Xantrex Truecharge wiring

pjcomeau · April 28, 2008, 09:37:50 AM

I'm looking at wiring my new Xantrex Trucharge20+ as in the picture. My question is, can I have a separate DC negative bus just for the charger connections and not "connected" to any other common bus?

Stu Jackson · April 28, 2008, 11:16:43 AM

Pierre, all of the negatives end up going back to the engine anyway, so I don't quite understand your question ("can I have a separate DC negative bus just for the charger connections and not "connected" to any other common bus?")

Also, even though there are three outputs from the charger, you don't necessarily have to use them. If, for instance, the first two of the three batteries shown are your house bank, you can eliminate one of the charger outputs because those two batteries are actually in one BANK. If you have a combiner or echo charger, then only one output from the charger to a PDP is necessary.

pjcomeau · April 28, 2008, 11:39:20 AM

The previous owner had the batteries setup as three banks, two house (with a switch) and a starting battery separated by another switch. I know the batteries may be in a circuit depending on where the switches are.

I wanted to know if I could wire/install the wiring just like the picture with a separate DC neg bus (that is the bus will only have charger connections. So if all the battery switches are in the "off" position, no other circuit would take place, that is the DC neg bus used by the charger wiring as described would not go to engine (or at least I can't see how). Is this OK?

Thanks

Ted Pounds · April 28, 2008, 11:52:59 AM

The negatives will always end up tied together. If nothing else all the grounds will meet at the negative terminal of the charger. So adding a separate ground bus for the charger would not achieve anything just like Stu said. Since the engine is connected to the negative terminal on, at least, the start battery it will always be connected to all the other grounds. (I'm using the terms ground and negative interchangeably.) Keep in mind the that the battery-switches only switch on the positive side of the circuit. The negative battery terminals are always tied to the ground bus (and hence to the engine). Hope this clears it up for you.

Stu Jackson · April 28, 2008, 01:23:16 PM

Pierre, Ted's right. I believe that the illustration is simply one of the many ways one could physically wire up the negatives and Xantrex chose to use that one - showing a buss bar - you could also use a Power Post, both made by Blue Seas Systems.

See reply #8 here: http://c34.org/bbs/index.php/topic,973.0.html It discusses what you have described as two separate house banks and a separate start bank. I recommend that you reconsider and combine your two house banks into one larger bank - the batteries will last longer and you'll be treating them better.

Also, after I put in my Link 2000 two months ago, and continued to have troubles with my fridge not working, I equalized the batteries. Assuming that your battery manufacturer says it's OK to equalize your wet cells (ONLY), because some 6V golf cart vendors do NOT suggest it, I recommend that you use the Xantrex charger to fully charge and then equalize your batteries. They will thank you for it and they will work better. Mine certainly have...

Ron Hill · April 28, 2008, 06:39:10 PM

Pierre : I think you could use the Xantrix wiring, but most of us didn't do it that way. We already had the negative battery posts wired together with #4 or #2 size wiring. So the simplest way for the single negative wire from the True Charge shore charger was to take that (-) wire to the furtherest battery negative post.
The negatives are all tied together as mentioned by Stu and Ted.

pjcomeau · April 28, 2008, 07:14:00 PM

OK,

Make sure I get this right. I could do as described above, but not necessary (wouldn't it be slightly better? Equal runs?). I will connect the negative wire from the charger to the battery negative with the longest wire run.

I'm thinking of still running the three positive runs and run the house bank switch set to all (that puts them in parallell, right).

Again, thanks

Jon Schneider · April 28, 2008, 07:53:43 PM

Pierre, your common ground is probably heavier gauge than you were thinking of installing as charging grounds, so you're much better off following Ron's advice. It's critical that all three banks be connected by a common ground for the charger, and, doubtless, that is how your existing system is configured. Regarding the positive leads, you really want to have an individual hot lead go directly and discretely to each bank. Do not go through the switch if possible. If you must go through the switch(es), connect the leads to the individual poles (i.e., #1, #2) on the switch, and then do not parallel the switch when you're charging. Put it in the off position or connected to just one bank.

pjcomeau · April 28, 2008, 08:00:00 PM

Sorry,

I'm definitely running the positive to the batteries. I was only referring to the switch in response to Stu about running the house bank as one unit instead of draining one side, then switch to the other.

Jon Schneider · April 28, 2008, 08:07:25 PM

Ah, I see ;)

Stu Jackson · April 29, 2008, 02:25:26 PM

Pierre, if you run with the house switch set to all (both) then you do not need to run both wires from the charger to each bank UNLESS you want to turn your 1-2-B switch OFF when you're off the boat - which would be a good idea. Think about how the current runs and then you'll see.

What this means is that IF you keep your two house banks separate as you now have them wired, then you will NEED to run the three positive wires from the charger to the three different banks if you want to leave your boat with the two switches in the off position.

What I continue to recommend is that you SIMPLIFY your system. Use the 1-2-B switch to get rid of your two house bank arrangement and connect the start bank to one of the two posts of your 1-2-B switch, and combine your two house banks into one big one. Either disconnect the separate switch for the start bank and run the start bank to the 1-2-B switch, or find some other way to be able to use either the house or startr bank to connect to your starter.

Also means less wiring from the charger.

Jon Schneider · April 29, 2008, 06:10:53 PM

Quote from: Stu Jackson on April 29, 2008, 02:25:26 PM
What I continue to recommend is that you SIMPLIFY your system. Use the 1-2-B switch to get rid of your two house bank arrangement and connect the start bank to one of the two posts of your 1-2-B switch, and combine your two house banks into one big one.

I'm a fan of the configuration that Stu is recommending, but the act of simplifying your system will complicate your life while you re-work the configuration without a ton of gain to be had. I configured my system the way Stu recommends, but that was because I was doing it from scratch. I actually had a very respected EE friend of mine desperately try to convince me to configure my battery wiring the way yours is. There is one advantage to it, which is that if one of the cells on one of your batteries shorts, you still have half your house amperage easily available and safely protected. This EE also recommended that I run only one bank at a time, switching between banks on alternate occasions. As Jay Leno and a bunch of Valley Girls would say, Oh puleeze. The argument for one large bank is that it's better to lessen the discharge level by combining banks. That said, you will double the number of discharges on one mega-bank versus two smaller banks. I chose to go with the conventional wisdom that minimizing the total discharge is a thing to be avoided, regardless of the frequency of discharges. I guess you get to choose your poison.