Battery Series-Parallel Basics

[rdanneskjold]

Hello All,

My first post here.

I am building an AGM battery bank, and I have a question about wiring these things in series and/or parallel. The current plan is to use 4 x 12V for 48V. but, why not five for 60V or six for 72V? or 144V?

I know balancing is an issue for series packs, but what are the concerns I should be aware of?

the candidate battery: https://www.lightcatchersolar.com/product-page/solar-specific-100ah-12v-volt-deep-cycle-agm-battery

-RD

 

[snoobler]

Welcome to the forum.

I don't see a parallel question.

Those higher voltage configurations have been done for various applications including lead-acid powered EVs.

Why are you building a battery bank?

If it's for a power system, you do 12, 24, 48V because hardware is readily available in those voltages. Go to other voltage and options get rare and prices get higher with the same headache at every component selection.

 

[rdanneskjold]

Welcome to the forum.

I don't see a parallel question.

Those higher voltage configurations have been done for various applications including lead-acid powered EVs.

Why are you building a battery bank?

If it's for a power system, you do 12, 24, 48V because hardware is readily available in those voltages. Go to other voltage and options get rare and prices get higher with the same headache at every component selection.

sorry, the 'parallel question' was implied.... it's a question about capacity, one way or the other. You answered my question--thank you!

This is for a battery backup power source for my home. at present the plan is to run my natural gas powered generator (which is actually tri-fuel) to charge the battery periodically during an outage. In the future I'll probably add additional battery capacity as also solar.

I live in southern California- the grid is pretty reliable here, but it is extremely expensive. Eventually I plan to disconnect from the grid entirely.

Thanks again,
RD

 

[Substrate]

Just know that going battery is roughly ten times more costly than the grid. Especially when you factor in a "lifestyle" of living off them, which means future replacment at higher prices, so it's not just a one-time cost.

The AGM's could actually cost you more in the long run than LFP, not just because of cycle life comparisons, but also that without major maintenance, solar with AGM usually leads to an early (er) demise. Doing AGM properly with solar takes some major effort.

Looks like you have multiple power sources other than the grid - i'm just hoping you are doing an actual power-budget vs cost, so you don't get hoodwinked by a fast talking salesman.

Also note that depending on the community in which you live, you WILL receive a bill for the minimum, even if you are totally off grid.

 

[rdanneskjold]

I know a guy who will spend $10 to save $1 in taxes. That ain't me, but I do get obsessive....

 

[time2roll]

I live in southern California- the grid is pretty reliable here, but it is extremely expensive. Eventually I plan to disconnect from the grid entirely.

Start with solar. Just got my annual bill. Shows I used 4,534 net kWh and paid $62.41 for the privilege. My 3 kW solar covers maybe half my usage. I time the power use to sell most of the power at the high TOU rates and use lots of power at off peak rates. Summer I am selling at over 60 cents and buying at 16 cents. SCE. My average bill was $200+ per month before solar. Almost paid for itself twice now. Not sure the same deal is available today but generating your own power is the first step to reducing your bill.

I don't think you will be saving money with a stack of AGM.

 

[Cidpineda]

Start with solar. Just got my annual bill. Shows I used 4,534 net kWh and paid $62.41 for the privilege. My 3 kW solar covers maybe half my usage. I time the power use to sell most of the power at the high TOU rates and use lots of power at off peak rates. Summer I am selling at over 60 cents and buying at 16 cents. SCE. My average bill was $200+ per month before solar. Almost paid for itself twice now. Not sure the same deal is available today but generating your own power is the first step to reducing your bill.

I don't think you will be saving money with a stack of AGM.

What do you mean? I have 24pcs of deep cycle batteries? Not saving? How? I spent 2500$ for a 300ah useable? 2 years free replacement? Walmart brand? Where on that is not saving? 2 years warranty so basically 4 years? For 400$ on 50ah?

 

[time2roll]

To save electricity start with solar to charge those batteries.

 

[anadiner]

Hello All,

My first post here.

I am building an AGM battery bank, and I have a question about wiring these things in series and/or parallel. The current plan is to use 4 x 12V for 48V. but, why not five for 60V or six for 72V? or 144V?

I know balancing is an issue for series packs, but what are the concerns I should be aware of?

the candidate battery: https://www.lightcatchersolar.com/product-page/solar-specific-100ah-12v-volt-deep-cycle-agm-battery

-RD

1st) why not double that: 4 in series (48v) then 4 more in series (48v) then in parallel which means volt stays same, add together amps IE) end up with 48v/200ah [doubled wh]

- important is type of controller. PVM requires parallel, as well as, panel voltage input = battery voltage output.

Important not to forget that.