Moving battery forward.

Hi, When my Mace 2.5 generator was out for repairs, the boat developed a slight list to starboard - expected since I removed about 160 pounds from the port side. I had previously moved two batteries from the port to starboard side to more balance the generator weight.

Well, no problem. The trim tabs were sufficient to trim the boat level at speed - but I noticed (couldn't help but noticing) that the ride had improved and the top speed went from about 15 knots to about 16.5 knots, enabling me to drop the rpm significantly to maintain my comfortable 13.5 knot desired cruising speed.

I think it is trim (forward/aft) rather than boat weight since when I carry 4 people, I can still achieve cruising speed at about the same RPM.

So, Is there any reason not to move the thruster battery forward under the bunk on the starboard side? Same total wire length with no new heavy wiring required, just relocate the switch.

I could easily used a sealed battery to control outgassing and potential spillage. Shifting 80 pounds from the port aft to the starboard forward would allow me to return the house batteries to their original location while still preserving trim.

We don't now use the space on the starboard forward for anything - hard to access under the bunk and topper.

Thanks for sharing your idea. /Stu

Before you change everything, why not disconnect your thruster battery and move it to where you want it and determine the results. I find it hard to believe that relocating the battery will make a significant difference.

Good idea. I'll take the bunk apart and do that today. I plan to get a AGM Cranking Battery - since only the surge current is an issue with the thrusters and they are nearly always fully charged - on shore power and underway. My present 1-year Walmart battery is going strong at 2.5 years, but the thrusters aren't spinning strong as long as they did when the battery was new, so it is time.

I would think trim lateral and longitudinal make a significant performance difference on a short fat boat...

captstu":3d3prhqv said:

Good idea. I'll take the bunk apart and do that today. I plan to get a AGM Cranking Battery - since only the surge current is an issue with the thrusters and they are nearly always fully charged - on shore power and underway. My present 1-year Walmart battery is going strong at 2.5 years, but the thrusters aren't spinning strong as long as they did when the battery was new, so it is time.

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You do realize that your charger does not differentiate between different battery types among your group. You have to go with one type throughout all batteries and set the charger accordingly. There should be settings for flooded, maintenance free and AGM. Although, The alternator has no settings so I am not sure how that theory works as it relates to the alternator.

So when all is said and done will the cost of buying an AGM and the work involved relocating the thruster battery and then perhaps the need to install a smart regulator to protect the AGM be worth it?

captstu":2z6jpmfp said:

Hi, When my Mace 2.5 generator was out for repairs, the boat developed a slight list to starboard - expected since I removed about 160 pounds from the port side. I had previously moved two batteries from the port to starboard side to more balance the generator weight.

Well, no problem. The trim tabs were sufficient to trim the boat level at speed - but I noticed (couldn't help but noticing) that the ride had improved and the top speed went from about 15 knots to about 16.5 knots, enabling me to drop the rpm significantly to maintain my comfortable 13.5 knot desired cruising speed.

I think it is trim (forward/aft) rather than boat weight since when I carry 4 people, I can still achieve cruising speed at about the same RPM.

So, Is there any reason not to move the thruster battery forward under the bunk on the starboard side? Same total wire length with no new heavy wiring required, just relocate the switch.

I could easily used a sealed battery to control outgassing and potential spillage. Shifting 80 pounds from the port aft to the starboard forward would allow me to return the house batteries to their original location while still preserving trim.

We don't now use the space on the starboard forward for anything - hard to access under the bunk and topper.

Thanks for sharing your idea. /Stu

Click to expand...

I just finished moving my batteries from the port side to starboard side and thought seriously about installing thruster battery at bow also. I want to add another house battery for my inverter.My thought was to have three house batteries on the starboard engine battery on port and install the thruster battery in the compartment in the bow above the thruster. Now the logistics of this is more complicated then moving a switch. Battery charger cables need to be moved ( on board charger). The terminals are not the same as they go forward on the boat At least my boat.There is a 3/O coming off the battery going to the battery switch at the panel. There are two leads coming off switch then thru a fuse and a #1 going back to stern thruster and a fuse and 1/O going to the bow thruster. Then an additional cable should be added for the engine charging relay this requires a substantial cable for the charging system if you want the engine to charge the thruster battery. It has to be separate from the power cable for the thruster. The fuses also have to be relocated. All of this can be done but its not has simple has moving a switch. Its a great idea and I haven't given up on it. I just have to find an area that I can get the wiring up there and insure it will not get damaged. I also think it needs to be vented witch can be done thru the anchor locker. I'm running a water line to the anchor locker for raw water wash. (This is a requirement after running the Mississippi,ohio and Tennessee river this fall the anchor and chain come up with a lot of mud). When I do this I will see if I can run wires up there too. Here are a few photos of new battery installation .

Brian Brown
Cutwater26
PORT-A-GEE

Looks good! I joined my thruster battery to the house and put a switch between them so I can isolate them from each other. I usually keep them joined though. I get extra power when on the hook and I also get the extra amperage when using the thrusters. Kind of a win/win. Moving the thruster battery to the bow seems like a lot of work and expense.

If one is determined to move batteries forward it seems like there is more weight and electrical benefit to move the house bank. Most of the house loads are powered from the buss located behind the helm so a much shorter run between batt and load. The existing supply cable could be used to carry alternator charge and supply the few misc loads that are currently connected in the battery compartment. If the thruster batt is moved forward it must still power the aft thruster via a long cable run.

knotflying":1klzvhsd said:

Looks good! I joined my thruster battery to the house and put a switch between them so I can isolate them from each other. I usually keep them joined though. I get extra power when on the hook and I also get the extra amperage when using the thrusters. Kind of a win/win. Moving the thruster battery to the bow seems like a lot of work and expense.

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I agree Knotflying, the install creates a lot more work and the weight of the extra battery adds up.Placing the battery in the bow may help in the boats attitude but I'm not sure if it is worth the efforts. I also paralleled the House bank with the Thruster bank via another battery switch. I did this for extra battery capacity while at anchor using the inverter. With engine running I keep the switch setting at house battery only. The 180 amp alternator can maintain all amperage demands for the 12v system and inverter. This also allows the Blue Sea relays to function properly too. When we anchor I switch to all and have enough battery capacity to last approximately 12 hours. Our boat is 100% electric. stove ,convection oven/microwave, refrigerator,TV, C-pap along with outlets for fans and crockpot are used.Careful power management is used. The hot water heater the Air unit is never used when at anchor. The inverter has an automatic shut down at 50% discharge approximately 11.3volts. In the morning I usually start the engine and run the engine for 10 or 15 minutes. This charges the batteries back up and warms up the hot water tank.
Brian Brown
Cutwater 26
PORT-A-GEE

Brian,

I value your advice.

the idea of moving the battery forward came about when I had to remove the Mace generator (about 160 pounds) for repairs. I had previously moved two batteries to the starboard side to balance the generator weight better - so the temporary removal required some trim adjustment.

The result was a 1.5 knot increase in top speed or a 400 rpm reduction in the engine speed necessary to maintain my high cruise speed of 13.5 knots. There was also visible, but unmeasured improvement in the bow up angle with nearly full trim adjustment.

So, I can see fuel economy improvement, top speed improvement or some significant combination if I can get some weight forward.

Is it worth it, I am expecting about a 0.7 gallon per hour improvement - between $2 and $3/hour if I keep the same cruising speed - but that may improve further when I test to find the most efficient cruise with the new weight distribution.

I also gain very valuable storage locker space in the stern - more and bigger fenders - no weight to speak of, but lots of space.

Exclusive of a new battery - my current one is weakening and beyond the warrant date by 18 months - I expect it to cos under $20 for some hold downs and take up no space since the area under the front bunk's front access port is unusable by anything you might need without removing the front bunk.

I'll let you know how this works out. I really like the Ranger design, but improving the trim will make it even better.

Thanks for the suggestions. /Stu

I am interested in your project. Please post your results and the install requirements. Some picture would be helpful too.
Brian Brown
Cutwater 26
PORT-A-GEE

BB marine":16ibo4fk said:

In the morning I usually start the engine and run the engine for 10 or 15 minutes. This charges the batteries back up and warms up the hot water tank.
Brian Brown
Cutwater 26

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Hi Brian,

What rpm do you run the boat to heat the hot water when at anchor? I have been unable to get the water to warm up with the engine in neutral. The engine does not get warm enough to open the thermostat.

Curt

I run at 1000 rpm to excite the alternator and keep it there for about 15 minutes in the morning. Engine temp is usually @ 140F to 150F The thermostat doesn't start to open until around 175F and fully open around 190F. There is an uncooled bypass in the heat exchanger for circulation of antifreeze thru the system. When the thermostat opens the coolant goes thru the cooled part of the heat exchanger and the by- pass closes off. The hot water is not hot.. Hot... but it is at least warm enough for washing up and dishes.
Brian Brown
Cutwater26
PORT-A-GEE

Thanks Brian,

I’ll try kicking up the rpm’s a bit next season before giving up. At idle, I ran it for a half hour and never got even a little warm.

Curt

I will take some pictures. in the meantime I’ve stumped!

It looks from the wiring the winless was connected to the two terminals one the bow thruster. After I disconnected the battery I tried the winless to see if woodwork. No battery works fine. So I tried the first thruster, no battery work better with the battery was installed. Makes me curious if the boat would go faster if I took the engine out?

So I tested the battery, now sitting with no wires on it at all, and found 11.87 V. The battery had just come off charge so I obviously it has a dead cell.

The question is how did the thrusters run with those thruster battery?

The answer is both charging relays are in the closed position even though the engine is off and the batteries are idling at about 13.2 V. My guess is that 13.2 V is enough that the charging relays thought things were being charged, and they were with the solar cell and a small trickle charger.

So going further I disconnected the red sensor wire leading age of the two charging relays. The only wiring involved is the power going to the Ft fuse, line from the power leading forward to the Forward thruster and the two lines from the thruster buss to the two charging relays.

With the sensor wires disconnected I expected both relays the open. The thrusters continue to work fine. When I disconnected one after the other of the two wires from the thruster power bus to the respective relays, the thruster continue to operate as long as either wire was connected.

It’s difficult for me to believe that both charging relays failed simultaneously in the on position. Anyone have any other ideas?


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796

Hey, Stuart. Do you have schematics for the ACRs? Not sure what your calling the "sensor wires" on the ACRs. All they need to function are the primary cables and a ground reference. And as long as the charger is operating they won't open. The ACRs open after 30s at 12.75v or after 10s at 12.35. "Lockout" voltage (presumably instantaneous) is 10.8V. If your boat is wired like mine the ACRs are landed on the batt buss, not directly on the batt terminals. So yes once they close they will stay closed as long as a charger is running regardless of the condition of the batteries. And if the charger leads are landed on the batt buss rather than the batt terminal then the ACRs will stay closed even with the batteries removed. With the ACRs closed and the thruster battery removed a momentary activation of the thruster likely isn't causing enough voltage drop to hit any of the voltage thresholds to open the switch.

NorthernFocus":l7fsexbv said:

Hey, Stuart. Do you have schematics for the ACRs? Not sure what your calling the "sensor wires" on the ACRs. All they need to function are the primary cables and a ground reference. And as long as the charger is operating they won't open. The ACRs open after 30s at 12.75v or after 10s at 12.35. "Lockout" voltage (presumably instantaneous) is 10.8V. If your boat is wired like mine the ACRs are landed on the batt buss, not directly on the batt terminals. So yes once they close they will stay closed as long as a charger is running regardless of the condition of the batteries. And if the charger leads are landed on the batt buss rather than the batt terminal then the ACRs will stay closed even with the batteries removed. With the ACRs closed and the thruster battery removed a momentary activation of the thruster likely isn't causing enough voltage drop to hit any of the voltage thresholds to open the switch.

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My Blue Sea isolating relays are wired directly to the batteries from Factory. There should be a ground wire,( on mine it is a yellow #16) and (2) #1 coming off the engine battery -one going to thruster isolating relay one going to the House isolating relay from the relay a #1wire should go directly to the corresponding battery ,if the run is long there should be a 175 amp fuse in line. Blue Sea recommends this installation and do not recommend going to a switch or a panel in-between the engine battery and isolating relay and then directly to the battery it is isolating. If the green light is on they are combined and in charging mode. If the light is not on it is open (not combined) and in a discharge. If you pull the thruster terminal (on my boat it is the # 3/O wire) off the thruster battery there should be no power to provide any power to either thrusters. Each system is wired independently of one an other. Engine-house-thruster. There are only two common links, the on board battery charger and the isolation relays both and isolate the systems. The only other link is the cross over from house to engine switch. As soon as you disconnect the thruster terminal off the thruster battery there is no link to anything in the syterm if there is something is not wired correctly. You need to trace your cables from the battery connection to the Fuse blocks and distribution panel something is crossed. Your isolation relays should only be wired between the batteries for them to work properly. Go online to Blue sea and confirm this information. I just completely rewired my battery system when I moved my batteries to the starboard side there is a lot going on in there so marking the cables and tracing them to where they go is very important. I actually found a few discrepancies in the factory install. I am the original owner so I know someone else didn't change something.
Brian Brown
Cutwater26
PORT-A-GEE

BB marine":2du3ivo0 said:

My Blue Sea isolating relays are wired directly to the batteries from Factory. There should be a ground wire,( on mine it is a yellow #16) and (2) #1 coming off the engine battery -one going to thruster isolating relay one going to the House isolating relay from the relay a #1wire should go directly to the corresponding battery...

Click to expand...

The 25 classics weren't wired that way. They were physically wired as reflected on the schematics which is all ACRs wired to the three busses. On the schematics the ACRs show up as a single block labeled "isolator". The factory has changed a few things since then. Also on the old boats there was an errant hot wire connected to the LED spade terminal on the ACRs(discussed previously in the forum). If that is the wire referred to in Stuart's post as the "sensor" wire, it is does nothing. I did away with it on my boat.

The 25 classics weren't wired that way. They were physically wired as reflected on the schematics which is all ACRs wired to the three busses. On the schematics the ACRs show up as a single block labeled "isolator". The factory has changed a few things since then. Also on the old boats there was an errant hot wire connected to the LED spade terminal on the ACRs(discussed previously in the forum). If that is the wire referred to in Stuart's post as the "sensor" wire, it is does nothing. I did away with it on my boat.[/quote]

Your right it is wired differently, instead of direct to battery it does go to the bus. They may have changed it based on recommendations from Blue Sea , who knows ? When I looked at the schematics it is still three isolated systems. Engine and House with common links battery charger, isolator, battery switch. Engine, House, and thruster/windless common are battery charger and isolator. When my engine is not running and batteries are at full capacity approximately 12.75 V and there is minimal discharge (Radio memory/CO) and batteries maintain 12.75 thruster to engine battery and house to engine battery are combined thru the isolating relays. If the voltage drops below 12.75 for 30seconds or more they go open when working properly. If they don't go open bad relay. It is a very easy test if the thruster battery is disconnected from battery and there is still 12V at thruster buss bar, disconnect the relay terminal to the thruster bus bar test for 12 volts if it's 0 then relay is bad .If there is still power at bus bar take each terminal one at a time off bus bar and retest until you find the lead that is back feeding the bus bar. Then trace that lead back and find the source that is providing voltage to that lead.
Brian Brown
Cutwater 26
POET-A-GEE

Brian,

It is hard to tell.

According the the wiring diagram, the alternator feeds an isolator and that, in turn feeds the three battery banks: Engine, thruster, and two house.

That is not how my 2010 Ranger R25 is wired. There are three bus bars named as noted above. From the House bus bar, there are two wires, each leading to a charging relay. they are 2 gauge wire. From the other side of the relays, there is a 2 gauge wire leading to the engine thruster battery.

The relays each have a read and yellow wire leading to the starting or thrusteer buss.

The net result is the two relays are engaged all the time, effectively paralleling the three banks.

The secondary effect is if I turn off the "house" and "engine" switches just inside the door, everything CONTINUES TO WORK, being hed from the thruster battery - that battery switch is after the ganging relays so is ineffective except ot protect the thrusters from a run away.

The third result is that the thruster battery carries the entire load of anything left on when the boat is idle - I usually leave the fridge to run if we are away for less than a day, sightseeing for example.

Now, in sightseeing position, the solar cells continue to charge the house bank, the load is carried by the thruster battery. Eventually the voltage drops and the isolation relays disengage so the solar charger is connected to the house bank and the load is connected to the thruster bank - or so it seems.

The ultimate result, when I return the voltmeter reads nearly 14 volts, the engine starts instantly, and the thrusters are dead.

I'm trying to figure out how to re-re-wire it, but I think the only solution is to replace the two charging relays with a single 3-diode isolation device and to move the solar cell charging to the front of the isolation relay so all batteries are change sort of equally.

This would effectively move the boat to the way the PDF on the TUGNUTS site that you cited is drawn. Good design. I don't think the Previous Owner made the change - it seems the engineers decided the charging replays had less loss (correct), were less expensive (also correct) and might have better reliability (debatable).

Thanks for the idea.