Outboard Charging and AGM Battery Compatibility

[BobSail]

I'd like to upgrade from flooded to AGM batteries on my H260, but cannot seem to get a definitive answer on compatibility with my Honda outboard's charging system. I've searched the forum archives and talked to dealers and vendors with conflicting results. Can anyone help? I have a 2004 BFP 9.9 D4XRT with electric start and tilt. I've been told it has a 12A regulated alternator, and the manual says it is capable of charging lead acid batteries, but does not go into any more detail. The manual's schematic does not provide output specifications. The battery vendor says maybe, maybe not and suggested I contact Honda. Honda referred me to the dealers for help. The person I contacted at mine didn't know what an AGM was, but said it should work just fine(?)The boat also has an independent AC(shorepower)charging system that can be converted to AGM. Thank you all in advance for any thoughts you may have!

 

[Corky]

Interested also

I will be interested in the responses as I am thinking about changing my motor to just what you have. How long of a shaft did you get, 20" or 25". In genral hoe do you like this motor and is the tilt necesarry due to the weight?ct

 

[Reudi Ross]

Yes

It is compatable with AGM's I have been using Concorde AGM's with nissan and honda outboards for years. Concorde recommends using the flooded battery setting for charging. Concorde marine batteries are sold under the "lifeline" label. Good choice.

 

[Pete]

AGM specs

The advantages of AGM batteries are no maintenance, sealed against fumes, hydrogen, leakage, or non-spilling even if they are broken, and can survive most freezes. AGM batteries are "recombinant" – which means the Oxygen and Hydrogen recombine inside the battery. These use gas phase transfer of oxygen to the negative plates to recombine them back into water while charging and prevent the loss of water through electrolysis. The recombining is typically 99+% efficient, so almost no water is lost. Charging voltages for most AGM batteries are the same as for a standard type battery so there is no need for special charging adjustments or problems with incompatible chargers or charge controls. Since the internal resistance is extremely low, there is almost no heating of the battery even under heavy charge and discharge currents. AGM batteries have a very low self-discharge rate (from 1% to 3% per month). So they can sit in storage for much longer periods without charging. The plates in AGM's are tightly packed and rigidly mounted, and will withstand shock and vibration better than any standard battery.

 

[BobSail]

Corky: we like our Honda 9.9 outboard

We have the extra-long shaft, which is listed as having a 27" "transom height". You can download operator manuals with specs from Honda's included link. We really like the motor. It has electric start and remote pedestal controls. The only downside is lack of a manual choke (electric starts have autos). It is a finicky cold starter, which might be managed better with a manual choke. After it's warm, it'll start with ease. On the 260, the electric tilt is a joy. Once the sails are up and underway, it's a flick of the switch to raise it out of the water, which can be done without taking your eyes off your course, or hand off the wheel. Likewise, if you need it quickly, it can be lowered with ease. Kind of like automatic transmissions and intermittent wipers: once you have 'em, you'll never go back!Thank you all for your input!