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BPoland · 12-31-2014, 06:41 AM

I try and limit myself to 1, as I call it "Stupid Question" per month. I know, the only stupid question is the one that isn't asked. My dad, who was an electrician in the Navy used to answer these from me, but he passed a couple years ago, soooo.....

On my 2014 Bay Star 3103, I have two house batteries tied positive to positive and negative to negative (in parallel) On one negative terminal of battery 1, I have two connections 1) the tie in cable to negative terminal of battery 2, and 2) a cable for House ground. On battery 2s negative terminal I have 3 connections. 1) tie in cable to the negative terminal of battery 1, 2) House ground and 3) Frame ground.

My question is maybe a simple one. Can I wire all the ground connections off of one battery? In other words can all the house grounds and frame grounds come off one negative terminal, or was there a reason that they split the negative connections across both batteries?

As always, your help is appreciated!

Old Scout · 12-31-2014, 06:55 AM

Cable configs on bats always make my head hurt--the reason they split up the grounds is so both bats get a balanced draw during charge/discharge. There was a interesting article in FMCA Mag about placing the positive and negative cables at opposite ends of the battery bank so current was pulled thru the entire bank. The concept is more obvious with 6 or 8 bats but assume it would apply to 2 bats as well.

lostinfla · 12-31-2014, 06:57 AM

Since both neg terminals are tied together, it doesn't matter which battery the grounds are connected to as long as the connecting wire will carry the amperage. That said, if you have a lot of ground wires, the best solution is to mount a grounding terminal strip hooked to one of the battery neg terminals and then tie the others to it. The more wires you have attached to a battery, the greater the chance of terminals coming loose and causing higher amperage draw, along with low voltage and more heat at the connection.

RodgerS · 12-31-2014, 02:24 PM

I think you should have addressed your questions directly to Newmar. The first question is what is the correct wiring for the batteries. The second question is if the wiring is correct as you see it, why do they do the wiring that way. The third question is why don't they do it the alternative way as you and Old Scout are talking about.

If everything is working correctly, why are you messing around with it anyway? Seems there is enough to do when it comes to RVs without solving problems that may not exist.

The final question is for those of us that give you advice. Does the advice rise to the level of expertise? If not, no big deal. Otherwise, reader beware and that applies to my advice as well.

Dr4Film · 12-31-2014, 02:34 PM

Quote:

Originally Posted by BPoland

My question is maybe a simple one. Can I wire all the ground connections off of one battery? In other words can all the house grounds and frame grounds come off one negative terminal, or was there a reason that they split the negative connections across both batteries?

As always, your help is appreciated!

They only split the House Grounds not the Frame grounds.

Personally I would not mess with it. The more grounds you have the better off you are. Usually when you have 12 VDC wiring problems it can almost always be traced to a bad ground somewhere.

There is probably a reason that the house grounds are wired that way and Newmar would have that answer.

Dr4Film ----- Richard

FixerCQI · 12-31-2014, 02:57 PM

The answer to your question is yes, because you are already wiring your grounds to one battery (a battery of 2- 6v cells). You can also wire them to one of the 6v cells if you like, as has been mentioned by lostinfla, but because of the "tie", again you are wiring to both cells. Lostinfla also explains the best (only) way to do the connections. However, after I have said all this smart a$$ stuff, I would first check the house wiring diagram to make sure there are not two separate collections of house grounds being fed from the two separate "HOUSE GROUND" points shown in your dia., if indeed they are two separate points. It's a little hard to be sure without the full wiring dia.

GaryKD · 12-31-2014, 03:17 PM

Hi FixerCQI,
Does your answer apply to 2 12 volt batteries wired in parallel? Your answer mentions only 6 volt batteries. The OP has 2 12 volt batteries.

BPoland · 12-31-2014, 04:02 PM

Sorry, I didn't mean to start anything. My question actually ties back to a previous thread about a mechanical battery cutoff switch. If I decided to install the switch on the (-) side, and I know there are valid opinions for both the (+) and (-) side. If I tied all the (-)s together, then one switch would do it. If I elect to keep them separated, as they currently are, then I have to use two switches, and introduce yet another possible point of failure. Since the battery cutoff switch in my Bay Star doesn't completely cut off the house batteries, I am forced to find an alternate method to keep the coach from killing the house batteries while in storage. It's stored inside, and there is 50 amp service available for an additional $20 a month, but I should be able to store it without having it plugged in.

Dr4Film · 12-31-2014, 04:16 PM

Bill,

The typical Battery Cut-Off Switches that get installed directly onto the top post battery terminals are sized correctly to go onto the NEGATIVE terminal ONLY. The positive terminals are too large for them to fit correctly.

The above is not true for side post batteries.

In your case based on the diagram you supplied you would need two, one for each battery.

https://www.youtube.com/watch?v=NPI3f3edL9U

Dr4Film ----- Richard

lanerd · 12-31-2014, 04:19 PM

Essentially and electrically, the two neg terminals are the same point. The resistance of the cable/connectors connecting them will be negligible and for all practical purposes, irrelevant. They just split up the connections to this point for simplicity and ease of connection.

Ron

bruceisla · 12-31-2014, 04:22 PM

Sometimes it's just a matter of convenience ... as you start to stack ring connectors, you run out of space. Sometimes, it's easier to run some wires to the left, others to the right. As someone mentioned, sometimes you need a buss.

RodgerS · 12-31-2014, 04:24 PM

"Since the battery cutoff switch in my Bay Star doesn't completely cut off the house batteries, I am forced to find an alternate method to keep the coach from killing the house batteries while in storage." That's an interesting concept.

Here is the process for caring for your stored house batteries and keeping them charged.
Winter Battery Storage & Maintenance

bruceisla · 12-31-2014, 04:33 PM

And if you really want to make yourself crazy, think about what happens to all that theory when the BIRD or your Boost Switch activates the Big Boy Solenoid

FixerCQI · 12-31-2014, 05:44 PM

Quote:

Originally Posted by GaryKD

Hi FixerCQI,
Does your answer apply to 2 12 volt batteries wired in parallel? Your answer mentions only 6 volt batteries. The OP has 2 12 volt batteries.

My bad GaryKD; Yes it does apply to any voltage. I did not see the 12v. I should have realized it would be 12v when connected in =, as most systems in house are 12v. Anyway, the important part is that you could connect to any of the negatives no matter how many cells there are as long as they are all in parallel.