house battery charging

[dogdoc]

Today was the first trip with new auto pilot and it was great, worked well until the low battery message came up. Today confirmed a problem I thought was occurring. The house battery is not being charged by the accessory charging leads from the motors. I have 3 batteries all new and good shape. 2 starting and 1 house. Both accessory charge leads go to house as yamaha rigging says. No problems with starting batteries, always around 13 volts and show charging is occurring when engines are running. There is no change in the house battery voltage when engines are running vs when powered off. When connected to shore power and on board charger running, all batteries show charging is occurring at 14+ volts. I am at a loss, pulled the cowl on one engine and the accessory lead is connected to what looks like a large black fuse block with 2 fuses which seem ok. Hoping someone can help me
thanks

 

[wspitler]

Is this a new problem? What was done to install the autopilot? Did the house charge before? Look for a ground issue. Make sure your house battery ground is also the engine(s) ground. This is a stretch, but depending on the voltage regulator on your motors, could it not be designed to provide two charging circuits to the same battery? Will it charge with only one motor running?

 

[dogdoc]

I had been suspicious house was not charging for awhile, I have a dedicated volt meter to that battery and it has been reading low, when starting are sig higher. Grounds are fine all connect at neg buss. Auto pilot was the straw that broke the camels back. Prior only drain was radio and garmin gps/ff. 5 hours of the hydraulic pump discharged the battery. Yamaha says the accessory lead is there to charge a second battery.

 

[wspitler]

I have the accessory leads that I installed myself and they all work fine. (F250s and F150). They each have a dedicated fuse on my engines. I'd try disconnecting each one and see if the other works. Maybe one is draining the other. I'd need a circuit diagram to troubleshoot the charging system.

 

[SkunkBoat]

dumb question but....Are the fuses in place in the motor for the Aux charge?

 

[SkunkBoat]

ALL batteries negs connected together?

 

[Hookup1]

There are lots of posts here about this issue. Start off simple. If you are not getting proper voltage reading check the fuses.

As others have said get a inexpensive voltmeter (Harbor Freight). Measure voltage at the batteries.
Battery switches set to each engine.
Charger off. motors off. Check voltage. Should be 12.8 vdc.
Charger on. motors off. Check voltage. Should be 13.1 vdc.
Charger off. motors on. Check voltage. Should be 13.1 vdc.

You need to be careful using the Garmin unit to measure voltages. I have found the voltage on say the sounder display to read low (house battery). The engine gauges, if you are setup that way, Tend to read correctly.

House battery charging is a little different. Ideally you have a 3rd-bank charger and one motor wired properly to charge 3rd-bank.
Charger off. motors off. Check voltage. Should be 12.8 vdc.
Charger on. motors off. Check voltage. Should be 13.1 vdc.
Charger off. motors on. Check voltage. Should be 13.1 vdc. Assuming you have a charging shunt from one of the motors.

If the batteries are discharged it may take a while (overnight) to bring them to a full charge. There are usually fuses on the individual charger cables as well as on your engines. The voltmeter will tell you what's charging and what's not.


And YES as Skunkboat said when did this start and are all the negative connections made.

 

[dogdoc]

Wiring is fine, all negs are connected in fact all connections are good. yes the small glass fuse is ok. thinking back the house battery probably has never been charged from the engines. my boat is on a lift i plug in the charger after every trip and we use very little 12v accessories until the auto pilot. that as i said was the straw. i did the volt meter testing as described and the starting batteries pass with flying colors at rest and when running. the house battery sits at 12.4 volts at rest and with both motors running. since both accessory charging wires are connected to the house battery the problem is the same with both engines. just to see, when plugged into the onboard charger all batteries read in the mid 14 volt range. i have attached some photos of the terminus of the accessory wire under the cowl.

 

[SkunkBoat]

so first things first, disconnect aux charge wires from House, make sure they are safe not toching anything, with motor running measure from motor ground to those fuses...should have 13ish volts if there is functioning charge. if not the "why ?" is at the motor.

If you have charging volts there then measure from motor ground to the aux wire at the battery end (wire that is disconnected)...should be exactly the same.... If not then aux cable problem...
if good then
Now measure from House Neg to that wire...same? That would mean it is charging.

if not then House ground is problem...

 

[SkunkBoat]

What kind of motor? 4 stroke or OX66? I have a thread here on charging problem from one of my old OX66s turned out to be stator coil

Yamaha Ox66 225 charging problem

oh, are you absolutely sure that your start batteries are charging correctly from the motors?

 

[dogdoc]

1977 ox66 saltwater

 

[dogdoc]

1997 sorry

 

[Hookup1]

Your problem is somewhere from the batteries to the motor. Seems everything "looks right" but something isn't.

I know you answered this but I want to confirm that all three batteries have ground cables that connect them together? Meter them out to be sure.

If you have two motors wired with aux charging shunts confirm with a handheld voltmeter the voltages from battery grounds to the block you have in your hand in the above photo. Check both sides of the positive connection to make sure the fuse is good. I'm having a hard time believing that both motors are not providing charging power but this will tell you.

 

[dogdoc]

engine covers off and starting anew, with less anxiety than yesterday. We were 28 mi offshore and lost all nav and radio when house bat went down. I will never forget hearing the wife say "there is an alarm and low battery reading on screen". The Ritchie got us pointed right, but need more backup. Forgot my cell phone so no compass/gps, did not program waypoints in handheld radio gps, no jumper cables, etc... As a kid who grew up in the shadow of the VAB and NASA triple redundancy moto I am ashamed to say I was poorly prepared. That will be fixed before next trip. As an aside when I go to Harbor Freight and they have a free item give away, 4/5 times I take the voltmeter the fifth time a tape measure. Cant have enough of each!

 

[wspitler]

You also need to have a way to use your starting batteries for the house as well. That gives you three batteries that can give you NAV & COMMS, not just one.

 

[teaklejr]

On our previous Tigercat the battery wires going from engine, through rigging then to the batteries went bad right in the middle of rigging tube. Over time water got in tube and just rotted battery cables away. Not that's what you got going on but figured I would let you knw.

 

[dogdoc]

So here is what I came up with. Pulled and checked fuses and contacts again, disconnected everything from house battery including aux cables

Starboard engine
voltmeter on aux fuse no voltage when off, engine running 8.5-9 v at fuse and 7 at aux cable, no change with increase rpm, when aux connected to house battery, v at fuse10-11 and at battery/aux 12.9 which is the current voltage of the battery, thus no charging going on just measuring the current voltage of the battery

port engine
vm on aux no voltage when off, engine running at fuse starts at 14 quickly drops to 10-11, at aux cable when running no voltage, when aux connected to battery 12.8v same as above, no evidence of charging

this is what makes me batty, because no voltage at port aux disconnected fuse and pulled plug did continuity test, no continuity between plug and battery ring of aux, then did same to starboard and was shocked to see same result, no continuity, but does seem to pass voltage.

I am at a loss and not sure where to go from here

HELP!!!!!!!!!!!!!!

 

[Doc Stressor]

You realize that the auxiliary charge cables have diodes that only allow current to flow in one direction, right? They are in effect battery isolators.

It would be helpful if you could post a diagram showing how all 3 batteries are wired including any switches.

 

[dogdoc]

To eliminate variables I disconnected everything from the house battery. It is just a 12 volt battery in the compartment with nothing attached, except negative connections to 2 start batteries and the neg buss, no switch. During my testing I was using 3 or 4 voltmeters simultaneously to get readings from various points all tied to a common battery neg cable at the buss

I understand the diode issue but by pulling the fuse and removing plug from rubber holder I was essentially ( I thought) just testing a piece of wire end to end

 

[Hookup1]

I am checking around for a wiring diagram but on my 2006 F150 shunt cables the fuse holder in at the bilge end of the wires screwed to the compartment sidewall. 50-amp fuse. Check your bilge for two. Chase the aux charging wire back to the tube.

Doc Stressor noted diodes. Is it possible the block you had in your hand had fuses or possibly they were diodes?



Update: Looking st this diagram I would say that item 2 contains your diodes and item 3 is your fuses (80-amp) one for starting battery and one for aux battery. High amperage diodes are difficult to test because there is no load. They may meter out ok but not really work. Given that they are inside the regulator consider replacing it. I have to believe the alternator is generating power and regulating - it is charging the starting battery. If the voltage isn't right at the fuse block its the regulator otherwise its the cable.