Battery confusion - Please advise

[wh33t]

Hey members,

I've been full solar offgrid for nearly 18 months in a 420sqft cabin/tinyhome.

My battery bank is 4 deep cycles wired in parallel. Here is a link to the batteries I'm using (http://www.walmart.ca/en/ip/1643906-.../6000016951063) they were $100 at Walmart and were basically all I could afford when I began my offgrid adventure.

Recently it appears as though my battery bank is acting strange. My controllers and voltmeter both report to me that my batteries are reaching 12.7v (full) by the time the sun goes down and within a few hours of no/slight use my batteries seem to go down to 11.9v. I checked the water levels today, many seemed low. I used up nearly 1 gallon of distilled water to top them back up. It was the first time I ever checked them.

So Ive been reading that because my water levels were low and we had sub zero celcius temperatures recently that maybe they have been damaged or sulphated? Maybe these are just **** batteries to begin with? Any ideas about whats going on and what I can do to fix them?

[Sunking]

Your batteries are toast.

First mistake you used 12 volt batteries in parallel. Second mistake you used RV/Marine hybrids vs deep cycle. Lastly no one knows what you need because you have not specified daily watt hour usage or location, so no tmuch we can recommend at this point.

[wh33t]

Your batteries are toast.

First mistake you used 12 volt batteries in parallel. Second mistake you used RV/Marine hybrids vs deep cycle. Lastly no one knows what you need because you have not specified daily watt hour usage or location, so no tmuch we can recommend at this point.

Whats wrong with 12v in parallel? Those batteries according to their ah rating is what I need. Are they toast because of the freezing?

[Mike90250]

Whats wrong with 12v in parallel?

2 in parallel can possibly work, 4 forget it, read this link - the lay out all the math for you, as to why it's not good

http://www.smartgauge.co.uk/batt_con.html

Those batteries according to their ah rating is what I need.

Batteries should only be taken no lower than 50% full, or you reduce their life greatly

Are they toast because of the freezing?

If they actually froze, they are toast/junk.
As batteries get colder, they have less available capacity, and that 50% point gets smaller.
If they have been deficit charged, they are sulfated, and therefor, toast/junk

[wh33t]

2 in parallel can possibly work, 4 forget it, read this link - the lay out all the math for you, as to why it's not good

http://www.smartgauge.co.uk/batt_con.html

Batteries should only be taken no lower than 50% full, or you reduce their life greatly


If they actually froze, they are toast/junk.
As batteries get colder, they have less available capacity, and that 50% point gets smaller.
If they have been deficit charged, they are sulfated, and therefor, toast/junk

I never drop them below 50%. That top 50% is my needs, roughly 3kw according to their Ah rating. Thanks for the advice. I will look into it! Much appreciated.

[Wakie]

If you shop for battery, go for real deep cycle
I own 4 rv deep cycle group 27 ( not marine or starting battery) mine are 650 CCA yours 850 CCA
The lower the CCA mean the plate inside the battery is thicker and more appropriate to be deep cycled
You can try to equalize the battery it can help regain some life in your battery
Check if you have a drain in your system
Last year i switch to 24 volt and it is way more efficient for the same battery
Good luck

[wh33t]

If you shop for battery, go for real deep cycle
I own 4 rv deep cycle group 27 ( not marine or starting battery) mine are 650 CCA yours 850 CCA
The lower the CCA mean the plate inside the battery is thicker and more appropriate to be deep cycled
You can try to equalize the battery it can help regain some life in your battery
Check if you have a drain in your system
Last year i switch to 24 volt and it is way more efficient for the same battery
Good luck

Thanks a lot for the encouragement and advice.

I want to stay on 12v because I want to be able to eventually distance myself from anything that uses AC to avoid inversion. Unless/until they make an AC solar panel, and power can be stored in AC I'm going to remain on 12v because of the wide arrangement of appliances I can get that use native 12v. I'm in a 420 sqft tiny home so running big powers when they are needed is not a huge expense. Plus I love being able to hook my truck up to my house with jumper cables and recharging my system when it's cloudy out.

I got the batteries I did because I didn't have much money and was greatly overwhelmed at all of the knowledge required to go offgrid. I'm gonna try for some of those Trojan 6v t105 next time around.

[Mike90250]

If you shop for battery, go for real deep cycle
I own 4 rv deep cycle group 27 ( not marine or starting battery) mine are 650 CCA yours 850 CCA..

Sorry, that is a "hybrid" battery, poor at deep cycle, poor at starting. True deep cycle batteries don't carry a CCA rating.

[Sunking]

I own 4 rv deep cycle group 27 ( not marine or starting battery) mine are 650 CCA yours 850 CCA
The lower the CCA mean the plate inside the battery is thicker and more appropriate to be deep cycled

If any battery has a CCA CA, or MCA rating is telling you it is NOT Deep Cycle.

[Wakie]

I don t know for sure if my battery is real deep cycle, it is printed --)RV deep cycle on it
The CCA rating is not on the battery, i found it in the catalog when i baught it
I baught it from Napa autoparts
The battery is still going strong after 3 year ( 30 weekend + 2 full week each year)
Btw, what do you suggest between november to january i bring back the battery at home
Put the battery on a float charge of 13.2 v or 13.6 v?
The battery is store in a cool place 30-35 farenheit
I can charge the battery at 14.4 v absorb for 2 hours then go float
It s all the setting i have on my home charger
Thank for advise

[Sunking]

I don t know for sure if my battery is real deep cycle, it is printed --)RV deep cycle on it

Don't feel bad, it is all marketing. A SLI aka Starting Lighting & Ignition are made in such a way so they can have very low internal resistance which enables it to deliver very high starting currents and be recharged quickly. The SLI battery is constructed wiht multiple thin spongy in textured plate to maximize surface area. In addition the plates do not fill the battery jar allowing room in the bottom of the jar for plate corrosion to accumulate as not to short out the plates. They do this because alternator voltage regulators operate at higher voltages, and that corrodes the battery plates and flake off and settle in the bottom of the jar.

A deep cycle battery is constructed with heavy thick plates that fill the jar. The thick plate last a lot longer and more mass to store energy. Down side is they have much higher internal resistance and thus not capable of delivering high discharge currents and cannot be charged as fast.

Hybrids are a cross between SLI and Deep Cycle. They have thicker and heavier plates than SLI, but not as heavy as Deep Cycle. They are capable of high currents but at the sacrifice of cycles. Hybrids come in multiple MARKETING NAMES like Golf Cart, RV Deep Cycle, Marine Deep Cycle, Liesure, Floor Machine, and so on.

Here are two good examples of the same battery. The Trojan T-105 and T-105RE. Note the difference in weight and warranty. The T-105RE is 5 pounds heavier with a longer warranty.The T-105 is a hybrid Golf Cart battery, and the T-105RE is Deep Cyle for Renewable Energy.