|
|
Member
Posts: 82
Location: Iowa | I recently purchased a 3 bank charger. The best place to mount it was in the back of the boat. I need to ad extensions to the 2 leads that go to the front for the 2 trolling motor batteries. What gauge wiring would you recommend? Cabela's has 15' extensions for $19.99, so I would need 2 of them. I can do it cheaper. I was leaning towards 10 gauge |
|
| |
|
Member
Posts: 1991
| I would go up a gauge just to be safe |
|
| |
|
Member
Posts: 102
| The handy dandy little book of facts and formulas says lamp or extension cord, 2 conductor, is good for the following maximum currents: 10GA is 28 amps, 12GA is 23 amps, 14GA is 18 amps, and 16GA is 13 amps. BUT then it also says that the maximum fused protection for the following is:14GA is 15 amps, 12GA is 20 amps, 10GA is 30 amps.
So, all you have to do is find the max current output for each bank while charging, and pick a fused wire size to match. The fuse book says to correctly size the fuse use 125% of the continuous load current and not to exceed the maximum current carrying capacity of the wire, so 30amps for 10GA is a no-no in their line of thinking.
For a 10 amp/bank charger which I'm guessing you have, I've seen continuous currents of around 13 amps when first turned on, so I'd probably go with a 12GA stranded copper wire lamp cord (or individual insulated twisted coper wire) and a try 15 amp inline standard blow fuse first and if that isn't enough you may go up to a 20 amp fuse. (Your charger should already have inline fuses I'd wager) You don't want a fast acting fuse as when the charger first turns on it may have a slightly higher current for a duration sufficient to trip a fast fuse. You can try visiting the Bussmann or Littlefuse web sites and get the graphs of the time a fuse can support currents greater than the rating before it opens if that helps.
If you want overkill, use the 10GA wire, but I think the 12GA is fine. Remember this is only for the charger, and it has nothing to do with the trolling motor amp ratings. Hope this helps a little bit.
Edited by Almost-B-Good 5/13/2008 7:40 AM
|
|
| |
|
Member
Posts: 82
Location: Iowa | Almost-B-Good, that help alot. I have one more question. I have the Promariner ProSport 20 Plus 3 bank charger. It says 20 amps in the manual, is that 20 amps per bank?
Edited by walleyes4*u 5/13/2008 9:04 AM
|
|
| |
|
Member
Posts: 3899
| that would be 20 amps max on any or all banks. These chargers will adjust the current to the bank that needs the most. If two batteries are fully charged, then most of the 20 amps goes to the last battery.
10 gauge will be just fine, but you could get by with 12.
Edited by Shep 5/13/2008 11:56 AM
|
|
| |
|
Member
Posts: 102
| From what I can tell (and I may very well be wrong) from some of the adds I saw on the net, it appears that your charger distributes 20 total amps among the batteries it is hooked up to, and that it is able to put almost the entire 20 amps into one battery if it requires that much. I would suggest that you wire for a 20 amp draw. If your inline fuses on the charger are rated at 20 amps, then I'd probably use 12GA wire, but if they are higher, then I'd use 10GA.
|
|
| |
|
Member
Posts: 2445
Location: Fremont, Wisconsin | I have seen many boats over the years that were wired with, lets say, less than desirable size as well as quality of wire. If you intend for this to work for many years, use the good stuff, pay the extra few dollars and then forget about it. Don't just use what you can "Get away with", go the extra mile now, it will save you money in the long run. 10 Guage/Marine Grade.
Denny
Fort Fremont Marine |
|
| |
|
Member
Posts: 3899
| If you look at conductor ampacities in NEC, you will see that most wire is derated starting with 14 ga on up. And that derating is based on residential and commercial codes, to provide an extra buffer of safety. Therefore, 14 is rated at 15 amps max, even though a 90C 14 gauge wire in free air may have an ampacity of 35 amps.
That said, it is best to just follow code, and size your wire accordingly. 12 ga for 20 amps will be just fine. If you have 10 on hand, by all means, go ahead. It won't make a difference. Meaning, your charger will not work any better. And yes, marine rated wire should be used for corrsion, and gas and oil resistance. |
|
| |
|
Member
Posts: 82
Location: Iowa | Thanx for the info guys. I will go with the 10 ga. I already have some on hand and will will have to get some more. |
|
| |
|
New User
Posts: 4
| I have a 3 bank charger. 1 bank for the starting battery and 2 for the trolling motor batteries. My question is, my trolling motor batteries are wired in parall for double the current, will my charger charge both batteries equally? |
|
| |
|
| They will charge equally if you hook up the negative to one battery and the positive to the other battery in parallel.
Bob :-) |
|
| |
On-Board Charger ?