Poll: Batteries/charging circuits

[NorthernFocus]

Based on what I've gathered from posts here in the forum, not all of our tugs with multiple battery banks are wired the same. So I was wondering...

For boats with three banks of batteries(start/thrusters/house), please reply indicating which battery bank is connected directly to the alternator.

When I bought my boat it was wired to the house bank. That's also how it shows up on the schematics that I have so I assume came that way originally.

 

[Todd]

All batteries are connected and charged by the alternator. There is circuitry to prioritize the order they are charged. I think it is starting, house, thruster.

 

[NorthernFocus]

All batteries are connected and charged by the alternator. There is circuitry to prioritize the order they are charged. I think it is starting, house, thruster.

The circuitry is what I'm getting at. Just thought it would be simpler/more straightforward to ask where the alternator cable is landed i.e. on which battery/buss/ACR.

 

[Kenny Marrs]

On the R-25 the cable will go to the engine start battery.

Thanks,
-Kenny

 

[NorthernFocus]

On the R-25 the cable will go to the engine start battery.

Thanks,
-Kenny

Presumably you mean the current model? My 2008/9 was wired to the no.3 buss. I've since moved it to the no.1. But am now thinking for optimum reliability it should land on no.2.

 

[Kenny Marrs]

Unless someone moved the cables we've always wired bank 1 Engine, Bank 2 House, and 3 Thruster. Andrew and I just pulled out the old manual to confirm this. Your ACR's are wired so all three banks will charge when underway.

Are you having charging or starting issues?

Thanks,
-Kenny

 

[NorthernFocus]

Unless someone moved the cables we've always wired bank 1 Engine, Bank 2 House, and 3 Thruster. Andrew and I just pulled out the old manual to confirm this. Your ACR's are wired so all three banks will charge when underway.

Are you having charging or starting issues?

Thanks, Kenny. No, no charging issues so far.

Yes unfortunately the manual doesn't match the electrical schematic for the R25 (that I downloaded from this site) which clearly indicates 1=engine, 2=thrusters, 3=house. And my boat was in fact wired according to the schematic. The alternator cable was labeled "no.3 buss" and was landed on one of the ACRs sharing a terminal with the no.3 bank. So effectively it was wired as labeled. The schematic is non-specific showing the alternator and all three batteries wired to a block that is generically labeled "isolator". Presumably that is the schematic representation of the two ACRs. Bottom line is that the schematic doesn't specifically show how the alternator is supposed to be wired. Which is why I started this thread.

But you provided the answer. Based on your comments it sounds like the factory philosophy is to wire the alternator to the engine bank. Which is all the answer I need. I re-wired it that way shortly after taking ownership. And I want to be consistent with factory specs so I can sell this puppy and move up the food chain. So I'm good 😀

 

[knotflying]

Well, this is an interesting topic because at one time I was helping a friend with a dead engine battery, really dead, and threw the parallel switch on to get the boat started. After about an hour of cruising I turned off the parallel switch and the engine died. I assumed, as with a car, once started the alternator took over and the batteries just got recharged. So because of that situation I assumed that the alternator charged the house batteries and the relays opened and closed accordingly. Since the engine battery was so dead the relay did not close and hence it did not charge or provide power to the engine battery. Sooooo, if my assumption is correct, that the alternator on the R-27 goes to the house, if that is so, then why would the R-25 be wired differently than an R-27.

 

[Kenny Marrs]

Did you check the voltage on all three banks once you turned the parallel off?

 

[Kenny Marrs]

So that old schematic does show the house as bank three. Regardless of how the banks are labeled the battery configuration stays the same. The forward two batteries always house, aft outboard battery is the thruster, aft inboard battery is the engine.

 

[knotflying]

Did you check the voltage on all three banks once you turned the parallel off?

Yes Kenny, and it was below the voltage threshold for the relay to close. Hence I would assume that the alternator was providing a charge to the engine battery while in parallel, but once off parallel there was nothing going to the engine battery. So I then assume that the alternator is charging the house and the engine battery gets its charge via the relay.

 

[boaterjoe]

This is an interesting thread that seems to get a lot of attention. One of the problems is that most of us do not know enough about batteries (parallel vs series, etc) and the C-28s and ranger tugs batteries are uniquely set up. I wonder if the factory or TugNut members might have a good article or website they would recommend so that we could all educate ourselves on our battery systems?
any good references out there - that one would want to recommend?
Joe

 

[NorthernFocus]

One of the problems is that most of us do not know enough about batteries...any good references out there - that one would want to recommend?

Sorry never got around to a reply back during the season.

First off, get a copy of the wiring schematics for your boat from the Ranger factory and learn how to read them. Even if you don't have the knowledge/desire to use the drawing yourself they should be made available to anyone hired to work on the electrical system. If your boat has been customized with more/less equipment than reflected on the schematics, mark up a copy "as-built" and save it as your master reference. Then It's not a bad idea to print a couple of copies and use a highligher to trace various circuits, scribble notes in the borders, etc. This is a good way to learn your system and can provide quick reference material to jog the memory when troubleshooting systems.

Batteryuniversity.com is a good place to find most of what you need to know about batteries, charging, etc.
http://batteryuniversity.com/

Here's an article explaining charging:
http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

And a not so good one(tedious) on parallel circuits:
http://batteryuniversity.com/learn/article/serial_and_parallel_battery_configurations

And one on how batteries work; starting vs deep cycle, etc.:
http://batteryuniversity.com/learn/article/lead_based_batteries

On the Blue Seas website you can find information on how the ACR(relays) work:
https://www.bluesea.com/products/7610/SI-ACR_Automatic_Charging_Relay_-_12_24V_DC_120A

Hope this helps.

 

[Osprey]

The original post on this thread was some time back but I just picked up on it due to the Northerfocus post today (23rd). My tug is a 2012 version of a R-27. For mine, the factory wired the alternator to the house bank (#2). ACRs make further charging connections to the engine (#1) battery and thruster/anchor windlass (#3) battery. In addition, one can link the house and engine banks via the parallel switch. This layout is consistent with the R-27 manual, p. 32) available on this site.

 

[snydzy]

Connecting the alternator to the larger house bank makes sense .... it would be the most efficient. Osprey is right, the schematics show the alternator connected to the house buss.

 

[NorthernFocus]

Connecting the alternator to the larger house bank makes sense .... it would be the most efficient...

From a practical standpoint given the size/length of the cables and charging amperage the efficiency of the circuit isn't highly relevant. Whether is is most reliable as wired is arguable depending on which engine the boat is equipped with and where the ECM draws its power.

...Osprey is right, the schematics show the alternator connected to the house buss.

The R27 schematics, yes. The R25 schematic is not specific. Unless there is a version other than the one available for download on this site.

It's evident from this thread that on the early boats there was a bit of confusion between documentation, intent, and practice.