Yet another battery question....

[Rocket1]

Hey all-

I have 4 T-105's in our 340 that are about 7 years old. The PO had all of them (plus the starting battery) stuffed in the aft laz, such that the floor of the laz broke. I removed everything, re-glassed the floor back in, and re-installed 2 of the Trojans. The other two ended up in the dock box.

Then in the trunk of my car. For 4 months.

I have brought them into the shop and connected them in series - and hooked them to an inexpensive 12 volt automotive type battery charger. They weren't low on water, and began to "bubble" within 10-15 minutes. The charger doesn't have any type of voltage adjustment, just two different charge rates - 2A and 10A.

They have been hooked up and bubbling for about 24 hours at about 7 amps (according to the charger) and 14.9 volts (as measured with my multimeter). They do not appear to have boiled off a significant amount of water to this point (all plates are well covered)

What are the odds that these batteries still have any useful life left in them, and what step should I take at this point to get that life out of them? They seemed to work fine when they were removed from the boat, but I don't know how much all of the sitting around has detracted from their usefulness.

As always, any input and feedback is appreciated.

 

[anchorclanker]

A lot depends on if the plates are sulfated, and if so, how bad. 7 years is about the average life expectancy of those batteries in a golf car being used every day. But even without use they still deteriorate at about the same rate. They have certainly met anyone's expectations of how long they should last.

You also need a hydrometer to check specific gravity (SG) of the electrolyte, and should have them load tested. But SG doesn't mean a lot either, all by itself. I have seen batteries with real high SG that had no capacity whatsoever, which meant they were heavily sulfated. You can also search the internet, there are some battery rejuvenating ideas out there such as using Epsom salt. I have no idea if it works but the stuff people are saying sounds interesting.

But what they are doing is dumping the battery upside down to pour out the electrolyte. First, the electrolyte is very toxic and should be disposed properly. Second, in the course of its life a battery builds up deposits on the bottom as material falls off the plates. That material is conductive. Dumping them upside down can put a lot of material between the plates leading to possible shorted cells. You know, a lot of what gets reported on the net is what worked. You don't so often hear of the failures or disasters. Thats why we watch youtube.

I guess what I am saying is if they cant pass a load test after 24 to 48 hours of charging, buy new ones and dont look back.

 

[Don S/V ILLusion]

If they are 7 years old, they are on their last legs. Anything you did to exacerbate their demise only aged them further.

 

[Bill Roosa]

If they still have a 13.6ish voltage on them after sitting overnight they still have some life left in them. The age is not so important as the number of cycles and how deeply they where discharged. probably no way to tell except to put them back in and keep an eye on the voltage. If it starts to go south call it quits and start the motor.
I have 4 T-105 and at 5 amp draw they don't get to 12 volts till after around 30 hours. they are at least 7 years old also.