Bear with me:
2003, Donzi 33ZX, 198 hours on motors and boat. dry stored both batteries to off.
Scenario, first time out for this year was today, CLICKITY CLICKITY in the water at my marina.
I am Navy officer and NEVER home, we are at war, 12 hours total on the boat the last two years. Never an issue until my last nice to have upgrade in 2006, added a sub amp, which the Sony amp tells to turn on, I have checked it and do not believe it is my power draw on my batteries.

Batteries replaced last summer, when two like them failed, ($250 batteries from Advance, the blue Marine ones) they are supposedly the high end ones vice regular old batteries, so they are new, stamped March 2007. The amps wire straight to the battery, 10G wire, but do not turn on unless I throw the breaker for the stereo. One wire from the stereo tells them to turn on.
Is it true that when a good or new battery drains so low from sitting, only a good old fashion charge will bring them back?
The boat started easily with a jump box (best damn $70 I ever spent). And she rocked otherwise once I got her started.

I know, not the best post I ever made, but I am turn key EVERY time for almost 10 years in 3 stock Donzi's, yet since I added the second amp for the sub I have not.

Thanks in advance.
Bryan Tuvell

Not clear on what batteries you presently have. Are they Optima (spiral wound- look like a six-pack?) If so, I hear repeatedly that they are damaged by full discharge. I buy Wal Mart group 27's every spring and give them away in the fall. Never been stranded by a battery problem. Batts don't like sitting- and neither do I.

There are three types of batteries- crank, deep-cycle and combo. You should only ever use crank batteries in main battery applications. Deep cycles and combos don't generally have the output capability to crank well- or for long. If you have a big stereo, you need a dedicated deep-cycle battery on an isolator. Then you can run at idle and not damage the battery/be able to start. You also need to check your system for current drain- something is pulling your batteries down. Put a test light in the line and start pulling fuses if it lights up.

Most systems have at least one circuit before the battery disconnects- the bilge pumps. I've seen others added in. These can burn your boat down. Pull the switches and see what's tied into the supply lugs. Also look for a pigtail on your + battery cables. Usually a 12ga. wire.

Never leave batteries in your boat on layups. Take them down the basement and keep them on a trickle charger over the winter. If you want to use a maintenance charger in the boat, don't use a $39 one. Get a good marine charger- the cheap one's will also burn up your unattended boat- and take all the one's stored around it with it.

"Most likely" discharged from sitting so long.

It sounds like a new set of batts is in order.. I also am not really a fan of the optima stuff. I dont see the value in it.. I would rather the conventionals, from my experiences with our shop they seem to last just as long & take the same abuse if not more than the optimas... Just my 2 cents.. Jamie / Lakeside Restorations

The stereo will put a small power drain on the batteries. the constant power is always still hooked up unless you had wired differently. If you don't disconnect everything from the batteries, then you should charge them once a month or so. I suspect they sat completely drained for too long and are now bad.

yes, batteries sitting for all that time will discharge, can you install a floating battery charger that will monitor the charge levels and charge as needed ? is it posible to plug the boat in somewhere ? even those battery tenders would work..just something that charges, monitors and shuts down, Rob

Thanks for the input, leaning on the they sat to long theory, once I got a good charge on them they were still sharp the next day.
Yes they are the blue marine Optima's, new last summer. The last set I had at 18 months when tested one was bad and the other caught fire!
After this set I will return to the Interstate Marine batteries, I know a friend who is a dealer.
Thanks
Bryan