Battery state monitoring on dual battery setup

[antaris]

Hello all, I am currently rewiring part of my new-old 208. It's running a Yammie 225 + kicker and has two batteries.

I intend to install the Blue Sea "add-a-battery" system (1 starter bat. and 1 house bat.) and was wondering how to best monitor my two batteries. Dual volmeters? Ampere-meters? both? Battery state meters?

In the case of voltmeters, is it reasonable to install one and connect a triple switch (bat1, bat2 and off)?
Or, better still, install 2 of the larger square voltmeters usually seen on larger yachts inside the cabin? I believe they are much more precise than the round 2-inch gauges...

Lastly, I know that a 5 dollar digital multimeter is my cheapest and most versatile tool, but I am planning on weekend trips with family, so I'd prefer to also have a continuous view... and not run around holding cables all the time!

Any suggestions would be welcome!

 

[seasick]

Sounds like overkill to me. I have two combo batteries. If you have a 'house' battery that isn't capable of starting your motor then you are at more risk that with two combos. I usually run on only one battery but switch which one to keep both charged. On long trips, I will g out on one battery and return on BOTH to top all both batteries. I do not use a charger and have never not been able to start. I don't have a lot of load when out, just the usual electronics. Should I run down a battery to the point where the motor won't crank, I still have the other one to relay on. Note that even after sitting on land all winter, my motor historically has started every spring. ( Batteries must be in good shape and fully charged before storage). There are no loads connected when in storage.
For that boat, amp meters aren't necessary since you can judge the state of battery charge by the charging voltage while underway. I use both the Yami gauge and the GPS voltage meter. No they don't agree are probably aren't super accurate but they are consistent and tell me how the battery is doing.
I hope that the weekend trips you mention are not overnight trips. There isn't a lot of room for 'family'

 

[antaris]

Cheers Seasick, I know I'm always a little over the top - although in this case a Voltmeter would be ok, no?

As for the Yammi gauge, I've not seen a Voltage number.... maybe I need to check again. From what I know the voltage that you see on the chartplotter (as you mention) is not precise...

As for the weekends, well, we're a small family (of two/three) and we're, well, small in size, so we'll fit!

 

[gw204]

Most of today's electronics have the ability to display input voltage. Since these will be wired to your house battery, you already have your meter there. Sure they are susceptible to voltage drop, but that should be minimal if the rest of your electrical system in in good shape and you'll still get an accurate picture.

For the starting battery, just get yourself a Yamaha voltmeter that matches your existing gauges.

Both will show battery voltage with the engine off, and both will show charging voltage with the engine running.

 

[BobP]

Google NEWMAR DCV

It's just voltage that works for me, but it's good so far.
Has three inputs no switching, has buit in selector.
When I kill the batts via heavy duty swicthes at the stern, it goes off too.

 

[seasick]

Cheers Seasick, I know I'm always a little over the top - although in this case a Voltmeter would be ok, no?

As for the Yammi gauge, I've not seen a Voltage number.... maybe I need to check again. From what I know the voltage that you see on the chartplotter (as you mention) is not precise...

As for the weekends, well, we're a small family (of two/three) and we're, well, small in size, so we'll fit!

If you have the Yamis 'digital' gauges, the speedo will display voltage if you press the mode button(twice if I remember). You have to select voltage everytime you shut down and restart, you can't make voltage the default.
Yes, the GPS meter tends to be off but it is off by the same amount each time. After a while it is not the absolute number you need to know, it is the 'normal' numbers.

 

[seasick]

As for the weekends, well, we're a small family (of two/three) and we're, well, small in size, so we'll fit!

You will be wanting a bigger boat
Since you will may have nav lights on while overnighting, I suggest two things: Definitely use only one battery for the overnighting so that if it runs down, you will have a good battery for starting and think about getting LED lights to replace the existing nav lights and possible cabin lights. Spend the bucks on new sealed LED nav lights not the LED replacement bulbs. They draw a lot less current.

 

[antaris]

@ BobP:
NEWMAR DCV and Blue Sea systems make these gorgeous things - cheers for the tip. Will probably do it, after I finish the basic rebuild (see if there's any dosh left - these things are expensive!)

@Seasick
Aha, I've got the digital gauges (2003 pedigree) - will check them out when I get my boat on the water...

As for LED lights, well I've got a list of all the bulbs on the 208 and was about to replace them - you're suggesting replacing the whole fixture. I might do it with the white light atop, the rest are staying, since all such things are expensive over here.... [And here refers to Greece, which is where I live! Trust me, all the parts are mega-expensive, not to mention that we are undergoing the most severe recession ever.]

Plus, gas costs as much as liquid gold (I believe about 1,5-2 times as much as over the Atlantic!). The same goes for the boat size - we WILL fit ! We MUST fit!! Could not possibly afford anything bigger, plus it's my first proper boat and I love it! Will post pics as soon as she's tarted up and ready, right after easter.

Many many thanks for all the useful tips, best regards from Europe! I will decide on the applied solution, after a long excel sheet calculation...

 

[seasick]

@ BobP:
NEWMAR DCV and Blue Sea systems make these gorgeous things - cheers for the tip. Will probably do it, after I finish the basic rebuild (see if there's any dosh left - these things are expensive!)

@Seasick
Aha, I've got the digital gauges (2003 pedigree) - will check them out when I get my boat on the water...

As for LED lights, well I've got a list of all the bulbs on the 208 and was about to replace them - you're suggesting replacing the whole fixture. I might do it with the white light atop, the rest are staying, since all such things are expensive over here.... [And here refers to Greece, which is where I live! Trust me, all the parts are mega-expensive, not to mention that we are undergoing the most severe recession ever.]

Plus, gas costs as much as liquid gold (I believe about 1,5-2 times as much as over the Atlantic!). The same goes for the boat size - we WILL fit ! We MUST fit!! Could not possibly afford anything bigger, plus it's my first proper boat and I love it! Will post pics as soon as she's tarted up and ready, right after easter.

Many many thanks for all the useful tips, best regards from Europe! I will decide on the applied solution, after a long excel sheet calculation...

I understand about the price differences. I have several friends living in Greece. Yes the anchor light on top is a good candidate for LED conversion since it would be on if anchored at night.

Enjoy your boat and safe sailing.

 

[antaris]

;-)

 

[1st grady]

If cost is a factor one of the most inexpensive additions is a second charging lead which is already wired into the yamaha outboard. (at least the HPDI and 4S motors) You would need to extend the lead which is dead ended inside the motor cowl to the battery. I had an ACR and replaced it with the second charging lead which seems to provide adequate power to the batteries. Being that you are using the battery to crank and run the house maybe a dual purpose (deep cycle and cranking) would fit the bill. Not the best for each function but it will work. Best option would be to have a dedicated marine cranking battery group 27 and a deep cycle group 27. Be sure to run all your accessories off the deep cycle and use the cranking battery only to start the motor. You should never (unless there is a regulator fault)have a problem starting for the first 4 years. I like to separate my house needs and motor circuits. Having a $5 multimeter is not a bad idea either. I keep one on the boat and use it occasionally. Additionally from what I understand you would not want to run the switch on BOTH, if one battery is week, it will draw down the strong one.

 

[seasick]

If cost is a factor one of the most inexpensive additions is a second charging lead which is already wired into the yamaha outboard. (at least the HPDI and 4S motors) You would need to extend the lead which is dead ended inside the motor cowl to the battery. I had an ACR and replaced it with the second charging lead which seems to provide adequate power to the batteries. Being that you are using the battery to crank and run the house maybe a dual purpose (deep cycle and cranking) would fit the bill. Not the best for each function but it will work. Best option would be to have a dedicated marine cranking battery group 27 and a deep cycle group 27. Be sure to run all your accessories off the deep cycle and use the cranking battery only to start the motor. You should never (unless there is a regulator fault)have a problem starting for the first 4 years. I like to separate my house needs and motor circuits. Having a $5 multimeter is not a bad idea either. I keep one on the boat and use it occasionally. Additionally from what I understand you would not want to run the switch on BOTH, if one battery is week, it will draw down the strong one.

The power demands for the 208 are not that great. Standard batts are 24s and as I mentioned, I use 2 combos, not one start and one deep cycle. You will need to change the trays for 27s and there isn't a lot of room to work with.
I have 4 years on the current batteries and probably will need to replace in the Spring. Let's see what happens.