Jumping a Sterling Battery Charger

[Bob S]

Sterling 30a Charger

Simple question. On your how to site you recommend jumping the outputs when supplying the total output to the house bank. I have both 10awg and 6awg wire available. The jump is only a few inches.Would 10awg be appropriate?

Bob S

 

[Maine Sail]

Yes 10GA is fine

 

[Bob S]

Thank you!

 

[Bob S]

Can anyone comment of the sound level of this unit? I was planning on installing it in the port lazarette where the original charger was installed. I have been rethinking of installing it under the chart table which is open in the MKIII. My wife is sound sensitive. I'm worried if I did and she complains of the noise she will be less inclined to sleep on her. Even though it is a nice looking instrument I don't want it openly visible.

Also had a question on the galvanic isolator install. How important is it to be close to the shore plug? I upgraded to a Smart Plug which is on the starboard side. I have more room if I install it next to the new charger.

 

[woodster]

the charger is super quiet the only noise i have ever heard is when you power it up or down and that is from the fan ...it runs for a few seconds or so and when it shuts off no noise that i can here ....just some cool looking lights on the panel with the amp reading....i will add that charger and the autopilot are some of the best items one can own on a boat

 

[jssailem]

charger and the autopilot are some of the best items one can own on a boat

That is great news Woodster as I just aquired one of each and working on the install before the season gets started in earnest.

 

[GonzoF1]

One related question:
I have redone my battery system and have 8 GC2 batteries. Can I send the three legs to different points along the bank of batteries? IIRC, the gauge of the individual legs is 6ga., however, so is the ground. Shouldn't the ground be a larger gauge wire or is 6ga still okay? I fired up the new rig yesterday and with just one charger leg attached, both the B+ and the GND got warm when charging at 60A.

 

[woodster]

you need larger wire and you also need to know how long the round trip is from + to - on the charger ...as for the three legs just use a jumper on the outputs and have one + wire going to the bats and one going to the - there is an article on installing the charger on mainsails how to site

 

[GonzoF1]

Sure... The round trip is just a few feet. According to the Sterling manual, 6ga is correct, however, since it got warm, I assumed that I could distribute the B+ load (kind of like lumping the three outputs together) by dropping the outputs to different point through the bank. The wires are in place from the original install (before I bought the Sterling) so it would be easy. Like I mentioned, the worry was the ground. If I use three 6ga legs for B+. what size should the GND be? I mean if 6 is good enough, why did it get warm?

 

[woodster]

i am not sure you can hook one wire to each battery if you have them grouped together as on bank you would be better off hooking the + to the + on the bank and then hooking up the - on the -at the other end creating a complete loop of the power ..insuring that all the bats got a good balanced charge i would use # 4 or even # 2 on both plus and minus with the jumpers at the charger ....you also have a temp sensor on that sterling and it hooks up at only one battery connection ...so my thinking is if you split the wire to each battery how will the sensor know what the other batteries temp is

 

[Bob S]

In the manual it states "any output not being used should be linked across to one that is". It depends on how you 8 batteries are set up. Are they one large house bank or two groups of four? Do you use an echo charger and run all your charging sources directly to your house bank? I do suggest at least reading through Main Sails How To:
http://www.marinehowto.com/

I have a simple set up that has been promoted by most of the experts on this site. I have all my charging devices going directly to my house bank with an echo charger to the reserve battery. I plan on jumping the two unused feeds to the third.

 

[Bob S]

Has anyone installed a galvanic isolator? It's a pretty simple device and part of an upgrade I'm performing in preparation of my first slip. I am thinking of installing it just before the charger which is probably 10' from the Smart Plug. I know they recommend it being as close as possible to the plug but I'm very limited in space. Does anyone see this as a problem?

 

[GonzoF1]

In the manual it states "any output not being used should be linked across to one that is". It depends on how you 8 batteries are set up. Are they one large house bank or two groups of four? Do you use an echo charger and run all your charging sources directly to your house bank? I do suggest at least reading through Main Sails

Read it... I get that it says to jump between posts, but wouldn't having two or three B+ leads to the same spot (or different spots throughout the bank) accomplish the same? And therefore only require me to increase the gauge of the GND cable? Is there any safety reason or uneven charging that could happen by this?

And to answer your question... eight cells, all one bank... Blue Seas ACR to starter bank.

 

[woodster]

why have three wires going to the same place when one bigger wire would do a better job...by using 3 smaller wires you are creating a possible voltage loss along with the fact that you have to fuse each wire individually...with one wire you only have one fuse to contend with and get better voltage in one package ...just a thought here if the cost of the wire is the problem ...what will the cost of repairing the damage if you use the three wire setup.... say from one fuse not blowing with the other two or visa versa....think boat fire when doing electrical always

 

[GonzoF1]

It is a simplicity thing. Right now the wires are there and are difficult to replace. I'll do it if there is a compelling reason.

 

[woodster]

your boat your choice

 

[Maine Sail]

One related question:
I have redone my battery system and have 8 GC2 batteries. Can I send the three legs to different points along the bank of batteries? IIRC, the gauge of the individual legs is 6ga., however, so is the ground. Shouldn't the ground be a larger gauge wire or is 6ga still okay? I fired up the new rig yesterday and with just one charger leg attached, both the B+ and the GND got warm when charging at 60A.

How long is the round trip run? I like to see charging circuits sized for 2% or less voltage drop. For a 10' round trip run this means 4GA wire. Regardless of what you do on the other + outputs the neg is likely undersized because it will be carrying the entire 60A because DC is a circuit...

How did you crimp on the 6GA terminals? What tool? Some of your heat may be coming from poor terminations and some from voltage drop/resistance..

 

[GonzoF1]

Round trip is less than 10'... I kinda figured that the GND would end up being too small, but the battery ends of the B+ I crimped as-per your detailed instructions on your Compass Marine page. I bought an FTZ lug crimper when I rebuilt the DC system on our trawler about 4 years ago. I treasure the tool... I use it all the time for friends too.

One thing I noticed it that the charger lugs I used (power, not flared starter) were filled with anti-oxide stuff. The grey paste you use in wire nuts if your house has aluminum wiring and you connect aluminum to copper. I didn't think anything of it at the time because I assume it wouldn't add resistance, but could that be causing excess resistance?

The other ends (at the charger) are pretty stout factory connections. I will reexamine them next weekend because I guess I need to get back up in there to replace the GND wire anyway (it is a pretty big effort requiring me to remove some exhaust tubing to get to... and even then, it's awkward). So I guess while I am in there, I will reexamine the path of trying to beef up the B+ wires too. **sigh** I had hoped not to have to do that <see below>

My original question also still stands. Let's say I increase the gauge of just the GND. Would charging performance become "unbalanced" if I place the existing B+ leads in several (or just 2) places across the bank? Specifically because, with an 8-cell bank, I have had to put batteries in separate boxes about 3' apart connected together with 2/0 wire.

Thanks!

 

[Stu Jackson]

Woodster and Bob S both answered your question, and Maine Sail's original How to wire a battery charger article also did.

Would charging performance become "unbalanced" if I place the existing B+ leads in several (or just 2) places across the bank? Specifically because, with an 8-cell bank, I have had to put batteries in separate boxes about 3' apart connected together with 2/0 wire.

You have one bank, right? One output to the bank, NOT multiple outputs to different batteries within the bank.

And to answer your question... eight cells, all one bank... Blue Seas ACR to starter bank.

 

[Bob S]

There are three grounds Earthing(AC), DC Negative and chassis. Is there a wire size restriction/requirement on the chassis ground? I have both 8awg and 10 awg in green. I am using 4awg on the DC Side.