AGM vs Flooded batteries

ldiorio

i have a quote from Northern for a solar system Kocera 250 watt panels .a magnum 48 volt inverter and Trojan L16re 370 AH batteries
since i am planning to install the batteries in my cellar and concerned with the gas issue--what would be a comparable AGM battery to the L16RE--
can someone explaain pros and cons using both in a solar application

BB.

Have you managed large battery/off grid before?

How sensitive are you to costs if something goes wrong with a battery bank (cells go bad, over discharging when kids leave everything on, electronics fail and over/under charge batteries, etc)?

-Bill

mike95490

AGM batteries can be a very expensive lesson in system management. And they still need the same vent requirements as flooded, because as they age and start to die, they can vent hydrogen gas just like flooded. But you don't get the daily acid mist.

CALLD

I believe AGM batteries are becoming the bridge between old school Flooded Lead Acid and Lithium technology. There are now even Enhanced AGM batteries that outperform the best FLA batteries (Google search "Lead Crystal Batteries"), they can even be discharged to 100% repeatedly although they are expensive...

The traditional belief that AGM batteries aren't cost effective versus FLA is losing traction nowadays. China is starting to produce some very cost effective deep cycle AGM batteries that are steadily putting Western produced FLA batteries out of competition. The biggest hurdles are perhaps import duties.

I have a pair of SonX 12v260AH (Re-branded Ritar deep cycle VRLA) batteries, priced at approx. $300 US, they are good for 800-900 cycles to 50% DOD. You do the maths... Had them for 1 year now and they are performing better than the day I installed them.

I prefer AGM's over FLA for the following reasons in order preference.

1) Low internal resistance, very high energy efficiency.
2) High rate performance, low polarization losses.
3) Fast charging, low self-discharge
4) No maintenance
5) No acid mist/non-spillable
6) Aestheticaly pleasing

Some minor drawbacks of AGM's

1) Low tolerance to over-charge
2) No SOC checking by SG
3) Difficult to equalize series cells that have become unbalanced.

softdown

Time and again, I read of people, especially newbies, killing the battery bank due to one simple mistake. If people are asking questions about various battery technologies, I tend to assume they have less than five years of experience with solar. That is why I default to "buy less expensive lead acid batteries the first time."

There are 100 ways to kill a solar battery bank. For many of us, that expense represents several years of disposable income.