Save my Batteries!

[ayurtdweller]

Thanks for the great forum!
I would like some suggestions to help keep my batteries from going to the scrap yard prematurely. They are 1 year old now.
Measured by Kill A Watt, my usage is 800 watt hours/day.

Here's my system:
2 x 250 watt mono Vmpp 31.1, Impp 8.05a. Wired series. http://www.altestore.com/store/Solar...0-Frame/p9879/
6 Trojan T105re @ 12v, 675 ah
TRACER 3215RN mppt Controller 30A 12V 24V
* Maximum Battery Voltage: 32V
* Max. Solar Input Voltage: 150VDC
* Max. PV input power: 12V/ 390W 24V /780W http://www.amazon.com/TRACER-3215RN-.../dp/B008KWPGAE

I am having difficulty keeping the batteries above 12.3 by the AM. I feel this is too deep and I am wondering if they are truly getting a good charge during the day. They seem to drop down to 12.5 right after sun down with an 80 watt load on them for 15- 20 minutes. Is this normal or OK?

I face South, 190* and the panels are unshaded 100% for about 5-6 hours/ day this time of year.

Area Code 03601. Acworth, NH

Batteries routinely get up to 14.2 , but I can't seem to obtain 14.6 for very long.

I believe my controller can handle another panel but I don't want to throw more PV at it unless it will help.
This controller has never run an equalize charge as far as I know. I am not even sure how it decides when to run equalize. I have not tested with hydrometer.
I currently have no other means of charging.

Whaddyathink?
More PV? More Battery? Better Controller?
Thanks for suggestions and questions.

IMG_0481.JPG

[ChrisOlson]

Batteries routinely get up to 14.2 , but I can't seem to obtain 14.6 for very long.

Well, what ever it is you go going there, you're not getting your batteries to Absorb V. Seems to me, without looking it up, the T-105's proper absorb voltage is around 14.9-15.0 volts and they have to be held at that voltage until the amps to them drops to 14A or the specific gravity of the electrolyte is 1.275. Failure to achieve that will result in sulfating them (if they aren't already).

[boostinsteve]

Looks to me like too many parallel strings, and not enough pv. Try charging one 12 volt bank at a time. The 3215rn isn't the best charge controller either, as that was what I has before. You can't really change any setpoints to get the correct charging cycles for your batteries. I stepped up to a classic 150 lite and love it.

[Sunking]

Well simple math immediately signals a few problems.

First you have a 30 amp controller with 500 watt PV power input. 500 watts / 12 volts = 41 AMPS.

Second minimum charge current required for a 675 AH 12 volt battery is C/10 or 67 amps. To generate 67 amps of charge current on a 12 volt battery is 67 amps x 12 volts = 800 watts, and a 65 amp MPPT Charge Controller.

So first thing is replace your charge controller, it cannot handle 500 watt input on a 12 volt battery.

With only 500 watts of panels, you can only handle 4 of the Trojan T-105's, loose two of them or come up with a 65 or 80 amp MPPT charge controller and 800 watt minimum panel power.

Lastly the biggest error you made is EVERY OFF GRID BATTER SYSTEM REQUIRES A GENERATOR and a AC CHARGER. A genny is a must have item so you can apply an EQ charge maintenance charge, and provide power on cloudy days. A solar system cannot EQ a battery, only a genny or commercial AC power can apply an EQ charge of 12 to 24 hours.

[PNjunction]

I would recommend raising those panels at least a few inches above ground to keep ground-clutter from shading the bottom cells.

Usually this happens when you are not looking, and of course when you go out to check, it has blown away.

Put at least a few inches of clearance between the panel and ground. Heck, I've seen tall blades of grass seriously degrade a panel when the angles are low and long in the winter on a true ground-mount that touches the ground.