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

[Hedges]

Here's a link suggesting 15 to 20 years for a forklift battery as a home battery.

Best Kept Secret In Renewable Energy

My search for the BEST off grid battery has ended!

www.susprep.com

People do report lifespans like that.
I've also heard, "You will kill your first set of batteries", so this would be for a second set.

 

[Woody]

Here's a link suggesting 15 to 20 years for a forklift battery as a home battery.

Best Kept Secret In Renewable Energy

My search for the BEST off grid battery has ended!

www.susprep.com

People do report lifespans like that.
I've also heard, "You will kill your first set of batteries", so this would be for a second set.

Lead forklift batteries have been the way to go for years. These batteries are made with more lead, thicker plates, … to way out last the typical deep cell. That’s why so many stationary off grid buy refurbished ones but start with a new one and treat it well, they last for years. These batteries can take abuse and keep on going. Plus, you can refurbish it for even more life. As for cheaper than LiFePO…kind of depends upon how you treat them, environment you keep them, the care and feeding of them, etc. These forklift batteries are still a very viable option for stationary off grid that have the space and means to move them into their permanent home.

 

[Horsefly]

I must say, this is a very entertaining thread! I have no other comments to make, else I'll risk finding myself in the midst of a mud wrestling match.

 

[Off Grid Thad]

Good luck moving a forklift battery. It is what they use for ballast on a forklift.

 

[Short_Shot]

Good luck moving a forklift battery. It is what they use for ballast on a forklift.

I mean.

Yes and no.

The battery on ours is nearly insignificant compared to the thick steel plate ballast mass hanging off the back of it.

Lead acid battery packs aren't light no matter where you source them from. 12v @ 200ah of the stuff weighs some 60kg or better, let alone a much larger forklift pack.

So it's not the form factor that is the issue.

 

[Sabre36]

Hi,
I saw this deep cycle battery at COSTCO at 150$CAD. It's half price of a 120AH GEL sealed battery.
If one keeps the battery outside during summer and don't care about hydrogen gas, why doesn't everybody buy those cheaper battery at COSTCO for their solar power installation?
Will it be half the lifetime or something?
View attachment 58325
View attachment 58324

Thanks folks!
Francois

Why not? Because it's not a deep-cycle battery. Only the sticker says "deep-cycle" but what's inside is not deep-cycle construction....

How to Murder Batteries in Half a Year



.

 

[12VoltInstalls]

That was interesting read.
class-action fraud suit right there

 

[Short_Shot]

That was interesting read.
class-action fraud suit right there

Eh.

Maybe, but if the documentation states vastly different acceptable operating parameters for what they call "deep cycle" they can still get away with it.

You also have to realize the laundry list of improper installation and care which happened with them, which was all spelled out in the thread.

 

[Sabre36]

That was interesting read.
class-action fraud suit right there

Except that the BCI has zero definition of what qualifies as a "deep-cycle" battery. This is why companies continually slap "deep-cycle" stickers on batteries that have a cycle life of 50-200 lab cycles when other companies only call it "deep-cycle" whan it can surpass 1000 or 1200 or 1600+ lab cycles.... It's called marketing.... No different than LFP makers marketing these drop-in batteries "drop-in replacements for lead acid"..... When a lead acid battery can disconnect itself from the DC bus, with no advanced warning, then they can be called a "drop-in replacement for lead acid".....

 

[A.Justice]

That’s an insane price?

That's literally one of the most expensive lithium batteries that money can buy. You can get 100 amp hours (12v) of raw cells for about $200 + BMS.

 

[Hedges]

Good luck moving a forklift battery. It is what they use for ballast on a forklift.

Some forklift batteries have 2V cells that can be moved individually.

I used a different battery, not packaged for forklift but similar capacity.
I have eight, 6V L16 batteries which weigh 120 lbs each for 48V, 405 Ah.
To go bigger, 2V L16 are 124 lbs and 1215 Ah.
Those are AGM. Shorter cycle life, but zero maintenance.

Sun Xtender Solar Batteries - Photovoltaic Battery

The Sun Xtender Battery line consists of specialty lead-acid solar, photovoltaic batteries, and renewable energy storage batteries manufactured by Concorde Battery Corporation.

sunxtender.com

 

[Wellbuilt]

Personally I strongly dislike the investment risk of needing to water batteries or check specific gravity. Miss a check up and suddenly need to move hundreds of pounds of equipment.

I’ve built a 100Ah 12V LFP pack and honestly It Was Easy. Get a JBD BMS and follow overkill solar BMS manual. It works.

Just chiming in. It’s still running and charging from solar every day for a year now.

Of course equipping oneself with new information is itself a cost. That’s what we are here for ?

The cost was 620 usd for the cells (1280 Watt hours) and 140 usd for BMS.

760 usd for 100 real usable amp hours 12V

That seam really good , and I’m sure I’ll change batty types the next time i change out my batterys
I’m on my third season with my GC battery now so may be I’ll get 3 or 4 more years out of them .
My battery’s don’t really take much maintenance I add water twice a year and check sg takes 2 or 3 hours a year ?
I spot check a few cells every month or so .
Water dosent really just vanish from the battery’s it takes a long time of hard charging hi voltage to use up water .
I only use 10% of my battery in the summer and up to 20% in winter .
To get 200 usable ah at48 volts it would cost you 6k and then they would have to last 10 years to equal my 27 /2800 bucks for 2 sets that last 5 years each .
There are still all kinds of people having problems with there battery packs .
I’m allso looking a 48volt fork lift battery’s in the 850 ah at 20hr rate for 5k
My place gets down to -15/20 for a few weeks every winter I have never see the inside temps below 32o on the first floor , I leave water jugs around to see if they turn to ice .

 

[Wellbuilt]

It can be though if a person takes the initiative to put the components together

What is every one doing to pass electrical inspection , get home owners insurance ?
My inspector and insurance Company have a lot of rules , they are not very happy about the hole off grid idea .
They are asking a lot of questions about my battery box and battery’s , I’m not sure if my enclosure is it gonna pass inspection ?

 

[curiouscarbon]

That seam really good , and I’m sure I’ll change batty types the next time i change out my batterys
I’m on my third season with my GC battery now so may be I’ll get 3 or 4 more years out of them .
My battery’s don’t really take much maintenance I add water twice a year and check sg takes 2 or 3 hours a year ?

Thank you for sharing your experience, that helps me learn.

I’ve only dealt with one bank of FLA before, ~80Ah 48V of 6V trojan batteries. Didn’t have the special water catching caps and I neglected the watering and they boiled over and onto the ground. My fault. Also dry warm environment probably encouraging evaporation. Maybe the inverter stopped it from becoming worse thanks to the thermocouple to the center of pack. But unfortunately the battery that boiled over was the one furthest from the temperature sensor, lol..

Anyways, LFP does have the complication of requiring >32F >0C charging conditions, preferably a couple degrees higher of course for margin of error. edit: Full speed charging shouldn’t happen at 32F, though. Need to be closer to 77F/25C for full speed charging.

If you ever do switch to LFP, be sure to check out the water tank anti-freeze pads that only heat up to ~70-80F and add insulation around pack. It should keep the power consumption of the temperature safety mechanism to a minimum.

Anyways, just kinda sharing random thoughts in the trade off space and absolutely not suggesting specific course of action ?

Nice idea of water jugs to check if frozen

Thanks again for sharing your experience?

 

[Wellbuilt]

Any time
i don’t know how you can have battery’s boiling over ?
It seams like a charging issue .
I charge my battery’s hard with a little extra absorb voltage and time , they seam to like that , I use a hand held temp sensor
And never see more then 75/77o battery temp even if it 90o out side .
my place is on top of a Mountain in the middle of nowhere , I had my wood stove burning the other night so my garage stays 66o if I don’t open the doors .

 

[Hedges]

Anyways, LFP does have the complication of requiring >32F >0C charging conditions, preferably a couple degrees higher of course for margin of error.

A bit more than that, for some brands which do publish such data, full charge rate (e.g. 0.5C) is only reasonably close to 25 degrees C. Near cold or hot limits, allowed charge rate decreases.
I think charge controllers ought to have a parameterized curve for that.
Since they don't, I would determine "C" rate and identify safe cold/hot limits for that current, change settings in BMS.

 

[Horsefly]

I think charge controllers ought to have a parameterized curve for that.

This.

I really wish there was a way to have the SCC - which already has the BTS temperature info - control the charge rate based on the temperature. Maybe there is one that does, but my trusty Schneider doesn't.

 

[Hedges]

This.

I really wish there was a way to have the SCC - which already has the BTS temperature info - control the charge rate based on the temperature. Maybe there is one that does, but my trusty Schneider doesn't.

Could probably be done by someone who writes code for Raspberry Pi or whatever and adjusts parameters by data link.

When Sunny Island is set for Lithium, it talks to BMS. REC offers one of the supported models. I don't think BMS requests current, rather voltage.
Sunny Island also talks to Sunny Island Charger or Midnight Classic, for lead-acid charging phase and voltage. In that case, it uses battery temperature sensor to adjust charging voltage, and I suppose commands higher for equalization. Using lithium and BMS it should similarly adjust voltage.

By monitoring voltage across (or data for digital) battery shunt, you could determine current and then adjust voltage of SCC to regulate current.
That would avoid excessive charge current when cold. Could also slow charging to allow equalization near full. At that point, might as well roll our own BMS? But battery temperature sensor and adjusting charge parameters would be a good start without much analog, just one ADC input.

 

[John Frum]

Could probably be done by someone who writes code for Raspberry Pi or whatever and adjusts parameters by data link.

When Sunny Island is set for Lithium, it talks to BMS. REC offers one of the supported models. I don't think BMS requests current, rather voltage.
Sunny Island also talks to Sunny Island Charger or Midnight Classic, for lead-acid charging phase and voltage. In that case, it uses battery temperature sensor to adjust charging voltage, and I suppose commands higher for equalization. Using lithium and BMS it should similarly adjust voltage.

By monitoring voltage across (or data for digital) battery shunt, you could determine current and then adjust voltage of SCC to regulate current.
That would avoid excessive charge current when cold. Could also slow charging to allow equalization near full. At that point, might as well roll our own BMS? But battery temperature sensor and adjusting charge parameters would be a good start without much analog, just one ADC input.

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.

 

[Horsefly]

My approach will be to allow the BMS to cut off all charging below about 40°F, and use the SCC power (and power from the battery if it is above about 60% SoC) to drive heating pads under the pack. I'll also have a second thermostat that will cycle the pads to ensure the aluminum heat sink the pads are under doesn't get too hot too fast.

This approach provides a binary approach to the charging: It's either on or it's off, depending on the temperature of the pack. The ideal solution would not be binary, but would adjust the current. You (@Hedges ) are right that there may be some other ways to manage it, but they add too much Rube Goldberg complexity.

I'm going to test my design on my patio here in Denver this winter. Not charging, but seeing how energy the heating uses in my insulated battery box. I may end up setting the thermostat and BMS to something higher - maybe 50°F - to ensure there is no problem.