I have all the supplies I need to begin re-wiring my coach batteries to install the shunt and to connect the Trimetric battery monitor. Presently I have no clue as to what the drain is on my batteries OR if I am fully charging the batteries with the solar setup, or the converter. I have the two 8D wet cells. The batteries are not on slides and one has to be a contortionist to check and add water. I will in the future change over to AGM's either 8D's or 6V golf carts in the future. I am installing a phenolic terminal board behind the batteries to make the future changeovers easier. I also plan on covering the terminal board to keep the road crap off the terminals. My question is should one lead of the coach batteries go directly to the boost solenoid bypassing the shunt or should all loads go through the shunt? I'm guessing I should keep the boost side lead off the shunt because of the current draw when using boost for start assist?
Roland
Shunts only go on ground cable and must connected at a place that both batteries go through shunt.
Remove battery ground cables from motorhome ground point.
Ground cable from battery #1 goes to ungrounded point A.
Ground cable from battery #2 goes to same ungrounded point A.
One side of shunt goes to same ungrounded point A.
Other side of shunt goes to motorhome ground point.
Point A could just be one side of shunt or be one of the battery negative posts.
Just be sure both battery negative terminals are on one side of shunt and motorhome ground point is other side of shunt.
Hopefully shunt capacity is large enough to carry all house battery loads, including engine start with boost.
No change to house battery positive cables, boost solenoid, isolator, etc
Measuring RV Battery Current with Shunts (http://www.beamalarm.com/Documents/measuring_rv_battery_current_with_shunts.html)
Dang Dang Dang thought I had everything I needed, planned on getting 3/0 welding cable from Discount solar in Quartzsite. They have 1/0 2/0 & 4/0 don't have any 3/0. All my supplies are for 3/0 because that is what is already there, did not want to go to a different size. Now I'm looking for a welding supply outfit in this area before I proceed. :( Guess I'll have to wait a bit before I crawl under the coach and install my modification. On the plus side it gives me more "thinking" time, want to get this right the first time around.
Thanks Barry, just checked the wiring setup for the shunt, does hook up on the negative side.
Roland
Because of all the strands, welding cable sags and will move around a lot more than battery cables so keep that in mind in planning your installation. If you use "tywraps", stay away from the "made in China" stuff. They don't last and are really terrible in the sun. Here is a site with what looks to be, long lasting ties: http://www.nelcoproducts.com/shopping/shopdisplaycategories.asp?id=1#.UOeKtaXC5zQ (http://www.nelcoproducts.com/shopping/shopdisplaycategories.asp?id=1#.UOeKtaXC5zQ)
Pierce
Pierce
Thanks for the link. My runs will be short so I won't have to worry too much about the sag. Getting the cable out here though will be a problem. Internet sales are 100' min length, I'm not planning on rewiring the whole coach. Looking for a welding supply in the area, may have to go to Tuscon.
Roland
Roland,
I'm not sure how far away Tucson is from you, but you can order any length of battery cable from McMaster-Carr and get some with a red jacket as well:
McMaster-Carr (http://www.mcmaster.com/#welding-cable/=kwlcyi) It would probably ship from LA so ground shipping time was no more than 3 days when I lived in Tucson.
If you do buy welding cable in Tucson, you can pick up some red heat-shrink at this place: http://www.elliottelectronicsupply.com/ (http://www.elliottelectronicsupply.com/) to put on the ends it identify them as POS. You can also label the ends and then put clear heat shrink over the lables to protect them. Just some ideas.
Hi Roland,
I have bought cable products from Wiring Products Co. They have the 3/0 cable in red and black. They sell in 5', 25', and 100' lengths. They are on the web at wiring products dot com.
Raymond
Checked out the website, they are selling five foot lengths for $90.25, ten feet $180.50 ??? I can buy 100' for $178.50 at skycraftsurplus.com. Has to be somewhere I can get a 5 to 10 feet of 3/0 for a reasonable price. I will call some welding supply houses in Lake Havasu City on Monday, they be closed on Saturday. Gosh I would almost buy 100' but I don't need that much and I can't be carrying all that wire around. If I can't get 3/0 then I will have use 4/0 for battery parallel connections and 2/0 for the short runs that I will have to make, I don't think the IR drop on a 1 foot length of 2/0 is going to hurt me very much.
Roland
Go to any welding shop, They will have short lenghts laying around, been cut off when some thing was dropped on them,
Roland, drop by here in san carlos mex' and in a few days I will be done with my battery change and should have around 4 or 5 ft of 4/0 left over. I am using all 4/0 welding cable, will not mess with anything less.
John H