Battery charging with an outboard

[sailingdog]

While I don't mind wouldashoulda taking a poke at me... Pedcab is brand new to the forum and should be given a bit more space to get settled in...

[WouldaShoulda]

Originally Posted by Cruisingdad

I am certain that Wouldashoulda is only joking with you guys. We must assume it is his attempt at being funny.

Attempt??

Why, you...

Message recieved, sorry pedcab, I didn't realize you were new when I went and busted your chops.

Yours is not a vessel one sees every day around here!!

[sailingdog]

The December 2008 join date might have been a good clue.

Originally Posted by WouldaShoulda

Attempt??

Why, you...

Message recieved, sorry pedcab, I didn't realize you were new when I went and busted your chops.

Yours is not a vessel one sees every day around here!!

[WouldaShoulda]

Originally Posted by sailingdog

The December 2008 join date might have been a good clue.

I am Ass and full of crap!!

[pedcab]

Here where me and my boat come from we use to say that "Excuses are to be avoided, not given arround like candy..."

But that´s OK. I didn´t fell ofended in any way, I just found it a bit odd to take a look arround the site and observing that all of the posts by Woulda Shoulda I´ve read are variations on the theme of making fun out of stuff others write....

But, as I´ve said, I´m not ofended, just amazed

[Saildoggie]

Welcome aboard!

Nugget looks like a sweet little Tri!

[waltsn]

Pedcab, interesting and good idea. I have the same problem you solved, Id bet a lot of others also do but maybe dont know it.

My about 1990 or so Honda BF8 (8 hp) has an alternator 5 amp charging system but NO regulator (I found this out when I had to fix the burned out rectifier from the previous owner). Id bet this is common in the smaller outboards with the 50-60 watt charging systems. Ive played a little with the charging system on my old Honda BF8 and it will continue to dump charge into the battery long after the battery voltage says it is "full".

There is one trip I take every year where I start the trip with fully charged batteries and end up running the outboard a lot and if I didnt know the outboard had no regulator, Id probably damage the batteries. I have flooded wet cell, Id really worry about this if I had AGM batteries.

One minor thing Id point out is that you may want to disconnect the circuit from the battery when the outboard is not in use since it would for example keep a three stage solar charge regulator from topping off the batteries as the charging voltage likely could not exceed 14 volts unless you had a big panel (the circuit shunts up to 50 watts or so to ground when 14 volts is exceeded).

[pedcab]

Originally Posted by waltsn

One minor thing Id point out is that you may want to disconnect the circuit from the battery when the outboard is not in use since it would for example keep a three stage solar charge regulator from topping off the batteries as the charging voltage likely could not exceed 14 volts unless you had a big panel (the circuit shunts up to 50 watts or so to ground when 14 volts is exceeded).

You´re right.

That´s why I have my electrical instalation arranged in such a way that, whenever I´m no t on board, neither the regulator nor none of the electrical appliances on board are connected to the battery leaving only my small solar panel directly connected, in order to keep the cells topped up.

In addition to this, my electrical switch arrangement only lets me charge the batteries whenever the electricl panel is switched off the grid (by means of an SPDT switch), to prevent any current spikes from the alternator to damage my auto-pilot, bidata, etc...

Like this



regards

[waltsn]

My previous owner had installed a switch between the outboard charging system and the battery. I’m guessing that opening this switch while the motor was running is why the rectifier was blown. (you likely already know this but the coil in the alternator makes a big voltage spike when the current is interrupted and it reverse breakdowns the diodes - with damage).

It looks like your circuit may also be fast and possibly low impedance enough to clamp this big spike if you disconnected the charger/regulator from the battery and protect the rectifier diodes. But I’m not sure... just wondering if you had tested this?

When I messed with my outboard, I added about a 100 uf, 100 volt cap on the output of the rectifier. This also clamps the inductive kick spike to safe levels and I can disconnect the alternator/rectifier/cap from the battery safely while the outboard is running (looked at with scope and tested about 100 times with no damage).

[pedcab]

Once again I agree with you and I must mention that I avoid to disconect the switch between the engine and the regulator while the engine is running. I´ve only fitted that to be able to select, prior to starting the engine, whether I want to charge my batteries or not and this way have the hability to keep the regulator from having to be dissipating when there´s no need for it.

Nevertheless, the selector switch which routes the circuit and selects between RUN and CHARGE modes can be switched on and of at will, provided that the ALTERNATOR/REGULATOR connection is not interrupted.

I have not tested it with a scope (for not having one available outside work) but I did test the circuit in use hundreds of times and, like you, I have no reason not to believe that this regulator/dissipator arrangement isn´t able to protect the rectifier from any transient phenomena.

Regards