Off-grid solar charge controllers

[Sunking]

Jonathon in my 33 years of working with DC plants I can tell you there is nothing special about L-16 batteries over any other kind of deep cycle battery. Al L-16 means is it has specific physical dimensions. In fact they are not designed for RE applications. They are like golf cart batteries in that they were designed for something else. In the case of L-16 batteries they were designed for floor scrubbers.

Like golf cart batteries they just happened to be available when RE applications started taking off, and re branded with RE labels by the various manufactures. What made them popular is the physical size.

As for Equalization, they are like any other flooded lead acid battery. They only require an Equalization Charge when specific gravity falls below 1.250 or wide ranging specific gravity of greater than 0.030, after being fully charged.

The bad news for RE users is solar charge controllers do not lend themselves well to an EQ charge. Many units have the feature built in them, but unfortunately due to the time and power limitations of the system in low insolation areas, they cannot often apply a EQ charge long enough to accomplish the job. In which case one really needs a generator and a standard AC charger to accomplish the job.

[john p]

Sunking your statement ""The bad news for RE users is solar charge controllers do not lend themselves well to an EQ charge. Many units have the feature built in them, but unfortunately due to the time and power limitations of the system in low insolation areas, they cannot often apply a EQ charge long enough to accomplish the job. In which case one really needs a generator and a standard AC charger to accomplish the job."" Is just so spot on but it is usually never thought much about,,
As its usually about 2pm in the afternoon even in high solar isolation areas(5Hrs) before the batteries are charged close to "full"' and that only leaves about 2 hours at most to do the equalization.. If you live in a 4hr zone or less then there is not ever going to be enough time to do a good equalization.

[Mike90250]

Sunking your statement ""The bad news for RE users is solar charge controllers do not lend themselves well to an EQ charge. Many units have the feature built in them, but unfortunately due to the time and power limitations of the system in low insolation areas, they cannot often apply a EQ charge long enough to accomplish the job. In which case one really needs a generator and a standard AC charger to accomplish the job."" Is just so spot on but it is usually never thought much about,,
As its usually about 2pm in the afternoon even in high solar isolation areas(5Hrs) before the batteries are charged close to "full"' and that only leaves about 2 hours at most to do the equalization.. If you live in a 4hr zone or less then there is not ever going to be enough time to do a good equalization.

and that's why my big honking generator shed is next to the battery shed. Summertime, I rely on long absorb times to bubble and stir the electrolyte, but winters, I'll have to crank the beast up and bulk the batteries for a couple early morning hours, and then let the sun do it's share. Winters with their deeper discharges, is when cells are more likely to get out of balance, and need Eq.

And another reason to look at LiFe or NeFe

[MikeR]

A good reference for charging L-16 batteries is a Sandia Labs report (year 2000) titled "PV Hybrid Battery Tests on L-16 Batteries" website:www.Sandia.gov/pv "

I just wanted to say thanks for the link, it was helpful.

[russ]

In a rush to drop a spam link MikeR referred to the Sandia link previously posted.

The link is good and correct but apparently easily misunderstood.

Russ

[conntaxman]

MPPT charge controller

I know that Im going to get yelled at.But here goes. Putting my panels together, now next is getting a charge controller. As now i only have about 4 -65 watt panels or 240 watts .I will be adding up to I hope to get 1000 watts. For now I just want to start testing and thinking of getting a 30 amp MPPT from ebay, oh here it comes, from china.Well their around 100.00 something dollars and seem to do all that the others do.I know you get what you pay for.and all that stuff. But if it works, then I would go for something like a Xantrex or Morningstar MPPT. who had tried any from ebay? one I was looking at was Item number 260759604937 that was 30 amp.or this one 130503211145 If all works out well I want to take one room with my computers off the gird. and them another room so on so on.
imput.
tks
John
I could always sell the first one. lol

[MarineLiner]

I know that Im going to get yelled at.But here goes. Putting my panels together, now next is getting a charge controller. As now i only have about 4 -65 watt panels or 240 watts .I will be adding up to I hope to get 1000 watts. For now I just want to start testing and thinking of getting a 30 amp MPPT from ebay, oh here it comes, from china.Well their around 100.00 something dollars and seem to do all that the others do.
. . . .
imput.
tks
John
I could always sell the first one. lol

[conntaxman]

MPPT charge controller

[QUOTE=MarineLiner;22350]

[Mike90250]

Yes, Im going to buy one,and I guess I'll try one of the ones off ebay,for now their alot cheaper.I still cant see the big difference in them.If BOTH (Made in USA or china) say they will do A/B/C/ then their is no difference EXCEPT for the cost.Because most of the componets come form china or over seas. I think that the Unions are driving up the cost on everything, and that is why they cost sooo much. oh well, if I buy one from ebay I'll see how it works and report back with either good news or bad news.
But I seen many vid. on the net from people using ones from over seas and they seem to like them and work good.
John

I've heard here and at other boards, of many of the junk boxes from ebay, that just don't work for folks, either DOA, or it's a simple switching controller with a MPPT label on it, and till you actually measure the inputs and outputs, you have no way to tell what a POS it is. And there are the MPPT ones that are 50% efficient... So, good luck, somebody got one, and made a video of it working.

[conntaxman]

MPPT charge controller

I've heard here and at other boards, of many of the junk boxes from ebay, that just don't work for folks, either DOA, or it's a simple switching controller with a MPPT label on it, and till you actually measure the inputs and outputs, you have no way to tell what a POS it is. And there are the MPPT ones that are 50% efficient... So, good luck, somebody got one, and made a video of it working.

......
Dose any0ne have a Blue Sky SB2512i That one looks pretty good for the price.I would like to hear form someone that had one.
John

[Mike90250]

Reports about Blue Sky, is that it is an alright controller. Not as efficient as more recent designs, but better than PWM when array voltages are above 20V. But be sure you check the spec's about their Max voltage Input.

[sunny alex]

charge controllers in parallel

hello, i saw a thread in which it was advised that charge controllers were not to be paralleled at input side, they also said one should never parallel two MPPT chargers. how about PWM/MPPT. with same input source i.e same panel, both rated for maximum panel current and voltage.
just curious.
xcan you explain how they really work?
i also read the thread between jon, mike and sunking on MPPT and PWM, trying to decide which to use in high temperature zones like NIGERIA..
thanks,

[garyhgaryh]

I know that Im going to get yelled at.But here goes. Putting my panels together, now next is getting a charge controller. As now i only have about 4 -65 watt panels or 240 watts .I will be adding up to I hope to get 1000 watts. For now I just want to start testing and thinking of getting a 30 amp MPPT from ebay, oh here it comes, from china.Well their around 100.00 something dollars and seem to do all that the others do.I know you get what you pay for.and all that stuff. But if it works, then I would go for something like a Xantrex or Morningstar MPPT. who had tried any from ebay? one I was looking at was Item number 260759604937 that was 30 amp.or this one 130503211145 If all works out well I want to take one room with my computers off the gird. and them another room so on so on.
imput.
tks
John
I could always sell the first one. lol

I just bought one from amazon (no tax or shipping). Looks like one of those well-see brands people are talking about:

http://www.amazon.com/gp/product/B004XCQ7AS/ref=ox_ya_os_product

It was either this or a popular 30a sunforce unit:

http://www.harborfreight.com/30-amp-charge-controller-94790.html

I'll let you know how it works when I get it.

I have 3 45-watt HF solar kits and I'll be buying 3 more..
Gary

[Sunking]

Gary you are just throwing money away with HF panels as they are very low quality with less than normal optimum electrical specifications.

[garyhgaryh]

Gary you are just throwing money away with HF panels as they are very low quality with less than normal optimum electrical specifications.

You are probably right, but they are cheap and seem to work well. I'm just toying with solar right now. The reason why I plan on buying 3 more kits is because I can get them for $150. Not bad, although they take more panels to get the same amount of power than the real deal. 15watt per panel isn't every much and take alot of space compared to the others.

What panels do you recommend? (link would be appreciated)