Battery shopping

[johnathanmatthew]

hey , been reading a lot of threads here and on other forums the past couple weeks, and
it seems like you guys really know what you're talking about/ so maybe you can help clear some
confusion or doubts that I have about the system I'm setting up




I read somewhere that an Ideal balance would have the solar panels generating 5-13% of
the batteries capacity rating, with a DOD somewhere between 20-50%

something like using one kwh a day with-


(four) 100 watt panels @ ~5 amps each



(one) 30A PWM charge controller



(two) Sam's club 6v 215Ah GC2 batteries





the batteries seem to be a limiting factor here for me. In the area here, of the batteries or
brands I've heard recommended, I can only find:



Trojan SCS 12v 130Ah for $250


Sam's club 6v 215Ah for $89 each


The guy at this place Battery Post also recommended a Trojan 12v 105 Ah, though i'm not
sure about the price, so i'm gonna call tomorrow


_____________________________________________




my goals are, at the core, to run at least one 100 watt water pump for half an hour, and a
300 watt electric rice cooker for about half an hour. I'd possibly want to run another water
pump also, with similar wattage.

right now I actually have two 100 watt panels, and I'd much rather use just these two, or even
just one panel, and a lower capacity battery, to save $300 on the panels that I don't have.
if the Sam's club GC2's are cheaper and higher capacity though, and I need to buy more panels
to keep a good balance, I definitely want to consider it. I can always find and plan on more things
to power.

I'm looking for suggestions on how to acheive these goals, using any variation really that you
can think of. I'd love to do two systems of a 100 watt panel each, but I don't know if that would
make sense given what batteries are available or advisable. As far as batteries go, I have access
to Walmart, Sam's club, Costco, and a few places like Autozone.





so you probably know something that I don't/ how could I achieve these goals without buying
more stuff than I need to?

[paulcheung]

If you going to buy Trojan battery, buy The T105RE, that is true deep cycle battery with smart carbon technology. 2 x 6 volt.

[Sunking]

Batteries require a charge current of 8 to 15%.

You are making a very expensive mistake using 100 watt battery panels and PWM controller. 400 watts of panels with a PWM controller is not going to make 1 Kwh/day year round as that requires 5 Sun Hours. Unless you live in Tuscon AZ or Hawaii, you will be in the dark all winter.

12 volt 215 AH GC batteries can only handle a 600 watt Inverter.

[johnathanmatthew]

If you going to buy Trojan battery, buy The T105RE, that is true deep cycle battery with smart carbon technology. 2 x 6 volt.

yeah, I've heard that the T105RE is really highly recommended/ I'm not sure that I'm able to spend money on two of those right now

Batteries require a charge current of 8 to 15%.

You are making a very expensive mistake using 100 watt battery panels and PWM controller. 400 watts of panels with a PWM controller is not going to make 1 Kwh/day year round as that requires 5 Sun Hours. Unless you live in Tuscon AZ or Hawaii, you will be in the dark all winter.

12 volt 215 AH GC batteries can only handle a 600 watt Inverter.

heck yeah, thanks for replying,

the 8-15% number is new to me, so that's great to know, and the 600 watt
inverter info is great too, I didn't know that. I've been looking in the 400-500
watt range for an inverter just because I don't really plan on powering anything
that uses more electricity than that.


I don't actually need to use 1kwh a day, so I'd love to scale down the hypothetical
set-up, but I'm not sure what battery to go with. this would be in South Carolina
and I see numbers for average hours of full sun between 4.5 and 5 for non-tracking
panels.


It's probably useful to say that these panels state an open voltage of 22.5v
and an optimum operating voltage of 18.9v. Also says optimum operating amperage
is 5.29A

[Sunking]

For a pair of golf cart batteries requires either a single 250 watt grid tied panel 20 amp MPPT controller, and 1 mounting bracket.

or

400 watt (4-100 watt battery panels) wired in parallel, 5 port combiner, 5 fuses, 4 mounting brackets, and a 20 amp PWM controller.

Both deliver the same amount of power of 20 charging amps a perfect C/10.

[Sunking]

I don't actually need to use 1kwh a day, so I'd love to scale down the hypothetical
set-up, but I'm not sure what battery to go with. this would be in South Carolina
and I see numbers for average hours of full sun between 4.5 and 5 for non-tracking
panels.

No you do not have 4.5 to 5 Sun Hours. That is yearly average which you do not use for battery systems. You use worse case in the months of December/January. You have 3.9 in winter months.

Lastly for 1 Kwh per day use you need a 400 AH battery.

[johnathanmatthew]

No you do not have 4.5 to 5 Sun Hours. That is yearly average which you do not use for battery systems. You use worse case in the months of December/January. You have 3.9 in winter months.

Lastly for 1 Kwh per day use you need a 400 AH battery.

Yeah, yearly average/ heck yeah, the 400ah number is good to know



I don't actually need a kwh a day/ I'd love to scale it down if there
were reasonable battery options. I'll just keep looking into batteries
I guess.

[inetdog]

Batteries require a charge current of 8 to 15%.

For those who have trouble remembering two digit numbers. the range can also be described as C/12 to C/8 or maybe C/7, with C/10 (10%) being the "ideal" for the typical FLA battery. The range is different for AGM (check the manufacturer's specs for a particular battery), and it so skewed to the low current side for most GEL batteries that they are not appropriate for solar PV purposes.

[Sunking]

I don't actually need a kwh a day/ I'd love to scale it down if there were reasonable battery options. I'll just keep looking into batteries I guess.

A pair of GC batteries is just fine. They can handle up to a C/4 discharge rate (50 amps on a 200 AH battery). But they will need a minimum 300 watts with a 15 amp PWM controller using battery panels, or a 200 watt panel with a 15 amp MPPT controller. That will give you roughly 600-800 watt hours of usable power in your area. Everything has to be balanced and matched to work with each other.

It all starts with determine how much power you need in a day. Not buy something and hope it works because that plan always fails. If you want 1 Kwh/day in your area requires a 400 AH battery, 350 watt panel with a 30 amp MPPT controller.

With PWM and battery panels requires 500 watts of panels and a 30 amp PWM controller.

A MPPT system using GT panels will cost you with battery around $1500. If you cheap out using an inexpensive PWM route with battery panels around $2000 plus combiners, fuses, larger wire adding a few hundred more on top of $2000.

PWM and battery panels is not the route you want, Spend the $400 on a MPPT controller, much less expensive than a $50 PWM controller.

[Living Large]

I don't actually need a kwh a day/ I'd love to scale it down if there
were reasonable battery options. I'll just keep looking into batteries
I guess.

Don't look at any batteries until you know exactly how much power you need each day. Otherwise, you will end up with a system that is too large or too small. You really don't want either to happen - because you are trying to be thrifty and also will have minimum needs.

Your power needs aren't trivial here. That is step 1, not step 3 or 4.

[Willy T]

While it is true that using GT panels is a cheaper system for the output you get, there can be a problem with shipping them. They cannot be shipped UPS and require truck freight shipping or specialized shipping and it can be very expensive for 1 or 2 panels. Solar panels are shipped to the distributor on a pallet of 20-25 panels. To ship to you they have to be boxed and are very fragile to put on truck freight and many arrive damaged.

Before you order, get a freight quote. It's best to try to source them locally from a Solar Company or Home Depot, Lowes and the like and beat the shipping cost compared to $40 - $ 50 or more per panel to ship them.

[johnathanmatthew]

Don't look at any batteries until you know exactly how much power you need each day. Otherwise, you will end up with a system that is too large or too small. You really don't want either to happen - because you are trying to be thrifty and also will have minimum needs.

Your power needs aren't trivial here. That is step 1, not step 3 or 4.

Thanks for trying to help, Living Large

my goals are, at the core, to run at least one 100 watt water pump for half an hour, and a
300 watt electric rice cooker for about half an hour. I'd possibly want to run another water
pump also, with similar wattage.

this works out to around 200-250wh right?





anyone have an opinion about these two batteries?

http://www.trojanbattery.com/product/24tmx/

http://www.trojanbattery.com/product/27tmh/

[johnathanmatthew]

While it is true that using GT panels is a cheaper system for the output you get, there can be a problem with shipping them. They cannot be shipped UPS and require truck freight shipping or specialized shipping and it can be very expensive for 1 or 2 panels. Solar panels are shipped to the distributor on a pallet of 20-25 panels. To ship to you they have to be boxed and are very fragile to put on truck freight and many arrive damaged.

Before you order, get a freight quote. It's best to try to source them locally from a Solar Company or Home Depot, Lowes and the like and beat the shipping cost compared to $40 - $ 50 or more per panel to ship them.

that's really interesting about grid-tie panels- definitely something i'll remember/ I'll probably check out Lowes, just to see what that situation is like

[noviasolar]

hey , been reading a lot of threads here and on other forums the past couple weeks, and
it seems like you guys really know what you're talking about/ so maybe you can help clear some
confusion or doubts that I have about the system I'm setting up




I read somewhere that an Ideal balance would have the solar panels generating 5-13% of
the batteries capacity rating, with a DOD somewhere between 20-50%

something like using one kwh a day with-


(four) 100 watt panels @ ~5 amps each



(one) 30A PWM charge controller



(two) Sam's club 6v 215Ah GC2 batteries





the batteries seem to be a limiting factor here for me. In the area here, of the batteries or
brands I've heard recommended, I can only find:



Trojan SCS 12v 130Ah for $250


Sam's club 6v 215Ah for $89 each


The guy at this place Battery Post also recommended a Trojan 12v 105 Ah, though i'm not
sure about the price, so i'm gonna call tomorrow


_____________________________________________




my goals are, at the core, to run at least one 100 watt water pump for half an hour, and a
300 watt electric rice cooker for about half an hour. I'd possibly want to run another water
pump also, with similar wattage.

right now I actually have two 100 watt panels, and I'd much rather use just these two, or even
just one panel, and a lower capacity battery, to save $300 on the panels that I don't have.
if the Sam's club GC2's are cheaper and higher capacity though, and I need to buy more panels
to keep a good balance, I definitely want to consider it. I can always find and plan on more things
to power.

I'm looking for suggestions on how to acheive these goals, using any variation really that you
can think of. I'd love to do two systems of a 100 watt panel each, but I don't know if that would
make sense given what batteries are available or advisable. As far as batteries go, I have access
to Walmart, Sam's club, Costco, and a few places like Autozone.





so you probably know something that I don't/ how could I achieve these goals without buying
more stuff than I need to?

if you need a battery for storage or something concerned with Solar, a lot of things that could be your Recommendations. Or for a project, whatever it is that requires energy. We can direct you.
Can you check on our

thanks

I have removed your advertising link and you get a one week ban for my trouble

[weijing3344]

If you going to buy Trojan battery, buy The T105RE, that is true deep cycle battery with smart carbon technology. 2 x 6 volt.

Do you knows ReneSola?Or Yingli, or Trina?
How about these quality,warranty,customer service?