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Old 23-09-2011, 01:06   #1
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Trojan Six Volt Batteries

Ok, I'm confused. Why is it that when I look at the amp hour specs for 6 volt batteries , they are so much higher than the 12volt batteries. My boat has 4 6volt batteries in it now , and I think they are about 8yrs old. I'm thinking why mess with something that seems to work. Thinking about replacing them with 4new t125batteries. This looks like about the least expensive solution. All the new agm and other fancy batteries are about twice as expensive. And my charging system is setup for the 6volt stuff now. When calculating amp hrs at 12 volts , do I just divide by two ? The t125 says it is 240amphrs . Does this mean 4of them should be about 480 amphrs at 12 volts ?
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Old 23-09-2011, 02:00   #2
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Batteries in series , add the voltage, same capacity. Batteries in parallel, same voltage , twice the capacity.

So two 6v in series to give a 12 volt system. The 12 capacity is the same as the individual 6v battery capacity.

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Old 23-09-2011, 02:11   #3
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Re: Trojan 6volt batteries

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Originally Posted by Svsilvergirl View Post
The t125 says it is 240amphrs . Does this mean 4of them should be about 480 amphrs at 12 volts ?
Yes 480 AHrs
I would stay with the 6v batteries.
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Old 23-09-2011, 02:11   #4
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Quote:
Originally Posted by Svsilvergirl
Ok, I'm confused. Why is it that when I look at the amp hour specs for 6 volt batteries , they are so much higher than the 12volt batteries. My boat has 4 6volt batteries in it now , and I think they are about 8yrs old. I'm thinking why mess with something that seems to work. Thinking about replacing them with 4new t125batteries. This looks like about the least expensive solution. All the new agm and other fancy batteries are about twice as expensive. And my charging system is setup for the 6volt stuff now. When calculating amp hrs at 12 volts , do I just divide by two ? The t125 says it is 240amphrs . Does this mean 4of them should be about 480 amphrs at 12 volts ?
2 batteries 3 cells each battery = 240 amp hours. ( the 6v have more lead and therefore better capacity with only 3cells. You'll notice one 6v is close to 1 12v with 6 cells in weight.). So yes you could go to 480 wired correctly. Where does your starting battery fit in?
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Old 23-09-2011, 03:31   #5
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Big, well designed and proven, lumps of lead...

I have Trojan T105's in Boracay.

I don't know what it is about the Trojans. Some bits of kit you only have to breath on them the wrong way and they break.

The T105's just keep on keeping on...
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Old 23-09-2011, 07:11   #6
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Re: Big, well designed and proven, lumps of lead...

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I have Trojan T105's in Boracay.

I don't know what it is about the Trojans. Some bits of kit you only have to breath on them the wrong way and they break.

The T105's just keep on keeping on...
Amen!
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Old 23-09-2011, 07:35   #7
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Re: Trojan 6volt batteries

As with most tings you get what you pay for!
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Old 23-09-2011, 07:50   #8
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Re: Trojan 6volt batteries

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As with most tings you get what you pay for!
I would go so far as to say that where boats are concerned, with most things you DON'T get what you pay for!

Trojan T-105's seem like a very welcome exception to that rule. You can pay an awful lot more for batteries...
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Old 23-09-2011, 07:58   #9
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Re: Trojan 6volt batteries

Unlike a 4D or 8D... a normal human can lift a T 105
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Old 23-09-2011, 08:49   #10
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Re: Trojan Six Volt Batteries

I spent the $ for four T-105 in the spring. After a summer on the boat I am glad I did. You are in Oregon also. I got the best price at ABE in Portland.
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Old 23-09-2011, 09:15   #11
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Wow thanks for the input. My starter battery is a regular 12 volt battery , and there are two banks of 2ea wired in series 6volt batteries. Only change I was considering was maybe replacing the 1-2-both switch with an echo charger relay or something similar. I need to dig a little deeper into the way the po wired things. She has a 100 amp alternator with an external regulator . Charges both the house and start battery , regardless of switch position . Has a separate 120volt charger and a 2000 watt inverter . Is there any advantage to having a charger inverter ? Adding some solar is on the horizon . There was a single solar panel wired directly to the house bank , not thru any controller or anything . The solar panel is a kyocera 48 watt 16.7 volt panel . This doesnt seem to be anywhere near enough solar. Guess the po put it on the boat while it was on the hard in Mexico for a while , just to keep the batteries up , while nobody was using the boat
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Old 23-09-2011, 09:18   #12
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Oops , forgot to ask , any reason everyone seems to go with the t105 instead of t125 ? Not much difference in price , and the t125 has better capacity?
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Old 23-09-2011, 09:28   #13
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Re: Trojan Six Volt Batteries

silvergirl., are they same dimensions??
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Old 23-09-2011, 09:37   #14
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Just a smidge taller zee , but all my batteries are under a seat in the nav station , plenty of room for a taller battery.
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Old 23-09-2011, 09:47   #15
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Re: Trojan Six Volt Batteries

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Just a smidge taller zee , but all my batteries are under a seat in the nav station , plenty of room for a taller battery.
in some boats there isnt room for the extra bit--my ericson couldnt fit anything taller than the 105s.... my formosa can fit godzilla..... but i have costco golf cart ones similar to 105s with a 10 yr warrantee.
friends use sams club golf cart batts with excellent results....
the costco ones were almost 2/3 the price of trojans. so far, so good, but i only bought 'em in march, 2011.
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