Inexpensive controllers and AGM batteries

[MagicMikeJ]

I know everyone here prefers the expensive name brand charger/controllers, but I'm on a tight/small budget. I can't afford to pay the same price for a controller that I do for a couple panels. I was looking at getting an AGM 12v battery, was hoping for a 150ah but may have to settle for a 100ah. I was also planning on just getting 1 - 150 watt panel. I understand that AGM's have different charging requirements than FLA's, but I'm not fully understanding what they are.

When looking at inexpensive charger/controllers, usually the only settings you can change are the voltage at which they stop charging (and I assume go into float charge), and 2 under voltage settings that relate to load, and I won't be putting the load thru the controller so that doesn't matter. Is this one setting enough to be able to use them with an AGM? When people ask the 'can it be used with agm' question, the answers always say something like"no, it says it's for lead acid NOT gels"...... and that doesn't really answer the question, since they ARE lead acid, just sealed instead of vented.

On a side note, I saw this one on ebay that says it's an mppt/pwm unit, and is a little more expensive than a standard pwm, but not that much. I have a feeling it's not really an mppt... any knowledgeable comments? They have a pretty ambiguous statement regarding it: （Controller Provided MPPT Maximum power point tracking Function, charging mode is PWM)

Link: http://www.ebay.com/itm/New-LCD-10-2.../111411804592? (it's to ebay, hope it's ok to post the link)

Thanks in advance for whatever comments are given.

[jony101]

The mppt on your link is a "fake" mppt (its reviewed on youtube and its certified fake). A good real mppt will cost in the 100 dollar range(ecoworthy 20 amp mppt is a good example). But for a 150 watt panel you dont need mppt. If the 150 watt panel puts out over 30 volts than mppt can be useful for you, but low voltage (20 volts) panels just need a pwm controller.

For a 150 watt panel all you need is a 10 amp pwm controller. I used a 15 dollar wincong 20 amp pwm controller I bought on ebay on both a 120 watt and 240 watt panel. Its reliable and never gave me any problems, it worked well on my agm batteries 75ah and 145 ah that it was hooked up to.

Agm batteries need about 14.4 volts to charge properly (but some might need more depends on the battery mfg) , float voltage is about 13.7 volts. Gel batteries are the ones that need special chargers. Agm are almost similar to FLA, but on agm you cant equalize them. If the controller has a equailize setting disable it. Equalize setting will cycle a high voltage pulse into the battery to desuphate the battery, agm dont need it and might damage the battery.

My advice get a 90 volt 30 amp combo meter (about 20 dollar on ebay) and connect it between the controller and battery, it gives you a very bright voltage/amps led reading that your controller is giving your battery. Its what i have, with it you always now the status of your battery. In my picture I made a fancy box for the combo meter, but no box is needed. The wincongs and cheap pwm controllers usually have no displays, thats why a combo meter comes in handy.

[MagicMikeJ]

Is WindyNation a better brand than the chinese 'solar 30' units I see going for around $30? The WN is $55 for the same 30 amps and same features it looks like.

I saw somewhere, I think it was Walmart advertising a Renogy 30 amp unit, in one picture said Renogy on the front, and 2 others said Solar30 on the front instead...... same mfg different logos (as is so common in pretty much everything these days)??

[PNjunction]

Since you don't really know what your requirements are, then a simple answer might just be to get 200w worth of panels, along with the controller they offer as a kit. Renogy and others have these that come with a controller. I think Renogy uses the Epsolar brand.

At the 200w level, the controllers tend to have ambient temperature compensation, and possibly "user customizable" paramaters that you can override the canned setups as your knowledge grows.

We're basically winging it, and at this stage the hands-on knowledge you'll gain may exceed the actual value of the gear itself. You may or may not kill a battery in the process, but that is the point of a learner-setup.

Attempts at figuring out which cc is best at the low-end of the market is kind of a crap shoot, and really filled with marketing hype. That being said, for my non-critical throw-around backyard renogy folding panel setup, the EPsolar cc that it came with works. Someday I'll put in a Morningstar, Steca or the like, but for a limited budget you really have no choice.

[SunEagle]

I know everyone here prefers the expensive name brand charger/controllers, but I'm on a tight/small budget. I can't afford to pay the same price for a controller that I do for a couple panels. I was looking at getting an AGM 12v battery, was hoping for a 150ah but may have to settle for a 100ah. I was also planning on just getting 1 - 150 watt panel. I understand that AGM's have different charging requirements than FLA's, but I'm not fully understanding what they are. When looking at inexpensive charger/controllers, usually the only settings you can change are the voltage at which they stop charging (and I assume go into float charge), and 2 under voltage settings that relate to load, and I won't be putting the load thru the controller so that doesn't matter. Is this one setting enough to be able to use them with an AGM? When people ask the 'can it be used with agm' question, the answers always say something like"no, it says it's for lead acid NOT gels"...... and that doesn't really answer the question, since they ARE lead acid, just sealed instead of vented. On a side note, I saw this one on ebay that says it's an mppt/pwm unit, and is a little more expensive than a standard pwm, but not that much. I have a feeling it's not really an mppt... any knowledgeable comments? They have a pretty ambiguous statement regarding it: （Controller Provided MPPT Maximum power point tracking Function, charging mode is PWM) Link: http://www.ebay.com/itm/New-LCD-10-2.../111411804592? (it's to ebay, hope it's ok to post the link) Thanks in advance for whatever comments are given.

MIke ---------------------Your first mistake is thinking about getting into solar power generation on a tight/small budget. The problem is if you spend little you get very poor quality or fake equipment like that "MPPT" CC you found. Fake as a 3 dollar bill. ---------------------You first have to determine what you want to do and then once a system is properly designed you can decide if you want to spend what it takes to cover it. ---------------------Starting out with "I don't have a lot of money so I will start small and then enlarge" is the wrong way of thinking and will end up costing you a lot more in the end. ---------------------So let us help you spend your money wisely. Oh I get nothing out of it except knowing I have helped someone understand solar technology.

[jimindenver]

The least expensive MPPT controller that is actually a MPPT controller is the Eco-worthy 20a. It is $102 shipped from the site and can usually be picked up for $85 shipped on ebay.

It has adjustable voltage set points for absorb and float. Will hold absorb for up to 300 minutes and has a equalization feature too. (new model) The features it is lacking is temperature compensation and voltage sense. Outside of that I have been using them for three years and they haven't let me down.

The next step up is the newer tracer line up for a bit under $200 and they do have TC. What they do with the temperature compensation is another question. The MS 15a MPPT was $225 last time I looked and it has all the features you could ask for.

[vudu]

I recently upgraded my (Renogy) pwm controller to this mppt controller ... it was 70 bucks

http://www.amazon.com/gp/product/B008KWPGS6?psc=1&redirect=true&ref_=oh_aui_detailpage_o06_s00

http://www.amazon.com/Vmaxtanks-VMAX-Rechargeable-Solar-Inverters/dp/B00DDYM1UC/ref=sr_1_2?s=electronics&ie=UTF8&qid=1441242097&sr=1-2&keywords=vmaxtanks

(I'm not an experienced solar person) Doing so got my 155ah [1] battery to float for the first time (other than charging it with AC via a trickle charger).
I believe I made a rookie mistake of buying this battery and expecting to well charge it with 2 panels - if I were to do it again I'd probably get 2 6 volt batteries or 4(series/para) panels and a 30amp mppt controller.

2 100w windy nation (in series)
155 ah battery
1) - http://www.amazon.com/Vmaxtanks-VMAX...ords=vmaxtanks

...
When looking at inexpensive charger/controllers, usually the only settings you can change are the voltage at which they stop charging (and I assume go into float charge), and 2 under voltage settings that relate to load, and I won't be putting the load thru the controller so that doesn't matter. Is this one setting enough to be able to use them with an AGM? When people ask the 'can it be used with agm' question, the answers always say something like"no, it says it's for lead acid NOT gels"...... and that doesn't really answer the question, since they ARE lead acid, just sealed instead of vented.

Yea, that caused me some head scratching.
One of the setting on this controller is 'Battery type' with 3 options
1) Sealed lead acid
2) Gel
3) Flooded

I'm using 1) - it seems to be doing the trick. The advice I'd give myself if I were doing this tiny system over is buy plenty of panels to well charge your battery.

As another example, I have 1 100w panel charging a 35ah AGM for my landscape system - and it does just fine bringing it to float (using a pwm) in a couple hours of good sun - coming up from about 30% discharge.

[Sunking]

If this is for everyday use or cycling, what voltage you set your controller at is really meaningless. There is no voltage high enough you could set. Unless you are one of the Rare Birds with over-sized panel wattage, your batteries are rarely ever fully charged. The best you can do is set the voltage as high as possible to force your Controller into BULK Mode for as long as sun falls upon the panels. That allows you to harvest every watt hour possible.

[PNjunction]

One of the setting on this controller is 'Battery type' with 3 options
1) Sealed lead acid
2) Gel
3) Flooded

Use the CC docs Luke to prove to yourself what the voltages are at those settings. Go by voltage, and NOT just the canned / silkscreened presets. At the low end, CC designers may just pull specs out of a hat. Here, they do have a gel setting, which indicates they *may* be on top of things, but you should doublecheck.

For instance, sealed lead acid may just mean 14.4v absorb, with NO equalization. Gel should mean 14.0-14.1v absorb and NO equalization. Flooded usually means 14.4v and may also include an automatic or manual EQ of 15.5v monthly.

These figures may differ somewhat, but if you don't check, and sealed-lead-acid is rated at only 14.2v in your CC, then you will quickly walk them down in capacity.

I'm using 1) - it seems to be doing the trick. The advice I'd give myself if I were doing this tiny system over is buy plenty of panels to well charge your battery.

That's fine. Just understand that you are not using pure-lead agm's, but those of the more conventional variety (if you are using pure-lead, let us know). In this case, the max continuous current due to the way they are manufactured and the compounds they use, is usually no more than 0.25C to maybe 0.3C.

As another example, I have 1 100w panel charging a 35ah AGM for my landscape system - and it does just fine bringing it to float (using a pwm) in a couple hours of good sun - coming up from about 30% discharge.

That's great, but is your cc on this project using a canned or silkscreen preset without checking the actual voltage? If it isn't near 14.4v for absorb, then you are most likely walking down capacity, which of course means shorter charge times! THIS is the real catch-22 for beginner's to look out for.

My suggestion since you are doing cyclic-service, and if the quality of the 35ah battery isn't some old abused ups-style trash, then set BOTH your absorb AND float to 14.4 - 14.7v. (see the battery docs of course) The sun going down will prevent staying in absorb for too long a period and this extended absorb will help to fully charge that battery - again provided it is in good condition in the first place.

[vudu]

Use the CC docs Luke

Docs? I'm a man OB1.

http://voile.org/panneaux_solaires/Tracer-2210RN.pdf

I read them, but am still not _certain_ which one this AGM pertains to. Pretty sure it is sealed, therefor using these settings.

Boost voltage 14.4V;
Float voltage 13.8V;
Boost return voltage 13.2V;

Hopefully those are in the ball park.

That's fine. Just understand that you are not using pure-lead agm's, but those of the more conventional variety (if you are using pure-lead, let us know).

Both these vmaxtanks were bought within a month or so. I'm unsure if they are pure-lead are but will research it. They seem modern and shiny.

That's great, but is your cc on this project using a canned or silkscreen preset without checking the actual voltage? If it isn't near 14.4v for absorb, then you are most likely walking down capacity, which of course means shorter charge times! THIS is the real catch-22 for beginner's to look out for.

There is no way to set them with either of the controllers I'm using as far as I can tell. So if I need to up the voltage I may be SOL - or get another CC.

I was monitoring it when it started floating it was at 14+ - a big relief compared to he PWM which never got above 13.5.

My suggestion since you are doing cyclic-service, and if the quality of the 35ah battery isn't some old abused ups-style trash, then set BOTH your absorb AND float to 14.4 - 14.7v. (see the battery docs of course) The sun going down will prevent staying in absorb for too long a period and this extended absorb will help to fully charge that battery - again provided it is in good condition in the first place.

They are brand new - if I have not killed them yet If they are not set exactly to that they are pretty close I think.

Thanks for taking the time to provide this great info!

Paul

[PNjunction]

Boost voltage 14.4V;
Float voltage 13.8V;
Boost return voltage 13.2V;

Hopefully those are in the ball park.

That's pretty much in line with the charging faq for them here:

http://www.vmaxtanks.com/FAQ_ep_42.html

You may want to take a look at the "commissioning" process for best overall life. You can either float them for up to 96 hours at 13.5 - 13.7, or if you are going to fast charge them (Ie with your solar), they want 14.5-14.9v for 12-24 hours.

If it were me, and seeing your CC manual, I'd be very tempted to put them into the "flooded" preset for this conditioning process. I note that flooded in the Tracer means 14.6v, with a 2-hour 14.8v EQ (this Tracer "eq" is not the traditional flooded eq of 15.5v but a much milder raising of voltage to only .2v above normal) I don't know when that EQ on the tracer kicks in.

Again, if it were me, with that controller and agm's that tend to get undercharged via cyclic solar anyway, I'd purposely choose "flooded" for the higher voltage - at the very least for the initialization process. Yet again, because of solar's natural light-switch at the end of the day, I'd also be tempted to just leave it in the flooded preset.

See how looking at voltage, and comparing it to your batteries requirements may mean that another canned preset might be a better idea, since canned preset labeling can be pretty generic. I'm sure the guys at vmax would have no problem with this charge regimen if you told them what the volatages were, although they may have zero practical experience with solar.

If it freaks you out, I'd just be sure to run the flooded algo for at least a week, and then you could back it down to sealed. Fortunately, that CC has no way of doing a true high-voltage eq as most of us are familiar with it, so it won't kill an agm with that. What WILL kill it is using "gel" with an agm. Yep, don't do that one.

[vudu]

...
If it freaks you out, I'd just be sure to run the flooded algo for at least a week, and then you could back it down to sealed. Fortunately, that CC has no way of doing a true high-voltage eq as most of us are familiar with it, so it won't kill an agm with that. What WILL kill it is using "gel" with an agm. Yep, don't do that one.

No it does not freak me out - I will put it in flooded battery type and leave it there for a week and see what happens.
I believe still (as sunking's sticky goes into in depth http://www.solarpaneltalk.com/showth...Your-Batteries) the fundamental thing is the panels are not enough energy to juice this battery.

Since it is a sealed battery I can't use a hydrometer without cracking it open so I left it unplugged entirely overnight. This morning the reading with a multimeter is 13.03. I think that means I have not done anything detrimental to it yet.

I may just keep this battery in the house instead of use it for solar - if our elect goes down, which it has twice this year for 4+ hours, at least I'll know I can plug my fridge in. And top it off with the AC charger now and then (I've done this once - it took a good 30 hours last time).

I'll pick up a couple of the 6v cart type batts for the shed - and get a hydrometer - I think maybe sunking thinks I'll need one

Thank you for taking the time to point me in the right direction. Paul