Battery charger?

Pseudomind

Okay I have a dual battery switch and dual batteries, I have had my boat on the trailer for over the past month and have been doing some electrical connections, the batteries are getting a bit low.  Can I just connect a battery charger across the negative and positive terminals, negative on one battery, positive on another and charge the batteries back up? 

If not what do  I have to do?

On another subject I am taking a new West Marine 580 VHF radio back to West Marine as I cannot get the NMEA 0183 connection to work, my Garmin 741xs list their version of connections and the 580 has their version.    I cannot get GPS position to the radio, though the radio works, and the NMEA 0183 is set up on the Garmin 741xs.  West Marine has no support phone or email for questions, and I am **** tired of playing multiple "What If Questions?" with wiring connections.  I have already also paid a technician to try and wire this and he cannot get it to work.

This should be a simple connection but the manufacture's will not use the same language and markings for their NMEA 0183 and I am tired of mucking with the whole affair.  One will list wires as port one or two + or - while anther does not. Dose a Garmin Tx connect to the radios Tx?  or does the Garmin Tx suppose to connect to the radios Rx?  Then which is positive and which is negative?  Just pure unadulterated BS.  It cost me as much for the tech as the radio alone cost.  Grrrr!

Pseudomind

I do not know why, in neither manual does it mention any thing about the "green" wire?

It has Garmin blue wire to radio yellow wire and radio bare wire to Garmin black.

This below is what finally worked?

Thanks "src" you are correct, it was (CORRECTION)

Garmin blue port 1(TX+) to VHF 580 yellow and the radios Green (RX-) 580 connected to Garmin ground (Garmin NMEA -) But there was no mention anywhere about connecting the 580 VHF green wire to Garmin ground.

I am still trying to obtain a battery charger answer?

bshippjr

They are in parallel with the switch in the "both" position and I believe that connecting your charger to one will charge both. However, your charger will be connected to the boat's electrical system in this configuration and it's possible to damage electrical components on the boat if you hook up the charger wrong or if it malfunctions. A much safer way is to leave the switch in the "off" position and charge the batteries one at a time. A better way is to purchase a dual bank marine battery charger and install it permanently in the boat (following the manufacturer's instructions). Then you can just come home and plug the charger into an extension cord and forget it. A quality charger will adjust to the needs of the batteries and can be left connected whenever the boat is docked or parked.

Pseudomind

Thanks, but here is the rub, the boat will be up on a rack in dry storage and the only time I could plug in a charger would be just a bit prior to use at the departure dock area.  So if I needed to temporarily connect a charger what would be the safest method to do so.  What if I just disconnected the positive lead from the batteries and then connected the charger?