What to replace my batteries with

[Omatako]

Originally Posted by SV Liberty

I'm actually a little down on the T105. I installed four of them in 2005 while cruising in Mexico, and ended up replacing them in 2007 (also upgrading to six instead of four in the house bank) before going out on a long-term cruise. After about three years, two of the six batteries had crapped out; a bad cell in each.

It's really interesting how different situations have widely different experience. My last set of four T105s lasted 9 full years and if I said I practised good maintenance on them I'd be lying.

I wasn't ready to put a new bank in at the time and a friend was "upgrading" (yeah well maybe it is) to AGM and ditching a set of six T105s that were also 9 years old but still seemingly OK. So I ditched mine, extended my battery box to fit 6 units and ran the used set for another year.

In January this year I replaced them (at 10 years old) with another set of 6 new ones. For me there simply isn't another deep cycle option. YMMV.

[SeaSon]

And of course, you want a start battery for the engine, not a deep cycle.

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[a64pilot]

Originally Posted by SeaSon

And of course, you want a start battery for the engine, not a deep cycle.

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Why?


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[Omatako]

Originally Posted by SeaSon

And of course, you want a start battery for the engine, not a deep cycle.

As mentioned in another post (maybe thread) I don't have a "start battery". I have a house bank of six T105s and then a have an emergency bank comprising two type 27 12v batteries.

Everything electrical on the boat is done by the house bank. If/when the house bank can't do my bidding (soft/flat), I switch to the emergency bank, start the engine, switch back to the house bank and charge it back up. This rarely occurs because I have a solar array (280W) and a wind gen which together replenish most of my daily amps consumption.

[Kokanee]

Originally Posted by SeaSon

And of course, you want a start battery for the engine, not a deep cycle.

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Starting batteries with high CCA ability aren't needed for the small diesels (<100 hp) found in most sail boats. The average deep cycle battery has more than enough cranking power to easily start them.

It's always a good idea to have a separate bank for starting if the house bank is low, but there is no reason it can't be the same 12V deep cycle battery as you have for your house bank.

[DeepFrz]

SailorLady323, most 12 volt batteries are not deep cycle so be careful what you buy. It is possible that the 12 volt batteries that you recommend are deep cycle but not likely.

[barnakiel]

I never use 6V cells for 12V systems.

I would get a plain Bosch or Varta starter battery, car grade. 12V if your starter is 12V.

b.

[Sailorlady323]

Originally Posted by DeepFrz

SailorLady323, most 12 volt batteries are not deep cycle so be careful what you buy. It is possible that the 12 volt batteries that you recommend are deep cycle but not likely.

Deep Friz
You are so wrong. Marine deep cycle. I am a VERY experienced sailor.

[leftbrainstuff]

We use Optima spiral wound AGMs for starting and Trojan flooded lead acid for the house. Both technologies are well proven.

I'm looking at carbon foam as replacements for our 9 year old Trojans. The Trojans are still working well but quite thirsty in their old age.

For only the second time in my career (AGM gell in late 80s early 90s) I can see new battery technologies becoming a commercial reality. I dont consider Lithium to be a cost effective option for house batteries even today.

I suspect that in 5 years we'll have some more options for house batteries. There is lots of commercial interest that will improve performance and lower specific costs in 3 - 7 years.

If your usage is not extreme then you can expect 2 - 5 years from even cheap car batteries. If you look after them.

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[SeaSon]

Deep cycle for house bank, start battery for start.

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[knockabout]

2 ac delco agm 750 cca each still going o.k after 16 months negligible loss so far
bought them from 24 hour taxi service station / easy walking distance from the river we moor in / it's the only brand they have / we hope the cab owners had done their homework properly / they were the right physical size to fit the boxes we didn't want wet acid in the wooden hull

[SSgtPitt]

Originally Posted by MVNoPlans

I have purchased my 6 volts at Costco. They are branded as Interstate and they are about $80 each. It is hard to go wrong at that price point.

I would be very interested to hear how those batteries hold up in the long run. Please check back and let us know. I bought the very best batteries, 225amp T125's and at $200+ dollars each I'm hoping they outperform and outlast $80 batteries by more than double.

[skipmac]

Originally Posted by Sailorlady323

Deep Friz
You are so wrong. Marine deep cycle. I am a VERY experienced sailor.

If you are basing this on the label on the battery be aware that there is often a big difference in the batteries that call themselves deep cycle. Very few 12V batteries labeled deep cycle are built with all the internal features found in 6V Trojan T105s and similar that make them exactly equivalent in function.

[The Garbone]

When we bought our old C27 our batteries were stored in the port side lazerette, just siting in there. We went with Sams Club batteries and bought some marine battery boxes to keep them in ($8 on Amazon). Easy and no worries about that boat hook falling and shorting the terminals.

[puffcard]

Another option that few go with but I did, was to use 12vdc golf cart batteries. They have the same footprint as a group 31, but are 2 inches taller and are 155 amp-hours. Two paralleled at a 1-2 switch gives you 310amp-hours. Mine were made by US Batteries and cost about $125 each. Didn't have to change any wiring, so increased by battery bank by almost 50% for about $50.

I second Optima spiral wound battery for a starting battery. Have one in a VW thats 9years old, after sitting disconnected for 7months while cruising started right up, I was amazed. They are totally carefree.

Good point about a battery box, a crowbar short will kill a lot of external regulators like Balmars. When moving battery leads unplug the regulator.