Trojan Batteries

[Paulus]

After 7 years I have to replace my 4 T105 batteries. Trojan batteries are available in the following, all are the same dimensions.  Two are in fair condition and 2 are in poor condition.  I had them tested at two separate shops.
T105  225 Ah  price $145
T125  240 Ah  price $165
T145  260 Ah  price $195
Would it make any sense to go with the higher Ah?  Would appreciate any feedback or input.  Will need these in the spring time.
Thanks,
Paul

[Stu Jackson]

Paul, it all depends on your energy budget.

[mainesail]

After 7 years I have to replace my 4 T105 batteries. Trojan batteries are available in the following, all are the same dimensions.  Two are in fair condition and 2 are in poor condition.  I had them tested at two separate shops.
T105  225 Ah  price $145
T125  240 Ah  price $165
T145  260 Ah  price $195
Would it make any sense to go with the higher Ah?  Would appreciate any feedback or input.  Will need these in the spring time.
Thanks,
Paul

Paul,

The T-145 is actually about 1" taller than the T-125 and the T-105. It always makes sense from a battery longevity stand point to go with the largest bank you can fit. From a longevity perspective you can never have a bank that is too big. A larger bank will be discharged less meaning more cycles. If your average load remains largely the same a larger bank will also yield some Peukert benefit which also leads to shallower discharges. This of course has to be balanced with "cost" so bigger may not always be best depending upon your budget..

The Duracell EGC2 from Sam's Club is a Deka / East Penn battery and costs about $84.00 each and has 230Ah's. These are excellent batteries for a LOT less money than a Trojan...

I suspect that with two batts in "fair" and two in "poor" that you may have had your bank improperly wired and two of the batts saw more use than the others taking them out of balance.....

[Paulus]

This was a load test.  They were wired according to John Gardner's post here on the site, 7 yrs ago.  Last summer was the first time that I noticed a change in the amount of time we could stay at anchor.  I check the batteries with a hydrometer, each cell every two weeks.  Last summer was the first time that I noticed a variation in the cells.
Paul

[mainesail]

This was a load test.  They were wired according to John Gardner's post here on the site, 7 yrs ago.  Last summer was the first time that I noticed a change in the amount of time we could stay at anchor.  I check the batteries with a hydrometer, each cell every two weeks.  Last summer was the first time that I noticed a variation in the cells.
Paul

Paul,

I would actually advise against checking the SG so often. You can cross contaminate the cells and allow for other contamination to enter every time you open them. Once or twice per year should be more than sufficient. As for the wiring I searched for John's article and only came up with this photo:



In that photo the two large red wires should be on the opposite battery from the neg lead. In that photo the batts do not appear to be wired correctly but I don't know what the red wires are for..

When wired like this the batts will stay in better balance:

[Paulus]

Thanks for the info on the hydrometer.  Will keep this info on file.  John send me a 6 page article on this upgrade by email.  The pic you  are looking at was on his own boat.  I used the second diagram as in your post.
The 2nd diagram I have in my boat book, send along with John's email and I believe it was your post originally.
thanks,
Paul

[Paulus]

Sorry, the post originally came from Casco Bay, ME   CS-36T
Paul

[stevewitt1]

Mainesail:

I admit that I'm not the coldest can in the six-pack, but usually not the warmest either.
I just want to clarify your schematic shown in the second as well as the photo too.
In the photo I see a jump (parallel) red wire at the top of the photo and a red Parallel jumper in the lower schematic too.  Then I am to derive this photo and schematic represent only one side of a two battery power switch?  There are 4 6V batteries that a series two each then the two paralleled to provide a total of 12V with large capacity but all on the SAME bank?

There must be another battery somewhere if the AB Battery switch is used, correct??
Steve
Visit us at www.ocontoyachtclub.com

[Paulus]

Steve, that is correct.  I do have a separate starting battery.
Paul