Solar charge controllers that can absorb at 14.8v. Let's make a list?

[doug720]

Temperature adjusted charging is the best, as is the exact voltage. But I'm curious - what happens when driving? The alternator is charging at a flat rate and is not temp adjusted. Is the vehicles charging system going to be upgraded?

I did not see the battery capacity in the OP or the loads/draws. This is important, as most solar systems charge at much lower rates than panel capacity due to sun angles and obstructions. Many times 50% or less. So unless one is staying in one location for extended times, the vehicles charging system is going to do much of the charging, and at much higher rates than the solar system.

I have found a non-temp adjusted multi stage smart charger and solar controller is reasonable, reliable and provides good charging that will keep batteries alive for many years.

I don't run Gel or AGM batteries, as lead acid works well for us. The capacity and life cycles we have experienced with lead acid versus the much higher initial costs for the others are not worth it to me.

 

[Mwilliamshs]

...The alternator is charging at a flat rate and is not temp adjusted...

While it of course varies from one vehicle to another over the last 120 years or so, most are temp adjusted and regulated.

 

[Mwilliamshs]

BTW I saw someone mentioned the Renogy ViewStar 30A PWM as something that fits the bill since its charge cycle is fully programable. I also want to point out that the 20 AMP version of ViewStar may be better suited for you since you indicated you needed something to support 200W. The ViewStar 20A PWM can support up to 240W, is a smaller physical size and its only $79 and fully programmable as well: http://www.renogy-store.com/20A-PWM-ViewStar-solar-charge-controller-p/ctrl-pwm20-lcd-vs.htm . I ran this prior to getting the SunSaver MPPT.

Thanks so much for the additional insight! Care to compare to the two chargers from your perspective? Why the swap?

 

[doug720]

While it of course varies from one vehicle to another over the last 120 years or so, most are temp adjusted and regulated.

But not to the specific battery. Unless the charge source regulated by a battery temp probe, no charge adjustment can be made. A vehicles regulator typically is a flat rate of charge, with no compensation for battery type or temp.

How will the alternator output be regulated? The alterternator is likely the primary and per the solar system sizing, largest charger? Alternator output 120 - 150 amps vs Solar 15 amps? The 15 solar charge is in real use, likely only 7 amps, necessitating the use of the vehicle to recharge the battery.

Not trying to argumentative, just curious, as we have two solar systems with battery's - RV and and an off grid cabin. Depending on loads, and how panels are mounted (Flat to roof?) we see an average of 50% output capacity. 200 watts is not much capacity.

 

[perkj]

Thanks so much for the additional insight! Care to compare to the two chargers from your perspective? Why the swap?

The Viewstar 20A PWM wasn't mounted anywhere on the vehicle. I'd just carry it and set it up any time I'd need solar. It would just sit on the bumper while charging via solar panel and then would pack it up when done. I wanted more of a permanent set up that could just be plug and play so to speak . While I could have squeezed the Viewstar in the same spot in the engine compartment, the Viewstar is not epoxy encapsulated (for environmental protection) like the SunSaver MPPT is so I wasn't sure how the Viewstar would hold up to dirt, dust, water splashes and heat from the engine compartment. I was going to mount the Viewstar in there and just use it till gave out (whenever that would have been), but I ended up getting a great deal on a brand new Sunsaver MPPT off ebay ($150 shipped). So with the Sundsaver being smaller than the Viewstar and the extra power gained by using a MPPT over the PWM, I decided just to go with the Sunsaver and my plan is to (eventually) sell the Viewstar.

Note you do have to invest another $50 or so in the USB interface to program the MPPT where as the ViewStar can be programmed standalone since it has an LCD display.

 

[DiploStrat]

But not to the specific battery. Unless the charge source regulated by a battery temp probe, no charge adjustment can be made. A vehicles regulator typically is a flat rate of charge, with no compensation for battery type or temp.

I can't speak to your vehicle, but my 2013 Chevrolet is temperature compensated and has a response curve set to Lead Calcium batteries. (A type of AGM with very frisky voltage requirements.) The real challenge is that my starter batteries are under the hood and typically much warmer than the camper batteries at the back of the vehicle. Anecdotally, the big challenges appear to be Toyotas (many of which top out at 13.9v and some Sprinters, which are said to be similarly limited. Fortunately, it is rather easy to boost the voltage on a Toyota up to the 14.5v range.)

As a practical matter, most people don't drive more than about six hours a day and while the alternator(s) is great at providing a bulk charge, you are probably going to need shore or solar power to complete the long hours of absorb charge. The good news is that you don't need all that many amps to cover background loads and an absorb charge.

The other reality of charging a big camper bank (I have 600Ah) is that you only get an hour or so of really high charge. After that, the internal voltage and resistance rises to the point that the charge rate is likely to be below 50A. My solar array typically provides between 20 and 30A, so the real world performance is actually pretty good.

 

[comptiger5000]

Battery temp compensation on alternators is pretty common. Jeeps have had it since the 90s with a sensor under the battery. On mine, the charge voltage was a little low for an AGM, so I added a resistor to the sensor wiring, making it think the battery is colder. That bumped it up about 0.1 - 0.2 volts over stock. In the dead of summer with a hot battery, I've seen it as low as 13.7 - 13.8 volts. Let it sit for a day or 2 in the middle of winter and it'll crank the voltage up to 15 or so for the cold battery.

 

[Mwilliamshs]

But not to the specific battery. Unless the charge source regulated by a battery temp probe, no charge adjustment can be made. A vehicles regulator typically is a flat rate of charge, with no compensation for battery type or temp...

I'm not aware of any vehicle with user selectable battery type so you're correct on that. Charge adjustments can definitely be made either by modifying the OE harness or computer programming. There are compensations for battery temp, as has been discussed in this thread.

...How will the alternator output be regulated? The alterternator is likely the primary and per the solar system sizing, largest charger? Alternator output 120 - 150 amps vs Solar 15 amps? The 15 solar charge is in real use, likely only 7 amps, necessitating the use of the vehicle to recharge the battery...

The output is regulated OE but other means could be the CTEK Dual 250S or other, similar DC-to-DC chargers if you wanted to control it that closely. Alternator output for me is 95 amps max rating. Split that with the starting battery, consider I'm rarely if ever at max rated rpm (3.08 gears, torque-y straight 6 that doesn't need high rpm to make power, etc) and that the alternator's output capability is irrelevant if the batteries cannot accept it and as DiploStrat has stated, they can only accept that high-amp charging when they're considerably discharged. Long story short, no, the alternator is not the primary charger. Yes, it does have the most output available but is by design not going to ever charge the OE start battery higher than 85% so the much larger and slower charging deep-cycle bank isn't at risk of being overcharged either.

Not trying to argumentative, just curious, as we have two solar systems with battery's - RV and and an off grid cabin. Depending on loads, and how panels are mounted (Flat to roof?) we see an average of 50% output capacity. 200 watts is not much capacity.

Relative to total load and battery bank size, 200w is a good match for ~225AH of batteries and <70ah average daily usage.

 

[Mwilliamshs]

...The Renogy ViewStar has a 30 amp capacity and adjustable absorption rate of 9-17v. At ~$140 it seems priced right too. Note: Renogy calls absortpion "boost" but defines it as "Boost Charge: When the battery has charged to the Boost voltage set-point, it undergoes an absorption stage" so I'm good with that.

The EP Solar ViewStar is the same unit as the Renogy above. EP manufactures the unit and Renogy is a re-seller. The unit sells for $125.90 on Amazon and other than longevity and accuracy concerns based on having never heard of the brand and limited reviews available, I think it'd be a great fit for me. Certainly like the price. Whether or not the $ difference between this and the Bogart SC2030 would pay off is a big question. The SC2030 itself is cheaper (like 5-10 bucks cheaper) but to match capabilities the SC2030 NEEDS the TM2030 and those 2 together run ~$275. The $126 ViewStar and this $36 monitor can supposedly match capabilities for about $115 less. HMM. The EP Solar ViewStar 20A technically meets my specs and costs only $71.90 from Amazon. That plus the Elite Element monitor gets me what I want (with quality a remaining question) for less than $110. DOUBLE HMM.

Two Renogy Elipse 100W panels would be $440 (219.99 each) and the EP VS 20 is $71.90 and the Elite Element monitor is $36. That plus cabling and what not (say $65) gives a complete solar system with DEEluxe panels IMO for $600.

The same panels ($440) plus the TM2030 and SC2030 ($275) runs $715 plus cabling and what not ($65) hits $780.

For a smaller budget I could run the TM2030, SC2030, and Renogy's less efficient, larger panels for $140 each: $275 + 280 + $65 = $620

Or for a real small budget I could run the EP VS 20 ($72), Elite Element monitor ($36), and the cheaper panels for $280 + cabling ($65) for ~$450.

Lots to think about.

I think (at the moment) the way to go is run the best panels I can and start off with the cheaper controller and monitor. If I want to upgrade later, it's a lot easier to change a controller/monitor than panels. I'll go ahead and run good heavy cables now so they can reused.

 

[ajmaudio]

I also believe the Bogart Engineering SC-2030 can also be programmed for high(er) voltages.

You would be correct! I have one of these with a trimetric battery monitor controlling it and it is fully programmable. This also gives you VERY detailed information on batter condition and state of charge, not just a simple voltage reading. Anyone looking to take good care of batteries should consider it. The designer/company owner is also a great help. If anyone has any questions about this unit let me know.

 

[Mwilliamshs]

The Eco-Worthy MPPT20-1 is a MPPT charge controller with programmable setpoints and sells for ~$102. The range of the setpoints is not specified as such in the manual but it appears 15.5v might be the upper limit so I'd say it should allow 14.8v. Translation of the manual probably leads to the confusion. The terminals do not appear suitable for large cables (see 2nd image). This charger does have some good feedback in the RV community.

 

[IdaSHO]

Nothing new. There are many threads on expo about the ecoworthy unit.

Its a nice unit, especially for the price.


I've been running that unit for a few years now.

But hey, I don't have any real experience, so you don't care.

:coffeedrink:



BTW, terminals are plenty good for 10Guage.

More than enough for a 20A system.

 

[rayra]

It isn't that he isn't interested in learning, it's that he's a self-centered arrogant *** who isn't interested in anybody ELSE learning anything from his seemingly odd / specific requirement. People might discover something useful for their own situations, but he doesn't give a rat-**** about that. Yet he sits here and demands other people's knowledge.

 

[Darwin]

I have an eco worthy, it will do 15.5 for absorption but the problem is that it only stays for like 10 min. max, I end up setting the float to 14.5 and leaving it there for a while to get more amps back into the batteries and then once full dropping the float back down. For the price I like this unit, I see avg. 12 amps from a 250 watt flat mounted 24 volt panel.

 

[Mwilliamshs]

I haven't demanded anything from anyone. If the information shared here can help someone, I hope they take full advantage. My odd/specific requirement is spelled out in the battery manufacturer specification/recommendation sheets on the first page. I really would prefer not clogging up a list thread with discussion of battery charging parameters, especially since there is so much discussion of that available elsewhere. I've posted specs and links for all the chargers discussed. Feel free to follow the links and discover something useful for your own situations. I have no idea how any of that might be construed as my arrogance or lack of giving a "rat-****" (that has an extra asterisk and is missing an apostrophe and an s, if you're trying to say what I think you are) but this is the internet so I reckon it comes with the virtual territory.