12 volt deep cycle batteries

You are right to blow the seal but the full name is "Valve Regulated Sealed Lead Acid Battery" The valve is fairly easy to force open by overcharge or too rapid charging, Because it is a valve (pressure release) not much gas escapes but some does.. I stand by my theory.

wa8yxm wrote:

My Theory as to The reason the sealed and starved (Agm is starved) do not last as long is that you can not replace liquid that boils off from overcharging or too rapid charging.

The case is 100 percent sealed. Liquid can not be lost. When it turns to H and O from electrolysis, it recombines into water inside the case.

You have to abuse one REALLY badly to make it gas enough to break the safety seal and vent.

Flooded wet properly maintained and properly charged typically go 7-10 years. Mine went 9

Sealed wet, Mine (Starting battery) also hit 9 (within a month of the flooded wet's) Actually it lasted a bit longer since the chassis was made in August and the body in May.

AGMs. Well mine did not last nearly as long but I ahve heard of them hitting 12 years (Exceptional) usually 5-7 is closer, and they cost more..

My Theory as to The reason the sealed and starved (Agm is starved) do not last as long is that you can not replace liquid that boils off from overcharging or too rapid charging.

midnightsadie wrote:
while in the rv ,but not in use, try puting a battery tender on them, it will pro long there life and you,ll always have a full charged battery.

And if "maintenance free" means AGM type, then being sure that they are fully charged and making sure that they are completely disconnected is almost as good. Over a period of 90 days, it's hard to tell whether they have been on a tender or not......if they are still healthy.

AND.....if you have access to power in your storage location, it is NOT necessary to bring them in from the cold, down to about -30F or so.

Oh and for the original question:
If they are AGMs, at least 7 years unless they are subjected to abuse.....like not being kept charged or discharging completely flat more than once.

Mine are 6 years old and still working great.

I figure seven years minimum, but sometimes get another year or two.

With two motorcycles, two tow vehicles, and two RVs, it pays to be diligent about battery care and maintenance.

while in the rv ,but not in use, try puting a battery tender on them, it will pro long there life and you,ll always have a full charged battery.

They will last about half as long as a battery that is alway charged or gets frequent charging if they are left in a discharged state or allowed to discharge below 50 percent.

A battery master switch that disconnects the battery from the RV's typical parasitic draws like alarms, circuit boards, etc, when in storage will add years to your battery life.