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Small Cabin Forum / Off-Grid Living / FLA Rescue
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gcrank1
Member
# Posted: 23 Nov 2021 15:46 - Edited by: gcrank1
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Guess that is what Ive become.....
I let my friends with boats and rv's know that when they figure they need to replace their 'marine/rv' bats just bring em to me. I give them a for sure junk bat for the 'core exchange'.
Last fall I got a marine dc that my friend said wouldnt run his trolling motor as long as it used to and he knew he would replace it come spring anyway. It read decent voltage; ie, 12.5?, checked the water level and put it on my smart charger that has a 'recondition mode'. Ive run that bat on the cabin solar for the past year.
Another friend has a good sized travel trailer with 1 bat that he says wont hold a charge. Ive tried to tell him he has phantom draw pulling it down so just keep it trickle charged. He wont. So he is going to buy a new one for next year. Im trying to get him to bring it to me now so I might be able to 'save' it (for me).
Just today I made my weekly trip to our 'recycle center', formerly known as the town dump. There sits a marine/rv dc 109ah, nice and clean with a round sticker that says 4/21, but the top is wet and it sat in a plastic box. It read 12.64v so I brought it home, popped the caps and WOW, acid to the top! I pulled a quart of excess water off it to just above the plates. Im thinking the owner 'topped it up' not understanding what that meant and put it on a charger thus making it upchuck as it charged.
My hydrometer is at the cabin so no cell check but it is on the smart charger right now taking a mellow 10a.
Might just have next years bat-bank for free

paulz
Member
# Posted: 23 Nov 2021 19:40
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Good score. A good friend of mine worked at an auto parts store that sold batteries. The store didn't own the batteries, they had a contract with a third party supplier who maintained the inventory and picked up the cores.

Often times they would sell a new battery, only to have the customer return it and buy an alternator, the real cause of the problem. The new battery would go on the core pallet since it couldn't be sold as new. I was allowed to take volt readings and swap my dead cores for these returns, basically new batteries.

'Twas a said day when my pal retired.

darz5150
Member
# Posted: 23 Nov 2021 19:43
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What kind of charger do you have? I bought a cheaper one off Amazon that seems to do what it's supposed to. 🤔
Do you have to run the repair mode a couple of times? I have on a couple batts, but it really does seem to give new life on some batteries.

gcrank1
Member
# Posted: 23 Nov 2021 19:52
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Oh man, what a deal you had with that!
Imagine that is still happening in every local where us cabineers need cheap 'storage', new bats back on the pallet as scrap. SAD
Recycling as I am Im not worried about not matching ages, etc, I try to match up bats with similar performance profiles.
Works for me
Im keepin my eye out for an LFP to end up on my source stack

Brettny
Member
# Posted: 24 Nov 2021 06:05
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I have a battery rotation also. Things like my log splitter, large tractor and sawmill all get old car batteries on the edge of dieing. Only the stores get the ones that cant start a 15hp gas engine.

I did have a napa battery last year read 12.6v but when I tried to start the excavator it would totally die out...the store got that one.

gcrank1
Member
# Posted: 24 Nov 2021 10:44 - Edited by: gcrank1
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As of a bit ago that 'new' bat is sitting at 12.8v/100%.
I let it sit off charger all day to see how it held.
Tomorrow I'll get some load on it, like jumpering to my v-twin B&S lawn tractor which I pulled the battery out of last week.

gcrank1
Member
# Posted: 27 Nov 2021 15:07 - Edited by: gcrank1
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Did the lawn tractor spin test but it is so unseasonably cold here that it turned hard and slow (30wt oil). Didnt really tell me much other that it can crank some.
Today Im doing a test with it fully charged (by multiple charging sessions over these past days, read by charger and verified by voltmeter). It holds charge fine over days of sitting, too.
Pulled out my suv travel fridge that says it uses 4.8a. This is one of those little units that just has a heat exchanger?, no compressor so I think that 4.8a is pretty much steady?
Figuring the bat is rated 109ah Im going for 100ah in the calc, so 50ah usable max, 25 for a 75%soc.
Im going to run it for 5 hrs and discon, let sit to stabilize from the load and see what voltage reading I get. Hoping it correlates closely with the charts online for fla.
Btw, I have a 'refreshing beverage' chilling within so Im not just wasting power

gcrank1
Member
# Posted: 27 Nov 2021 19:22 - Edited by: gcrank1
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Ran a bit overtime on my load test, 5hr and 25min.
Gave a 1 hr rest time
Dig v-meter says 12.39, right where the fla chart says for 75%soc.
My calcs worked out, I was hoping for 12.4, only off by .01 but I did run a bit long.
This discharge is my target in the cabin solar system use, 25-30%. This past season I could recover typically by 11am though still sun until 2pm (then conifer block).
So, looks like I WIN
Darz, I spaced out your charger question (blame turkey daze).....
I bought this 'SOLAR'PRO-LOGIX 20amp (pt # PL2320) off Amazon; it was not terribly expensive but is my Best charger now (Ive got 6?, mostly old school and a couple trickles). This is 6/12v, 20/10/2a, fla/agm/gel, with % and voltage dig readout.
I do run a new to me battery through a full cycle, let rest and re-run. Some old ones I did 3 times and they bucked up pretty good.
Ive run it a lot in this past year, am really quite pleased.

gcrank1
Member
# Posted: 29 Nov 2021 14:43
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The bat has sat since discon from the charger at 10pm, 11-27 when the charger had gone to shutdown/bat full.
As of 1pm today it reads 12.84v.
Too bad we are pretty much done for the season at the cabin, Im anxious to add this one to my other two for a 3 parallel bat 12v bank, should give me 150ish ah's to 50% or my pref at 25%dod /75ah's. By my calc that will be close to what a 100ah lfp would give me if using 80% (a nice, safe number too).

paulz
Member
# Posted: 2 Dec 2021 19:59 - Edited by: paulz
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I just bought a hydrometer at Auto Zone. If I ever knew how to read one, I've forgotten. I charged the 4 bats in my shop bank a couple hours ago, they are reading 12.6v now. The hydrometer shows in the white band, which I take it is marginal. About 1235 on the scale, whatever that means. They are old 5-6 years, and die out pretty quickly with the lights on.
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darz5150
Member
# Posted: 2 Dec 2021 20:15
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Do all the cells read the same/ish?
If not. You may need to equalize them. That's why I asked gcrank about his charger. The one I have is the FoxSur. It's not that expensive. And it really does help out. I am sure others can elaborate more. But it sorta boils down to.... Volts really don't tell much by itself. But with knowing what's going on inside the battery + volts gives you a better idea of battery health.
I know you probably have a load tester. Charge the batts up good. Then hit them with the load meter. No good load results usually means no bueno. Or you might have to recondition your batteries.

paulz
Member
# Posted: 2 Dec 2021 20:22
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I only measured 2 cells, I"ll see in the morning. I do have a load tester. They probably could use more charging.

darz5150
Member
# Posted: 2 Dec 2021 20:30
Reply 


Check out the charger that crank has. And even the one I have. I have 2 Wally world deep cycle batteries that are at least 11 years old that the charger helped out. Plus a bunch of not new lawn and garden batteries that the charger seemed to give a second chance.

gcrank1
Member
# Posted: 2 Dec 2021 23:21
Reply 


Top bats with distilled water, some 'sealed' fla have a segmented top rather than caps that looks like you cant get in, but....
Charge fully, check voltage, let rest then give another charge cycle.
Do a load test, any that fail right off are done, discard.
Let other(s) rest, check voltage, you might not have lost too much. If you wonder just charge up, then rest.
Check voltage then do hydrometer. You want the cells to be close more than the 'reading', not that the read is not important. There are charts online of what the read should be (no instructions with the h-meter?) but it needs to be adjusted for temp.
I like to see 80% or more on my keepers or they dont have enough beans left for anything meaningful.

paulz
Member
# Posted: 4 Dec 2021 08:39 - Edited by: paulz
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Quoting: darz5150
Do all the cells read the same/ish?


Checked all 24 cells yesterday. There was some variance, most were at the divider between the white and red on the scale (around 75% according to this chart), but some were off quite a bit either way. I did notice the end cells of each battery seemed to be lower than the middle four. Voltage was at 12.55 after sitting overnight with no load. I ran the genny/charger for almost an hour, voltage at 12.85 when I shut it off but still no hydrometer readings in the green.

Guess I'll start looking at those smart chargers but without grid power I would have to run one for a long time off my cabin bank (LFPs) and inverter.
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paulz
Member
# Posted: 4 Dec 2021 10:11
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This smart charger is on sale this weekend, locally, about 30 bucks. Says it has "High frequency current pulse can be used to recondition car batteries that are weak, sulfated or deeply drained."

But, according to the instructions, the repair mode only kicks in below 10.5 volts, so no reconditioning or balancing for better bats.

I looked at the Solar Pro and Foxsur you guys have, don't see any documentation if they do anything different.
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darz5150
Member
# Posted: 4 Dec 2021 10:27
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Check and see if you can manually change the charge modes. That is how mine works.
That one might automatically kick into the repair mode at that voltage.

gcrank1
Member
# Posted: 4 Dec 2021 10:36
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Fwiw, I dont expect much at that price point.
As cheap as I tend to be the low-end products too often end up being low-performance/low-no value.

paulz
Member
# Posted: 4 Dec 2021 10:38
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Says auto only. Click the pdf link for instructions.
https://www.harborfreight.com/4-amp-fully-automatic-microprocessor-controlled-battery -chargermaintainer-63350.html

gcrank1
Member
# Posted: 4 Dec 2021 17:09
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Paul, as said, Im cheap, or frugal...or I just don't want to get ripped off. I had a bunch of traditional transformer chargers that still work but after reading so much about 'smart chargers' I started looking at them.
I took a chance on this one I mentioned prev, gotta say, it has worked for over a year with no issues. It has been my go-to and used often. I am satisfied.
Hope it doesnt die soon because I like what it has been doing for me and at this point consider it a good value.

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