Time to Replace Batteries

[KnotYet]

Most watering can be avoided by installing Hydrocaps , if there is room.
Hydrocap |

X2 for the Hydrocaps.
They reduced my battery maintenance to about 3-4 checks per year.

 

[Larry M]

I'm looking at changing out my 2 Deka 8Ds with 6 Trojan J305 6vs. I will have to modify the box but checking Trojan website, they get really crappy reviews. What is your experience or better options?

A question; What about your battery boxes and rewiring? The J305s are 14.09” tall, will they fit in your existing boxes? We changed our 8Ds to Trojan T105s and height wasn’t a problem. When we removed our 8Ds, we upped the capacity and changed to 10 Trojan T105s so my numbers are off for your application but... The batteries were about $1250. To replace all the wiring, lugs and heat shrink the cost was several hundred dollars just for materials. I was able to makeup the cables. If I had to paid someone to make the cables and rewire the new configuration, easily another $1,000. The batteries were the cheap part.

 

[RickyD]

A question; What about your battery boxes and rewiring? The J305s are 14.09” tall, will they fit in your existing boxes? We changed our 8Ds to Trojan T105s and height wasn’t a problem. When we removed our 8Ds, we upped the capacity and changed to 10 Trojan T105s so my numbers are off for your application but... The batteries were about $1250. To replace all the wiring, lugs and heat shrink the cost was several hundred dollars just for materials. I was able to makeup the cables. If I had to paid someone to make the cables and rewire the new configuration, easily another $1,000. The batteries were the cheap part.

I definitely can fit the J305s vertically. I'm shy about 5/16" in width. I may have to rebuild the box which is wood and not a huge project. If I just have to go up it is not problem. If I switch the L & W I can fit by adding a little to the length of the box which might be the easiest. My next thought would be say, if I'm going up 2-1/2"s for the J305, maybe go up more and fit the L16s. Next time on the boat I'll check to see if I'll be blocking anything by doing so. My box is on the engine room floor between the engines. It could be blocking good access under the engines to go 16".

 

[clyde]

hmmm...8D`s are a bitch to handle, i would use 2 6v batts to replane each 8D, and as said, a group 31 for starting...i use 2 group 31`s in paralell for starting my single volvo! lotsa amps! 2 6v`s will fit where an 8D was...tight sqeeze, but i got mine in...clyde

 

[MYTraveler]

Three points above that, IME, are absolutely true:

1) It is easy to kill AGM's by not keeping them fully changed. Running them down completely (as might happen if you lose shore power for a few days) is enough to do severe damage to the batteries' capacity.

2) Golf cart batteries are great (not only because they are designed for deep cycling, but they are easier to lug around than an 8D).

3) A lead acid batter can often be rejuvenated by "equalizing" -- but at 8 years, I wouldn't expect too much.

 

[Beaverlake]

And check out Battery Watering Systems products. Once installed almost no vertical clearance required. Topping off is eazy peazy. Tipped the scales to FLA for me. I’d love to know where Larry. Got Trojan T105s for $125 each! I’m in the PacNW, went with Costco Interstate GC2s.

 

[markpierce]

Last month replaced six AGMs ten years old which no longer would accept a charge. Fortunately, the engine batteries had sufficient charge to start the engine so could make it to the boatyard for replacements.

 

[catalinajack]

Wow, ten years is a long time. My eight Deka golf car batteries are three years old. I will be replacing them at six, maybe seven years old regardless of appparent condition. I do the same with vehicle tires, that is, replace them when most folks would push them another 10,000 miles.

Last month replaced six AGMs ten years old which no longer would accept a charge. Fortunately, the engine batteries had sufficient charge to start the engine so could make it to the boatyard for replacements.

 

[FF]

"What is your experience or better options?"


First is a SOC meter (state of charge) , otherwise you are just guessing.

 

[Jameung]

For your power needs, sticking with the 2 8D and 1 Group 31 AGM batteries is a reasonable choice. Changing the configuration might entail additional electrical work and costs. Opt for reputable brands like Optima, Lifeline, or NorthStar for quality batteries. Consider the battery capacity (Ah) to ensure it meets your requirements. Adding a battery monitor system is beneficial to track the battery's state of charge and health.