Honda BF135 40 amp Alternator/ Charge Regulator?

[Pete in NY]

I am upgrading the electrical system on Miss Pam with a new charger/inverter and will probably be changing out the batteries to new AGM types. After reading about AGM vs Gel vs Flooded type batteries I learned that it is important to set up the new charger for the specific types because each requires a different charge cycle and different voltages in the different stages (bulk, accept and float). This is easy to do with the Link2000 attached to the charger/inverter when charging from shore power or generator connected to the shore power inlet. I also read that with AGM's that a max bulk charge should not exceed 14.2 volts as a conservative voltage to avoid destroying a new battery by over charging. So... shore power/generator charging should not be a problem.

But, how about volts from the alternator?

My question is: How many volts does the 40 amp alternator from the Honda BF135 charge at? Marketing information on the web says that the alternator is an "on demand" type. Will the alternator charge the AGM's in 3 stages at different voltages (not likely) or does it just put out a constant voltage? What is the max voltage if the batteries are say 20-25% discharged? After reading about some member's problems with Optima batteries, I wonder if some of our boat's batteries are being over charged by the alternator on the engine.

Can the output voltage be regulated on the engine or is there another device (like a charge regulator?) that needs to be in place before the batteries to prevent the alternator over charging AGM (or gel) batteries? Will a charge regulator work with the Honda 40 amp regulator?

 

[thataway]

There is a lot of controvsery about AGM batteries. First they are not the same as Gel cells. Gel cells should not be charged at over 14.00 volts (some say they will tolerate 14.10 volts. But when you look at the literature on the AGMS, it will vary from the same as the Gel cells (which generally is not held to be the case) to up to 15 volts. Several manufactuers say that the AGMs should be equalized at up to 15.8 volts peroidically--others say not to.

I have been running AGM's for over 10 years (and I used Gels about 15 years ago--and gave up on them because of the voltage problems). I have not seen any adverse effects (decreased charge capacity or longvity by charging at 14.4 or so volts.) Generally outboards are not as well regulated as some of the 3 stage regulators will regulate an alternator. My Honda 130 is a 35 amp alternator and puts out about 14.3 to 14.4 volts. I have a 115 Yamaha which puts out 14.4 volts and my Suzuki 150's put out 14.4 volts. (44 amps)--I have been running AGM batteries on all of these.

Yes, on the shore power, I sent the chargers to "AGM". AGM's will take a more rapid charge than a flooded lead acid.

I suspect that you could fit a 3 stage regulator to an outboard output--but it is different than a car alternator or marine alternator which is set up for the high voltage directly from the alternator, where as the outboard alternator output goes thru its regulator (probably external, on the engine, so it is already regulated).

I would do like most of us and just use the motor with AGM's and not worry about it....but don't use Gel Batteries.