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Slowboat 37

Senior Member
Joined
Aug 29, 2010
Messages
191
The Lilli Belle has 5 8-D batteries. 2 house, 1 start, 1 windless and 1 bow thruster. It seems to me that since the thruster is used only when the motor is running and then only for a very short time, that battery could be added to the house. Then the thruster could be added to the windless battery. I freely admit limited knowledge in this area, but it sounds right. Doesn't it?!
 
Slowboat. My thruster, windless and davit are all on the same battery. No issues...
Cheers
 
I would think that one good battery could service the windlass and thruster...but not sure what the distances are involved so a battery near the bow may still be the best solution due to cable sizing.

I'm not sure what the windlass draws amp wise...but the average, mid-sized trawler windlass is somewhere between 65-150 amps. Say the thruster draws near but less than 200. Even running together, at 350 amps...that's not anymore than a whole boat inverter may be drawing and for a longer period of time than the windlass and bursts from the thruster might be.
 
The hassle might be the STYLE of batt.

Deep cycle batts do great at feeding the house bank, starts do just that , start the engine.

8D is a size like 9W in shoes and does not specify what service the batt was built for.

Yes ,the house can be joined with the others , except not with the dedicated start batt.
 
Our battery system is pretty simple. The davit, windless, thruster are all fed via the house bank (1125 amps). The windless draws the most during retrieval and that is when we're leaving the anchorage so the altenator helps. The thruster we hardly use.

As psneeld mentions, wire sizing and distance from the battiers to the windlass/thruster is important. We have 4/0 cables to both. Sure we could move a set of batteries to the V-berth but it has worked well for us since we've owned Hobo. We like simple. :)
 
A question- Couple of you fellows mention seperate battery for the more serious demands. As there are no dumb questions, right? :angel:

I have a 1-2-off seperation switch in normal use. One is house and two is start. How do you deliver charge to the dedicated third battery? Mind now I have a small craft with a simple wiring process.

Were you to say how I would do it I would respond "With jumper cables".:whistling: How often do I anchor in a given year? Perhaps a dozen times, so after each use, I'd throw the jumper cables on while I am running.

I know this is a barbaric concept and unacceptable, needs to be cleaned up with a proper method of delivering a charge to this "Third Battery". How so?

Thanks:flowers:

Al-Ketchikan(Bridge to Nowhere) Alaska
 
Two options both simple.

Wire the isolated battery to one of the other two batteries but put an on/off switch on the positive cable so that you can isolate the 3rd battery when you are at anchor.

Buy a small battery charger 5 or 10 amps for the isolated 3rd battery and charge the battery when you get back to the marina.

Of the two options I have mentioned I prefer the direct wiring as being simple and less expensive provided you can easily get to the on/off switch. The only downside being that if you forget to turn the switch to off you no longer have an isolated battery. The size cable you use would determine whether the cable can be used just to charge the battery or also to start an engine. Given that you currently can use jumper cables I would just limit the size of the cable to that necessary to charge the battery.
 
Slowboat,
You don't say whether any of your (5) 8-D's are located forward, which would make a difference.

The simplest system would consist of all 5 batteries wired together as one large bank. Simplest wiring, no switches to mind. Most efficient for charging and discharging. The worry? What if I let the bank get so low it won't start the engine? This would have to be almost flat dead, as such a large bank can start most diesels at 80-90% discharged. If you have a genset with it's own starting battery, problem solved. Just start the Genny and put some charge into the large bank for a short time. Seems an extreme answer, because we're accustomed to complicated technical systems. Pooh has a single bank of 8 golfcarts (separable into 2 and 6 with a 1/2/B/O switch) with no genset. Been working flawlessly for 17 years. And yes, I have a battery monitor (Link 1000) to let me know when it's time to charge.

Mark Richter, marine electrician since 1998
 
Another solution is to use a battery combiner. It's a $100 box that charges multiple banks from a single charger. It only connects the batteries when there is a charging voltage present and keeps the banks isolated all other times.

More info here:
http://www.yandina.com/combInfo.htm
 
I prefer the high current BlueSea ACR. ACR stands for automatic charge relay. The large unit can be used to combine your house bank with a starting bank for emergency starting. Size the wire properly and in auto mode you don't have to remember to do anything. To use the forced combine feature (emergency start) a BlueSea ACR control switch is needed. This can be an expensive way to isolate and charge a house bank but it's operation doesn't require any input if left in the automatic mode.
Bill
 
If the thruster battery is mounted remotely via smaller wires to its charger how does it get charged and isolated from the main battery bank??
 
My boat also has 5 x 8D batteries, 4 provide start for main engine and generator as well as house power. The 5th battery is installed to provide power for the bow thruster and has an independent 10 amp charger. Both banks are connected to a 1 - off - 2 switch. If I was to run my main bank down I can switch to selection 2 and use my thruster battery to start any engine on the boat. Everything is monitored by my Link 2000.
 
I don't understand why people have 8-D batteries for starting engines less than 200hp. I use a group-27 on th FL-120 and never have a problem.
 
I don't understand why people have 8-D batteries for starting engines less than 200hp. I use a group-27 on th FL-120 and never have a problem.

Just a guess, but it might come in handy at -20, or if you had "issues" and were days away from anywhere or anyone. We've got a 4D for our 100hp...just in case...
 
How many start their Lehman in -20 without some sort of block heater?...silly if they do.

Even with priming when necessary and multiple starts an group 27...it is more than enough battery.

I switched over 2 years ago after talking to American Diesel and researching the amp draw of the starters.

I Leave NJ in December for Florida...last year I had to start and break ice out of Baltimore in 15 degree weather...the Group 27 was more than adequate with multi-viscosity oil and no block heater..and has been for the last 2 years with this trip in similar conditions.
 
Well...while it's gotten down to -20 outside, it's never been that cold in the engine room because of the comparatively balmy north Pacific heating things up from below. Just making a point that a larger battery adds some insurance in areas where there are no towing services and help could be days away. Might be overkill as you say though.
 
A question- Couple of you fellows mention seperate battery for the more serious demands. As there are no dumb questions, right? :angel:

I have a 1-2-off seperation switch in normal use. One is house and two is start. How do you deliver charge to the dedicated third battery? Mind now I have a small craft with a simple wiring process.

Were you to say how I would do it I would respond "With jumper cables".:whistling: How often do I anchor in a given year? Perhaps a dozen times, so after each use, I'd throw the jumper cables on while I am running.

I know this is a barbaric concept and unacceptable, needs to be cleaned up with a proper method of delivering a charge to this "Third Battery". How so?

Thanks:flowers:

Al-Ketchikan(Bridge to Nowhere) Alaska

Al, I'd definitely recommend a combiner/ACR as others have. It's a simple solution to allow you to care a charge with a second battery from a single source after the primary battery comes up to voltage. Check out the Yandina and Blue Sea sites for specs and prices. The Blue Sea units are more stout and more expensive. The Yandina units are more affordable and smaller, but capable and reliable.

I have the Yandina 100A combiner and will change to a Yandina 160A model that's sitting in my locker waiting for the alternator change out later this week. If I were to buy today, I'd get the Blue Sea ACR, but both units will do the same thing reliably and safely. Best thing is that when the charge stops, the batteries split and no load is shared. If you override this auto feature with a switch, you can lose this protection.
 
Well...while it's gotten down to -20 outside, it's never been that cold in the engine room because of the comparatively balmy north Pacific heating things up from below. Just making a point that a larger battery adds some insurance in areas where there are no towing services and help could be days away. Might be overkill as you say though.

Then better have 80, 8D's...never can have too much! :socool:

The point is...if you have to crank for more than a few seconds to start, or for a few minutes to bleed...all the battery in the world won't start your engine...there's something else that's wrong.

A group 27 has enough crank in it to try several starts and several bleeds even at fairly cold temps if you are "smartly" using 15W40 or even a lighter weight synthetic at those temps despite what the "other smart" folk say who blindly follow a 35-50 year old owners manual and use straight 30 or 40 weight.

After several attempts at starting and no success...I would assume a reasonable person has some other means of throwing some charge back into the start battery while you run diagnostics on the engine. If not...maybe it's time to assess the "big picture".....
 
Then better have 80, 8D's...never can have too much! :socool:

The point is...if you have to crank for more than a few seconds to start, or for a few minutes to bleed...all the battery in the world won't start your engine...there's something else that's wrong.

A group 27 has enough crank in it to try several starts and several bleeds even at fairly cold temps if you are "smartly" using 15W40 or even a lighter weight synthetic at those temps despite what the "other smart" folk say who blindly follow a 35-50 year old owners manual and use straight 30 or 40 weight.

After several attempts at starting and no success...I would assume a reasonable person has some other means of throwing some charge back into the start battery while you run diagnostics on the engine. If not...maybe it's time to assess the "big picture".....

1) Right. I'll start saving for those 8D's and paint the boot stripe a good six inches higher :thumb:

2) Yup on the 15W40.

3) Working through the recharge options before committing the cash, and working on the diagnostic skills as time goes by...
 
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