quote:Originally posted by Sea Ranger
[brWhat about when your running, is it a good idea to put the battery switch in the both position(combined), that way your charging both batteries while your running.
I did agree up until this last post, sorry Jim.
I think, I am starting to sound like a broken record but, I have towed a lot of fishing boats in due to “dead” batteries!
First, I do agree that most sport fishing boats really do not have the need or require a “deep cycle” battery? For “most” smaller boats, it is just an added expense and really not that much of an added benefit; however if there is a need for the extended continual discharge of the battery that would be deep cycle. A deep cycle battery is designed to provide a steady amount of current over a long period of time. They are rated by both number of discharges and amps. There are deep cycle batteries with adequate amps for starting - I had three of them on my Diesels. Normal starting batteries are not designed for that deep discharge and they will fail - due to the thinner plates. Only the end-user knows which is best... and I “need” the “deep cycle” and they are rated to start my engines!
Running the battery switch in “BOTH”…
IS A “VERY” “VERY” “BAD” IDEA! Eventually – you will lose!
For those interested, you might want to start here?
http://www.sportfishingbc.com/forum/topic.asp?TOPIC_ID=14902&SearchTerms=battery
By using that “both” switch, you are in fact “paralleling” those batteries. If doing that the batteries “absolutely” need to be matched; to include, type and “age”! Mismatched batteries will indeed create problems, more sooner than later. If you have one battery fully charged and the other battery fully discharged, if that switch is in “both” those batteries “will” equalize, period! Meaning, if both batteries “are good”, you will end up with two batteries half-charged. If you are trolling on a 6 amp kicker, in “best” case scenario, you will have 3 amps “per hour” going to those batteries? NOT GOOD! Also please note: Most electronic starting systems require around 12 volts to start the main engine! More NOT GOOD – you will lose!
In the “both” position again, best case scenario, it will take twice as long to charge two batteries running on your main, as the charging AMPS will be split between two batteries. If the batteries are mismatched (including age), they will accept the charge at different rates and can create an “over charging” condition of one of the batteries. That equates to “bad” battery, period. If there is a “bad” battery, that battery will continue to drain the good battery. Again – NOT GOOD! If there is a “bad” battery, even with the alternator/stator putting out “max amps” it will still try to charge that bad battery and won’t be able to put enough charge to the “good” battery, it will discharge! And again, since they are trying to accept the charge differently that could also create an overcharging situation causing the good battery to go bad. Trolling with one discharged battery in the “both” position - you “WILL” “FLAT OUT” “LOSE!
Depending on how much equipment you are running – “DO NOT” assume any battery is being charged, regardless of that switch position? At an idle, you will be lucky to put 17-amps charge to the battery, using your main. Using a small kicker more like 4-6 amps. So a good question is, how many amps are you using?
Starting out with a “good” discharged battery (meaning something like anchored at night and I run it down) I “start” on the “reserved” “charged” battery – that is the point of having two batteries! I give that one enough time to put the amps back to it. Then I would “highly” recommend switching to the “discharged/dead battery and run off that the “entire” time – hoping to charge it up? And save the good battery for when I need it – someday you “will” need that reserved battery! If you have a 40 amp stator (which I do), and you run at cruise, it should put 40 amps charge back to the battery in an hour’s run. Sorry, that does not define the actual “state” of that battery or the remaining amps - just that you put 40 amps charge to it. That’s not taking in consideration the amps your other equipment is using/used in the one hour run? Two Scotty downriggers use 15 amps/hour - Don’t even think about an anchor winch? I wouldn't even be thinking of turning off my main under those conditions, without knowing I had a "good" battery in reserve!
Regarding the wire size… that really depends on the length of the run. Longer the run – bigger the wire, but there can be too much of a “big” thing. They have charts for that, stay with the charts and you will be fine.