed the antique inverter. so that fixwed.
i ran a wire from the - bus to the engine block.
thats were i have my doubt. i have read pros and cons about that.

[Quique]

Originally Posted by ozskipper

This is getting scary! No one here wants you dead or wants your boat burnt to the keel. Please get an electrician to look at it. Or even a technician- heck even a mechanic. But someone technical. You say you have no money for it. How about using the money you would spend on the next two cartons of beer you were going to drink on the boat instead. In the long run you will be much better off.

hahaha!
what will i drink then