Battery Question re Starting vs Deep Cycle: Brett and others

I have 3 new blue top 34m batteries. They are not the deep cycle variety (D34M).

What are the drawbacks of using them as a battery bank for the stereo. I traded for them, so I can't return and was just thinking of using them until they were no longer good - but, unsure how long this may be because they are advertised as "starting" batteries. The RC is 100 minutes and the deep cycle version is 120. Am I ok using them? Because they are "starting" batteries, how should they best be maintained to prolong?

Also, recs on how to wire the battery bank? I bought a blue sea 9001e, but that's the extent. How should I mount the switch? Pics? Any battery mounts? Seen some cool billet mounts for optimas on ebay.

Lastly, when I do replace, I know Deka is a preferred brand,, but are diehard platinums any good? Specs look incredible.

SSorry for so many questions. Thanks in advance.

Are you planning on using all 3 as your house bank, or will one be for starting? If not, what kind of battery is the starting? This will have some bearing on how you use the switch.

proper maintenance will have the most effect on thier lifespan, but also to the degree you discharge them will impact thier life. You will probably be better served to recharge them with a shore charger of some kind and not rely on the alternator.

The house bank batteries need to be wired in parallel (+ to +/- to -). Ideally, all loads, except the auto bilge B+ need to be wired to the "C" post of the switch. Then wire the + of the main cranking to switch post "1" and the + of the house bank to the switch post "2".

Thank you - just two for the stereo - this would leave me with a spare. There is a less-than-a-year-old interstate in there now - should I just replace it too?

Again, I have 3 and was gonna hook two up as a dedicated stereo bank and keep one as a spare.

Keep in mind that the dual purpose battery is less tolerant of repetitive deeper cycles, a group 34 is an undersized battery as compared to a standard group 24 and that the dual purpose 34 is around 50 amp/hours where a typical flooded group 24 deep cycle is about 65 A/Hs.
As for comparing battery to battery specs, you will usually see a strong correlation between the weight of a deep cycle battery and the amp/hours. If the amp/hour specs are off the chart but the battery doesn't weigh more then I would question the validity.

David
Earmark Marine

I would use the two for the house/stereo bank and then replace the current LAWC (lead acid wet cell) Interstate with the 3rd as your main cranking. This keeps all the same battery technology. No charging issues is if you want to run with the switch in "Both". Or, keep the Interstate as the main, and just run with the switch in either "1" or "2".