Best Controller for Gel Cell

[Canine]

I picked up 4, 139a/h (per battery), gel cell batteries that are three-years-old. Am favoring a Morningstar controller, but am also interested in the Blue Sky controller that allows excess solar energy to be diverted to a dump load. While salvaging excess solar wouldn't be a huge gain, using whatever energy one can squeeze out of the solar panels would be that much more efficient. Even if it is used only for partially heating the interior or pre-heating water. My primary concern is using the best controller that can be adjusted to best charge a finicky gel cell. If I can salvage any excess solar, that would be a bonus.

What would be the best controller for the C&D brand batteries?

 

[jimindenver]

My Morningstar controller is highly adjustable which is what I needed for the Lifelines. I would suggest looking at the manual of any of the controllers to make sure they can be set as needed.

 

[akrvbob]

I really know nothing about gel cells, but I am a big fan of the Blue Sky 3000i. Using just what's on it's face (no other purchase) you can set the absorption voltage up to 15 volt and the time you hold it at absorption voltage.
Bob

 

[jimindenver]

When considering a diversion load, check and see what the limitations of the load terminals are. In some cases it isn't enough to do a lot.

 

[BradKW]

Bob:  "I am a big fan of the Blue Sky 3000i. Using just what's on it's face (no other purchase) you can set the absorption voltage up to 15 volt and the time you hold it at absorption voltage."

It sounds like you saying that isn't a common feature on controllers, which has me wondering why not? Also, after reading several product descriptions for the BlueSky 3000i from different vendors, I couldn't spot this feature in the literature. Not saying it isn't exactly as you describe, just asking how do I identify this feature in the 3000i and other controllers I might be considering?
TY

 

[Optimistic Paranoid]

Gel batteries require a lower charging voltage than either Flooded or AGM batteries, and can, in fact, be damaged if charged with flooded settings.  Morningstar's Tristar MPPT controllers have a special setting for Gel batteries, the absorption setting is 14.00 volts, as opposed to the higher 14.40 to 14.70 settings available for Flooded or AGM batteries.  There is also a "Custom" setting that you can program yourself with a PC if you need really special settings.  All of this information is available in the Tristar manual, which you can find on their website as a pdf.  I'm not sure if their pwm controllers also have a Gel setting or not, you'd have to check that yourself in their manuals.

The other issue is: were you planning to also charge the house batteries from the engine?  Cause I think there is a real chance that would damage the Gel batteries.

Regards
John

 

[SternWake]

Are you sure the batteries you got are actually gel batteries and not AGM?  Lots of people tend to call any sealed battery a gel cell, but gelled electrolyte and electrolyte absorbed in a Glass matt are two entirely different batteries.

Are these Used Telecom batteries?

Figuring out the manufacturer recommended absorption voltage is the best course of action, and a controller which allows adjustment of voltage and duration.

As for the load diversion, I'd not use it if my sb2512i controller offered it.( the 2512ix does)

If I have excess solar that day, I plug in the laptop to charge, or crank up my fridge, or perhaps turn on the 50 watt heating pad under my shower bag, if I worry about it at all.  Its not as if one is burning fuel doing nothing when one has excess solar, pouring money down the toilet.

I understand not wanting a solar watt to goto waste, but this is not an issue, and when dwelling full time is not likely to happen often anyway.

So if you find a controller you like that can handle you wattage, and has adjustable ABSV and duration, but does not have a load diversion, don't stress it.

In many cases automatic=oblivious

I am not familiar with all the current offerings on Solar controllers, and anything other than my sb2512i, would be hearsay.

Here is a pretty good read about batteries from C&D tech:

http://www.cdtechno.com/pdf/ref/41_2128_0212.pdf

 

[Canine]

They are AGM not gel cell. Doh! I was looking at some gel cell, too, but went with AGM. Honestly, I thought the ones I got were gel cell. These have a higher a A/H rating, so that sold me. I can't believe how something so small can weigh so much!!

I'm not sure if they are from Telecom specifically, but they are from an application that I believe may be exactly what Telecom uses them for. (Cell phone towers, repeaters, etc.)

The one in the link below is what I was thinking of using. Once the batteries have all the juice they need, the extra power, whether it comes from solar or wind or any generator, can be diverted into a dump load. It looks like I could get up to 70 amps of diversion which would be more than my pv panels could deliver. JimInDenver, that would be better than an LVD. While an LVD seems to be the same thing as a diversion controller, it can handle no more than about 20 amps, which wouldn't take advantage of all the excess solar power I would have. An LVD would be better than nothing (like a 50 to 200 watt heating pad), but would like to take advantage of all the sun I absorb.

http://www.blueskyenergyinc.com/products/details/solar_boost_3024il_duo

It is adjustable for AGM's or other types of batteries. The manufacturer recommended charging  for my batteries is 13.5 to 13.8 volts; this looks like the one for me so far. ($500+ though! Ouch!)

Sternwake, I'm surprised you wouldn't use the LVD option if you had it. If you were in a colder environment or had more of a desire to heat water, would you then use the LVD option? What you do is a manual version of taking advantage of excess solar, but I want to have an automatic function to work when I'm gone.

Optimistic Paranoid, the alternator on the 78 Ford is small, so I didn't have plans to do that. When I eventually replace it with a larger one, I will consider that route. If I do, it will be routed through the controller if that is possible.

I'm glad to hear you guys/gals are using either the Blue Sky or Morningstar- that is what I narrowed it down to.

BradKW, I looked at the manual and it says it can change the charge; the factory setting is 14.4v. If that is correct, I am surprised it isn't emphasized in the description as that is an important feature with the variety of batteries we see nowadays.

After reading about the Solar Boost Duo, is a combination MPPT/PWM controller with the PWM being the slave controller that would allow a resistive dump load. If I understand that correctly, having both in one system is a neat idea.

Do PWM's generate more heat as they are less efficient? The energy from the generator has to go somewhere and it sure seems like it would be heat.

 

[akrvbob]

It sounds like you saying that isn't a common feature on controllers, which has me wondering why not? Also, after reading several product descriptions for the BlueSky 3000i from different vendors, I couldn't spot this feature in the literature. Not saying it isn't exactly as you describe, just asking how do I identify this feature in the 3000i and other controllers I might be considering?
TY

I've never looked at the product descriptions. I have a friend bought one and read the manual to learn how to do it. You can always download the manual to find out exactly what they can do.

No, several controllers require you to buy other things to get a display and control over them. Why? So you have to buy something else and keep the price down for people who don't want that feature.
Bob