Hey guys, this is my first post here and I have a question. We just installed (18) 250W panels on our house, but for some reason they sent me 19. I didn't have authorization to install 19 panels on my home, so I called the company and they sold me the extra one at cost. I installed it on my RV with a 3000 W pure sine inverter. My battery bank consists of two, six volt golf cart batteries.
We boondocked all summer in the National Forests and beaches (lots of shade or over cast conditions), and what I found was that I need a bigger battery bank. Not double the ample hours bigger, but a little bigger). For this reason and the size, and weight factor, I was hoping to add a large 12 volt deep cycle battery to the golf cart bank.
I going to relocate my current battery bank and install them under the dinette seat (that I already plumbed and vented to the outside with a large DC powered computer fan). Is this possible? Can I add a single 12 volt battery to my (2) 6 volt battery bank (wired in a series of course). Logically I don't see why it would matter, but I wanted to double check. Thanks for your time.
waltben said
03:49 PM Aug 28, 2014
Everything I've EVER seen about battery banks is that all the batteries have to be the same size, capacity and age. Any differences between them causes them to charge or discharge each other all by themselves. It's the same reason one doesn't use an old battery with a new one in a flashlight or whatever. Besides that, one 250 watt panel wouldn't charge more than your two 6 volt batteries (if they're of decent size) in less than a couple of days. I've 400 watts and over 20 amps going into four T-105s and it takes at least two days of good sunlight to recharge them from 60% SOC. Since we don't boondock for more than a couple of days at a time, that's OK.
Lonney Wade said
11:32 PM Aug 28, 2014
If the 12 volt battery is smaller than the (2) 6 volt batteries, when I say smaller I mean amp hours, the 12 volt battery will come up first in charge and the (2) 6 volt batteries are not charged all the way which will over charge the 12 volt battery and it will die first, it will die a dry death. You will have fun scratching your head with this one !!!!
Lonney
-- Edited by Lonney Wade on Thursday 28th of August 2014 11:34:39 PM
jimindenver said
07:58 AM Aug 30, 2014
My suggestion would be to add two more 6v under the dinette and leave the originals where they are.
May I ask what the company said was cost on the panel?
Bill and Linda said
02:55 PM Aug 30, 2014
waltben wrote:
Everything I've EVER seen about battery banks is that all the batteries have to be the same size, capacity and age.
What he said.
You do not want to mix battery types / sizes or even old and new batteries.By old and new I mean batteries older than 6 months (max IMO) with new batteries.If you do you will ruin some if not all of them.Sorry, just the way it is.It’s that chemistry / electricity thing.
If you want more capacity the only real way to do that is to purchase batteries of like kind, including brand, to make up the bank size you require or you will be wasting your money. Banks of 6 volt batteries are considered by most to be the best choice. You do want deep cycle batteries. But remember, batteries should not be discharged to more than one-half their rated capacity or you will seriously shorten their life. So a bank with 200AH is good for only 100AH of discharge
The Schweitzers on the road said
06:53 PM Sep 16, 2014
waltben wrote:
Everything I've EVER seen about battery banks is that all the batteries have to be the same size, capacity and age. Any differences between them causes them to charge or discharge each other all by themselves. It's the same reason one doesn't use an old battery with a new one in a flashlight or whatever. Besides that, one 250 watt panel wouldn't charge more than your two 6 volt batteries (if they're of decent size) in less than a couple of days. I've 400 watts and over 20 amps going into four T-105s and it takes at least two days of good sunlight to recharge them from 60% SOC. Since we don't boondock for more than a couple of days at a time, that's OK.
x2 on your statement regarding battery setups.
I am puzzled about the time your panels need to recharge your battery bank. Doesn't sound right to me. Your bank is 464 amphrs. 60% SOC is about 275 amphrs left, so roughly 190 amphrs to recharge. With the panels producing over 20 amps one day of good sunlight (8-9 hours) should recharge the bank almost completely. The next day would be the topping off. If you need at least two days to recharge there must be something wrong. What kind of controller do you have installed?
We have two T105 and 230w panels. Whatever we use overnight is recharged the next (sunny) day.
Hey guys, this is my first post here and I have a question. We just installed (18) 250W panels on our house, but for some reason they sent me 19. I didn't have authorization to install 19 panels on my home, so I called the company and they sold me the extra one at cost. I installed it on my RV with a 3000 W pure sine inverter. My battery bank consists of two, six volt golf cart batteries.
We boondocked all summer in the National Forests and beaches (lots of shade or over cast conditions), and what I found was that I need a bigger battery bank. Not double the ample hours bigger, but a little bigger). For this reason and the size, and weight factor, I was hoping to add a large 12 volt deep cycle battery to the golf cart bank.
I going to relocate my current battery bank and install them under the dinette seat (that I already plumbed and vented to the outside with a large DC powered computer fan). Is this possible? Can I add a single 12 volt battery to my (2) 6 volt battery bank (wired in a series of course). Logically I don't see why it would matter, but I wanted to double check. Thanks for your time.
If the 12 volt battery is smaller than the (2) 6 volt batteries, when I say smaller I mean amp hours, the 12 volt battery will come up first in charge and the (2) 6 volt batteries are not charged all the way which will over charge the 12 volt battery and it will die first, it will die a dry death.
You will have fun scratching your head with this one !!!!
Lonney
-- Edited by Lonney Wade on Thursday 28th of August 2014 11:34:39 PM
May I ask what the company said was cost on the panel?
What he said.
You do not want to mix battery types / sizes or even old and new batteries. By old and new I mean batteries older than 6 months (max IMO) with new batteries. If you do you will ruin some if not all of them. Sorry, just the way it is. It’s that chemistry / electricity thing.
If you want more capacity the only real way to do that is to purchase batteries of like kind, including brand, to make up the bank size you require or you will be wasting your money. Banks of 6 volt batteries are considered by most to be the best choice. You do want deep cycle batteries. But remember, batteries should not be discharged to more than one-half their rated capacity or you will seriously shorten their life. So a bank with 200AH is good for only 100AH of discharge
x2 on your statement regarding battery setups.
I am puzzled about the time your panels need to recharge your battery bank. Doesn't sound right to me. Your bank is 464 amphrs. 60% SOC is about 275 amphrs left, so roughly 190 amphrs to recharge. With the panels producing over 20 amps one day of good sunlight (8-9 hours) should recharge the bank almost completely. The next day would be the topping off. If you need at least two days to recharge there must be something wrong. What kind of controller do you have installed?
We have two T105 and 230w panels. Whatever we use overnight is recharged the next (sunny) day.