Why shouldn't I buy a 120AH Deep Cycle Battery at COSTCO for half the price of a GEL ?

[HRTKD]

I tried to Keep It Simple Stupid with my battery warming system. Yes, a varied charge rate would be good. But if you simply keep the batteries well out of their unhappy zone then you don't need to worry about the charge rate. My warming pads keep the batteries between 35° F and 45° F.

For my RV trailer, the batteries stay there all year. The trailer sits at a storage lot, without moving, December through March. I'm there working on the trailer those months, so I need some power, but not much. I hunt in October/November and that's when I really need power and the temperatures are well below the 32° F cutoff for charging. But since I'm actively using the trailer and the furnace is on there isn't an issue. For this situation, the batteries are above 60° F.

 

[Hedges]

I'm using jbdtool and a tiny bit of perl to control my ac2dc charger.
Not adjusting charge current for temperature though as my charger is fixed current and has no BTS.
The aims charger that that is popular does have BTS and could be controlled via an arduino or pi.

But can you change constant voltage setting dynamically?
As battery gets full, that causes current to taper off. As we know, when someone has reduced voltage a battery due to high resistance charging leads, current reduction occurs at lower voltage. You should be able to regulate current regardless of SoC by adjusting voltage.

I tried to Keep It Simple Stupid with my battery warming system. Yes, a varied charge rate would be good. But if you simply keep the batteries well out of their unhappy zone then you don't need to worry about the charge rate. My warming pads keep the batteries between 35° F and 45° F.

If you are able to regulate temperature most of the time and have an (elevated) low-temperature cutout in the BMS as backup protection, that works too.

But I would want to be able to have PV > 0.5C, use it as needed by inverter but limit what battery receives.
Once battery reaches charger's CV operation at 3.4 or 3.5V/cell that occurs. But at lower SoC battery would take everything SCC can deliver.

 

[John Frum]

But can you change constant voltage setting dynamically?

I found some doco that suggested this can be done with some jiggery pokery.
The solution is specific to the iota dls chargers.
I might do it someday.
I can look for the doco if if you are interested.

 

[Hedges]

I can look for the doco if if you are interested.

Thanks but don't do it on account of me. I'm not using lithium at this time, just trying to be "helpful" to advancing use of the batteries or protecting them with available BMS.

Since I use AGM with Sunny Island, it is just CC/CV with temperature and other tweeks built into their algorithm.
If I ever put in lithium, likely would use REC since they communicate. Which probably doesn't know to do this current/temperature curve.
I'm considering putting my spare system with 100 Ah 48V AGM on my truck, but that would be a good place to use LiFePO4 or a lighter weight lithium. It has MSTE "Sunny Island Charger" which only has various lead-acid profiles. With data link to Sunny Island its voltage targets get adjusted. But I don't know if SMA remembered to code that when the targets come from BMS. Old features need regression testing when new features or market support are added.

 

[John Frum]

Thanks but don't do it on account of me. I'm not using lithium at this time, just trying to be "helpful" to advancing use of the batteries or protecting them with available BMS.

Since I use AGM with Sunny Island, it is just CC/CV with temperature and other tweeks built into their algorithm.
If I ever put in lithium, likely would use REC since they communicate. Which probably doesn't know to do this current/temperature curve.
I'm considering putting my spare system with 100 Ah 48V AGM on my truck, but that would be a good place to use LiFePO4 or a lighter weight lithium. It has MSTE "Sunny Island Charger" which only has various lead-acid profiles. With data link to Sunny Island its voltage targets get adjusted. But I don't know if SMA remembered to code that when the targets come from BMS. Old features need regression testing when new features or market support are added.

It started to bug me so I went digging.

IOTA DLS-30 Battery Charger / Power Converter

I just checked All Electronics (Van Nuys, CA), these Used/Pulled IOTA DLS-90 units are still available at $125.00 each. 13.4VDC, 90A POWER SUPPLY /...

forums.qrz.com

 

[Hedges]

It started to bug me so I went digging.

IOTA DLS-30 Battery Charger / Power Converter

I just checked All Electronics (Van Nuys, CA), these Used/Pulled IOTA DLS-90 units are still available at $125.00 each. 13.4VDC, 90A POWER SUPPLY /...

forums.qrz.com

I like analog so much better than .ddl installed in Windows 1234 and getting broken every time there is some forced update.
It can be controlled by DAC, op-amp, digital PID chip, or anything else under the sun.

 

[Off Grid Thad]

Unless you have something like "1" battery, fractional C rate charging is all you are likely to achieve. By fractional I mean well below .5C
At that .5C on a BB 100Ah battery is still 50 amps at 14v DC. That would be a minimum of 800 watts of solar panels installed, probably needs 900w to get a constant 700 actual. A single battery like that is no more inconvenient to lug around than a 6 pack of your favorite beverage.
2 batteries would mean 1600 to 2000 watts of panels. Not something you are going to see on top of an RV every day.
So now we are well into fractional charging. I have 4kw of panel at different locations and angles to capture sun at various times. I had it set up like that for my 1600Ah of lead. My absolute peak charge in the day is 2200w. I have 7 of my 10, 272Ah DIY packs installed. At peak I am getting 315w per battery, 22 amps,,,, .08C. even when or if I rearrange the panels the best I can realistically hope for is .1C When I add the last 3 box sets to my system there will be no chance I will ever even get to .1C without more panels. And that is a LOT of space taken up with 10 4x6 foot panels. Personally I would probably go with 200w panels from now on.. Just too big and hard to mount.
My batteries are now inside a heated space, without even the full 10, just the 7 I have ready I would need 950 amps at 14v DC, (13.3kw) something along the lines of 18kw of panel to reach .5C at best, in summer for only 5 hours a day and a cable the size of my leg to go the 5 feet from charger to batteries.

Anyhow, my point, finally.. If your bank is small enough that charge rate at lower temps is an issue, it is small enough to just take inside during those few months. if it is so large moving it at all is a problem, you probably have a smart charging system and enough panel to run a few heat pads prior to charging, that and you can't generate so much power you need to throttle it back.

 

[olignyf]

$150 Kirkland battery vs $799 on sale Battle Born Battery is basically a wash.

100Ah 12V LiFePO4 Deep Cycle Battery

The 100Ah 12V LiFePO4 Deep Cycle battery is the pinnacle of battery technology and the lightweight drop-in replacement for lead acid batteries.

battlebornbatteries.com

You will need to replace the Kirkland battery at least three to four times in the next 10 years while the Battle Born Battery will most likely last ten years assuming proper care. So assuming no price change in 10 years for simple calculations, you can spend $799 today for 1 Battle Born or purchase 5 Kirkland batteries in the next 10 years.

Note that Kirkland battery is 150$CAD vs 799$US. Here the 100AH Battle Born is 1299$CAD ?

I wish I had unlimited time & money to buy both and do a side-by-side test then post a video... ?

 

[Off Grid Thad]

Try this on for size.
Use Amazon US and ship it to Canada. Its 100 shipping and then the exchange rate. Beats the stupid Amazon.ca price

 

[Woody]

Wow didn’t know the money exchange rate was that bad.

Don’t worry the way America is printing funny money these days soon the Canadian Dollar will be worth several times our dollar.

FYI last month I purchased 10w solar panels for just over $16. Placed a reorder and now they’re $20 each. No inflation here citizen, move along.

 

[Off Grid Thad]

FYI last month I purchased 10w solar panels for just over $16. Placed a reorder and now they’re $20 each. No inflation here citizen, move along.

That is not inflation.
It’s Capitalism.
Charge as much as you can get away with.
Raise price till people quit buying then reduce it so people think they are getting a deal.
When in doubt read PT Barnum’s book.

 

[Woody]

Sorry Off Grid Thad but…


So ”digitize” aka print Trillions out of thin air and the buying power of the US dollar reduces. Note that this chart now about 2 years out of date a trillions more created. ?

I grant you supply/demand and numerous other facts influence the value of a country’s money but the net result of inflating a country’s money supply is that you can not buy the same goods for the same price as time moves on. Nice to be the world’s reserve currency and being able to get away with inflating our money supply out of thin air. Why do you think our debt holders are so pissed at the US. Borrowed money from them and we are now paying them back with dollars that aren’t worth as much (buying power) as when we borrowed it.

I tell my kids that when I was a kid I could buy 10 candy bars for a dollar everyday/any day. 12 for a buck when they were on sale. Today I can’t even buy one at regular everyday prices but sometimes when they are on sale for about buck. Or how about a Mc Donald’s burger, fry, and drink with change back for less than a buck. Oh gee here I go sounding like my mom. She used to tell us kids when she was a girl about going to the movies, getting a large popcorn and drink all for a quarter. I wonder what my kids story will be? Maybe something like, we used to get ——- for a dollar and now it’s only $10 or whatever.

No inflation here citizen, move along now and be a good citizen. Nothing to see here.

 

[Off Grid Thad]

Woody
I can not disagree with a single vowel if that.
and this was the beginning if it. to the hour.
December 23, 1913. The law that created the Federal Reserve System.

 

[12VoltInstalls]

December 23, 1913. The law that authorized the Federal Reserve System

The banking power was already there.

“We” just authorized a central bank which the bulk of The Signers Of 1776 spoke strongly against.

 

[12VoltInstalls]

That is not inflation.
It’s Capitalism

No. Capitalism is a free-market system of engaging in trade.

Some people/companies under capitalism gouge; gouging isn’t explicitly a characteristic of capitalism though, like a given, expected byproduct.

inflation, on the other hand, is the rise of the cost of goods and services.

USA basically had no inflation for 20+ years
Now we have covid - and got inflation, too.

 

[Horsefly]

This thread has gone completely off topic, and off the rails. It is now just like 99% of all the drivel on the Internet.

If we can't stay on the topic of this thread, can we at least stay on the topic of DIY Solar?

 

[circus]

Note that Kirkland battery is 150$CAD vs 799$US. Here the 100AH Battle Born is 1299$CAD ?

I wish I had unlimited time & money to buy both and do a side-by-side test then post a video... ?

My local (WI) Walmart for your #27 battery. $82. The larger #29. $90. Not recommending, just saying.

 

[Mia]

Well, if nothing changes, rumor is that Americans can enter Canada starting Monday

 

[Mia]

Nope, via autos, as well as by air... only if fully vax’d ?…. [My last 2 responses were to disappearing posts apparently, lol! oh well]

 

[Hedges]

This thread has gone completely off topic, and off the rails. It is now just like 99% of all the drivel on the Internet.

If we can't stay on the topic of this thread, can we at least stay on the topic of DIY Solar?

Twenty years or so ago I could buy an Optima AGM battery for about $100.
Today it costs about $300.
(official) Inflation has been 0% to 2% during that time.
If that was 2% real inflation for 20 years, I'd be paying $149 for that battery.
About 5.7% would give a tripling in price.

Optima Mustang Performance Battery; Yellow Top D34/78 (79-10 Mustang) - Free Shipping

FREE SHIPPING! Premium Power. The Optima YellowTop high-performance AGM battery is the one true dual-purpose automotive battery available for your Mustang, with

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