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gwhiznel

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I've seen several discussions on battery configurations, but I still don't get it. Any assistance would be appreciated greatly!

I have recently purchased a 2004 Sundancer 320DA. It has two Mercruiser 350 Horizons, with v drives. It has a 5Kw Kohler Generator, and 4 batteries. It appears that there are two banks of batteries, located on the starboard side of the engine compartment. A Port & Starboard bank, with two batteries in each bank, apparently they are hooked up in parallel. Not quite sure what each bank services, or what type of battery is in each bank. I gather that certain batteries should be "starting" batteries (engines/generator), and others should be "deep cycle" batteries (house load). Here's the dilemma, both engines start up just fine, but the generator won't. When I've got the 12v service on, the batteries seem to discharge at a nominal rate. The generator starts right up when the battery charger/inverter is on shore power. Still haven't tried to start it with engines running.

Do I need to replace some/all batteries? If so what kind, and where to position these replacements. I've seen "dual purpose" batteries out there, but are they as good as specific batteries in the right location? I'm not an electronics wizard, so please keep any responses simplified. Thanks for trying to make sense of my ramblings, if you need further info, just let me know.
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First things first. As this boat is fairly new to you, why not check out the condition of your batteries before you go any further? I would start by disconnecting all of the batteries and check them out individually with a load tester. It may be a good idea to take a pic of the cables before removing them so that you can put them back as they were before you started this exercise. Hopefully, they are all good. If not, replace them as a pair. Do not install one new battery + keeping an old battery in the same bank because your bank will now only be as good as the worst battery. Deep cycle batteries for your house load bank. Are these sealed batteries? If not, check the water level in them and only use distilled water to top them up. After you are satisfied with the condition of your battery banks you can move on to your generator starting issues. It may be as simple as the position of your battery switch if you have one. Please keep us informed of your findings.
 
That looks like a low emissions generator, 5ekg I think. Don't think that was stock for a 2004 320. 5e was the model of the day. So if its been added or replaced check how it is wired.
 
If your batteries generate enough power to crank a V8, surely they would be capable of powering a little generator starter. Always a good idea to conduct initial systems checks, like electricaldoctor said, because you don’t know the condition. But but it seems strange unless your generator is pulling from only one of the batteries which happens to be bad.

Do you get a solenoid engaging sound when you try to start the generator? Any sounds at all in the engine room?
 
As mentioned above the item linked below is a good low-dollar investment for boat owners with multiple batteries.

This will sound silly...but have you checked around for a fifth battery? On the floor between the engines possibly? Any other spots that could hold a battery dedicated to the generator?

https://www.amazon.com/gp/product/B000AMBOI0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

stee, I have ten vehicular batteries to maintain. Never thought about getting one of these. I just ordered one. Thanks.
 
Thanks Fellows, great input and really appreciated. I've resorted to a marine electrician coming out to check/test the batteries (only 4, I double checked), wiring and inverter/charger, so I know what's going on, or not. Hopefully he will be able to analyze the wiring, battery types and bank positions and the destination circuits. The water level is good in all batteries (only 2 years old), and if replacements are needed, I'm going with sealed batteries. Any recommendations on which brand works best? The Generator is a replacement 5ekg installed about four years ago. It's only got 36 hours on it and the solenoid does click when attempting to start. When it runs, it's like new.
 
As mentioned above the item linked below is a good low-dollar investment for boat owners with multiple batteries.

This will sound silly...but have you checked around for a fifth battery? On the floor between the engines possibly? Any other spots that could hold a battery dedicated to the generator?

https://www.amazon.com/gp/product/B000AMBOI0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Definitely going to pick one of these up for future use. Thanks for the tip!
 
If your batteries generate enough power to crank a V8, surely they would be capable of powering a little generator starter. Always a good idea to conduct initial systems checks, like electricaldoctor said, because you don’t know the condition. But but it seems strange unless your generator is pulling from only one of the batteries which happens to be bad.

Do you get a solenoid engaging sound when you try to start the generator? Any sounds at all in the engine room?
The solenoid does click, but not enough power to turn over. A local mechanic thinks it might be connected to the deep cycle (house load) batteries vs. the start batteries. He's going to check next week, we'll see. Thanks for the input.
 
Thanks Fellows, great input and really appreciated. I've resorted to a marine electrician coming out to check/test the batteries (only 4, I double checked), wiring and inverter/charger, so I know what's going on, or not. Hopefully he will be able to analyze the wiring, battery types and bank positions and the destination circuits. The water level is good in all batteries (only 2 years old), and if replacements are needed, I'm going with sealed batteries. Any recommendations on which brand works best? The Generator is a replacement 5ekg installed about four years ago. It's only got 36 hours on it and the solenoid does click when attempting to start. When it runs, it's like new.

I've gone two rounds of replacing boat batteries with Duracell batteries from Batteries Plus. They are made by Dekka. There are gobs of threads around these parts addressing the different types and brands of batteries. From a price/performance perspective it's hard to justify anything other than lead acid. But it's also hard to compete with the bling and ease of install (weight) of the AGM and/or gel setups.

I'll summarize what I've come away with after hours of reading on this site on batteries: 1.) replace all of your batteries at the same time for max peace and happiness, 2.) replace them all with "combo type" batteries - starting/deep cycle as there aren't many true "deep cycles" out there, 3.) size them based on how long you'll be on the hook (Group 27 is probably perfect for 80% of the casual users in sub 40 footers) and a soft 4.) the more sophisticated battery chemistries lack ROI (flame away :):)).
 
First things first. As this boat is fairly new to you, why not check out the condition of your batteries before you go any further? I would start by disconnecting all of the batteries and check them out individually with a load tester. It may be a good idea to take a pic of the cables before removing them so that you can put them back as they were before you started this exercise. Hopefully, they are all good. If not, replace them as a pair. Do not install one new battery + keeping an old battery in the same bank because your bank will now only be as good as the worst battery. Deep cycle batteries for your house load bank. Are these sealed batteries? If not, check the water level in them and only use distilled water to top them up. After you are satisfied with the condition of your battery banks you can move on to your generator starting issues. It may be as simple as the position of your battery switch if you have one. Please keep us informed of your findings.
Great feedback, thanks! Getting all 4 batteries (only 2 years old) tested next week. Battery switches (2) are on when attempting to start. It might be that the generator is connected to the deep cycle vs. starting batteries. We'll see.
 
You may want to consider the following:
Battery #1 + #2 House Load
Battery #3 Engines starting
Battery #4 Generator

With this configuration, if all other batteries are too weak you will always have a fresh dedicated battery to start the generator which will send power to the battery charger. Does your battery charger have 3 charging outputs?
 
The first year I had my boat the generator wouldn't turn over, but both the engines would.
I replaced all four batteries, and it fixed the problem.
 
You may want to consider the following:
Battery #1 + #2 House Load
Battery #3 Engines starting
Battery #4 Generator

With this configuration, if all other batteries are too weak you will always have a fresh dedicated battery to start the generator which will send power to the battery charger. Does your battery charger have 3 charging outputs?
That makes sense, I'll have to see how they are configured once we test them to be sure they are all good. I believe the charger has multiple outputs.
image6 (15).jpeg
 
That makes sense, I'll have to see how they are configured once we test them to be sure they are all good. I believe the charger has multiple outputs.
View attachment 78635

Yep, according to the label you have 3 charging outputs so could configure as electricaldoctor proposed.

Also, according to the label it supports only lead-acid type batteries. This is important to know if your replace your batteries and want to consider a different type such as AGM or gel. These types have a different chemistry and need a charger can can charge them differently than typical flooded type batteries. If you wanted to change battery types you would also need to install a different type of charger.
 
Something still seems amiss. Your original photo indeed shows two banks of batteries though you have a three bank charger.

I sure wish you could find that missing battery :):) ha. As mentioned above if you do replace your batteries you should find that third charger lead and give the generator it's own separate battery. That's how your boat would have been setup from the factory.

FWIW - I once owned a 340 that had two batteries on the floor between the engines. Accessibility is horrible but if you need to find a spot for that fifth battery...it'll work.
 
Ask the electrician to draw up a little schematic once he figures everything out.

This could go a long way in trouble shooting at a later date.

By the way in looking at your charger above you may want to go ahead and ask the electrician to change out the charger to a smart charger. He's already going to charge you for showing up.....might as well put him to work for an hour. Depending on your boats electrical set up 20/30/40 amp service pick on of the ProMariner ProNautic Series of smart chargers to match. Your batteries will thank you.
 
If I'm reading your owner's correctly, it looks like the 4th battery (top, right in the pic) is added by Sea Ray when there's a bow thruster and/or genny.
 

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