Ranger 31CB #3 battery dead, but a bilge pump still works

[cavok]

Trying this on a different forum for answers!

Our thrusters stopped working, so we checked our battery bank and realized that the #3 was showing below the min reading of 8V, so we assumed it was drained. Unable to charge it up via engine or shore power. Thrusters are on the #3 battery, as are the bilge pumps. However, when we turn on the #2 bilge pump, the DC volts jump up to 11.3V, and the bilge pump turns on. Nothing happens with the #1 bilge pump, it appears dead.

I'm wondering if maybe we have a small charge left, and that will power the #2 bilge pump as a last ditch option, but not the #1. Also, the placement of the #2 and #3 batteries are reversed from the diagram (can't imagine that matters, though).

Anyone have any thoughts? I didn't see this addressed in the manual.

 

[GaylesFaerie]

What type of batteries do you have? Flooded Lead Acid (FLA), Absorbed Glass Mat (AGM), Lithium, etc? I have FLA and for them 8V is way past dead. 11.3 is also a shot battery buy maybe it can rally a few amps to power a bilge pump. Below is a table showing voltage and percent charge that I use to manage / monitor my batteries that may be of help:

FLA = Flooded Lead Acid
Each FLA cell is approx 2.1 volts wired in series = 12.6 to 12.8 voltage at rest.
FLA Bulk and Absorption Voltages are both 14.2-14.6v
FLA Float Voltage is 13.4v
FLA will self-discharge at about 6-8% per month.
FLA can have 300 charge cycles provided Depth of Discharge is kept to 50%
FLA practical available capacity is 35% (assumes no time for Float charging)
FLA bank charger rate = minimum of 10% of bank capacity and max of 25%

FLA BATTERY VOLT TABLE

%CHRG VOLT Specific Gravity
100 12.70 1.265
95 12.64 1.257
90 12.58 1.249
85 12.52 1.241
80 12.46 1.233
SHALLOW CYCLE DISCHARGE LIMIT (no problems here)
75 12.40 1.225
70 12.36 1.218
65 12.32 1.211
60 12.28 1.204
55 12.24 1.197
50 12.20 1.190
45 12.16 1.183
40 12.12 1.176
35 12.08 1.169
30 12.04 1.162
25 12.00 1.155
DEEP CYCLE DISCHARGE LIMIT (there be dragons here)
20 11.98 1.148
15 11.96 1.141
10 11.94 1.134
05 11.92 1.127

14.2 to 14.4V = Optimum Bulk/Absorption charge voltage for FLA
13.2 to 13.4V = Optimum Float voltage to maintain full charge

When a load is applied, Voltage can temporarily drop into the 11s or even 10s.

A note about battery replacement: if your dead battery is connected to another bank by an ACR, you should replace all your batteries together. If you add a new battery to lets say 2 others in a bank that are older, they will charge at different rates when the ACR connects them all. In other words, the new one will get up to 100% quicker than the others but because they all are charging together, the other two will keep charge flowing from the charge source and overcharge the new battery reducing its service life.

There is a lot going on with batteries on these boats and how to maintain and monitor them. Some replace their batteries every 3 years regardless of their condition to be on the safe side. I plan on doing that after one exploded in my battery compartment last summer, even though they appeared to be in good shape going on 4 years.

HTH, Gary

 

[cavok]

Thanks for the information, Gary. Looks like we have AGM deep cycle batteries. I'm assuming from the factory, as the boat is only a 2018. We'd prefer not to replace all the batteries, seeing as the boat has been rarely used and the other batteries look to be in good shape.

That's alarming that your battery actually exploded.

 

[knotflying]

I personally stick with flooded and replace every 3 years. Some of the tug models have difficult access to the batteries so those folks will most likely go AGM. There is a system though that allows for filling the cells easily and they can't be over filled the product is called Flowrite. Nine times out of ten battery failure is related to owner error. I would rather replace a $90 battery than a $250.

 

[BB marine]

You have a couple of things going on. (1) your thruster bank is dead and is below ACR Voltage (lock out) so the battery will not charge from the engine or charger. You must jump the battery bank from a battery bank that is fully charged until the ACR sees voltage at that bank above 11 Volts then the ACR will will close if there is a charging source available. (2) the reason that the bilge pump did turn on with the manual switch and show voltage 11V + is the voltage source is coming from the house bank. The manual switches are from the house bank and the 24/7 (auto bilge pumps) battery source is from the thruster bank which in your description is depleted.

It sounds like your battery (thruster battery bank ) may have a bad cell causing it to discharge or you have some 12Volt draw. The first step is to charge the truster bank. The easiest is to use jumper cables and jump the thruster bank to the house bank and turn your battery charger on monitor the thruster voltage. When you see the thruster bank at 12v take the jumper cables off and make sure then charger is still charging the thruster bank. Fully charge the bank and once fully charged. Let the battery rest with no charge and load test the battery bank to see what the battery condition is. Also check to see that both auto bilge pumps are now functioning.

 

[cavok]

You have a couple of things going on. (1) your thruster bank is dead and is below ACR Voltage (lock out) so the battery will not charge from the engine or charger. You must jump the battery bank from a battery bank that is fully charged until the ACR sees voltage at that bank above 11 Volts then the ACR will will close if there is a charging source available. (2) the reason that the bilge pump did turn on with the manual switch and show voltage 11V + is the voltage source is coming from the house bank. The manual switches are from the house bank and the 24/7 (auto bilge pumps) battery source is from the thruster bank which in your description is depleted.

It sounds like your battery (thruster battery bank ) may have a bad cell causing it to discharge or you have some 12Volt draw. The first step is to charge the truster bank. The easiest is to use jumper cables and jump the thruster bank to the house bank and turn your battery charger on monitor the thruster voltage. When you see the thruster bank at 12v take the jumper cables off and make sure then charger is still charging the thruster bank. Fully charge the bank and once fully charged. Let the battery rest with no charge and load test the battery bank to see what the battery condition is. Also check to see that both auto bilge pumps are now functioning.

Wow, that is some really detailed information, thank you for that! It all makes more sense now, not something I was able to find in the manuals.

As far as jumping the battery, we didn't know if we'd be able to jump it and charge it up enough, so I was on my way to pick up a 15 Amp portable battery charger, which is something we could use for other vehicles, also, and is pretty cheap.

I'm thinking that maybe the problem with this battery is that we used the thrusters going into the dock, shut the boat right down, and then didn't use it for months, with nothing charging the thruster bank up. It would be great if all we have to do is jump it or recharge it.

 

[cavok]

I personally stick with flooded and replace every 3 years. Some of the tug models have difficult access to the batteries so those folks will most likely go AGM. There is a system though that allows for filling the cells easily and they can't be over filled the product is called Flowrite. Nine times out of ten battery failure is related to owner error. I would rather replace a $90 battery than a $250.

I can guarantee you, this battery failure is related to owner error. :? Reading about battery types, though, I think we'd be better off sticking with the AGM's that we have installed now. Our difficult access, lack of desire to change/service the batteries more than needed will make it easier to suck up the cost.

 

[Ralf H]

Hi Cavok,

Looks like you already have solid info from others here already, but I will reiterate the fact that the charging relay will not charge once the voltage drops below 11v (I don't remember the exact voltage, but it's close) and to not forget that continued running of a 24/7 item like the bilge pumps will draw down the battery potentially below that and set up that scenario. I think you're on your way to getting this resolved, but please let us know if you have any other questions.

Cheers!

Ralf

 

[sgeary]

We moved our 24/7 circuits from the thruster fuse block to the house fuse block.
If we have a water leak when we are not on the boat, it buys much more time for us, or a dock neighbor, to detect and solve the problem.
And the propane sensor and co2 detectors draw minor amounts of power.

 

[BB marine]

We moved our 24/7 circuits from the thruster fuse block to the house fuse block.
If we have a water leak when we are not on the boat, it buys much more time for us, or a dock neighbor, to detect and solve the problem.
And the propane sensor and co2 detectors draw minor amounts of power.

The danger to that is if any one were to turn the house battery bank battery switch off you have no bilge pumps at all. The house fuse block is powered thru the house battery bank but can be shut off by turning the battery switch off. The way the boat is originally wired the 24/7 circuits are wired before the thruster battery switch.They are 12V powered 24/7. Is the house battery switch turned off regularly? No ! But it can be turned off by mistake. Can the 24/7 battery fuse block be turned off? No! The only time if the batteries were physically disconnected or dead. The other draw back to house bank battery bilge pump is if you have an inverter/charger and the inverter is left on while at the dock. While plugged into a shore power outlet the charger is working and charging the batteries. If there is a storm or power outage then the charger now is switched to inverter. If any 120 volt items are plugged into the outlets they are now powered by the inverter. No charger, refrigerator, and any items plugged in are pulling house bank power. The bilge pumps are pulling house bank power. If the house as enough draw over a day or two and the house bank goes below 11 volts and the power comes back on the house bank will not charge and the bilge pumps are no longer going to be in use. If this same thing happens when pumps are wired to the 24/7 the thruster bank and house bank are not connected so the thruster battery will be available for bilge pumps providing the thrust battery bank is in good condition.

Bottom line if you have a good working charge system and batteries maintained and inspected regularly you should have no issues with the way the boat is wired from the factory. Just my opinion.

 

[sgeary]

Brian,

I did not provide adequate details in my initial posting about how we moved the 24/7 circuits from the Thruster Battery to the House Battery.

This was done by moving the Thruster Fuse Block battery cable from the Input (always hot) side of the Thruster Battery Switch to the Input (always hot) side of the House Battery Switch. In effect, I now have two House Battery fuse blocks--the original fuse block that can be switched off by the Battery Switch, and the second (ex: Thruster Fuse Block) that cannot be switched off by the battery switch. It was a simple one wire change.

And as an unrelated aside, the 2015 Promariner inverter does not have auto switching. You have to manually switch it from Charging to Inverter via the remote panel. A shore power failure will not cause it to starting inverting any loads that may have been left on the alternating current circuits.

 

[knotflying]

Brian,
And as an unrelated aside, the 2015 Promariner inverter does not have auto switching. You have to manually switch it from Charging to Inverter via the remote panel. A shore power failure will not cause it to starting inverting any loads that may have been left on the alternating current circuits.

I think you are incorrect. The promariner remote has three positions. Down is usually used while at anchor and inverter is on all the time to supply 110 v power.

Middle position is off.

Here is the important one, up position: This position is used while on shore power and engages the charger and automatic transfer switch. This position can also be used while anchored and off shore power. When off shore power it "hunts" for a load. If a load is recognized the inverter kicks in. This is important because if you leave your boat while on shore power and the shore power fails, and you have things on that will create a load, then the inverter kicks in and with a high load, your batteries will drain.

Don't ask how I know this. :lol:

 

[sgeary]

Knotifying,

Thank you for the correction regarding the Promariner inverter. Your more exact description of the three modes of operation from the remote is right on.

Because Inverter mode draws close to an amp of power when looking for a load, at anchor we always stay in the OFF mode except when we are actively running an alternating current load, and then return the remote to the Off position.

At the dock in the Shore Power/Charging mode, we are blessed with benign weather in San Diego, so we don't leave any alternating current loads plugged in when we leave the boat. If we had to leave a bilge heater running, then the opportunity to run the house battery down due to shore power failure would exist.

 

[cavok]

Hi Cavok,

Looks like you already have solid info from others here already, but I will reiterate the fact that the charging relay will not charge once the voltage drops below 11v (I don't remember the exact voltage, but it's close) and to not forget that continued running of a 24/7 item like the bilge pumps will draw down the battery potentially below that and set up that scenario. I think you're on your way to getting this resolved, but please let us know if you have any other questions.

Cheers!

Ralf

Thanks, Ralf. We just removed the #3 battery, checked it, and lo and behold, it's fully charged and 13.5 Volts. So now I'm not sure what the heck is the problem, why the battery is not showing any voltage nor seems to be connected to anything. I'm also not convinced that the factory didn't reverse the positions of the #2 and #3 batteries, and we might have pulled out the wrong battery. We'll check the other battery tomorrow when it stops raining. If that's not it, I have no idea what the problem is.

 

[sgeary]

There is a 1 amp fuse in the Thruster and the Start Battery 24/7 fuse blocks that protects the wiring for the Bank #2 and Bank #3 volt meter readings at the main DC panel. If that is the meter showing no voltage on the battery, perhaps this fuse is the issue.

These are the fuse blocks in the battery switch compartment on the far side of the compartment. The two smaller fuse blocks are for the Start Battery and the Thruster Battery. The larger fuse block is for the House Battery.

 

[cavok]

There is a 1 amp fuse in the Thruster and the Start Battery 24/7 fuse blocks that protects the wiring for the Bank #2 and Bank #3 volt meter readings at the main DC panel. If that is the meter showing no voltage on the battery, perhaps this fuse is the issue.

These are the fuse blocks in the battery switch compartment on the far side of the compartment. The two smaller fuse blocks are for the Start Battery and the Thruster Battery. The larger fuse block is for the House Battery.

Thanks, sgeary. I had checked the fuses, hoping that was all it was, but to no avail. We pulled out what was supposed to be the #2 battery, and that is close to dead, can't be recharged. Looks like the positions of our #2 and #3 batteries were reversed from where the manual specified. Lesson learned, not everything in our boat is placed where the manual says it is, so next time wear glasses and look carefully at what's connected to the battery before you go to the trouble of taking it out!