Anybody using AGM battery with Yamaha OB's

[Hunkydory]

Have read this thread with much interest. We have twin Honda 40's and in spring 2006 switched from the wet cell to AGM batteries, so that is what batteries we used on our 2007 Alaska wilderness cruise. On that cruise up until the time the charge coil went out on one of the motors had no problems with batteries keeping charged and this was with no charging at docks and one six day outing where we slow cruised much of the time on one motor. Wallas was running most of the time along with the other electronics. Didn't have to use the Honda 2000 generator to keep up the batteries until we lost the charge coil on the one motor. Went the rest of cruise using the generator and the one motor to keep the batteries up. The last 90 miles up the Lynn Canal was on only the motor without a charge coil using the generator on the go to keep batteries up.

When these batteries finally go will replace with another set of AGM's. Correct me if wrong but my understanding is with them there is no damage or lessoning of the battery life by going under the 50% charge. There ability to do double duty as cranking and deep cycle was my main reason for switching from the wet cell to them and on a cruise I switch back and forth between the batteries for there use as house or for engine cranking.

Harvey to bad you can't use them with your Yami's they sure have worked well so far with the Honda's.

Jay

[Doryman]

Jay & Harvey -- I looked up the specs of the Honda 40 and it also has a 10 amp charging alternator -- identical to the Yamaha.

Warren

[hardee]

Roger (Dreamer), Thanks for the kind offer on the generator time. In reality, you are probably close about the use,

[Simplicity]

This discussion has me wondering about my battery situation. One Lead acid went dead and I had an AGM27 that I replaced it with.Is it a problem having one AGM and one lead acid? It's a CC23 with Honda135. Ignorance is bliss until something goes wrong.

[NORO LIM]

I believe mixing battery types is probably a mistake, although there may be sophisticated (and expensive) chargers that can accommodate differing types. I have AGMs and had Les install a better charger than came with the boat precisely so that the charger can be set for AGMs and can supply enough charge from the generator or shore power.

The question of charging from my two Yamaha F50s is another issue - one I'm still not clear on. Ironically, I chose the Yamahas over Hondas in part because (in 2006, at least) equivalent sized Yamis had bigger alternators (17 amps versus 10 for the Honda). I think part of what's going on here is comparing across makes, models, and years. I think, for instance, both Honda and Yamaha have increased amp output in some of their models as they have gone from carburetors to EFI.

Maybe it's just wishful thinking since I'm 6 months into a significant investment in these AGMs, but I'm in Thataway Bob's camp on this and am reasonably confident that my set up will work. I have a good charger, constant shore power when at home, and a generator I can carry. So even on extended trips I am optimistic about keeping the batteries in good shape.

[Plan C]

Harvey,

Who's working on your boat in PT? Is it still here? When you put her in, we ought to make the coffee run to Nordland!

I have been doing a lot of studying of batteries in the last few years. I first had an electric conversion car (old VW Rabbit truck) and now have a Zenn NEV. These cars teach you batteries!

I might say my knowledge isn't wholly relevant to marine use. It is primarily in deep cycle, high amp usage. My first car had open flooded lead acid. Ventilation was good, so it didn't matter if they boiled a bit for equilization charges. The Zenn car, which has batteries inside the car has Discover EV-31 AGM's. I think they cost around $350 each. I am not dazzled by them and may well at replacement time go to floodies, with an active ventilation system when charging.

The general wisdom is that gel or AGMs are good where the battery is not ventilated, or where the battery experiences a lot of bouncing. The bad news about them is that they need their own charging algorithm, they are short lived compared to lead acid, and they cost way too much. Lead acid is your best buy, by far.

For your proposed use, Harvey, with batteries in the bow with no ventilation, maybe there is an argument. Downside is that you will need very long cables. Putting batteries in the stern will be usually the best answer, using SLA (sealed) batteries. Interstate is a decent brand. Exides will cost less and last less time (may be okay trade off if you are someone who watches the battery condition). Trojans are considered the best of the lower cost batteries.

Last spring I had a weak house battery, so I moved the better engine battery to the house position, and put a nice Trojan in the engine position. I watch them to be sure they are charging properly.

Dave

[Plan C]

More...

I think the one most important thing I have learned about my boat batteries is that I need to charge them AFTER using the boat, on the trailer at home.

When I finish for the day, I tilt the engine up for trailering, then tip it down at home to drain. Earlier engine needed starting for flushing - even worse. So by the time you get home, your engine battery is slightly discharged. The house battery, if you didn't charge with the engine, might be a little low. Lead acid self discharges as I recall 3% a month. Letting your battery sit in a discharged condition will significantly shorten its life.

I'll give a plug for the absolute best relatively inexpensive 12V smart charger I know. It is the BatteryMinder 12248. I use mine a LOT, and have even bought a second one. This is the lowest cost charger with temperature compensation. It will charge at 2-4-8 amps, and has algorithms for lead, gel and AGM's. They are durable and well sealed (and compact). You can get them from Pacific Battery for $120, including the temp compensation hookup.

Dave

[thataway]

There are several sites which have very good information on batteries--and one of these deals with off the grid use where there is daily drain and re-use.

http://www.windsun.com/Batteries/Battery_FAQ.htm

AGM batteries and Gel Cel batteries cannot be equated--and although the lead acid battery is more economical to purchase and to run, it is not necessarily a longer lived battery.

The deeper you discharge a battery (either lead acid or AGM) the shorter its life span. If you discharge 80% regularly, the battery will last half the cycles of a 50% discharged battery--and if you only discharge 20% it will last many times longer than a 50% discharged battery. Just being an AGM does not make it able have a longer life with deep discharge. An AGM can take a higher rate of charge, but with our C Dories, this is not usually a feature we need.

Yes, it is best to top off your batteries with a charger after using the boat. But I get 4 years or more use of batteries without topping off. I also agree that the Battery Minder is an excellent charger (but it is not a marine charger)--and the pulse feature prevents sulfation.

Also I find that if you have a boat in storage, that a solar cell will keep that battery fully charged.

[Doryman]

Bob, thanks for the great link. I went there and while I was reading the FAQ I checked the numbers on my ProSine control panel. It says that my house battery has 13.2 volts. However, the FAQ says 100% charge is 12.7 volts. Do I have more than 100% charge? Or if they are apples and oranges numbers, how do I find out the voltage that the FAQ is referring to?

Thanks,
Warren

[NewMoon]

Hi Warren,

For that 12.7V to be the right indicator of a full charge the battery has to have no load on it, and to have been sitting for maybe 24 hours since the charge completed. If the charger is still connected or has been so recently the voltage will be higher. That's why folks who want to know the state of charge of their house bank like the amp-hour meters like the Link from Xantrex.

[Doryman]

I have to buy yet another piece of hardware instrumentation now? Aauugghh!!

Warren

[Captains Cat]

[Plan C]

>For that 12.7V to be the right indicator of a full charge the battery has to >have no load on it, and to have been sitting for maybe 24 hours since the >charge completed. If the charger is still connected or has been so recently >the voltage will be higher. That's why folks who want to know the state of >charge of their house bank like the amp-hour meters like the Link from >Xantrex.

Good points on checking voltage. Your float charge (if charger is connected after the charge) should be in the 13.1-13.3V range.

The Xantrex Link 10 is an excellent meter, but way overkill for our boats, in my opinion. As has been suggested before, you can spend $15 on a voltmeter at WalMart that plugs into your cigaret lighter. Between 20-80% state of charge, voltage is a good if not perfect indicator of charge. It is certainly as good as we need.

>although the lead acid battery is more economical to purchase and to >run, it is not necessarily a longer lived battery.

Not true. Check specs on battery sites. The quality flooded or SLA battery has more cycles. Degree of discharge is not an issue (above 20% SOC). Roughly, if you charge more frequently (lower discharge) or less (deeper discharge), the amount of energy in the battery is about the same. Staying above 40-50% is just safer to avoid a too-deep discharge.

When you figure cycles and overall cost, the humble SLA battery should be an easy choice.

Dave

[thataway]

Warren,
Not to worry--you don't really need a amp hour meter. Battery charging and discharging is dependent on chemical reactions. There is a surface charge on the plates, and it may cause the voltage by a volt meter to read high just after a charge, or low after a discharge. The battery voltage needs to be read at a "steady state" of 3 hours after any charge or discharge of the battery. For practical purposes, the measured voltage is a good measure of state of charge--but the amp meter method is the most accurate.

Dave.
I am sure that you realize that all flooded lead acid batteries are not equal--for example. There are different thicknesses of plates, surface area, and separators etc.
You cannot compare a Rolls battery (high quality) with an Exide (mid quality). Nor can you compare a Traction battery by SBS with a golf cart by carried by Sam's club.

From the link I posted above (and available many other places on the web or in technical bulletins) are typical battery life spans:

Starting: 3-12 months
Marine: 1-6 years
Golf cart: 2-7 years
AGM deep cycle: 4-7 years
Gelled deep cycle: 2-5 years
Deep cycle (L-16 type etc): 4-8 years
Rolls-Surrette premium deep cycle: 7-15 years
Industrial deep cycle (Crown and Rolls 4KS series): 10-20+ years
Telephone (float): 2-20 years.
NiFe (alkaline): 5-35 years
NiCad: 1-20 years


If you look at battery life vs depth of discharge, the comparable AGM and Flooded Lead acid batteries will both have similar life spans--and the life span of comparable batteries are dependent of depth of discharge. A normal "Cycle" is from fully charged to 20% discharged and back again.
This is for a quality lead acid (either AGM or Flooded lead acid):
10% DOD (depth of discharge) =5000 cyc. 20% DOD= 1800 cyc, 30%=1800 Cyc
40% = 1400 cyc, 50% = 1000 cyc, 70% =760 cyc and 80% = 500 cyc

SLA is just an abbreviation for "Sealed Lead Acid".
Again, there are some differences in battery design, but because the way the battery is used, and the construction it may have more cycles than some other batteries. However technically an AGM is a form of SLA battery.

The small SLA's such as are used in our rechargeable boat searchlights, or the computer back up power supply, the SLA and VRLA are designed with a low over-voltage potential to prohibit the battery from reaching its gas-generating potential during charge. Excess charging would cause gassing and water depletion. Consequently, these batteries can never be charged to their full potential. To reduce dry-out, sealed lead-acid batteries use lead-calcium instead of the lead-antimony. Thus these batteries are not designed to allow deep cycling. I am not familiar with SLA, as you visualize them used in boats--except as I noted above, and perhaps you can provide me some examples.

[Hunkydory]

Bob

Either I've missed it or no one else has mentioned it. How about the marine duel purpose deep cell and motor cranking AGM batteries. The set I bought through Cabalas is a Group 24.
with---
400 cycle life
1195 marine cranking
945 cold cranking
178 minutes of reserve capacity

This year will be there forth season and as mentioned they worked well for us on our last Alaska cruise.

They had the best numbers going for a group 24 duel purpose battery at the time they were purchased and my past experience with Cabalas has been outstanding.

I know going duel purpose means you have to give some on both sides, but those numbers if true match up pretty well with either cranking or deep cell on their own. I can't remember for sure but believe the price was $125 per battery. My understanding is still due to there be duel purpose they can be run below 50% and not be damaged. With our use on boat knew the previous wet cell lead batteries were being run to low and their life shortened. Maybe the cranking with larger motors could be a problem along with the way they are charged, but that is not a problem with the smaller 40 hp Honda's, so quess will just have to see how long they last. Right now three seasons doesn't seem that bad to me.

And Harvey---Have only the two batteries. Use one to the house at a time except at times when wanting to start the wallas before starting motors. Usually on a extended cruise monitor the batteries and switch between them to the house and for starting making sure one at least is not to far down. Not as much a concern now that we carry the Honda 2000 generator. Without it on our last cruise we would have been in serious trouble when we lost the charge coil on one motor and the other the oil crankcase filled with gas could run only in an emergency for a short while. Later found the cause of gas flowing to crankcase nothing more than a stuck thermastat and cold water.

Jay