Max Depth of discharge

wa8yxm wrote:
One of the reasons I so like GC-2 Golf Car batteries is they are DEEP CYCLE (note I used all caps) Recommended maximum depth of discharge is 50%

Now MARINE/deep cycle (notice how the Deep cycle went lower case) should be run down not more than about 25%. some say 20..

Also DEEP CYCLE do a better job of recovering from an "OH @#$@#" discharge.

Trojan lists cycle life vs. depth of discharge. For most RV users, 6V GC2 cycle life at even 75% DOD is higher than many will experience in a decade. IIRC cycle life is over 500 cycles at 75% DOD. 50% DOD yields 1,000 ish cycles.

Now, even Trojan true deep discharge 12V have a much lower life. about 500 cycles at 50% DOD

Yeah, I am prob going to run this dealer battery low and not really care. Give it an early death and have a good reason to go get 2GC's again.

One of the reasons I so like GC-2 Golf Car batteries is they are DEEP CYCLE (note I used all caps) Recommended maximum depth of discharge is 50%

Now MARINE/deep cycle (notice how the Deep cycle went lower case) should be run down not more than about 25%. some say 20..

Also DEEP CYCLE do a better job of recovering from an "OH @#$@#" discharge.

So not going under 12.1v is a a safe bet for now I guess?

We prob do 10 nights w/o shore power, and 20-25 with it, each season.
If I get over 30 nights - with my weekend warrior work schedule - I am golden.
Might go to Costco and get some 6v's after we get back next week.

The link gobb posted shows this chart:

“Trick is getting them back 100% tip top charged...” Yes, and an adequate solar system with a good controller does that for me most days.

You can discharge 100% (10.5 volts) and accept shorter life. Life needed may depend on use. Say you are part time and and make 10 trips a year and do an 80% discharge 3 times each trip. That is 30 cycles per year and they may still last 8 to 10 years. 240 to 300 cycles. Trick is getting them back 100% tip top charged and many converters cannot do this very well.

Otherwise close to 50% is a more practical goal. But I am not turning my furnace off if I go a bit lower before I can get some charging going.

Full time cycling every day best to stay in the top 40% with periodic extended charges to get back to 100%.

There is no “max depth of discharge.” You trade discharge for life cycles. The less you discharge,the more cycles you get. See https://www.trojanbattery.com/pdf/Signature_Trojan_ProductLineSheet.pdf

Trojan says you can expect 1,250 cycles if you discharge to 50% on its Signature line.

50% for golf carts and true deep cycle lead acid batteries (800 cycles) The batteries need to be fully charged otherwise there may be permanent sulphation and capacity loss. Fully charge and equalize at least every seven cycles.


20% for Si02 (1500 cycles) or 50% (2800 cycles), zero maintenance, no sulphation so no need to charge to 100%. Can be used down to -40 About 1/3 the cost of LI

I've found The 12 Volt Side of Life is very helpful for 12 volt system and battery information.