Looking for Battery Wiring Solution

[jjudge]

I have a Sailfish 252 with dual Yamaha 150HP HPDI's. There are two start batteries and a deepcycle house. There are also 3 seperate switches (1, 2, both, and off). I believe the previous owner added the third switch whcih doenst seem necessary to me. There is also a 3 output guest charger isntalled. I know there are many different ways to wire the configuration, however i am looking for somthing that is simple. I have thought about adding a ACR / VSR but would prefer not to spend more $ on the boat this year. Is there a way to use the existing parts (maybe do away with the 3rd switch) and achive battery isolation during discharge and combined banks during the charging cycle? also, should the house battery only be used while the motors are not charging the banks or at all times? if i can only achieve the above mentioned using a acr / vsd, should the guest charger be wired to each battery or only to one of them.

lots of questions i know...just trying to get it right!

 

[BobP]

It sounds like what you have is OK. And what you have is not original design.

the two motors have two batteries to share (back up eachother) via the two selectors, the house battery may use one of the others as a backup, after all, what happens when the house batt runs down?

the Yamahas have an optional aux DC charge output, so it may be wired to the House to keep it charged while running. The 3rd switch, alternately, may be wired for use as a simple on/ off switch, which is needed anyway.

The three output charger is correctly wired to each battery individually.

You never should run with any selector on "both". This way each motor has it's own battery to charge, and if a defective battery occurs, it will not ruin a second battery.

And when you leave the boat at the dock for the week, turn all switches to off.

If you take a sheet of paper and follow the leads to the switches you can draw a sketch of what you have , exactly. Then go to the Blue Sea website and compare what you have to the various different schemes shown.

 

[gradyfish22]

As Bob states, this system seems ok. It seems like the 2 start batteries are seperate, one for each engine. If you read the owners manual, one battery selector should be on 1 and the other on 2, the owner's Manual should state which goes to which position, this is a typical Grady configuration, although Grady also wires the house electronics to one of those batteries. It seems like the previous owner might have had issue sor did not like this set up. Typically, a second battery would be added to that battery bank that is used as the house to handle the electrical load of your electronics, lights, etc while on the water. For most boaters this works fine and is not a problem, but with only one start battery that could be pushing it, reason why the previous owner changed the system. The reason for the seperate 3rd switch is to "isolate" the deep cycle battery from draining from the starting battery bank, the switch is supposed to allow this bank to operate without draining off that bank, but depending on how it is wired, possibly charge from the engine is wired to. Personally, I am a fan of the blue seas dual circuit battery system/switch for this configuration over just a regular battery switch, this is the only way you are truely isolated from each bank, but will charge both banks as needed off the engine, and can combine the batteries for starting if you have run low. I like to keep things simple personally, I've seen little to no issues with having 2 starting batteries as the house bank and running all the electronics off it and one engine, and having a seperate battery for the other engine, that stand alone battery for that engine should mean you always have a battery to start off in an emergency. If you perfer the third bank with a deep cycle, I would recomend the blue seas system or something similar, I have seen guys have issues keeping that bank charged on the water is not wired correctly.

 

[BobP]

GF22, in addition, the 3rd battery (House Bank) may have been added to avoid the electronics resetting each time a motor is started, same reason I'm doing it particularly since the radar takes 40 seconds to warmup and leaves me blind until then - seems like a lot longer when nose deep in fog and hearing boats around me while on the drift.

The original configuration connected the house load including electronics to the same switch terminal one of the motors was connected to, so it too can have a choice between two batts should one die.

And the house bank can be a single batt or mulitiple banks in parralel or equipped with protective isolators.

 

[jjudge]

thanks for the replies...very helpful. i would like to keep this as simple as possible, but not having much experience with this has led me to asking questions. since there are three batteries and three existing switches i would like to utilize them as logically as possible. since i tend to troll on a single engine quite often, i want to make sure that i am not leaving a bank uncharged while operating like this. perhaps the best solution is to reinvest in the blueseas three bank setup using two dual circut switches and two Auto charging relays.

the other thing i noticed (unrelated) is that there is a single #10 wire running through a cheesey 40amp breaker which is carring 100% of the system house load which includes radar, gps, sounder, shower sump, fresh and raw water wash down pumps, all guages, lights (nav and spotlights), etc. i think the only thing that is idependant of this is the vhf and bilge pumps. i am considering running two # 8's forward from a 60 amp breaker to the switch panel and sepearte fuse panel for accessories. any suggestions?

 

[BobP]

I doubt it's a #10, perhaps an 8 awg. The breaker is too big for a #10, it wouldn't protect it.

You have to find out if your Fs are equipped with the optional aux charge feed, then the selected motor battery and house bank will be getting charged by any single running motor.

Actually you do have it very simple, as long as house bank is being charged by one or both motor aux charge feed.

 

[jjudge]

surprisingly it is a #10. I am not sure if that is original or not, but it is how it is shown in the owners manual. I have decided to go with two individual # 8's from a 60 amp breaker. One for the switch panel and one for the other fuse blocks for accessory feeds.

 

[BobP]

Unless a #8 awg wire is good for 60 AMP, your breaker needs to be smaller since it is supposed to be protecting each feeder.