Not sure what goes where when charging.

[philtheskipper]

I drained my batteries pretty good by doing a lot of cranking today. Can I charge both of my batteries at the same time without disconnecting them from the boat? If yes how do I hook up the charger? I have 2 batteries with your typical switch(1,2,both,off). I will be using a Sears automatic 10 or 2 amp charger.

 

[Ralph 123]

Re: Not sure what goes where when charging.

Hook it up to one of the batteries and put the switch on All it will charge both. Set the charger for the lowest amprage (2A in your case)so you get a nice long slow charge.<br /><br />About your switch<br /><br />the 1 position connects just the first battery to the system<br /><br />the 2 position connects just the second battery to the system<br /><br />the All position connect them both (in parallel) at the same time<br /><br />How you should be using your switch<br /><br />Prior to starting the engine, the operator would turn the battery switch to the BOTH position so that he or she had the full cranking power of the batteries. Once the engine started, the operator would leave the switch in the BOTH position while powering to the day's destination so that both batteries were charged. Once a sailboat began sailing sans engine, or a powerboat dropped the hook, the operator would (in theory) turn the battery switch to the 1 or 2 position, so that the other battery would be reserved for starting. When it was time to crank the engine again, the battery switch would be turned to BOTH, or possibly to the reserved battery, and the engine would be started. <br /><br />The problem, of course, is that this requires a lot of thought on the part of the operator, who is trying to relax in the first place. The inevitable result is that at some point, the boater accidentally leaves the battery switch in the BOTH position, resulting in two very dead batteries.

 

[Boatist]

Re: Not sure what goes where when charging.

Phil<br />Yes you can charge both batteries in the both position. I would use the 10 amp automatic setting. 10 amps will not hurt any battery bigger than a motorcycle battery. Also with two batteries the current will be split so in therory only 5 amps each. You average car battery today is charged by a 60 to 100 amp alternator so 10 amps is not going to hurt them. There is some risk in putting the batteries in the both position in that should one battery be bad, the bad battery can take all the charge from the charger and also discharge the good battery. For me I charge thru a battery isolator to prevent one battery from discharging the other.<br />Anyway if both batteries are good you can charge in both. I would not leave switch in both when not charging. While in the both position you really have one big battery and if one discharges so does the other. You can charge each battery on it own if you leave the switch set to 1 or 2.<br /><br />I do not know how your boat and batteries are set up. I set mine up so that every thing I need to run the boat runs on battery 1. (Starter, Bildge blower, Bildge Pump, Nav Lights, Compass Horn, Wiper, Trim Tabs).<br />Every thing else is on battery 2. (Depth finder, Radio, Loran C, Gps, 12 volt outlet.<br />I charge thru a battery isolator so only time I would ever turn switch is if starting battery (1) is dead, then I would turn to 2 and start off battery two.

 

[Ralph 123]

Re: Not sure what goes where when charging.

To prevent damage to a fully discharged battery (as you said yours are), the current should be less than 1% of the CCA rating during the first 30 minutes of charge. <br /><br />If left unattended, cheap, unregulated trickle or manual two stage battery chargers can overcharge your battery because they can "decompose" the water out of the electrolyte by electrolysis. Avoid using fast, high rate, or boost chargers on any battery that is sulfated or deeply discharged.

 

[philtheskipper]

Re: Not sure what goes where when charging.

Thanks for the info. The batteries are not totally drained yet. I stopped using them when I could tell that the cranking started to slow a little. Figured I better stop before I added another problem, and charge the batteries.

 

[Solittle]

Re: Not sure what goes where when charging.

A couple of thoughts:<br /><br />1. Use both a volt meter and hydrometer to check state of batteries.<br /><br />2. Check water level frequently and use distilled water when needed.<br /><br />3. Check out a little charger called BatteryMINDer on the web. I have had one for about 6 months & like it so far. It has logic to de-sulphate a battery and can be left on at all atimes.<br /><br />3. Most alternators have a very low output. I will set my switch to 1 or 2 and use that battery on the way out. I then switch to battery 2 for on the way back. I feel that this gives me the best chance of having enough juice from one or the other or both to get home.

 

[philtheskipper]

Re: Not sure what goes where when charging.

Now that I got the batteries charged I know I'm not getting any spark. I see another post in my near future.