A better "moderately" priced solar controller

[booster]

The battery temp sensor on our Morningstar MPPT 15 controller had failed on our last trip, so I went to the AM Solar site to order a replacement, and also an extra so I can switch between banks. To my surprise (the MPPT 15 had been their go to for smaller systems), they no longer have the MPPT 15 and it is replaced by a Blue Sky, it appears. I went to the Blue Sky site to read up on it, as AM Solar showed two different remote panels, and on the high end stuff like Outback, that would indicate programmability. Same thing with Blue Sky, it appears. If you spring for the "Pro" remote you can set all kinds of parameters, very similar to Outback. The Pro also has the capability to be a battery monitor like the Trimetric, with a shunt to the batteries. Very cool.

One of the settings you get was the "ending amps" for indicating full batteries, which has become my favorite setting, I think, as it does the best job of indicating what is going on. The problem with ending amps is that it can be messed up by loads running to the van, if the amps used are checked at the charger/controller output. The big question I had was if the Blue Sky read the amps at the output of the controller, or from the shunt to the batteries. If they read it at the shunt, extra loads wouldn't matter, which would make for a super system. I called Blue Sky and asked where they sense the amperage for the ending amp cutoff, and was told it was from the battery monitor/shunt. If the tech was correct in what he told me, this would totally eliminate overcharging on the solar, while simultaneously making sure the batteries were totally full, with no operator input needed. Likely that they use what on the Trimetric would be the fully charged indication. You need the ending amps, full absorption voltage, and a time delay to signal full charge.

Controller and Pro remote are between $400-500 so not cheap, but not much more than Morningstar, and if you add in a Trimetric, about the same, but with lots more features. I won't be replacing ours unless the Morningstar fails, as we have it working fine, but with a bit of operator interface needed. But if I were starting from scratch, the Blue Sky would be the unit I would get. (When I put on our solar a few years ago, I hadn't even heard of ending amps or the need for higher absorption voltages).

I did ask the tech if they are hearing more about overcharging and cooking of batteries, and he said they have as there has been a trend to larger solar systems in relation to battery bank size. Makes sense, as now folks are getting to full on the batteries instead of cycling around a lower state of charge. He specifically mentioned the drying out of AGMs.

[booster]

I have been doing some more reading on solar controllers, especially the Blue Sky with the Pro remote. The installation instructions for the Pro remote seem to be the best I have seen in explaining how all these things work. It is full of technical stuff with very good explanations. If anyone is interested in the "why's and wherefor's" of solar, and regular, charging it is worthwhile read.

Here is a link to the manual on their site.

http://www.blueskyenergyinc.com/uplo...-ProRemote.pdf

They address the ending charge current issue head on with this statement in the manual, basically not endorsing timers only, even though they sell some with only timers.



As with most of the other charger builders, this is hidden deep in the remote control panel information. If you just go looking for what features, like ending amps, the controllers or chargers have, they will not be listed in any of the charger or controller information, but only in the optional remote stuff. This appears to be true for Outback and Magnum also. I would think that they would like to list all the things that can be done, but add a note you need the good remote. Perhaps they are just used to dealing with pro installers that are aware of all the things.

I think Blue Sky has this stuff figured out.

[booster]

We had what appeared to be a temp sensor failure on the Morningstar solar controller on our test trip, so I figured I would add the temp sensors for the other battery bank at the same time I replaced it. Morningstar would temp control fine of internal sensor, but would go high when remote used. Got it all ready to install and checked the sensor with a meter and it looked to be fine, so went looking for symptoms online and got information that showed a sensor failure wouldn't give the symptoms we had. Oh well, probably the controller then. Still under warranty I think, but didn't want to take it out, wait, etc. I just got some contract hours at my old employer, so I figured I had some free money to spend, and I ordered the Blue Sky controller and remote. Put it in the last couple of days. Would have been easy with more space, but tougher on ours as it had to mount in a different place, needed the on/off switch to be on the panel wiring, not battery to controller wiring, and had to figure out how to piggyback the battery meter function off the Trimetric shunt we have. Took a while but works well. Easy to program, no computer required.

It works exactly as expected. Charges to absorption voltage and ending amps and goes to float. Did it in less than 4 minutes on a full battery. As long as the battery is below float voltage, you can switch bank and have it do a complete cycle again, so we can charge the banks separately which is nice because they don't match.

It looks like it will take care of all the overcharging issues and still allow us to be set so that we consistently get maximum charging in all conditions. Very little intervention required, I think. Turn it off when in storage, or when on shore power, should do it, and the shore power would only be if there were a long charge cycle needed. If near full they both could run fine together.

The big surprise is the cost compared to the Morningstar + Trimetric which you need to be even close to comparable.

Morningstar Sunsaver MPPT, remote, cable, Trimetric with shunt and cable = $600

Blue Sky, with Pro remote, shunt, and cable =$475

Really is a no brainer, I think

[Boxster1971]

I have the Blue Sky with Pro remote and four GS-100 panels from AM Solar on my 2013 AS Interstate. It's a great system!