What should be hooked to the starting batteries?

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battery count

Gray Dog, you have have surmised that I am not an electrical guru, I kept my battery banks designated to each motor plus house sets. Due to my decrepitude and age I chose 70 lb. glass matt (AGM) group 31 batteries, total of 10. each Cummins C6 has three starting batteries hooked together, remaining 4 for house and a simple wet cell group 24 for the generator. Why? I personally could carry each one and install. I use an Outback power management system to keep fully charged and controlled min/max float per the battery manufacturer. Windlass off the start batteries only when the motors are running. Overkill? maybe but so far the system works very well and even I can understand and service.
 
RCD, not saying anything about electrical guru. I would prefer to have golf cart batteries instead of the 8D's and will probably change out when these batteries die if space permits. What I think is different about my wiring, which came this way with the boat, is that a single battery is both house and start with the ability to parallel the aux battery if needed when starting. My Cummins engine wants 950 cold cranking amps and can usually be supplied by the house battery but I routinely do the parallel as over kill.
 
Marine Trader

I purchased a 1985 Marine Trader 40 Sundeck in April of this year. I don't why? But she had just reeled me in. She had been on the hard for how many years ?? and they (owners, brokers) just wanted to dump her. Sea trials were a bust, but the surveyor said "this is one hell of a boat. (had to limp in on the stb engine) . Im Stoopid. After a summer and part of fall, I have to say this baby is the love of my life. Been working withe her all season now and with new electronics and engine maintenance she looks like Julia Roberts in Prety Lady, and she is ready to make me happy.
 
I was going through the survey and now I think I know what it was that really drew the batteries down. The 110v hot water heater!

I take possession next week and will figure it out for sure but that would draw things down quickly.

Hey Drago post a photo of your Marine Trader!
 
I was going through the survey and now I think I know what it was that really drew the batteries down. The 110v hot water heater!

I take possession next week and will figure it out for sure but that would draw things down quickly.

Hey Drago post a photo of your Marine Trader!

Hot water heater should not be hooked into the inverter circuit for the very reason you are describing. Some one did a quick and dirty inverter installation, see this all the time.
 
Realize the Cummins QSB 5.9 has an electronic ignitions. IF for some reason the start battery is weak, and you have the bow thruster hooked to the start battery, when the battery voltage drops to some where between 10.8 and 10.5, the engine will shut down. This happened to me while docking. I replaced the start battery and moved the bow thruster to the house batteries bus. I can live without the bow thruster while docking if necessary. I cannot live without the main engine.
 
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Please excuse me for my over simplistic answer but the answer is kind of in the question... What should be hooked to the starting batteries? The starter. :)

L
 
Please excuse me for my over simplistic answer but the answer is kind of in the question... What should be hooked to the starting batteries? The starter. :)

L

I would add, and the necessary electronic associated with engine.
 
I have always had stone-age engines with no dependency on battery level once started. Now I know why I liked it that way.

Derik, I have rebuilt from scratch the battery setups in several boats now including all the big cables, alternator controllers, ACRs, battery switches, you name it. It isn't cheap, but in each case I wanted to end up with a system which did not require even one battery switch to shift from underway to moored at pier or at anchor.

For your new-to-you boat I have little to add to the good direct advice here, but I would add for you to start out finding who does what to whom by disconnecting both (all) battery banks' positive leads and switch off any and all battery switches. Disconnect shore power. Now, make sure the inverter cannot be turned on. I know, how could that happen, but believe me, stranger things have happened. :)

Next connect one bank at a time with battery switches still off to ensure somebody did not wire something around your switches. If nothing (especially the inverter) turns on, good. If the inverter can be turned on, that is NOT good - fix it so you know for SURE which batteries are providing power under which battery switch selections.

Then alternately connect and disconnect the banks with the battery switches being used to direct power while switching all the 12-volt equipment on to find out where the power is really coming from. Include any and all battery switch combinations.

After you are done, connect a each bank in turn to be sure the inverter does not draw from both unless you were to so choose by a battery switch selection.

Now you know just how screwed up the setup is and can begin to apply some of the wonderful advice here.

I support comments about running thrusters and windlasses off the start bank on the condition that the engine(s) is/are running. It is my setup.
 
Makes a lot of sense I'll do exactly that. I am looking forward to chasing down the Gremlins!
 
We haven't really had any difficulty running down the overall capacity.

We too have a parallel switch so the two big banks can be instantly joined for starting one or the other engine. And a genset so we can start that and charge everything if necessary. And a back-up battery in the dinghy in case we have troubles with the genst battery, and one of these days I'll probably get a pair of jumper cables to keep on the (diesel) boat to simplify that even more.

I think I've used our parallel switch twice over the last 13 years, and even that was in a situation known to draw down one of our banks severely... not at all a surprise.

I don't disagree with the common wisdom, but we don't have that setup... and the potential cost of reconfiguring our battery banks seems to me to exceed the potential gain.

-Chris
Same here on our DeFever 44. Eight golf car batteries serve as both house and start batteries, a common setup on DeFevers. Two group 24s serve to start either of our generators and can easily be jumped if the house bank is depleted which does happen occasionally as we all know. Recently, that occasion occurred. I ran down the eight gc batteries to 20% but they still easily started my Lehman 120s. So, it would seem that having dedicated start batteries is neither the preferred setup or the best, just different.
 
Realize the Cummins QSB 5.9 has an electronic ignitions. IF for some reason the start battery is weak, and you have the bow thruster hooked to the start battery, when the battery voltage drops to some where between 10.8 and 10.5, the engine will shut down. This happened to me while docking. I replaced the start battery and moved the bow thruster to the house batteries bus. I can live without the bow thruster while docking if necessary. I cannot live without the main engine.
Wise change Old Dan. Recently in a lock on the Illinois River I witnessed an out-of-control boat ( Mainship?) crash into the lock wall at way more than idle speed. She bounced off the wall and into the stern of a beautiful American Tug 41, then back to bow into a railing with the pulpit stuck under the railing. The culprit was a depleted thruster battery to which the electronic engine controls were wired or perhaps was wired in the way your boat was. The failure happened at the most inopportune time. Always do, don't they?
 
Yes, I too favor cables for shifter and throttle but, I also favor a naturally aspirated engine.
What I failed to remember is, I could have paralleled the house and start battery, long enough to get myself out of a jam.
 
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"I ran down the eight gc batteries to 20% but they still easily started my Lehman 120s. So, it would seem that having dedicated start batteries is neither the preferred setup or the best, just different."


I am still a belt & suspenders guy , bit understand the joys of all deep cycle batts for extra house service.


I wonder if the new LI battery jump starter is made with enough ooomph to start a cold diesel?
 
Realize the Cummins QSB 5.9 has an electronic ignitions. IF for some reason the start battery is weak, and you have the bow thruster hooked to the start battery, when the battery voltage drops to some where between 10.8 and 10.5, the engine will shut down. This happened to me while docking. I replaced the start battery and moved the bow thruster to the house batteries bus. I can live without the bow thruster while docking if necessary. I cannot live without the main engine.

Good point Dan. :thumb: Electronic engines open up a whole new world.
 
Yes, I too favor cables for shifter and throttle but, I also favor a naturally aspirated engine.
What I failed to remember is, I could have paralleled the house and start battery, long enough to get myself out of a jam.
Just after the lock failure I described I was talking to another Looper and opined that I prefer cables for just that reason. He agreed but related his experience with having a throttle cable break soon after he bought his boat. Then, two days later, Murphy struck, he broke another cable. Can't win with boats. I think though that there may be a design flaw in the cable routing perhaps too many bends, sharp bends creating stress on the ends. Just a guess. After having broken two cables I would have a spare on board.
 
Just after the lock failure I described I was talking to another Looper and opined that I prefer cables for just that reason. He agreed but related his experience with having a throttle cable break soon after he bought his boat. Then, two days later, Murphy struck, he broke another cable. Can't win with boats. I think though that there may be a design flaw in the cable routing perhaps too many bends, sharp bends creating stress on the ends. Just a guess. After having broken two cables I would have a spare on board.

Ah yup, spare cables don't take up much room.
 
"After having broken two cables I would have a spare on board. After having broken two cables I would have a spare on board."

When installing the new cables run the spare (or two) at the same time you run the working cable. Old motorcycle trick.

The series 33 cables are meant for outboards , the heavier 43 cables better for bigger boats.

https://www.go2marine.com/product/242303F/4300cc-tfxtreme-control-cable-43c.html
 
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Starting batteries should only start engines and as said an anchor windlass may be wired to them but engines run when hauling anchors. All else on house batteries, get a good marine electrician as inverters can be tricky and requires a big fuse , also check amp draw from your fridge, some can be quite high.
 

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