battery information

[icarus]

I was doing a bit of research to back up an argument and cam across this web site. http://www.batteryfaq.org/. It is very well laid out and loaded with good information about many kinds and styles of batteries. It goes along well with the NAWS battery information page.

Icarus

[crewzer]

Tony,

Yeah, Bill Darden has done a great job with that site. I've had it bookmarked for years; now you know the source of some of my info! One feature that I really like is that Bill regularly updates the site with new information.

Regards,
Jim / crewzer

[icarus]

Jim,

Both those links should be required reading for anyone who owns a battery. There was one item I questioned him on, and am awaiting a reply. He suggest that you should avoid large % drawdowns of deepcycle batteries (obvious to most of us), but he further goes on to suggest that you should also avoid small ~10% drawdowns as well. I have always tried to run my system with a drawdown of ~10% and then recharge most every day, and generator charge if I get close to 20%. Question is, am I hurting my batteries (4 L16's) by running them this way? I can't really run them down more than 10% without adding some unneeded load(s). Seems kinda silly.

Your (or anyone else's) opinion would be appreciated.


Once again for all your help on so many subjects,

Tony

[crewzer]

Tony,

I saw that comment, but I’ve not seen it anywhere else. I’m not aware of any chemical or physical reason for avoiding discharges of less than 10%. In fact, Trojan says: “Shallow discharges will result in a longer battery life.”

My outdoor hybrid marine/deep-cycle battery may be a good anecdotal example. After two years of RV service, my Interstate SRM-27 spent the last 4-1/2 years powering my outdoor LED lights, where the typical daily discharge ranges from ~2-1/2% to ~5%. It’s finally failing, but 6-1/2 years of outdoor service from this type of battery with maintenance limited to PWM charging and adding water (no EQ’ing), that’s not bad at all.

However, recharging from a <10% discharge appears to be very inefficient. Accordingly, the economically efficient discharge range is ~15% to 25%.

I’ll be curious about the response to your inquiry.

Regards,
Jim / crewzer

[icarus]

Jim,

I too have read on the Trojan site about cycles and depth of discharge. I know of no other technical reason that will damage or short live the battery.

On the other hand, I understand that the last ~10% is the least efficient % to get in. On the other hand it doesn't seem to make any sense to run down to 80% with a unneeded load, when the panels fill it every day from 90%.

I have gone ~10 years on 6 l-16s 2 of them have failed, but the remaining 4 seem to be going strong, so I guess 1 in year 9 and the second in year 10 so in spite of myself, I must have been doing something right. (Didn't even equalize them until year 8 because I didn't know what that was!)

Icarus