Changing Batteries Monster Bat's to Trojan T-105's

[DayDreamer41]

Looking for some professional input as to how this looks, I am replacing my 3 x 4D's with 6-Trojan T-105's. The current setup appears to treat all 3 4D's as a single bank, with only (1) fuse on the bank, trouble is there are (2) batteries under the Nav Station seat and the other is under the cabin sole next to the Nav Station with interconnecting cable approximately 3' long, so I am thinking that I need a fuse on the positive side of the batteries under the cabin sole to protect the interconnecting cable back to the Nav Station. Connecting cables will be 2/0 tinned copper cables.

Please don't hesitate in providing your comments and ideas

Mark

 

[Maine Sail]

That is a perfectly fine way to wire up series parallel port/starboard banks. The only issue you may have with banks under the sole are intrabank temp differences..

 

[DayDreamer41]

Thanks MS, not much I can do about the bank arrangements as this is the method the manufacturers left for me.

The charger is a xantrex Freedom 20 with the temp sensor currently wired to the positive terminal of the battery under the cabin sole, would not this temp sensor be better on the bat's under the Nav seat, as I would think this area would get warmer than under the cabin sole?

 

[Allan12210]

A question I have is: Does your energy budget require 3 pair of batteries? Can you get by on 2 pair? I see your shore re-charger capacity (20 amps) is like mine and I only have 2 pair of batteries. I understand 10% of capacity to recharge capability is a desirable target. So, in my case I am at about 5% charger current to battery bank. It seems to work ok for me, but the boat is at the dock 90% of the time, so I do get a slow recharge should I run the batteries down low. Just curious as to your needs and capacities.

Thanks.

 

[DayDreamer41]

The boat is equipped with a 100 Amp charger as for house requirements I could get what I need from 2 pair, but the vessel being equipped with a windlass and a bow thruster which are both amp hungry devices I am prone to stick with the original arrangement as provided by Hunter, granted the batteries which were installed by the OEM are not near the capacity of the T-105's which will have the combined Ah's of 675.

 

[Maine Sail]

A question I have is: Does your energy budget require 3 pair of batteries? Can you get by on 2 pair? I see your shore re-charger capacity (20 amps) is like mine and I only have 2 pair of batteries. I understand 10% of capacity to recharge capability is a desirable target. So, in my case I am at about 5% charger current to battery bank. It seems to work ok for me, but the boat is at the dock 90% of the time, so I do get a slow recharge should I run the batteries down low. Just curious as to your needs and capacities.

Thanks.

The Freedom 20 is a 2000W Inverter / 100A Charger

 

[Maine Sail]

Thanks MS, not much I can do about the bank arrangements as this is the method the manufacturers left for me.

The charger is a xantrex Freedom 20 with the temp sensor currently wired to the positive terminal of the battery under the cabin sole, would not this temp sensor be better on the bat's under the Nav seat, as I would think this area would get warmer than under the cabin sole?

Temp sensor goes on neg terminal of battery with most potential to get warm...

 

[DayDreamer41]

Maine Sail, I have read that instruction in your writeup's, mounting the temp sensor on the negative terminal is contrary to the manual for the Xantrax charger?? will it provide a better temperature guide for output amps of the charger if mounted on the negative terminal?

 

[Maine Sail]

Maine Sail, I have read that instruction in your writeup's, mounting the temp sensor on the negative terminal is contrary to the manual for the Xantrax charger?? will it provide a better temperature guide for output amps of the charger if mounted on the negative terminal?

The Xantrex manual is wrong and grossly out of line on this. Would not be the fist time nor will it be the last with Xantrex, pretty much par for the course with them. You want a real treat, read the Echo Charger manual.... D'oh....

You can't fuse a temp sensor or it won't sense temp accurately. Anything connected to a positive battery terminal must be over-current protected thus the temp sensor goes on the negative terminal. Optimal location for a temp sensor is on the side of the battery, but most charger manufacturers don't send sensors designed for this. Next best spot is on one of the lead terminals and seeing as you can't fuse a temp sensor, then the negative terminal is the only location a temp sensor can be mounted.

The temp sensor does not dictate what the amperage will be. It tells the voltage regulation circuit the temperature of the battery and the regulation voltage is then moved either down, if hot, or up, if cold, to keep the batteries within its acceptable safe charging voltage parameters.

Charge current flowing into the battery is dictated by the batteries SOC (internal resistance) and terminal voltage.

 

[Allan12210]

The boat is equipped with a 100 Amp charger as for house requirements I could get what I need from 2 pair, but the vessel being equipped with a windlass and a bow thruster which are both amp hungry devices I am prone to stick with the original arrangement as provided by Hunter, granted the batteries which were installed by the OEM are not near the capacity of the T-105's which will have the combined Ah's of 675.

Thanks for the clarification. It will be nice to have all that capacity.

 

[DayDreamer41]

Great explanation MS, I guess I have to retake your class having mixing up voltage and amperage when dealing with outputs from a smart charger, but if its any consolation I did understand the principals.