Using the Twin Battery Switches with Parallel

[Devildog]

I am totally confused on the twin battery switches with parallel. Would you guys mind sharing:

1. When do you turn each battery switch on.
2. When do you turn each battery switch off.
3. When do you turn the parallel on and off.

If you could start from the time you get in your boat (before engine start), while cruising, at anchor, and putting it away for the day.

I am feeling like a big dummy on this, but I have never had twin batteries before. I am hoping there is an easy process to all of this than what I received from the Yamaha Tech.

 

[Kevin M]

When you are ready to splash the boat, you turn on both the start and house battery. The parallel is only used for an emergency start when you may have drained one or both of the batteries. It uses the power of both the start the motors. When I anchor, I shut off the starter and only use the house battery to power the boat for music etc.. This way, I know I will have a good battery on start up.

 

[Devildog]

Thanks for clarifying KevinM. That makes it really simple. Would you confirm that both batteries will charge automatically when cruising around.

 

[bronze_10]

Only the one selected I beleive.... that's why most have a trickle charger at home.. when they sre not in the water the batteries r on the charger.

 

[Evildwarf]

The parallel switch sets the batteries in a parallel wiring position which is different from series wiring and produces more power . When you wire batteries in series vs parallel the power output is of one battery where parallel is a multiplication of the battery power....I think I have that right...
It's a similar concept with a two stage pump in "series" (pressure mode) or parallel (volume mode) configuration, power vs amount of output
I'm not the smartest guy around so others probably understand this better than me.

 

[Kevin M]

Both batteries charge albeit slowly while under way.

 

[biglar155]

The parallel switch sets the batteries in a parallel wiring position which is different from series wiring and produces more power . When you wire batteries in series vs parallel the power output is of one battery where parallel is a multiplication of the battery power....I think I have that right...
It's a similar concept with a two stage pump in "series" (pressure mode) or parallel (volume mode) configuration, power vs amount of output
I'm not the smartest guy around so others probably understand this better than me.

Let me give this a shot:

First, you do NOT want to connect your Yamaha Jet Boat batteries in series - the voltages will add, you'll get 24v in your electrical system and start letting the magic smoke out of things that are not designed for it.

Series means the positive of Battery A connected to the negative of Battery B. You then power your system by using the positive of B and the negative of A. Don't do this unless you are intentionally converting your electrical system (including the engine computer and starters) to 24v. In other words, don't do it on these boats.

When the "parallel" switch is open (off) then the batteries are isolated from each other (Technically, the negatives are still tied together but for our purposes they are isolated.) They are not in series (which you didn't say, but I felt it was implied) they are simply isolated.

When the "parallel" switch is closed (on) then the batteries are tied together in parallel. This means that the Positive of Battery A is connected to the Positive of Battery B and the negative of Battery A is connected to the negative of Battery B. This ADDs the available current from both batteries together. (Output power DOES multiply since power is proportional to the square of the current. "Twinkle Twinkle Little Star, Power Equals I-Squared R")

So if each battery is capable of giving you - let's say for the sake of keeping it simple - 100 amps, then in parallel they will be able to produce 200 amps working together.

So why do this? Mostly, as mentioned, if one battery is dead and you need to get power to the system that the dead battery is responsible for - usually starting the boat. (But if music is going to give you a better chance of obtaining your romantic objectives than starting the boat will, just remember you've got a pack of signal flares on-board.)

Keep in mind that if the "bad" battery has shorted internally (common on boats due to the jostling around they get), then hooking the batteries in parallel is likely to quickly drain the good battery as well.

 

[subysti]

With the factory set up both batteries do not charge while underway. First the system fully charges the starting battery then it will charge the house battery. That's the difference with the blue seas ACR is that it combines both batteries for charging after a 20 second delay when started. I'm not sure if our engines put out enough amperage to charge both batteries simultaneously though. It would be a real slow trickle charge.

 

[Nbnverb]

Let me give this a shot:

First, you do NOT want to connect your Yamaha Jet Boat batteries in series - the voltages will add, you'll get 24v in your electrical system and start letting the magic smoke out of things that are not designed for it...........

This board is great... I just purchased a 2017 AR240. My dealer told me when I'm "on the go" turn all three on. (contradicts what the manual states). If I just want to float and listen to music, keep house on, but turn other two off. Of course, when storing(dry) all three off.
I am putting the boat in the water for 4 days. Should I keep house on (as I would in float mode) for the Bilge?? or?
Any advice would be awesome.....

 

[Julian]

All you need to do is turn on both battery switches.
You only turn on the "Combine" if your starter battery is dead.

Both batteries will charge while under way, one at a time. It will charge your starter battery first, then the house battery. So you don't need to mess with any switches to get both batteries to charge.

 

[Nbnverb]

All you need to do is turn on both battery switches.
You only turn on the "Combine" if your starter battery is dead.

Both batteries will charge while under way, one at a time. It will charge your starter battery first, then the house battery. So you don't need to mess with any switches to get both batteries to charge.

Julian, Thank you. Sooo, if I have the "Combine" switch turned on, will both batteries still charge (one at a time)?

 

[props2you]

Julian, Thank you. Sooo, if I have the "Combine" switch turned on, will both batteries still charge (one at a time)?

Both batteries will charge regardless, starting battery first, then house battery. "Combine/Parallel" switch simply uses the remaining power from both batteries to start your motor(s). The "Combine/Parallel" switch is only engaged for the purpose of starting an otherwise dead boat, you needn't not worry about switching it on, only for that purpose.

When you go out for the day, turn on "House" & "Start", when you come back, turn them off. It's really that simple. If you are out floating and running 3, 1000 watt amps pushing 4, 12" subs for 8 hours, you're gonna have a dead battery and gonna need to use "Parallel", which will use the remaining juice from BOTH batteries.

Also, there is a low battery alarm on your boat to tell you when you're running low and need to take a cruise or get power to it somehow. With an E-Series that has solar charging panels, I am never worried as it is constantly trickle charging, on or off.

Good Luck!

 

[Matt Phillips]

Turn the house and start batteries on at the beginning of the trip. Turn them both off at the end of the trip. Only use the Emerg parallel if one battery is dead. Typically the house battery needs to be on for the bilge pump to cycle.

At the end of the trip, I'd also recommend you put a charger on your house battery as it will likely need a top off. I learned that lesson the hard way a few years back. I had the boat in the water for 5 days at Shasta, then turned the batteries off, and about two weeks later went out for another two days. At the end of the second day, my house battery was dead.

Since then, put the house battery on a solar trickle charger I rigged for my old boat and that took care of the problem. I also upgraded from the group 24s that dealers typically install in our boats to a 27 for the start and a 31 for the House. I haven't had a problem since. If you're curious about how I did the solar charger, here's the DIY on it: https://jetboaters.net/threads/solar-battery-charger-install-w-pics.3414/

 

[Nbnverb]

Thank you both.....! Have a great 4th..!

 

[Mrkheiser]

I know this is a very old post but I wanted to ask if using the switch to parallel my batteries (for good) is a bad idea or not.

I’m buying the power pole charge which calls for the starting battery and house battery to be in parallel (the system will manage drain and charging). My question is do I need to buy wires and create a parallel connection or can I use the switch long term?

Thanks

 

[FSH 210 Sport]

I know this is a very old post but I wanted to ask if using the switch to parallel my batteries (for good) is a bad idea or not.

I’m buying the power pole charge which calls for the starting battery and house battery to be in parallel (the system will manage drain and charging). My question is do I need to buy wires and create a parallel connection or can I use the switch long term?

Thanks

Why are you buying that system? The oem BEP switch is designed so that you don’t get stranded by depleting your start battery for house loads.

As an fyi, I just measured the alternator output of the engines, they are 7 amps at idle and 13 amps at 3500 rpm’s each.

 

[Mrkheiser]

What motors do you have?

I’m buying the system because I plan to do a few trips from Florida to the Bahamas and my brand new 24v lithium trolling battery would be great as a extra backup to start and that system creates a setup where that is possible.

I will probably remove the BEP system and wire in parallel

 

[FSH 210 Sport]

TR-1’s.

Okay I see what you are trying to do. Why not just return the 24V battery and get two 12v’s and wire them in series? Then you’d have twice the back up. Without the complexity of that switching system.

I’ve seen that system demonstrated and it relies on an electronic based switching system, which up till now was only 12v to 12v.

To answer your original question you could probably use the emergency parallel switch but now you have tied the house and start batteries together… that doesn’t seem like a good plan.

 

[Mrkheiser]

Returning the battery is not an option (bought the boat with it) the charge system definitely allows for 24v lithium to charge the 12v house / start battery.

Another positive is the ability to see all of my battery charge states on my simrad unit I will also be able to manage which batteries get charged first. ( it just moves current from the charged or charging battery to the one I choose)