Solar Power Off-Grid Battery Bank Testing - Discharge

A simple capacity test on a 450 amp-hour battery bank. The results should scale for larger loads and capacities. My batteries are Trojan T105s.

Category:

Science & Technology

Tags:

• solar
• solar panel
• pv
• pv panel
• charge controller
• sun
• sun power
• photovoltaic
• solar energy
• kllawatt
• solar boost
• solar boost 50
• blue sky
• blue sky energy
• minnesota
• engineering
• watt
• trojan
• trojan t105
• battery
• batter bank
• power
• inverter
• off-grid
• amp-hour
• watt-hour
• capacity
• flooded lead acid
• trimetric

[TheKilog69]

Nice job on all of your testing all diffrent ways.Having watched all this I,m trying something new.I just got 2-90watt sopray mono panels that match the 1 on top of my tracker.I,m am building a new improved tracker for these 3 macthing panels.I will the hook them to a single 300 watt GTI,and go full time that way with this build,i think from what i have learned from your tests this could be a wise use off power,as ihave plenty to recharge my daily use of 1.25kwh thru my battery,&Inverter.TKS G.W

[Fearlessthinker]

@TheKilog69 Can't wait to see what you come up with! Thanks for the comment.

[ottopuppy]

What a great Video, this has answered a lot of my questions i have on my solar system!!

Keep up the good work.

[Fearlessthinker]

@ottopuppy You're welcome. Good luck with your system.

[electrodacus]

Edge of cloud effect was interesting first time I here about thanks for that.

As for the battery capacity that is specified in case of those battery for a 20h discharge on a 10h discharge capacity will be smaller the discharge efficiency is decreasing.

Same go for charging efficiency the higher the power the lower the charging efficiency.

I will use LiFePO4 it seems more expensive but is not 2000 charge cycle at 80% discharge and better charge, discharge efficiency so I need about half. 

[Fearlessthinker]

@electrodacus I'm not sure what causes that cloud effect. It's amazing. I wonder if it can be artificially produced in some way. Thanks for the comment.

[lpdavisakgto]

Just installed 3600 Watt sharp s and outback inverter and 8 400 ah l 16 s

[SouthernPioneer1965]

Pure sine wave inverters use a bit more energy to produce the same amount of usable current as a modified sine wave inverter,also you might want to rethink running your 105's down to 50% it will reduce battery life, think 20% discharge that gives you 90 amp hours...

[Fearlessthinker]

@AussieHomestead I've not used them enough to have a respectable opinion, but these are used in 95% of the golf carts here so they are very good quality and are at a good price, both factors that work in our favor. People with larger systems tend to go with L16 Trojans. Thanks for the comment and good luck with your system!

[helloman1976]

Almost forgot, the T105-RE version, if you have that version, is designed to go to 80% discharge and has a 7 year warranty and they are designed specifically for solar applications. They will last 10+ years if you drain them to 50% or less as long as the 50% isn't daily or constant, just occasionally. My batteries don't get monitored so I drain mine down to 10V constantly and they are still running strong, got them from Walmart and it's been a year now. :)

[helloman1976]

Your amps probably went up because your voltage went down, focus on watts. Also, the reason your inverter is using more power is likely because of induced heat and loss of efficiency due to heat. My 2 cents anyway...

[electrodacus]

@Fearlessthinker Is probably a sort of lens effect and you can probably increase the output by using a mirror to reflect light on the panels but you need to take care to not exceed to much the spec output since it will probably age the panel faster not sure the limit.

But you can have your panels in the winter produce as much as in the summer especially that is cold and they do not get hot.