Benefits of Gel batteries

[Gambia river lodge]

Hi,
I was recomended by my local battery supplier to purchase Gel batteries for a system i am building. They are 180ah Decka 8ggc2 6v, i know i am to late because on there recommendation have purchased them now, but for others, are there any benefits other than what seems to be 'maintenence free'.

[s.xavier]

Gels and AGMs batteries are pretty cool imo. They each will have a place but it really comes down to what it is you are trying to do.

What type of system are you looking to setup?

[Naptown]

Gel batteries are generally not good for RE systems. The charge rate is too low to be able to recharge with solar without damaging the battery. Sunking has a better explanation than I do.

[Gambia river lodge]

Naptown, that is what i mean, as you have said charge rate is much lower, in my case i should be ok with the array being in Gambia West Africa, my average sun hours is 8.5 and maintenance is a big thing for me, however my batteries are plastered with a great big SOLAR sticker, that appears to be very missleading, but are there no other benefits, why would anyone in the western hemisphere even consider these?

[russ]

Naptown, that is what i mean, as you have said charge rate is much lower, in my case i should be ok with the array being in Gambia West Africa, my average sun hours is 8.5 and maintenance is a big thing for me, however my batteries are plastered with a great big SOLAR sticker, that appears to be very missleading, but are there no other benefits, why would anyone in the western hemisphere even consider these?

Because of shyster companies and salesmen misleading people.

[Wy_White_Wolf]

Naptown, that is what i mean, as you have said charge rate is much lower, in my case i should be ok with the array being in Gambia West Africa, my average sun hours is 8.5 and maintenance is a big thing for me, however my batteries are plastered with a great big SOLAR sticker, that appears to be very missleading, but are there no other benefits, why would anyone in the western hemisphere even consider these?

Now we know why your having such a problem with batteries. You're way over-estimating the solar insolation for your location. I find no place in Gambia that averages over 6 hours.

Here's a link to solar insolation in Gambia. http://www.gaisma.com/en/dir/gm-country.html. Pick the location closest to you and use the "Solar energy and surface meteorology" chart


WWW

[russ]

As WWW pointed out - people generally over estimate the amount of light available. Hours early and late are not of much use. A person can expect approximately 85% of the insolation at a given site to be of use.

You then start with the derating for panels, inverters, wiring, batteries, less than optimal siting, specific local conditions. Mike has pointed out that at his place there is often a morning fog which slows everything up.

[Sunking]

Naptown, that is what i mean, as you have said charge rate is much lower, in my case i should be ok with the array being in Gambia West Africa, my average sun hours is 8.5 and maintenance is a big thing for me,

I think you are wrong on every account. No place on earth receives 8.5 Sun Hours, but really has nothing to do at all with your question what soever. So no use discussing that here on this thread.

The problem is charge rates, For Gel batteries the rate needs to be C/20 or less. So if you have say a 1000 AH battery, th charge amps should be 1000 AH / 2 h = 50 amps or less. In a properly designed and sized solar system the charge current on a 1000 AH battery is going to to 100 to 125 amps. Applying that charge current to a 1000 AH gel battery will destroy it on the first charge or two.

AGM and Flooded are completely different animals.

[Gambia river lodge]

Thanks for the replies,
I guess i have another mountain of work to do. Agree with sun hours, (was thinking of hot working hours) but what a pain in the backside these batteries have turned out to be. I still ask, why would any supplier recommend these!! SK i was thinking of half that size, but never the less i will have to rethink of what to do with these bloody batteries, i am almost out of time as i leave on Tuesday and very little internet there for research. Thanks for the 'wakeup' call, never to late to learn but in this case, very expensive!!
Thanks Mike.

[Sunking]

why would any supplier recommend these!!

Like anyone else with a product they are having trouble selling, they will say and do just about anything to get rid of them.

Even here in the USA you can find a few solar distributors that will carry Gel Cells, but the majority do not for said reasons. Gels Cells are popular with the alarm and emergency egress lighting industry where they can put a battery in a sealed box, trickled float charged, forget about it for 5 years, and only intended to be used once and hopefully never to be be used at all.

[Gambia river lodge]

Thanks SK, i know you hate this but, if i dont ask i wont get, i was planning on 3 banks of 8x6v 180ah @48v = 540ahr, with the 40amp and 35amp mppt controllers (you have also told me i screwed up there, by listening to the suppliers!!) and with plenty of 200w panels can i use these, OR. Can they be converted to electrolite?
Thanks Mike.

[Mike90250]

..i was planning on 3 banks of 8x6v 180ah @48v = 540ahr,.....

.... OR. Can they be converted to electrolite?....

Mike B. jumping in here.

So you are thinking of a 48V 1620Ah bank ? That should have at least, nearly 100A of charge current, to meet the minimum charge rate. And that would take close to a 6,000W PV array, about 30, 200W panels.
Much less PV, and you won't get the batteries charged properly, and they are likely to die early.
My bad, I'm thinking flooded batteries, since that's the pattern burned into my head. This charge rate would cook gel batteries. But you are not supposed to use gel for solar, another effect of a salescrook making money at your expense . I'll butt out now.

converted to electrolyte ? You mean, can gel batteries be converted to flooded cells ? Not possible. You would need new batteries. I don't know if the supplier can take them back, and exchange them for flooded batteries, or if they have already shipped.

[Sunking]

Are these gel batteries you are talking about?

I assume so. If that is true at 540 AH / 20 H = 27 amps. All you need is 1600 watts of panels and a 35 amp MPPT controller. Any more power than that on a 48 volt 540 AH Gel battery risk damage to the batteries. With 200 watt panels arranged in a 2 x 4 configuration.

As for converting gel to flooded is not possible.

[Gambia river lodge]

Sorry Mike,
I am trying to keep things simple and in the process forget to explain what i am doing, for now i need to build 3 seperate arrays and battery banks, yes all on their way (shipping one way 5,100 us/d) so they are not coming back, i have 108 x 200w panels and 6 x pcm 5048, 40a and 4 x pcm6048, 35a mppt controllers.
As SK pointed out with the controllers, the specification doe's not seem to stack up (but looked great at the time) along 48 x Decka 8ggc2 batteries, (again looked perfect at the time), i do have other batteries (2v 440ahr tractions) that i will now use in my 3 arrays, however, will i need to offload these F-----g gel batts or is there some use for them with the components i have.
Thanks for bad news about converting them (yes flooded, in the bottom of my crocodile pond i think)
Thanks Mike.

[Gambia river lodge]

WHAT A RELIEF!!!
SK i was writing when you posted, can you please check out the batteries for me just to be sure, (great big SOLAR sticker on them) i think they are USA made, and for peace of mind, (i have not slept WELL because of GEL!!) give me the layout for an array with these things, note'bly should i keep the arrays and batteries seperate.
Thanks Mike.