Lead acid vs agm

[Markus]

For a garage project, is agm worth the extra money? I just want a couple of batteries till I understand how solar works. Then I'll work on building my own lithium batteries. I am thinking of using 6 months to understand, then before winter hits move on to building my own.

 

[Supervstech]

It depends on what you will be doing with them.
If your usage pulls the batteries low, agm can handle deep discharge and still be useful. Lead acid won’t tolerate much discharge for long.

 

[Markus]

Right now I have lighting in my garage(leds) and multiple outlets for power tools. My furnace will be added for the winter.

 

[Supervstech]

Lighting with led should not drain much, but keep track of wattage.
Power tools can deplete a battery very quickly. You don’t want to draw down below 50% of capacity, so know the capacity of your batteries. If it is a 100Ah, (1280Wh) don’t use more than 50Ah

 

[Markus]

Yeah, i understand the 50% I would like to try to extend my aili meter cable from my shed(where the batteries are) and mount it on the garage wall to see where I'm at.
I started this because I had spare time with this virus thing. Now I find out that I will not be teaching this summer(enrollment too low). So my battery plan (lithium)has to wait till after fall semester starts. That's why the lead or agms are of a short term interest.

 

[MisterSandals]

I just want a couple of batteries till I understand how solar works.

I'd recommend starting your "lithium battery" learning as soon as possible. Its easier than you think to get started - you can learn and test without a BMS. This process takes months. I think you'll be glad you started sooner rather than later.

What is your budget for agm batteries? Lets see what we can find to compete price-wise in the lithium battery type.

 

[Ampster]

If your long term goal is Lithium I would suggest flooded lead acid because it is less expensive. It is also messier and the acid plume will make your transition to Lithium much faster. FLAs are more forgiving than AGM and it is fun seeing the bubbles on FLA. Be sure you wear goggles when you do that.

 

[RobinWMartin]

Hi Markus I just want to share my experience with pretty much exactly what you're doing. I'm a electrician in the uk but my experience with day to day maintenance of a battery bank is woefully low. I opted to over spec my inverter/charger and everything else I could afford for future use while keeping the system small enough to be a test bed for now.

I opted for 4 x 12v lead acid in series as I got it all inc cables, fuses, shunt etc for $370. I figure that if it goes nuclear then i'm not going to be upset. When I choose to throw down $2000+ on a lithium pack i'll have a better idea of what to look out for and hopefully my safety systems will be all functioning to catch any issues.

Having said that these batteries are crappola. The Wh I actually get out them is enough to run my house on tick over (about 3-400W) for about 3-4 hours. Power tools be damned, it will hit the low voltage threshold in minutes.

Even though these batteries are awful and I wish I had more Ah to play with, i'm not spending any more money on lead acid. I'll continue to play and test, especially to learn all the nuances of the charger, inverter and PV system as a whole in relative monetary safety. Do I wish I got AGM to test with? Maybe...but what am i going to do with 4 x 12v AGMs when my ideal system is fully operational? Sell them? Maybe. Or better just use the flooded as backup/test equipment I've already written off.

Lots of ifs and buts.

 

[Markus]

Thanks for all the replies. Lithium would be great Right now but the surprise 3 months off work doesnt provide income for extras. I have I 80ah used battery(50.00) that I used for testing to make sure it all powered up like it should. I know I should and probably will just wait for the lithium.

 

[Silentpower]

Hi,
you won't really learn anything useful about lithium while gaining experience with lead acid. Agm-lead acid., same thing. Only difference is that fibreglass is stuffed between plates with agm (absorbed glass mat). Lead acid is really difficult with renewable energy storage. If you're going to spend money, spend it all on lithium and read good technical advice on here. After 7 years of hell living with agm, I invested in lithium nmc and haven't looked back.

 

[sunshine]

I have I 80ah used battery(50.00) that I used for testing to make sure it all powered up like it should. I know I should and probably will just wait for the lithium.

A $50 used FLA battery is the same as a $2000 liFePO4 when they are both flat!
If its a garage project and with access to mains power then that mains power should be sufficient to provide any extra power you require during your experimentation.

 

[Markus]

I've got grid power in the garage so no big deal as this is just to get my feet wet. I have decided to go the liFePO4 route this fall. I will just keep my eye out for anyone ordering a batch of cells when i'm ready or I'll just order them myself.

 

[sunshine]

The same situation here.
Currently I have 8 panels connected and a single 12v battery that wasn't able to start our car. A constant voltage power source takes over when needed.
The past 6 months have seen LiFePO4 going from an expensive alternative to lead acid to now being a no brainer.
These cheap 280ah ones could be arriving by sea container in a few months so expect to see another large price fall.

 

[AE4KR]

A ham radio club near me recently found a large, institutional UPS user getting ready to replace their big AGM batteries. This is done on a schedule, even if there's no reason to believe they're bad. They were five years old with a 10-year warranty.

The good news is, they got them donated free. The bad news is, they weighed 750 pounds each, and required a 3/4-ton pickup and a rented engine hoist to move. In any event, the repeater site's mains-charged emergency back-up battery bank is now set for another five years.

If you know people in the IT department at your school, see if any of those guys have contacts who might know of such opportunities. My wife would kill me if I brought a gigantic AGM battery into the garage, but hey - at least it would be hard to kill it with small charging goofs. Besides...I've been looking for a reason to introduce myself to that new neighbor with a forklift!

 

[Delmar]

My recommendation: AGM if placed inside the living space and FLA if outside. Battery acid and humans do not coexist.

Are you looking for something cheap and disposable until you can afford lithium? User thr0ttl3j0ck3y purchased 6V cores, assume from golf cart service. Technically are free because you can return them and get your core charge back.

While accelerating or climbing hills my golf cart can easily draw +100A. Used cores are slow for golf cart service, but have lots of capacity left for minimal learning usage.

 

[Markus]

I have checked out everything from golf cart batteries to used valance batteries to building my own cells. I have decided to just wait and build my own lifepo cells.