Electrical Connection

[hcrisp]

The battery cable I removed from the boat is 1/0 gauge. At least, it fits snugly in a 1/0 lug. It is un-tinned and the strands are thicker than marine quality. More rigid. Also, there is no ID on the insulation. No markings of any kind.
In the beginning, before removing the engine from the boat, I bought some 4 gauge after reading the Moyer Manual as I knew I was going to re-wire. In fact this is the cable I used to start the engine recently after 8 years dormant.

Question #1: Am I happy with the 1/0 wire? One of the weird things about it is attaching it to 5/16" fuse block post on the battery. This seems like major overkill. I have lots of the 1/0 since I am moving the batteries closer to the engine.
I'm thinking use the 1/0 to the starter and ground and use a piece of the 4 gauge for alternator output to the starter. And then using the 4 gauge for the house side. Please correct me if I'm headed off somewhere unpleasant.

The PO only had one battery for both engine and house. This I am going to change by adding a deep cycle battery for the stuff I will be adding to the house side. I am definitely going to change this as the wires disappear behind the liner and I can't tell engine from house even before they disappear.

Question #2: Do I install the Blue Sea "Add a Battery" ACR and switch? I am leaning heavily toward this option which sounds perfect as long as the ACR works. Either "On" or "Off" seems to simplify things. Not that we can't manage our batteries with "1, 2, Both or Off".

Howard

[Mo]

Howard,
I had a starter / deep cycle combo and a true deep cycle battery on the boat for house. The deep cycle ran it's course in 3-4 yrs and I think it was because I have that HD alternator on there (90 or 100 amp...can't remember). Have since installed a second starter / deep cycle combo (so now both are) and haven't had a hitch with that. I use the boat almost daily so the engine does start up and pump a quick charge into them while I get off the dock etc. I have never had those go down...never.

Keep in mind we do just weekend trips etc and the rest is beating around my area here with mostly the autopilot working...not allot of draw on things. All lights except my stern hull running light are LED's...

I am not an electrical wizard at all...far from it. I think allot of what you need to install will depend on what you are doing with the boat.

As for the heavier wire...I'll leave that to Neil or Hanley...but less resistance ??

[ndutton]

Question #1:
No problem going bigger. The heavy stranding however indicates it's conventional building wire and not typical for marine application. As far as approvals go, it isn't tinned anyway so that ship has sailed. The keys to a good installation are solid, corrosion free terminations and support of the cables independent of their connections. My view is I wouldn't use it based on the stranding. I have plenty of heavy cable around from my business but when it comes to the boat, it's fine stranding for me. I figure the ABYC and USCG have their reasons even if I'm not completely up to speed.

Question #2:
I don't have and have never had an ACR so I have nothing constructive to offer other than there's a reason I don't have one.

[Al Schober]

Howard,
The reason for the thin strand stuff is for flexibilty. If you're going from a fixed point to a fixed point, the fat strands should be fine. If you're going to an engine on resilient mounts, the thin strand stuff would be preferred.
My boat originally had 2 group 27 batteries with one of those ubiquitous A/B/Both switches. This left us stranded a couple of times. Before our Maine cruise in '99, I wanted more house capacity to run the radar and the nav lights overnight. I didn't think one group 27 would cut it, so I added a group 24 - just for the engine. That gave me 2 group 27s for the house bank, which worked fine. Engine battery is on it's switch, house bank is on it's switch, and never the two combine. Well, I have a thing called a 'Combiner' for charging.
Alternator output has been moved to the house bank. When that comes up to 13 v, the combiner closes and sends charge current to the start battery. This system has worked very well. The group 24 is plenty for the Atomic 4, and the house bank has since been upgraded to 2 of group 31s.

[hanleyclifford]

1/0 is fine though a bit of overkill. If you have a high output alternator it is a good idea to ground the case with the same size you are using at alt output (#4) not relying on the bracketry. It is also a good idea to protect the circuit on the negative leg just before it returns to batt -

[thatch]

"Worth a thousand words"

Howard, Just one last question, How did you get a picture of Neil working at his craft?
Tom

[ndutton]

That's why we make what we make.

An electrician completes a repair at a doctor's house and presents him the bill. The doctor says, "WOW. I'm a doctor and I don't make that much."

The electrician replies, "I didn't make that much when I was a doctor either!"

[BunnyPlanet169]

Been there

Hi Howard:

This got a bit long winded, but I find this stuff fun!

I did exactly what you're about to do 6 years ago.... I'd be happy to chat offline - my username at gmail. If you haven't got it, may I recommend the Nigel Calder book, "Boatowners Electrical and Mechanical Manual". No Atomic 4s, but a very well thought out electrical section.

I added the first page of my schematic and a couple pictures to your "mess" post. It was designed for coastal cruising, and some power to expand.

I used 3 Blue Sea switches, each a simple off/on, and an ACR (automatic charging relay). I have 2 group 24 batteries for house loads, and a dedicated group 24 for starting. House and Start are each isolated by a dedicated switch, and can be manually combined with the third middle switch. Blue Sea makes solid buss bars to link the switches, so the installation is quite compact.

I put the ACR in parallel with the middle 'combine' switch. What's nice about the ACR is that it charges both banks without any manual switching. I leave the House and Start both turned on, the middle 'combine' off, and never touch a thing. If I need to combine (I haven't), I turn one switch. The ACR keeps them separate and charged, without the voltage loss of a diode isolator. The Blue Sea device also has an ignition sense circuit, to separate banks when starting. Nice little device.

Primary battery cables should be sized for minimal voltage drop at any predictable load, as well as for charging. Using lead acid, the charging rates are a lot lower than we'd like, and the primary battery cables will/should always be bigger than what you're running from the alternator. 1/0 is huge for a 27 footer unless you're contemplating an electric winch on the foredeck....

Wiring should be sized for the specific application, but your Bristol and mine are probably pretty similar. For my boat, I used #2 for primary battery wiring (batt to terminal blocks, batt to starting motor, batt to switches and ACR).

The Anchor product is flexible, the stranding tinned for corrosion resistance, the insulation is rated 105C, and it's UL listed for marine use. It ain't cheap ($4.00 /foot on a 25' spool), but you'll never replace it.

My alternator run ended up being #8, and it's also fused separately. I'm using the 55A alternator from Moyer, and the Ispro 40Amp meter with built in shunt. I've never seen it past maybe 25A for more than a minute or two. The batteries limit the charge current - I'll never see full alternator output, and it'll last longer as a result.

I suggest you start with a power budget. List all the things you know you will use (nav lights, masthead, steaming, cabin, VHF, depth/speed, GPS), then add in anything else you may want (chart plotter, radar, sonar, refrigeration, that big-ass winch...). I used Excel. I had a line for each item, and wattage from the manufacturer. I had two columns, reasonable use ( for me I think 4 hours), and fantasy use (12 hours). Think about duty cycle. Do the math and you'll come out with amp hours consumed during a day.

Then things get interesting. Really, how many batteries do you want to carry? How many can you fit? This was most significant for me. How much stuff you really going to power? It's all a balancing act. Re-adjust the budget. Actual useful amp hours from a deep cycle lead acid are about 30% of nominal, in that the battery is usually being used between 80% and 50% charge. Don't want to go lower, and you'll usually not top them off unless you run the motor a lot, or have solar or wind.

Sorry to go on.... Give me a buzz!

Jeff
S/V Bunny Planet
Bristol 29 #169

[lat 64]

+ 1 on Nigel Calder's book. (I've recommended it before)

Howard, was that photo from Tiblisi in The Republic of Georgia?

Here's a pic I took of a Godzilla snare in Tokyo in 2011.

[hcrisp]

Good Advice

Good Advice, guys. As usual. After listening to you so far with great results I am not going to change horses in the middle of the stream. I'm going with the tinned marine grade #2 cable. I can use the Ancor #4 I bought for the house side. The un-tinned 1/0 will collect dust.
Genuinedealz has #2 for $3.25 ft. Defender for $3.69. That's cheap for never having to worry about it again.
Neil, can you point me to your thread where you give your reasons for not liking the ACR/on-off switch combo?
Howard

[ndutton]

I confess I post so much that certain posts get lost in the pile. What's my post count now, over 4000? That's embarrassing.

My opinion of combiners or automatic charging relays is they are an unnecessary gadget that provide little if any benefit to a captain who is on top of things and they complicate troubleshooting. As is often the case, my opinion is in the minority but that never bothered me before. Issues I have:

1. I decide which bank gets the charging voltage, not some doo-hickey. I absolutely do not want my isolated engine starting battery combined with anything unless I say so.
2. Combining a low bank with a higher bank for charging has the effect of averaging the state of charge the regulator sees. This causes the low bank to take longer to recharge than if it were being charged by itself due to a lower amp output, at least initially.
3. Unless they've evolved into using latching relays these gadgets consume power themselves. No thanks.
4. Some of these gadgets add voltage drop. No thanks again.
5. Ain't it interesting the entities that sing the praises of ACR's are often the ones offering them for sale?
6. Charging systems worked fine for over 5 decades without these gadgets. Now we need them? Not me, I have no problem turning a switch.

[Dave Neptune]

Kiss

Well said Neil! I have to totally agree with the KISS rule and skipper compitance. I spent a few hours at Catalina working with a buddy on his new Bene-43 chasing voltage drops. All of the fancy krap was doing most of the dropping and being able to PUSH BUTTONS to operate relays to switch charging duties with all of the connections was a joke. He had 3 voltage gages and was concerned about all the different readings each time he'd switch things around. My advise get a battery switch and deep blue sea the rest. Nice pun I say.

Dave Neptune

[ndutton]

All I want to worry about is the tequila supply.

[hcrisp]

Here we are again with good advice. And good puns.
I like all your points, Neil, and intend to keep it simple. No worrying about "automatic' gear.
Thanks again,
Howard

[ndutton]

Remember, I'm in the minority. Judging by the number of members who have ACR's/combiners I expect there will be following posts with differing opinions.

And I LOVED Dave's pun, your on-topic pictures too. This discussion reminds me of a comment made by a plumber on a commercial project 25 years ago. We were finishing up a building and he was setting toilets. Y'know what toilets can cost? He'd finished up in the office I was working, gave the handle a push to test and a giant smile came to his face as he said, "There ain't nuthin' like the action of a thirty dollar toilet!"

Sometimes simple just works. And works and works.