Voltage drop whilst using the electric windlas

[simonfraser]

yesterday morning i pulled 50m of 8mm chain up in one go, not under great tension, can see that by the chain flapping about as it comes up
the battery voltage dropped down to 11V with the KAD 44 idling (i normally pull up about 20m and then give the system a rest)
a 20 min run at 3000 revs sorted the low battery voltage

but, how to avoid this, when dropping the chain, i could put the engine in neutral and rev it to ? 2k in order for the aternator to at least put some charge back in
how effective would this be ?

leaving in the morning the engine is obviously not warm, so running it at 2k revs when cold would not be the best ?

what do others do ?

 

[petem]

Has it always done that Simon?

 

[mcanderson]

This sounds like you have a battery that is dying. How old is the windlass battery? Does it perform a secondary function? Do you also a bow thruster? What happens when you run this to you voltage?

The other cause might be corrosion at a terminal/wire end which is causing such a high current load.

 

[simonfraser]

this is the first time i ran the windlass for this length of chain non stop
a normal 20m haul or starting or bowthruster does not drop the V below 12.5
wired to a set of red tops, 2 years old

 

[jrudge]

More likely than not the battery.

 

[halcyon]

yesterday morning i pulled 50m of 8mm chain up in one go, not under great tension, can see that by the chain flapping about as it comes up
the battery voltage dropped down to 11V with the KAD 44 idling (i normally pull up about 20m and then give the system a rest)
a 20 min run at 3000 revs sorted the low battery voltage

but, how to avoid this, when dropping the chain, i could put the engine in neutral and rev it to ? 2k in order for the aternator to at least put some charge back in
how effective would this be ?

leaving in the morning the engine is obviously not warm, so running it at 2k revs when cold would not be the best ?

what do others do ?

What amperage is the windlass ?

Brian

 

[simonfraser]

What amperage is the windlass ?

Brian

12V / 320W / 45A

 

[alt]

When I use my bow-thruster, the voltage goes down (engine always running). This is because batteries are at the stern, bowthruster some 30+ ft away. There is no battery at the bow. I use the bowthruster very little so I just live with it and it's always short blasts.

 

[halcyon]

12V / 320W / 45A

Have you tried it without engine running ? if battery voltage collapses so will alternator voltage, a surface charged battery would give similar to what you see, a good battery should supply 45 amps for sometime.

Brian

 

[simonfraser]

Have you tried it without engine running ? if battery voltage collapses so will alternator voltage, a surface charged battery would give similar to what you see, a good battery should supply 45 amps for sometime.

Brian

interesting, never heard of that until now, supplied by two red tops = AGM

 

[Momac]

Is the engine (and battery charger) charging these batteries properly ?
eg resistance due to corroded electrical connectors , loose battery terminals, faulty isolator switch.

 

[Deleted User YDKXO]

When I use my bow-thruster, the voltage goes down (engine always running). This is because batteries are at the stern, bowthruster some 30+ ft away. There is no battery at the bow. I use the bowthruster very little so I just live with it and it's always short blasts.

Be aware that, if your thrusters are powered by the engine start batteries and your engines are electronically controlled, then using the thrusters when one or more of the engine start batteries is dying may cause the voltage to drop so much that the engines stop altogether, as happened to me earlier this season when backing into my berth. Luckily the day was saved by some very prompt fender action by the SWMBO

 

[DavidJ]

Question for Halcyon (who would have been a part of the Sealine design) How is the bow thruster battery charged from the engines. I notice the shore power transformer has three outputs but of course the engines only have two.
“Sorry for the hijacking but it’s kind of on topic”

 

[halcyon]

Question for Halcyon (who would have been a part of the Sealine design) How is the bow thruster battery charged from the engines. I notice the shore power transformer has three outputs but of course the engines only have two.
“Sorry for the hijacking but it’s kind of on topic”

Not an employee, a supplier, used to design and manufacture the switch panels and charging systems for them from 82, long story. From around 96 they designed their own systems, even longer story, think they went onto either a diode splitter or relay linked to alternator warning light. Only got involved when they were in a hole, shunts etc, plus if I could make a buck or two out of it.

Brian

 

[petem]

I'd be checking the batteries and the charger (my 2003 charger gave up the ghost over the winter).

I'd also be careful about running with poor batteries as it can cause stalls (as per Mike's post above) and potentially wreck your ECU.

Pete

 

[DavidJ]

Not an employee, a supplier, used to design and manufacture the switch panels and charging systems for them from 82, long story. From around 96 they designed their own systems, even longer story, think they went onto either a diode splitter or relay linked to alternator warning light. Only got involved when they were in a hole, shunts etc, plus if I could make a buck or two out of it.

Brian

Thanks, all the best

 

[Birdseye]

yesterday morning i pulled 50m of 8mm chain up in one go, not under great tension, can see that by the chain flapping about as it comes up
the battery voltage dropped down to 11V with the KAD 44 idling (i normally pull up about 20m and then give the system a rest)
a 20 min run at 3000 revs sorted the low battery voltage

but, how to avoid this, when dropping the chain, i could put the engine in neutral and rev it to ? 2k in order for the aternator to at least put some charge back in
how effective would this be ?

leaving in the morning the engine is obviously not warm, so running it at 2k revs when cold would not be the best ?

what do others do ?

the voltage drop depends on your wiring, the location of the power source, where you are measuring etc, so its impossible to answer your question sensibly without further detail.

the power of your windlass motor is likely to be about 1kw, much the same as the engine starter. When you start your engine the voltage will drop sharply, sometimes as low as 9v. Again depends on wiring etc.

 

[alt]

Be aware that, if your thrusters are powered by the engine start batteries and your engines are electronically controlled, then using the thrusters when one or more of the engine start batteries is dying may cause the voltage to drop so much that the engines stop altogether, as happened to me earlier this season when backing into my berth. Luckily the day was saved by some very prompt fender action by the SWMBO

Something which did cross my mind, thanks for your info.

I'm KAD300's so i'm guessing the answer is YES, my engines could die.... I think?!

 

[Assassin]

Many batteries are not designed for long, high current discharges and running a winch for long periods is very similar to cranking your engine for long periods, flattens the battery quickly.

Check your cold cranking amps of your battery and you have a starting point, then check the discharge rates for your batteries as many are based upon the 20 hour discharge rate, some are 40 hours.

What does this mean? in simple terms you have an example 100 A/H battery and it is based upon the 20 hour discharge rate: Most people believe this will give them 100 amps for 1 hour, it wont, it may give 100 amps for 1-2 minutes or slightly more for better batteries.
Batteries based on the 20 hour cycle will give 100 amps and to ascertain how you divide the battery amperage by 20, in this example case it would be 100 amps divided by 20 = 5, or a maximum of 5 amps output for 20 hours which gives 100 amps rating.

Now you look at your cold cranking amps or CCA and see what it is, E.G. if your battery is 500 CCA and your winch requires 600 amps you are already exceeding your battery capacity and damaging it.

 

[halcyon]

Many batteries are not designed for long, high current discharges and running a winch for long periods is very similar to cranking your engine for long periods, flattens the battery quickly.

Check your cold cranking amps of your battery and you have a starting point, then check the discharge rates for your batteries as many are based upon the 20 hour discharge rate, some are 40 hours.

What does this mean? in simple terms you have an example 100 A/H battery and it is based upon the 20 hour discharge rate: Most people believe this will give them 100 amps for 1 hour, it wont, it may give 100 amps for 1-2 minutes or slightly more for better batteries.
Batteries based on the 20 hour cycle will give 100 amps and to ascertain how you divide the battery amperage by 20, in this example case it would be 100 amps divided by 20 = 5, or a maximum of 5 amps output for 20 hours which gives 100 amps rating.

Now you look at your cold cranking amps or CCA and see what it is, E.G. if your battery is 500 CCA and your winch requires 600 amps you are already exceeding your battery capacity and damaging it.

OP says it is pulling 45 amp.

Brian