Changed to solar and...... Wow!

[Olly]

Hi Ringo,
This is really a different topic so I will contribute but I have written about it on this thread recently http://www.dr1.com/forums/living/125688-need-couple-used-but-good-6v-batteries-please.html
Windeguy and I disagree on this but I have put it into practice for over a year now. This is what I have found. If you have a complete string of Batteries in a group of say three others - We have 12 batteries , three strings of four to give us 24 Volts . Put all new batteries into one string. Do not mix them with older batteries. In the other strings of old batteris , if one fails put in a "Similar" Battery. Capacity, approx age and definitely charge state must be similar. So in your case Ringo you would replace 8 new batteries , keep the old "Good" ones to replace batteries in the "Old Battery strings"

Check batteries using Battery Load Tested, disconnecting that string from the charger. ie remove a middle link somewhere.
Try to get "similar " batteries together.
I disagree with WW too. These batteries are in series in each string - each string will charge as if it stands alone. So long as you keep "each string the same " it works.

Hope that helps - HTH in TLA

Olly and the Team

 

[Ringo]

Hi Ringo,
This is really a different topic so I will contribute but I have written about it on this thread recently http://www.dr1.com/forums/living/125688-need-couple-used-but-good-6v-batteries-please.html
Windeguy and I disagree on this but I have put it into practice for over a year now. This is what I have found. If you have a complete string of Batteries in a group of say three others - We have 12 batteries , three strings of four to give us 24 Volts . Put all new batteries into one string. Do not mix them with older batteries. In the other strings of old batteris , if one fails put in a "Similar" Battery. Capacity, approx age and definitely charge state must be similar. so in you case Ringo you would replace 8 new batteries , keep the old "Good" ones to replace batteries in the "Old Battery strings"

Check batteries using Battery Load Tested, disconnecting that string from the charger. ie remove a middle link somewhere.
Try to get "similar " batteries together.
I disagree with WW too. These batteries are in series in each string - each string will charge as if it stands alone. So long as you keep "each string the same " it works.

Hope that helps - HTH in TLA

Olly and the Team

This is why asked the question. One side of me says... the older banks will bring down a ruin the new bank. But they ARE individual banks.... but strung together as........ ONE?

Differing opinions with different points of views and conclusions is wonderful. Given a little time and discussion we will learn.

Not sure if it will be the correct answer, but we learn.

I've Googled this to death along with most of my questions. YOU guys are a LOT better then Google.

Thanks guys. Great info from all.

 

[Olly]

Ringo , the situations we find here are pretty unique! We will all learn. Never stop learning was a famous quote by " someone"
Olly and the Team

 

[william webster]

This is why asked the question. One side of me says... the older banks will bring down a ruin the new bank. But they ARE individual banks.... but strung together as........ ONE?

Differing opinions with different points of views and conclusions is wonderful. Given a little time and discussion we will learn.

Not sure if it will be the correct answer, but we learn.

I've Googled this to death along with most of my questions. YOU guys are a LOT better then Google.

Thanks guys. Great info from all.

In reading here, I see we all have different opinions... but we're all amateurs.

Can we somehow get a definitive answer? to the question : can you or how do you mix batteries?

I am not going to do it tonite, but I will try later, to get to the bottom of this.

My installer is adamant about this - don't mix them.

We shall see and keep learning.... it s a new thing , this solar - still learning

 

[Olly]

WW,
Was your installer an Electrical Engineer - PE etc or just a trained technician or less ?

Olly

 

[william webster]

WW,
Was your installer an Electrical Engineer - PE etc or just a trained technician or less ?

Olly

Not sure Olly, but I gave the website earlier. He should be documented there.
His name is Richard Ellis 809-768-4073. He would be happy to talk about this.
He's American with a Cdn backgound who lives in Cabrera.
He just finished an orphange in Haiti.

Thinking about battery banks, obviously if the banks aren't linked then one bank cannot affect the other (one would assume).
If hooked up together, then they will affect each other

 

[Olly]

WW and all,
There are a lot of aspects to this issue and a number of types of battery. The situation I am discussing is 12 Deep Cycle Lead Acid batteries in a series / parrallel arrangement connected to a fairly sophisticated 5.5 kW 220V invertor.

From what many of you are saying is that you have solar, battery banks some with Gel Batteries, sophisticated solar controllers and I am not addressing that situation.

I have let you know through other posts what has happened and will continue to update you. Perhaps we should start a new thread for this!


Olly and the team

 

[william webster]

WW and all,
There are a lot of aspects to this issue and a number of types of battery. The situation I am discussing is 12 Deep Cycle Lead Acid batteries in a series / parrallel arrangement connected to a fairly sophisticated 5.5 kW 220V invertor.

From what many of you are saying is that you have solar, battery banks some with Gel Batteries, sophisticated solar controllers and I am not addressing that situation.

I have let you know through other posts what has happened and will continue to update you. Perhaps we should start a new thread for this!


Olly and the team

Yes, mine are gel type and very controlled.
They will not let themselves "expire", auto shutdown.
When charging, they will not overcharge - they slow down as they top up.

Its the OutBack System that I have.

 

[windeguy]

While Olly has seen reasonable success in added a bank of new batteries to old ones, I suspect that the new batteries are being quickly "aged" into the condition of the remaining banks. Now that could still be a good trade off over buying 3 or 4 banks of batteries at one time if the total lifetime is a good financial trade off.

I recommend calling directly into the sales engineers at Trojan, US Battery etc. They should be able to answer your questions about adding a new bank to old banks of batteries. Here are there contact pages:

Trojan Battery Company

U.S. Battery - Contact Form

 

[windeguy]

From everything I have read about Gel batteries, they are best for remote applications where maintenance is hard to perform on a regular basis. For most applications, including most applications in the DR for household use, wet cell lead-acid batteries such as the Trojan T-105 are more cost effective.

 

[Olly]

Windeguy, WW -
will keep you posted! That's all I can say at present.
But yes it is a complicated trade off and cost is a factor.

Thanks for the acknowledgement of "reasonable success" Windeguy!

Olly and the Team

 

[Frank the Tank]

Very interesting and informative thread.

 

[Ringo]

From everything I have read about Gel batteries, they are best for remote applications where maintenance is hard to perform on a regular basis. For most applications, including most applications in the DR for household use, wet cell lead-acid batteries such as the Trojan T-105 are more cost effective.

Interesting.

But let us look at the trade off's of wet vs gel.

I boiled my 3 banks yesterday, 24 older batteries. It took 4 hours at 40 amps. If done once a month, what is the costs just to boil them?
Any real difference in the cost while in the float stage? Bulk charge after a blackout?
Also the cost to maintain them? The mess and acid that has to be cleaned up and replacing battery cables?
Do gel last longer? I think we all agree that we are lucky to get 4 years out of our wet batteries then it costs more to keep them charged and to boil.

Being that I can not boil my wet batteries from my solar system, just not enough amps, I have to use the generator or my great and wonderfull friend......... EDENORTE. (I used the generator but also had pool and washer/drying going)

 

[william webster]

I don't have my file w/me but I think the gel batteries are $300 eack +/-.... not sure.

Life is much better than 4 yrs.

 

[windeguy]

I don't have my file w/me but I think the gel batteries are $300 eack +/-.... not sure.

Life is much better than 4 yrs.

Then the Gel batteries would have to last about 6 years to be cost effective if $300 each is the price in the DR. Are they 225 AH batteries?

 

[windeguy]

Found some reasons why one Solar Power company no longer sells GEL batteries

Found some reasons why one Solar Power company no longer sells GEL batteries

Interesting.

But let us look at the trade off's of wet vs gel.

I boiled my 3 banks yesterday, 24 older batteries. It took 4 hours at 40 amps. If done once a month, what is the costs just to boil them?

48Volts X 40 Amps X 4 Hours = 7.680 KWH X$RD 10.86/KWH => $RD 83 per month to equalize.

Any real difference in the cost while in the float stage? Bulk charge after a blackout?

YES INDEED: I found this at

Deep Cycle Battery FAQ

Gelled batteries, or "Gel Cells" contain acid that has been "gelled" by the addition of Silica Gel, turning the acid into a solid mass that looks like gooey Jell-O. The advantage of these batteries is that it is impossible to spill acid even if they are broken. However, there are several disadvantages. One is that they must be charged at a slower rate (C/20) to prevent excess gas from damaging the cells. They cannot be fast charged on a conventional automotive charger or they may be permanently damaged. This is not usually a problem with solar electric systems, but if an auxiliary generator or inverter bulk charger is used, current must be limited to the manufacturers specifications. Most better inverters commonly used in solar electric systems can be set to limit charging current to the batteries.

Some other disadvantages of gel cells is that they must be charged at a lower voltage (2/10th's less) than flooded or AGM batteries. If overcharged, voids can develop in the gel which will never heal, causing a loss in battery capacity. In hot climates, water loss can be enough over 2-4 years to cause premature battery death. It is for this and other reasons that we no longer sell any of the gelled cells except for replacement use. The newer AGM (absorbed glass mat) batteries have all the advantages (and then some) of gelled, with none of the disadvantages.

So this company would push AGM batteries instead.

 

[william webster]

Then the Gel batteries would have to last about 6 years to be cost effective if $300 each is the price in the DR. Are they 225 AH batteries?

Sorry, don't know the answer to that.

My conversations w/ my contractor is always in the 8yr +/- time frame for battery life

 

[Ringo]

Thanks windeguy. I have been reading since my post. The Gel's just don't seem to have the Amp hours and a little sensitive to charge rates thus adding charge time. The AGM's look good but the price looks over double with no real advantages.

My personal conclusion is that the T105 are the best for my application. I'll live with the acid mess, cable replacements and watering.

Thanks for doing that math for me/us.

I'm a little slow (er) this morning and construction people here starting driving me nuts starting at 8:30.

Other thoughts/research guys? Certainly I'm open to learning more.

 

[william webster]

I mentioned earlier that my charge and discharge is very controlled.

Now I know why.... gel batteries call for a slower charge.

Ringo, you're right - the fancy controllers can be programmed for specific battery types.

 

[Frank the Tank]

What has been your experience with these?