Unsafe Battery Cable Route?

[Sky_Boss]

This is my battery compartment overview




After learning the virtues of the AUX BATT switch, I delved deeper into the realm of my battery system. Keep in mind that the dealer replaced the house batteries and I don't know if there was a size difference but the chassis battery was put in service August of 09. The problem is that the chassis battery is a side post and the negative cable was routed between a threaded bar used to hold a battery down and a battery. I'm concerned that the threads will chew away the cable cover.



My thoughts are to replace the chassis battery with a slightly bigger one with top posts. The current one is an Interstate MT-75/650 CCA (9 X 7.25 X 7.625) With the Interstate MTP-78DT/800CCA (10.3 X 6.875 X 7.8) The replacement would be a bit longer but based on eyeballing it from the pic, shouldn't be a problem. It has top posts that will help avoid the current situation.

I am assuming that going from side to top posts I will need new cables. so...

1. Does anyone agree that the cable routing is a problem?
2. How hard would it be to recable the entire battery system?

[mr300ce]

Maybe you can just turn the battery around, which will also make it easier to access the terminals. Nothing wrong with the side terminal batteries.

[RV Wizard]

You would likely never have a problem with the cable in the coaches lifetime. The vibration may cut through the cable insulation but never enough to cut the ground connection loose. If this were the 12+ cable the issue would be totally opposite.

[Sky_Boss]

Originally Posted by mr300ce

Maybe you can just turn the battery around, which will also make it easier to access the terminals. Nothing wrong with the side terminal batteries.

That is too simple.


I work for the government, I need a more complex, incomprehensible solution that costs a lot of money. LOL

Well, from the pic I clearly have enough positive cable available to move, so I just need to look into how much slack I have for the negative cable. I would think that while I am doing that I can make sure the battery is in good charging shape before I make a final decision on it. I had an incident right after picking it up where I had to jump it to get the engine started but I think that may have been more cable/terminal related.

Tanx

[Sky_Boss]

Originally Posted by RV Wizard

You would likely never have a problem ... If this were the 12+ cable the issue would be totally opposite.

OK...Can't resist...GEEE Mr. Wizard.

Good point regarding potential affect regarding - vs + cable danger potential. I can stand down from Def Con 2 now. LOL. I'm thinking the other suggestion to just turn the battery around fits the bill. Even if I had to replace the negative cable to make that work, I like it. I suppose the only counter is whether having the terminals above the open compartment bottom MIGHT cause some problems with water. (Ya...that is reaching but I am such a worry wart. LOL) However, the retracted stairs would shield that area anyway.

TANX!

[powerboatr]

you could add a piece of thick rubber anti chaffe material to the negative lead at the contact point of the threaded rod.
A tech putting it in that way imo was not a smart person
granted its only the negative, and it wont cause to much harm if it does chaffe through, maybe radio static, flickering lights, etc

[BFlinn181]

Turning the battery around would make the terminals more accessible for maintenance. If the threaded rod chafing is a concern, about 10 inches of an appropriate sized vinyl hose from Home Depot slipped on the rod will shield the threads.

[Paul R. Haller]

Oh my gosh, it's a ground battery cable. It doesn't matter, worry about the something else, but if it bothers you too much put some loom around the cable and worry about the price of gas. The other end of that cable goes to the frame. Worrying wont make any difference on either one.
-Paul R. Haller-

[Sky_Boss]

Originally Posted by Paul R. Haller

Oh my gosh, it's a ground battery cable. It doesn't matter, worry about the something else, but if it bothers you too much put some loom around the cable and worry about the price of gas. The other end of that cable goes to the frame. Worrying wont make any difference on either one.
-Paul R. Haller-

Well...keep in mind it has been a while since I new the difference from an Amp and a ohm in the ground. LOL

Long story short, battery didn't test too good and wouldn't start the motor. I replaced my 650 CCA battery this afternoon with an 800 CCA Interstate battery with both top and side connections. I turned that sucker around too. LOL

I used the top 12+ so I replaced that cable and then used the side 12-...for now. There is a lot of excess ground cable so on some boring day I will need to pull out the house batteries so I can get to the connector and put in a shorter cable. I also took the time to dress out the house batteries. All and all...I feel much better about it.

[okmunky]

When you do "need" to change out the house batteries you might want to consider going to pairs of six volt golf cart batteries. I just upgraded my bank and am very pleased.

Also, here is some good info about RV electrical systems, including batteries

http://www.rvcruzer.com/electrical/t...4798206&sr=8-1

[okmunky]

Sorry this is the correct link

Electrical Tutorial

[Paul R. Haller]

[QUOTE There is a lot of excess ground cable so on some boring day I will need to pull out the house batteries so I can get to the connector and put in a shorter cable. [/QUOTE]


All kidding aside a great place to go for best quality cables is the welding shop They carry heavy finely stranded welding cable in 04 right up to and including 4/0. They also carry heavy duty all copper lugs and my shop, if you buy it all from them, will crimp on the lugs for you for free. Seriously, it's way cheaper and better quality cable then sourcing it elsewhere. In all my work on electrical stuff, and I have done a lot, on heavy draw 12 volt stuff like running inverters, bigger is better. In my rig, all my battery connections to the inverter from the battery, to frame, and battery to fuse connections, I use 4/0 cable. Even from the converter, since I can't get large cable into the connector lug on the converter, I use 2 #4 cables on both the positive and negative side to prevent voltage loss. My converter has 2 connectors on each output.This is often an overlooked weak point and RV dealers don't have a clue.
In my most recent purchase I asked the dealer to install 2 6 volt batteries instead of 1 12 volt when I purchased the 5er. That required him to make a new cable between the new batteries because now you need to wire the batteries in series instead of parallel. He installed a #6 wire between the batteries. What a monumental error. If I draw max power out of the inverter, I'm draining about 300 amps for a 3000 watt inverter. What do you think would have happened to that #6 wire? It would have fried the first time I tried the inverter.
Your batteries and their ability to supply power is dictated by ohms law. In the real world that translates to the size wire and it's length are what limit the batteries use. Small wire size and longer runs induce more resistance. More resistance reduces voltage and amps go up and so does heat. Why shoot yourself in the foot to save 10$ on cable. Go the biggest you can buy and still be reasonable. Go 4/0 for all battery connections and clean everything well! Your batteries will be happier for it and heavy cables really don't weigh that much more and they will provide you more power to use and less waste in heat.
-Paul R. Haller-

[Sky_Boss]

Barb, Paul,

Thanks for your thoughts. I agree about the use of 6 volts in series. Just can't get myself to do it since I got 2 brand new 12V house batteries in the deal and I haven't even had the rig a week yet. LOL

As I replace some of the main battery cables I was thinking of using 2 gauge since that is what it appears I currently have. Should I go bigger than that?

It makes sense that leads to/from inverters and converters need to be as "big" as possible to avoid the things you talk about. I'm just starting to get the basics on inverters and converters so your ideas are very helpful.

[Cat320]

Originally Posted by BFlinn181

... If the threaded rod chafing is a concern, about 10 inches of an appropriate sized vinyl hose from Home Depot slipped on the rod will shield the threads...

I use pieces of old hoses for chafe protection, held in place by strap ties.