Thank you - I like keeping to only 1 day of terror! Always enjoy the bliss & your talks. PS Gary Calder also addresses this issue with a heavy fuse - but I appreciate your explanation on how you have to attend to it if blown & what circumstances surround the boat at that time. Much appreciated.
One of the things about starter motors is their current draw critically depends on how much torque is required to spool up the motor. On a cold day with thick oil, current draw is dramatically increased. Strangely, current draw is actually higher when the battery is depleted, for the following reason. To muster the torque to turn the crankshaft, the battery needs to overcome a specific input power threshold, so these motors are designed with low resistance to ramp up power consumption when the rotor is locked. Power input is the product of voltage and current. So if supply voltage is low, the crankshaft won't begin to spin until current rises higher. With a dying battery you end up with a higher current draw, and current runs for longer when it takes longer to get that crankshaft turning.
Great topic. It got me thinking about a low voltage battery needing more current to start. It would be interesting to try this with my 300A MRBF. It seems that Rod an Marine How To is recommending always using fusing and saying only a dead short would blow the fuses so I have MFBF fuses where I did have no protection.
Hi Danny, fusing starters is definitely doable and should be done at a universal level, meaning it should be part of the code. There might be some trial an error in sizing a fuse, as none of the engine manufacturers are providing any recommendations or specs for fusing a starter. As a point of reference, my starter is fused, but it took me some time to get the correct size of fuse.
When I was just 20 years of age I worked for a yacht charter cleaning boats etc. One day at the dock I tried to start a 26 foot flying bridge type cabin boat with a V8 inboard. Instead of starting, smoke billowed out from the engine compartment. I quickly pulled the hatch and saw flame through the black smoke. All I could do was empty one of those ABC fire extinguishers on it which surprisingly snuffed the flame. By then I think the battery was exhausted and the starter cables were history. Fortunately it wasn't a 4D or 8D battery. At that time I believed the heavy starter contact solenoid stuck. I'm guessing that a properly spec'd fuse would have prevented that. Now after having read the no-fuse policy, I propose a solution. Why not fuse the starter main circuit anaway but also wire in a by-pass switch of the type used to switch batteries? If the fuse blows at an inopportune time, just flip the bypass. Batteries should always pass a dockside pre-trip fitness test (what would that list look like?). Regular voltage drop measurements across connections and proper AWG comes to name a few come to mind. Cheers!
Nigel Calder recommends a 300 A slow blow fuse at the battery for a typical auxiliary diesel with a 12 Volt starter, stating that this is enough to avoid nuisance blowing. Do you agree that it is?
It will always depend on the starter, the engine, and the cable to the starter from the battery. 300A might be a good number, I don’t have access to that kind of data to say for sure. Just make sure the cable to the starter can support the 300A. If the starter locks up or runs continuously with an undersized cable you could be in for a fire. If you can send me the model number of your starter I can try to help you choose a setup.
Hi Torsten, my own starter on my 30 HP engine was fused 13 years ago with a 300 amp fuse. That said fusing a starter circuit should be done with care as you would not want to ever have an accidently blown fuse and then consequently not being able start your engine in a dire emergency. It's all about pros and cons of each decision.
@@PacificYachtSystems On my old boat, I put a 60 amp 58 volt fuse on the diesel starter battery. The starter received no voltage. I removed it and the starter worked again. The fuse did not blow however. If the fuse was undersized at 60 amps, shouldn't it have blown?
I used to work for a boat manufacturer here in Australia, we started putting in 750 amp ANL fuses in the main feed to each start battery, never had one blow in normal use starting up to 1150 HP Scania V8 diesels, It would have been handy just before we started doing so where I had a situation on a brand new boat, turning on the start battery isolator for the first time, engine room filled with smoke, Isolator fused closed, had to cut the cable... turned out the engine manufacturer wired the alternator pos to neg .
Great video as always. Now I ask myself why are battery protective boots bad in this situation? And would protective boots be good for the house battery?
Great stuff Jeff. I am still having trouble with understanding. a few items. Electrolysis, stray current from other sources and finally my boats Englehard Corrosion Monitor. Where can I find the answer to these mysteries?
hi Jeff, can I install an SMH connector as a quick service disconnect on my house battery bank? as long as the SMH connector is rated for the load and fused, would this break any ABYC standards?
The article I read was in the February/March 2021 issue of BoatUS magazine The article was written by Charles Fort but there is nothing on the internet about it. If you would like the magazine I can mail it out to you.
Hello at PYS, I have a question, not related to this particular video, but maybe is a good idea for another video... When I purchased my 87 Carver 28, it had the obligatory rats nest of wires stacked on the battery terminals for things like down riggers, and fish finders. Obviously I would like to add an auxiliary fuse panel to the switched side and clean all that up. My question is: What kind of fuse panels are suitable for use inside the gasoline engine room? Are ATO fuses ignition protected? Is ATC better? Do I need a special panel? Thanks, I love your vids. Keep up the good work, Cap'n Hippy
Great question, some boatbuilders like SeaRay have DC distribution panels in their gasoline engine rooms, not sure where they get them build for Ignition Protection. Reach out to Blueseas to find out and let us know what you find.
@@PacificYachtSystems Well, I did some research on the googly webs, and called the folks at Blue Sea (who were really super nice and helpful), and today/yesterday I learned the difference between ATO and ATC fuses. So, to answer my question, it's not really the box that matters in regards to ignition protection (chemical proof, yes), but the fuses themselves. Which made sense to my logical brain, since the sparky part shouldn't be the box itself; but the fuses. But I wanted to double check. I can't believe I've been a boater this long and didn't know about this! I'm pretty handy too, do my own electrical work.. Am I the only one? Seems pretty important actually. Like... Is every boater who ever added a CanTire inline fuse holder cruising around in a time bomb?!!
People still do fuse their starter wires anyway. It is simply optional. A 300 amp Blue Sea ANL fuse has a long time delay of over amperage before it will blow. I have 2 banks, starter and house and 2 rotary battery switches. If the starter fuse ever blows, and it has not for a 392 v8 yet, I can rotate house switch to both, the number 2 position switch lug runs a wire down to the starter wire buss, and I can start with no fuse in the circuit. I dont fuse my house battery switch , I fuse the buss connections, one for inverter 500 amp, one for house 150 amp , one for Lectrasan 100 amp. I could always change things if I wanted.
Scott, you bring a good point, because the ABYC code doesn't require fusing the starter, that doesn't mean it cannot be done safely. I too have a fuse on my starting circuit and it's well sized to protect the wiring, fuse never blew accidently in 14 years.
Normal running is both switches on #1, swap banks, both switches on #2. Combine banks, either switch on 1+2, with other switch on 1,2, or 1+2. Isolate a bank to off is off. So put switch to off, other switch 1+2, that banks runs everything.
My starter battery box for group 29 and 31 made by Attwood is much longer than the battery. I put the Blue Sea ANL fuse holder on a block of wood meant to keep battery from sliding around. Now here is another idea for keeping starter wires off until you crank the engine. Use a starter relay inline from start battery wire. connect the relay control wire to the ignition switch so it is on when you turn key to start position. Wires are then dead all the time except for when turning key to start. If two 2 engines and 2 keys, use common 10 amp or so diodes inline with the wire from each key switch to the added in starter relay which is immediately wired at the positive battery terminal. Diodes act as one way valves, so turning either key means will only crank the appropriate engine, otherwise turning either key will crank both engines at same time. Put the starter relay after the rotary switch if you want, like if something else is powered directly off the battery, you can figure this out, it is easy. Advantage is the entire starter wires have no power unless you actually turn key to start, so there is no short to cause a fire. If there is a short, you will know immediately, your right there, engine wont crank.
Jeff, PYS, I'm having a difficult time accepting the notion that a starter will draw more current from a partially discharged battery. Have you ever tested this in a shop or laboratory environment??
Physics say its so and ohms law helps us to visualize the concept. In dc circuits, resistance is typically fixed so if voltage dips, current must rise. Hope this helps.
Hahaha. Finally. The truth. It’s ok to not run fuses everywhere as long as you do a really good job with the installation. I swear, the strictness of some boaters and their "dire" warnings and finger wagging advice has harmed more boaters both in damage and just giving it up than helped. There are so many ways to do things on a boat. Best thing to do is have complete understanding of what your working on and use common sense that pertains to the boat and operators. Life is best when freedom of expression, even in engineering and installation, is present.
it's right in the ABYC guild lines that a starter circuit does not need to be fused. However it's not a bad idea as long as it's big enough to never trip under normal use.
A temp sensor on the main power cable and a motorized main switch that cuts the connection would be a better soulution than a fuse. If the temperature on the cable gets so high that it will start a fire...no other scenarios are worse..My opinion..
@@PacificYachtSystems In the real world you can use a 500A plus contactor ,with no fuse, activated by the starter key. Only for the cable between the starter and the starter battery. With this solution you will never have an unfused cable during normal operation. Only when you use the starter motor. Can altso be combined with a bypass main switch if you are afraid of contactor malfunction.
As always, Jeff has the answers and the explanations for all questions I have!
Thanks Jonas, appreciate the feedback.
Thank you - I like keeping to only 1 day of terror!
Always enjoy the bliss & your talks.
PS Gary Calder also addresses this issue with a heavy fuse - but I appreciate your explanation on how you have to attend to it if blown & what circumstances surround the boat at that time.
Much appreciated.
One of the things about starter motors is their current draw critically depends on how much torque is required to spool up the motor. On a cold day with thick oil, current draw is dramatically increased. Strangely, current draw is actually higher when the battery is depleted, for the following reason. To muster the torque to turn the crankshaft, the battery needs to overcome a specific input power threshold, so these motors are designed with low resistance to ramp up power consumption when the rotor is locked. Power input is the product of voltage and current. So if supply voltage is low, the crankshaft won't begin to spin until current rises higher. With a dying battery you end up with a higher current draw, and current runs for longer when it takes longer to get that crankshaft turning.
You just have the best videos !
Great topic. It got me thinking about a low voltage battery needing more current to start. It would be interesting to try this with my 300A MRBF. It seems that Rod an Marine How To is recommending always using fusing and saying only a dead short would blow the fuses so I have MFBF fuses where I did have no protection.
Hi Danny, fusing starters is definitely doable and should be done at a universal level, meaning it should be part of the code. There might be some trial an error in sizing a fuse, as none of the engine manufacturers are providing any recommendations or specs for fusing a starter. As a point of reference, my starter is fused, but it took me some time to get the correct size of fuse.
You are such a smart guy wish you were close to Pennsylvania.
Ah yes, I often think of yachts when I think of Pa.
@@realhusky Do I detect sarcasm Jeff?
Hey Cisco kid, in my past life was a Cisco nerd too. Thanks for the feedback.
@@PacificYachtSystems Jeff I don’t get it please elaborate on I often think of yachts when I think on PA I think your being funny but not sure.
Electricians are always clever.. Really! it's a complicated job, they have to be.
When I was just 20 years of age I worked for a yacht charter cleaning boats etc. One day at the dock I tried to start a 26 foot flying bridge type cabin boat with a V8 inboard. Instead of starting, smoke billowed out from the engine compartment. I quickly pulled the hatch and saw flame through the black smoke. All I could do was empty one of those ABC fire extinguishers on it which surprisingly snuffed the flame. By then I think the battery was exhausted and the starter cables were history. Fortunately it wasn't a 4D or 8D battery. At that time I believed the heavy starter contact solenoid stuck. I'm guessing that a properly spec'd fuse would have prevented that. Now after having read the no-fuse policy, I propose a solution. Why not fuse the starter main circuit anaway but also wire in a by-pass switch of the type used to switch batteries? If the fuse blows at an inopportune time, just flip the bypass. Batteries should always pass a dockside pre-trip fitness test (what would that list look like?). Regular voltage drop measurements across connections and proper AWG comes to name a few come to mind. Cheers!
Nigel Calder recommends a 300 A slow blow fuse at the battery for a typical auxiliary diesel with a 12 Volt starter, stating that this is enough to avoid nuisance blowing. Do you agree that it is?
It will always depend on the starter, the engine, and the cable to the starter from the battery. 300A might be a good number, I don’t have access to that kind of data to say for sure. Just make sure the cable to the starter can support the 300A. If the starter locks up or runs continuously with an undersized cable you could be in for a fire. If you can send me the model number of your starter I can try to help you choose a setup.
Hi Torsten, my own starter on my 30 HP engine was fused 13 years ago with a 300 amp fuse. That said fusing a starter circuit should be done with care as you would not want to ever have an accidently blown fuse and then consequently not being able start your engine in a dire emergency. It's all about pros and cons of each decision.
@@PacificYachtSystems On my old boat, I put a 60 amp 58 volt fuse on the diesel starter battery. The starter received no voltage. I removed it and the starter worked again. The fuse did not blow however. If the fuse was undersized at 60 amps, shouldn't it have blown?
I used to work for a boat manufacturer here in Australia, we started putting in 750 amp ANL fuses in the main feed to each start battery, never had one blow in normal use starting up to 1150 HP Scania V8 diesels, It would have been handy just before we started doing so where I had a situation on a brand new boat, turning on the start battery isolator for the first time, engine room filled with smoke, Isolator fused closed, had to cut the cable... turned out the engine manufacturer wired the alternator pos to neg .
Hey Nick, interesting stuff, thanks for sharing.
Great video as always.
Now I ask myself why are battery protective boots bad in this situation? And would protective boots be good for the house battery?
Hi Rudi, sorry for the confusion. Protective boots are good. They are commonly used on batteries, starter solenoid, alternator, etc...
Great stuff Jeff. I am still having trouble with understanding. a few items. Electrolysis, stray current from other sources and finally my boats Englehard Corrosion Monitor. Where can I find the answer to these mysteries?
Hi Mike, would suggest you read Nigel Calder's Boatowners Mechanical and Electrical handbook.
@@PacificYachtSystems thank you sir.
hi Jeff, can I install an SMH connector as a quick service disconnect on my house battery bank? as long as the SMH connector is rated for the load and fused, would this break any ABYC standards?
Hi Jarret, what's an SMH connector and what's your thought on using one?
Hi Jeff I was wondering what information you had about the cellular 5G interfering with GPS satellites.
Hi Jason, first I find out about this. Can you share a link to read?
The article I read was in the February/March 2021 issue of BoatUS magazine The article was written by Charles Fort but there is nothing on the internet about it. If you would like the magazine I can mail it out to you.
Hello at PYS,
I have a question, not related to this particular video, but maybe is a good idea for another video...
When I purchased my 87 Carver 28, it had the obligatory rats nest of wires stacked on the battery terminals for things like down riggers, and fish finders. Obviously I would like to add an auxiliary fuse panel to the switched side and clean all that up.
My question is:
What kind of fuse panels are suitable for use inside the gasoline engine room? Are ATO fuses ignition protected? Is ATC better? Do I need a special panel?
Thanks, I love your vids. Keep up the good work,
Cap'n Hippy
Hi again.. just to add to my question...
I'm not necessarily asking what brand of fuse panel, but more what TYPE of panel.
Thanks again
Great question, some boatbuilders like SeaRay have DC distribution panels in their gasoline engine rooms, not sure where they get them build for Ignition Protection. Reach out to Blueseas to find out and let us know what you find.
@@PacificYachtSystems Well, I did some research on the googly webs, and called the folks at Blue Sea (who were really super nice and helpful), and today/yesterday I learned the difference between ATO and ATC fuses.
So, to answer my question, it's not really the box that matters in regards to ignition protection (chemical proof, yes), but the fuses themselves.
Which made sense to my logical brain, since the sparky part shouldn't be the box itself; but the fuses. But I wanted to double check.
I can't believe I've been a boater this long and didn't know about this! I'm pretty handy too, do my own electrical work..
Am I the only one? Seems pretty important actually.
Like... Is every boater who ever added a CanTire inline fuse holder cruising around in a time bomb?!!
Ahh.. very good point.. I never thought of that :)
Thanks for sharing.
People still do fuse their starter wires anyway. It is simply optional. A 300 amp Blue Sea ANL fuse has a long time delay of over amperage before it will blow. I have 2 banks, starter and house and 2 rotary battery switches. If the starter fuse ever blows, and it has not for a 392 v8 yet, I can rotate house switch to both, the number 2 position switch lug runs a wire down to the starter wire buss, and I can start with no fuse in the circuit. I dont fuse my house battery switch , I fuse the buss connections, one for inverter 500 amp, one for house 150 amp , one for Lectrasan 100 amp. I could always change things if I wanted.
Scott, you bring a good point, because the ABYC code doesn't require fusing the starter, that doesn't mean it cannot be done safely. I too have a fuse on my starting circuit and it's well sized to protect the wiring, fuse never blew accidently in 14 years.
Normal running is both switches on #1, swap banks, both switches on #2. Combine banks, either switch on 1+2, with other switch on 1,2, or 1+2. Isolate a bank to off is off. So put switch to off, other switch 1+2, that banks runs everything.
My starter battery box for group 29 and 31 made by Attwood is much longer than the battery. I put the Blue Sea ANL fuse holder on a block of wood meant to keep battery from sliding around. Now here is another idea for keeping starter wires off until you crank the engine. Use a starter relay inline from start battery wire. connect the relay control wire to the ignition switch so it is on when you turn key to start position. Wires are then dead all the time except for when turning key to start. If two 2 engines and 2 keys, use common 10 amp or so diodes inline with the wire from each key switch to the added in starter relay which is immediately wired at the positive battery terminal. Diodes act as one way valves, so turning either key means will only crank the appropriate engine, otherwise turning either key will crank both engines at same time. Put the starter relay after the rotary switch if you want, like if something else is powered directly off the battery, you can figure this out, it is easy. Advantage is the entire starter wires have no power unless you actually turn key to start, so there is no short to cause a fire. If there is a short, you will know immediately, your right there, engine wont crank.
Thanks for sharing Scott!
Jeff, PYS, I'm having a difficult time accepting the notion that a starter will draw more current from a partially discharged battery. Have you ever tested this in a shop or laboratory environment??
Physics say its so and ohms law helps us to visualize the concept. In dc circuits, resistance is typically fixed so if voltage dips, current must rise. Hope this helps.
Thanks
Welcome
Hahaha. Finally. The truth. It’s ok to not run fuses everywhere as long as you do a really good job with the installation. I swear, the strictness of some boaters and their "dire" warnings and finger wagging advice has harmed more boaters both in damage and just giving it up than helped. There are so many ways to do things on a boat. Best thing to do is have complete understanding of what your working on and use common sense that pertains to the boat and operators. Life is best when freedom of expression, even in engineering and installation, is present.
it's right in the ABYC guild lines that a starter circuit does not need to be fused. However it's not a bad idea as long as it's big enough to never trip under normal use.
💯
Thanks Javier.
A temp sensor on the main power cable and a motorized main switch that cuts the connection would be a better soulution than a fuse. If the temperature on the cable gets so high that it will start a fire...no other scenarios are worse..My opinion..
Thanks for sharing.
@@PacificYachtSystems In the real world you can use a 500A plus contactor ,with no fuse, activated by the starter key. Only for the cable between the starter and the starter battery. With this solution you will never have an unfused cable during normal operation. Only when you use the starter motor. Can altso be combined with a bypass main switch if you are afraid of contactor malfunction.