Twin 40s battery question

[Pandion]

Folks, I recently happened upon an old discussion (http://www.c-brats.com/viewtopic.php?t=59&sid=95bde120bbb205b4ca4584d273f6730c) of battery wiring for twin Honda 40s, and now have a better understanding of why the charging coil in my starboard engine got fried (once for the boat's previous owner, once for me).

Aparently, each engine needs to be wired separately to its own battery, and having both engines' charging systems connected to the battery switch (a configuration the factory may have used for a while) can cause damage to the charging coils.

Oops. I will rewire the system as advised.

Can anyone tell me what the correct battery size is for a Honda 40? I can't find that info in my owner's manual.

Thanks.

[NancyandBud]

Andy,

We aren't home to look at what we have.

I know each is directly wired to one battery. Each battery has a switch in the cockpit. We do not have a "house" battery.

I'm making a very short jumper cable to be able to connect the positive terminals if I need to "jump start" one of the motors. By starting the motor with the "low" battery, I can then remove the jumper cable and then start the motor with the "good" battery.

This link shows, in the section titled "New way" how to obtain the same results with a 1, 2, both, off selector switch.

http://continuouswave.com/whaler/reference/dualBattery.html

I'm too lazy to remove the current switches and rewire a new one.

[thataway]

Generally what is "said" 13 years ago is still true.
1. each engine should be wired so it goes to its own battery.
2. never run the engine with both outboard engines feeding one battery
3. Never run an engine so that the charger is not attached to any battery.

A lot of other things have changed. There is now the "center fielder" by Balmar, which allows two engines to run into a battery bank, but this is made for alternator engines, which use the specific Balmar regulators.

AGM batteries have come along, and they will take a lot more charging power.

There are some things I disagree with--and part has to do with boat usage and way things are set up.

"A charger is not necessary" Yes, if the boat is run at least once a week--or daily--as commercial boats. And, there is no heavy house load.

Nowdays, we see more boats with refrigeration, with heavy house loads, more electronics, etc--and there is a need to fully top off house batteries===and if the engine is not run enough, to top off start batteries.

I happen to use 3 group 31's on my 22--why? I use a combiner, I have heavy house and electronic loads, and don't run my boat every week. I want low self discharge, but also ability to charge fast, and discharge fast, if necessary...

For the average 22, with twin 40's--a set of group 24's lead acid batteries is the way the boat should be rigged, with one battery to each engine. If you are going to be using a lot of house load, then you can look at ways to add a 3rd battery, but for most of us, not necessary.

[Pandion]

Thanks folks. Would you go with dual purpose or starting batteries? And what might recommend one brand of battery over another?

[Foggy]

In planning the electrical set up for my 2014 CD 26 Venture with twin Honda 90s,
I've gone thru the learning curve to now know twin outboard engines each
require their own starting battery. Before getting to this point, I wanted one
12V starting battery for the engines and two paralleled 12V batteries for the
house. Then the Honda rep said "Nope, you need 2 starting batteries if you
have twin engines" but never explained why in this day and age.

So I end up with 2 Group 24 flooded lead acid (Interstate) marine cranking
batteries, one for each engine, and 1 Group 27 flooded lead acid deep cycle
marine battery for house needs. I want to switch the Gr 27 to a Gr 31 but don't
know if there is space. I mind their recharging needs and they have worked well
to date. Could have spent more $$$ on AGMs but why?

My manual for a single BF90 Honda minimum requirement for a starting battery is
"12V-55Ah/5HR  (65Ah/20HR) (CCA582A)".

A quick search for a single Honda BF40, the manual say only "12V - 70AH".

Aye.

[chimoii]

Maybe Yamaha is different to Honda. I have never owned a Honda outboard so I really don't know. When we took delivery of our 2008 Venture 23 with twin 60 hp Yamahas I was surprised to find only one battery switch. In addition, the boat was equipped with one starting battery and one deep cycle battery, both group 27.

It was explained to me that by using an ACR both batteries would be charged as necessary when running but that only the deep cycle battery would be used for "house" purposes, ensuring the starting battery available for the motors at all times. The battery switch was [is] simple with positions off/on/combined. This last position obviously brought both batteries together if necessary to crank a motor. Once one motor is running, of course, the output from that one can help start the second. Both motors are wired to charge the one system. The layout can be seen here https://www.bluesea.com/support/reference/170/Battery_Management_Wiring_Schematics_for_Typical_Applications if you look for 2 motors/2 batteries. On shore power the guest battery charger is wired for two banks, monitoring and charging each as necessary.

Coming from an age where I was told that each motor needs its own battery and should only charge that battery [a view that still seems to be common in the marketplace] I was skeptical. I bought an emergency jumpstart battery and have kept it in a locker under the V berth since, taking care to bring it into the open air for periodic charging. I have never used it.

Coming from the Chesapeake Bay where hot summer temperatures and perhaps not the greatest battery charger meant that I was replacing batteries every 2 to 3 years I wondered how this "new technology" would affect battery life. Each year for six years I hauled the batteries out of the boat and down to the Interstate warehouse for load testing. They don't sell batteries retail but were happy to do the test since I had Interstate batteries. Each year both batteries reached spec for new status. I knew this couldn't go on forever and I didn't want to pay for two new batteries at the same time but I again came from an age where you didn't mix old with new. Educated by the Interstate expert I now know that this is quite possible using the circuitry with an ACR. Last year I subsequently bought a new group 29 deep cycle Interstate battery to use for "house" and moved the original deep cycle group 27 to the starting position. Obviously the wiring needed a change. Both batteries fitted perfectly since the group 29 is only slightly larger than the 27.

A photo showing the whole setup is in the Chimo album showing the boat in October 2016.

Sorry for rambling on but hopefully this is of interest to someone.

[CDory23]

chimoii, I have twin yami 40's on my 22 and have the same Blue sea systems ACR system you have. I installed myself and followed the Blue sea systems instructions and wiring diagram which does have a battery for starting and a house battery obviously wired through the switch. So yes both motors are wired to the dedicated "starting" battery and I have not had any issues for 2 years......should this be of concern?

Also a note, I've always been under the impression that with a system like this you want both batteries to be the same type and age so they charge evenly, I understand why you chose the different style batteries but you may want to consider getting a duplicate to the starting. I chose to get 2 dual purpose baterries and I"ve had good results. Maybe someone else will chime in on that concept.

[thataway]

Agree that both batteries should have the same age, size, type and characteristics.

As long as the battery has adequate MCA (Marine Cranking amps ) or CCA (Cold Cranking amps) as what the engine manufacture requires, then a dual purpose battery is fine.

For some time folks were not using AGM batteries with Yamaha engines. For some reason the engineers at Yamaha didn't think that AGM batteries met their criteria. I know lots of folks (including myself-at one point) who used AGM with Yamaha, and had no problems.

I have a single Honda, and use Group 31 AGM--the Group 31 because I need the amp hours and the ability to rapid charge because of the refer/freezer. (I charge at C/3 (1/3 capacity) example: My batteries are rated for 110 amp hours. I charge at a little over 30 amps--monitoring the temperature of the battery)

[chimoii]

[CDory23]

+1, I have been very happy with Blue Sea Systems customer service and technical troubleshooting.

[thataway]

[Hunkydory]

During the 16 year life of our twin Honda 40 hp powered boat, it started out with group 24 flooded lead acid dual purpose marine batteries, then due to the tight confinement of them in the starboard lazaret, making acid level checking difficult, I switched to Cabalas, group 24, AGM dual purpose marine. We are now on the 2nd set of these. None of the batteries I've replaced have gone bad before replacing, but thinking it prudent to lower the chances of that happening in some remote location by replacing after 5 or 6 years with them still good.

Our wiring set up is simple with each battery dedicated to a single motor, but with a 1, 2, combine or off selector switch to allow for combining to start the Wallas or if one battery does go bad. I alternate between them for house battery use. We do a majority of our cruising on one motor at displacement speed & for the most part will during that time have the switch set to the house for the battery being charged. In the past I have twice had a charge coil burn out. Both times, it was caused by having the batteries combined, while running both motors in conditions, where I was having to do excessive throttle adjustment for an extended period of time. I now no longer combine them when both motors are running, but in the past, when I did, it was for many years under extended cruising conditions & the charge coil only went out, when the conditions were causing unbalanced charging between the motors to an extreme point. After this happened to us on an extended Alaska cruise in 2007, I talked to Les at EQ & he explained to me why it happened.

Battery chargers were recently discussed on another thread, but being as they do effect batteries, I'll comment about chargers here. I readily accept there are better onboard chargers than Guest & many would be better off switching to one of them, but in our case & maybe some others like us, where amp draw is fairly low, when hooked to shore power at the dock, on the go or at anchorage, the cheaper Guest is more than adequate. For us the original Guest 2610, 10 amp charger is still doing fine after 16 years of service. During these years, It has been used here at home during the off season, at the dock in Yellowstone, at many different marinas in SE Alaska & extensively while cruising & powered up by our Honda 2000 generator without any damage to our batteries.

Jay

[chimoii]

You are absolutely correct Thataway. Instead of 'each battery' I should have said 'both batteries'. Your quote para. 2 "How does an ACR work?" says it even better.

[Pandion]

Jay, when you're using your charger, do you hook it up to one battery and put the switch on "both?"

[Hunkydory]