Using morningstar prostar 30 controllers in ways for which they were never intended.

oil pan 4 wrote: »

Is "sealed" the best option for AGM?

Depends on the model, but in your case yes. One should always go by the actual absorb voltage spec, and not just the canned settings or silkscreens. For instance, the SunSaver models have only sealed and flooded. In this model, "sealed" is about 14.1v, which is ok for gel, but will UNDERcharge a "sealed" agm. Thus, with that model, you choose flooded as a better choice in cyclic duties.

If you KNOW what you are doing, and using very high ends agm's, you could get away with setting flooded on the prostar 30, BUT you had better use the remote temperature compensation probe.

For now, your choice is ok.

Remember to always connect the battery to the controller first, and to the panels last.

The next application I am considering is using a Morningstar prostar 30 to charge my LiFePO4 batteries, a 4 cell series bank of AMP20 cells using no more than a few hundred watts of solar. I am thinking the "sealed" setting might be best for this too? Has any one tried this?

STOP RIGHT HERE.

Can you use it? Yes, but you had BETTER know what you are doing. It is not made for lifepo4, but you can put it into operation safely. That means using the GEL VOLTAGE setting of 14.0v. Obviously, this is not a gel, but we are going by voltage specs as a workaround. The reason for only 14v gel is that there is no reason to take lifepo4 to 100% SOC charge, and in your hacked together batteries, it is likely they are unbalanced. Setting it low for 14v allows a little wiggle-room.

You know that you have to DISABLE any sort of temp-comp right? And with this controllers built-in ambient temp-comp transistor peeking through the front, that means you have to DESTROY or cut it out, relying on the controller to default to no temp comp like my 15a Prostar. Not all controllers will like having their temp-comp circuitry cut out and still function.

My 60 amp hour LiFePO4 battery gets very hungry when it runs low and likes to drain every extra amp of power a vehicle alternator can produce, causing the belt to squeal and the alternator to get hot.

Yeah, that happens because of the low internal resistance, the alternator just maxes out forever etc. Many marine guys have found out this situation too. Not just with lifepo4, but in some cases with very low IR "pure-lead" lead batteries as well.

I would like to limit the charge with something other than a charge limiting resistor, unless I have to.

Instead of a hack, how about a decent charger - again something that can be shoehorned into use as long as you use the right voltages. In your case, either a Samlex SEC1215ul (15a) or SEC1230ul(30a) charger. That keeps the cells at .5c or below during charge, and also set to GEL (14v) is a reasonably sane stopping point, especially for any battery hacked together with cells of unknown origin.

Lifepo4 has been discussed elsewhere here, but I warn you to do a LOT MORE RESEARCH on the subject, and not just from "e-bike" or other forums that have no qualms about duct-taping unsafe crap/used/reject cells together. I'm personally using new GBS prismatics, although Winston or CALB are the other major players. No duct-tape crap on my bench.

I was hesitant to discuss the morningstar for use with lifepo4, since it is not really made for it, but have a feeling you might plow ahead anyway and at least give you some guidelines for proper use - especially for homebrew stuff.

I sure hope you did an initial top-balance on those cells.

Maybe any sort of followup should be done in the new battery tech subforum, as lifepo4 threads and discussions always turn ugly unfortunately.

oil pan 4 wrote: »

Oh no I don't have to use a Morningstar controller, I just read on here pretty recently that there still were no dedicated LiFePO4 charge controllers on the market.

You may want to look at Genasun for lifepo4 specific solar charge controllers. I've seen 'em at batteryspace and elsewhere.

The cells I bought were all new A123 cells made in korea, all with the same lot number. If they were rejects a least they were new and consistent rejects.

The new cells for the last few years have been made in the US in Livonia. You have to be careful with the Korean cells if you did not get them from an authorized dealer, as some early models were experimental, designed for differing customer needs, and can be generally hard to track down at this point for who/what they were really intended for. You may want to check with WB9K over on Endless-Sphere. Certainly I hope you don't have any missing the proper amount of kapton-tape, cut off cell tabs, missing zipper-fuses, and the like.

Basically you got several year old new-old-stock or worse, so be careful.

Personally, I'd ditch those questionable Korean cells, and start fresh from a REAL authorized A123 dealer. They ARE great cells, no question there. For our solar storage needs, perhaps a bit too much, but certainly they can be used.

I have a high budget for these things, I don't have to buy the cheapest most rejected unwanted mismatched junk like people on the ebike and scooter forums.

Ok, cool! At least do a sanity top-balance with a single-cell 3.7v charger. Or grab hold of an iCharger 306B, maybe a Cellpro PL8 and power supply for them. While a simple 4S / 12v battery setup like we are using doesn't need obsessive top-balance or bleeder boards (if used within reason), it is still wise to initially do the single-cell or totally automated hobby-charger with balance leads to a sanity check upon receipt or once in awhile.

I already know my LiFePO4 battery works, its been starting my diesel for about 2.5 years now.
The LiFePO4 batteries have already lasted far longer than any lead acid batteries I ever had in my diesel between 2006 and 2012. Just about every year I was replacing a battery, some times both of them. I was not using the cheapest economy batteries.

Yep - they do great when taken care of. A123's are certainly made for SLI duties with their high-C burst ratings.

Here though, from a solar storage standpoint, we don't need A123 like high-rate (10C and so forth) capabilities. The standard large-prismatic from GBS, Winston, CALB with only to 3-5C or so bursts are far greater than we'll EVER need! Not to mention, they are already pre-made for you! You can even get the cells fully wired with bussbars, compression panels and the like.

So yes, I'm with you - lifepo4 has it's place if you can justify needing / paying for the capabilities at the outset.

In reality, one can go far with lead with proper maintenance - or if you need extra oomph without wanting to pay for lifepo4, then a "pure-lead" agm, which is just under the rung for energy density and performance than lifepo4, may be worth a look. Like all things, they need proper maintenance to get the most from them.

oil pan 4 wrote: »

Hey that Samlex SEC-1230UL charger was pretty much exactly what I was looking for to put on my inverter generator for battery charging.

Yep - I use a Samlex SEC-1215UL set for GEL because it is accurate to 14.0v, which is where I like to end up at with my 4S GBS bank. Definitely not outdoor use!

I am not worried about charging the LiFePO4 batteries too fast when using solar or external charger. I was only ever planning to use a max of 15 to 20 amps of solar capacity, same with any external charger.

While you are using A123 which can handle super-high charge current, with the typical large primatics from GBS, CALB or Winston, 0.5C is the recommended max, although you CAN exceed that if you are on top of things. Certainly no more than 3C - 5C for short bursts.

The piece of gear that I built my own battery charging rig for was my inverter generator hybrid which will only ever use an AGM.

I like AGM too, provided you actually don't UNDERcharge them, which is easy to do with solar. Pure-leads like Optima, Odyssey/Enersys and so forth. I'm a big fan of very low IR. It was my gateway battery chemistry to lifepo4.

The Genasun's are very expensive, but consider that they are designed for marine use, and are very hard core internally. The default for their lifepo4 series is at 14.2v, and if you wanted a custom voltage like I would at 14.0v instead, that would be a $50 custom addition to a special order.

Of course there is also MasterVolt but we are starting to get into the stratosphere.

You sound like you are on top of things though, and a Morningstar with the temp-comp sensor removed can be shoehorned into use with the right voltage adjustments. Not all morningstars will still function with that removed, so check to see where it specifically mentions in the addendum that if the sensor fails, it will still work, just sans any temp comp. Probably immediately voiding the warranty obviously.

Definitely BB for lead acid.  I hate it when I see guys using the inverter cutoff as the cue to stop, when it should have been done well beforehand.

Lifepo4 with an SLI application may not have a problem with a very shallow dip to 10.5, especially with the A123 cells.  But your advice is well taken - when using lifepo4 for continuous draw applications, then stopping at 12.8 or just below near 80% DOD is a wise idea.

Under a slow draw condition, going down to 10.5v would be really taxing on the lifepo4, even though many new users see 2.5v/cell as the minimum on the spec sheets.  3.0v/cell is the practical minimum when doing slow "sub-c" current draw.  Going deeper to 2.5v is going to cost you.

So I'm glad you brought that up as the situation is kind of the same, even though the chemistry and absolute voltages are a bit different.

oil pan 4 said:

then I will have to wait until summer to see how much they can really produce.

I have to wait until winter to see how much power (watts) my panels can produce.  I have to wait until summer to see how much energy (kwh) per day my panels can produce.

--vtMaps