Using Electrics while battrey is not charging . . .

ramio · August 12, 2008, 21:31:57 CET

Hi Guys, This topic sort of confused me. First to gazzetta, I would like to point out that usually it was common practice to connect VHF direct to one of the batteries trough an in-line fuse. This for safety so that even with all electrics disconnected you still have power to VHF. I suggest one uses the main motor battery.
Re charging current. Please identify between the starting curren of battery , and the charging current.
Starting current is the max current the battery can usually give for a short time to crank engine.
The charging current needn't be so high. The more the charger produces the shorter the charging time. Usually batteries that have been used to start an engine would be back to near full charge from alternator in a short time. Current may start high but will drop as battery is charging. Under normal usage on our type of boats, the alternator is supplying enough current to charge batteries, and supply the boat's electrics.
There are alternators which have two outputs hence charging two seperate batteries without the need to connect them together. On my boat, I have two engines each with its own staring battery. Through the service switch I can select which battery I use for all other services apart from engines. With the same swithch (on both) I can parallel the batteries for more power, or to charge both with one alternator. Have been using this syestem for 12 years. Even with one alternator down, I can still run all

skip · August 12, 2008, 21:41:17 CET

Mario, ever come across this 120amp limit that is being referred to?

On my dads boat we had the VHF wired direct, but I didnt do it on my boat as the power connector on the center console is exposed to the elements and I was worried if it rains with the VHF not connected (I dont leave it on the boat!) it might cause a short, or drain the battery. For now I have taken a further precaution of putting plastic bags around the exposed connectors that go to the VHF and the GPS etc.

fishfinder · August 15, 2008, 07:37:51 CET

Skip, Inboard engines have a much bigger alternator and there are some which was 2 alternators of 220Amp. Only outboards have 120Amp alternator and I believe that the reasone for not going to a bigger is because of the size. I still manage to charge all the 4 batteries that I have but as I said 1 by 1 is what the agent persisted that we have to do.

skip · August 15, 2008, 16:03:54 CET

You have a 40amp alternator on your Suzuki 115

http://www.suzukimarine.co.uk/outboards/tech.php?ref=DF115TL&y=07

The_Gaffer · August 15, 2008, 17:08:50 CET

If you go to www.westmarine.com, under batteries and chargers, there is an article how to wire up a circuit to charge more then one battery for single engine boats. I followed the advice of this article and in that way I charge my 2 house batteries together with the cranking battery on my boat.

fishfinder · August 16, 2008, 12:29:28 CET

Yes skip, I have 40amp on my 115.

ramio · August 16, 2008, 18:29:45 CET

Skip never actually heard about the 120A limit, but again I never worked on outboard motors. Re VHF/GPS connectors, I wouldn't wrap plastic bags around the connectors as condensation will do more damage trapped as is, in bag. What I suggest is either spray very regularly with water repellant oil, or better still get a can of "All Defend" from the MA Fra range and spray the connections once a season. Its a hell of a protector on electrical connections. I used it initially on my soldered electrical connections 12 years ago. They are still solderable. My connections for VHF lasted 12 years.

Gaffer, those set ups you mentioned used to charge more than one batteries at a time usually use Diodes. There is a volt drop across the diod that stops the battaer from charging short of about 1.4v. Anybody with an electronic background can explain to us better.

skip · August 16, 2008, 18:36:48 CET

Thanks Mario, where can I find All Defend locally?

Can concur about the voltage loss over a diode, hence if you use a combiner you get the same effect without the voltage loss.

Gazzetta · September 01, 2008, 09:23:44 CET

Do you know shops who sell split chargers ?
Eretric ? Caruana ?

Chris

ramio · September 01, 2008, 17:59:03 CET

Skip, I once got a twin output charger from eric once. These chargers usualy take an output from two seperate windings, hence no loss of voltage. I'm sure he still stocks them. If you have questions to ask on the subject, he is the man. Ask for eric at the shop, he'll tell you.
Re All defend, not all stock it, but check with petrol stations who stock armourall. I thinl that is the make. Will check exactly next time down the garage.