Stupid battery question

[Jeremyvmd]

So I need to replace my batteries this year and I was thinking of how I can make it easier for myself as those 4d's are heavy and (IMO) overpriced. So my idea was to replace each single 4d with either a pair of grp 34 or 31's in parallel. Both of those should give me a little more CCA and RC than my existing setup and be easier to move in and out. Should be relatively easy to modify the wiring for the setup. Has anyone else done this? Is there something Im overlooking that would prevent this from working the way it does in my mind? I'm comfortable with wiring and setting it up correctly as Ive spend more time behind a wire stripper than I really would like to have, but it can never hurt to get a second opinion.

[Jeremyvmd]

the other question is what are other people running for batts in a 28te? I am considering possible stepping down to three grp 31's or a set of 4 34's or 65's. With the genny I don't think im gonna be using too much juice while on the hook or drifting (lights and electronics package...maybe stereo) but allways have the option of turning on the genny...any opinions or ideas?

[djpeewee]

Ever thought of two Trojan 6v golf cart batteries in series? You can then run two sets in parallel. Probably the best bang for your buck. The GC2 form factor is smaller than a group 31. I've done this on a couple of boats and a camping trailer with great success. The Trojan T105's last forever. I got 8 years out of the last set.

[catalina_mike]

8D for the house and a 31 for the engine. We have no built in generator.. I went with AGM because I have enough maintenance to do on the boat already. T105's are great to use and I wouldn't be opposed to doing that. I was at Catalina and wanted a easy like for like changeout. In a slip or on the hard the 6vdc Trojan's gives superior performance in my opinion.

[Nancy]

We have a very simple setup: three Group 27 batteries. One is dedicated to the engine. The other two are in parallel for house use. This configuration holds us for 24 hours on the hook. The fridge is the big draw.

[Jeremyvmd]

Yea going with the 2x batteries from batteries plus, they are agms made by northstar so decent batts and available local to me. Im wondering if a single 31 has the umph to start a peninsular...that's probibly the biggest issue, gonna call peninsular tomorrow to talk to the. I really appreciate all the info and advice so far. I did consider the 6v Trojans, but my idea was it one of the paired up batts has an issue I can allways disconnect it and it's pair can bandaid me through till I get a replacement. If a 6v dies im SOL till I get another one.
Nancy im glad to hear about the 27s workin for Ya. Gives me hope that I might be going in the right direction, just not looking forward to R&R a 130lb battery, so if I can go smaller and get the same juice it's easier on me...

[joreyn]

Check out the Firefly group 31s. New technology prevents sulfation, and allows very deep discharge, so you can shrink the number of batteries. They also recharge very quickly and are not harmed by being operated at a partial state of charge for long periods. Reputedly, they are much longer lived because of all of this, so they are very cost effective.

[Jeremyvmd]

My problem is that the beast requires two batteries for starting. So my starting side is two batts automatically and I don't think a single 31 will replace the ah of dual 27s or a single 4d:/. Looked today and dont think I have room to do what I wabted. Might end up keeping one 4d as a house and swapping in a pair of 34s for starting:/. Gotta scratch my head

[Chris & Dale]

You can create a house bank of 3 and starting bank of 1 turned sideways as I did using Gp 31 AGM's. Was tight and took some "engineering" but was most definitely was worth it. With the 3 Gp 31 AGM's for our house bank I installed a 2000W inverter which will take care of an overnight on the hook, no problem. Here's a link to my installation project writeup/photos. Did all the work myself, again, giving me more insight to the workings of our boat.

viewtopic.php?f=27&t=5951

Good Luck!

[Jeremyvmd]

Problem with that plan is my starting bank HAS to be two. So unless I want to start the boat off both the house and starting bank (as it is now) I have to do a dual batt on the start side and either a 4d or find room for two of sonethin else. Sadly the access to the generator cover latches are part of my problem. That bugger takes up some serious space:/. On the other side I have the water heater, bilge pump and autopilot pump which makes it difficult to stretch the batteries outboard. Im gonna pull the batts and take a better look with the 4ds out and see where I can create some space, but it's not looking good. I'd love to have the setup on a single start then 2-3 batts as a house bank, but I called peninsular and they said it was a no-go

[Beta Don]

What engine do you have that requires a paralleled pair of starting batteries . . . . and where did you read that was a requirement?

Don

[Jeremyvmd]

Peninsular beast. I called the manufacturer and they told me it requires two batteries with at least 800cca each to start it.

[Pedro]

I wonder if that's why if I forget to switch my batts from the 8d house, it cranks slowly and that's when I realize it's not on all which s how I usually crank her over, my 8d is 400ah, and probably 1300cca so it's not quite up to 1600cca recommended by Penninsular,

[Jeremyvmd]

Yea likely the reason. For the time I got to use her this season the twin 24s for starting worked great with the 4d as a house batt. Nice to not have to use the house batt to crank