Anybody using AGM battery with Yamaha OB's

hardee

We are running twin 2004 Yamaha 40's with 2 Group 24 NAPA automotive weet cell batteries. Here's the situation.

Well, I took the boat into the boat mechanics, They are a Yamaha Warranty Service Center, since I need to replace my 5 year old NAPA auto batteries, (2 group 24's, one in each lazarette) I had found West Marine had AGM Dual purpose batteries on sale. I liked the idea for a couple of reasons. 1. I could maybe avoid putting in a house bat, and put in a pair of group 27's, or 2. IF I add a house battery system it would be AGM (to maintain all batteries of a simular type) and I could put them up under the V-birth and not have to worry about fumes.

So, the mechanic says that Yamaha does not support using AGM or any type of battery other than a flooded wet cell bat. and it is looking like I am stuck with the old flooded type.

Showed it to me from the Yami shop manual. Has to do with, not that it will damage the charging system, but that the charging system will shorten the life of the batteries. Same for Jell or dry bats.

So I am looking for experience with AGM bats and Yamaha charging system. Any Ideas? What are your recommendations? Is there some sort of electrical gadget I can put in line somewhere to make the engines think they are charging the wet cells? I would really prefer the dual purpose AGM due to the way we use power on the boat. Don't really need to go to G-27's if I can put in the AGM dual purpose.

Being seriously mechanic/electrical challenged I am looking forward to the response of experience and knowledge resource here in the pub.

Thanks in advance,

Harvey
SleepyC Moon

Sneaks · Posted: Sat Feb 28, 2009 12:30 pm Post subject:

The Jenny B has two AGM batteries in the starboard lazarette. Yes the long term charge requirements are such that they are easily overcharged with conventional chargers. Never had a problem with the Yamaha 75 charging system and the AGM's, and it's going on 5 years now with the original batteries. Probably because they didn't get many long LONG charges using the engine. I had a battery charger powered by shore power for long term use that was specifically designed for AGM batteries.

If it were a real problem, not a theoretical CYA by Yamaha I think we would all have heard of it long ago. It's definitely not in my F75 manual.

Don

SEA3PO · Posted: Sat Feb 28, 2009 1:33 pm Post subject:

The larger Yamaha motors have a different charging system...much more output.... on my 03 Yamaha 40's I think the total output is something like 10 amps....it's really very basic... much more like a lawn mower charging system than a modern alternator system...

I had never thought about the batterys causing my charging problem...but yes... my charging system failed the first time out after I changed the batterys.

Excellent catch... Thanks

Joel
SEA3PO

NORO LIM · Posted: Sat Feb 28, 2009 4:55 pm Post subject:

Something doesn't add up. Apparently the AGM battery folks don't feel it's necessary to warn you that your Yamaha will hurt their batteries, but the Yamaha folks do?

I will be following this one closely, as I have twin Yamaha 50's, and three AGM batteries. The engines are rated at 17 amps each. If this is even a theoretical problem, surely it can't be unique to Yamaha. I know some other makes put out more amps for a given hp size.

I have a good on-board charger and most of the time, most of the charging is done by shore power. However, I do run the boat a lot and have taken some very long trips. So far, no problems.

What might Matt Gurnsey or Les Lampman have to say?

hardee · Posted: Sat Feb 28, 2009 5:23 pm Post subject: Yamaha and AGM battery issues

I have contacted West Marine, and still waiting for a reply from their technical department.

Curious what others are experiencing?

Harvey
SleepyC Moon

thataway · Posted: Sat Feb 28, 2009 7:29 pm Post subject:

Many people confuse the charging voltage limits with gel cells with AGM batteries. The AGM will live fine on the charging voltages of the outboards (which are not as well regulated as some smart chargers). But a gel cell will be damaged by voltages over 14.1 volts.

I run an AGM on my 18 foot CC with a Yahama 115 hp, Output voltage of 14.4 volts (same as with my Honda and Suzuki motors)--all of which are charging AGM's --with no problems--and good longivity.

Grumpy · Posted: Sat Feb 28, 2009 9:12 pm Post subject:

Twin Honda 2008 135's and 200AH of AGM's. No problemo so far.

Merv

Doryman · Posted: Sat Feb 28, 2009 9:35 pm Post subject:

Twin Yamaha 150s. Stan at EQ installed Optimas last winter and they have worked fine thus far.

Warren

Steve Grover · Posted: Sat Feb 28, 2009 10:51 pm Post subject:

All those larger motors have real alternator charging systems.... the 40 and 50hp motors just use a charging loop... much more basic... also low amperage output...

Joel
SEA3PO

Steve Grover · Posted: Sat Feb 28, 2009 10:58 pm Post subject:

We are at Steve's house having dinner....we still have not made it home from the Lake Mohave trip... my son in Reno is much better, hopefully we will be heading home next weekend...

Joel
SEA3PO

hardee

marvin4239 · Posted: Sun Mar 01, 2009 12:29 am Post subject:

I got up this morning and went to Sears for two AGM's got home installed them and then checked the website Aurgh is Murphy's Law getting ready to strike? Like others have mentioned I think the problem is with gel batterries

hardee

Marvin, Hope you are OK. Again, I am running twin 40 Yamaha and the issue, according to the boat mechanic is that the Yamaha charging system my shorten the life of the AGM's.

I would sure like to see who has been running AGM batteries with Yamaha OB for the longest time and see how the bats are holding up.

Harvey
SleepyC Moon

marvin4239 · Posted: Sun Mar 01, 2009 9:38 am Post subject:

Thanks Harvey I'm fine on oxygen about 50% of the time and trying to get off it. I have and appointment with Pulmonary Doctor tommorrow to discuss more on a lung transplant. The thing that suffered the most was my boat. While in the hospital my battery switch was left on and boat not plugged into shore power. Something was left on and drained the batteries down to 6 volts hence the replacement. Incidently the factory installed carbon detectors have a low voltage alarm.

I understand your concern about the AGM's especially since it says not to use them in Yamaha literature but everything I've read says the AGM's charging characteristics are very close to lead acid but gel type are different. Sure would be nice to hear of someone using them with a Yamaha 40 or maybe a Honda 40 or 50 they only have a 10 amp charging circuit. I bought mine at Sears and they give a 3 year full replacement warranty rather than the prorated warranties.

hardee · Posted: Sun Mar 01, 2009 1:30 pm Post subject: living life to it's fullest

Marvin,

Thanks for the reply, glad you are doing better. Sorry to hear about the battery drain while you were gone. Good to hear about the Sears battery. I'll have to check with them. I liked the price of the WM for being dual purpose. Best wishes for the Pulmonologist appointment tomorrow. You are living life to it's fullest, enjoy, travel safe and continue to strive.

Harvey
SleepyC Moon