RV solar noob here

> The problem is that there are so many false MPPT type CC's it would take many pages to list them all

List the known-good ones.

> we are stating a fact that for a very large percentage of CCs that do not work well with a small wattage system. You can disagree but please don't label our posts as FUD."

So say it that way without the "low cost MPPT" language. That language is what makes it FUD.

> What I try to say is that the decision to purchase what they are looking at is up to the poster since each person has their own level of spending.

Agreed.

> others are greatly disappointed that their system is not working the way they thought."

Including people with $600 controllers. Again, price is not the driving factor.

Noob here again. It's been interesting watching the back and forth here, and I'm going to ask my EE son to peruse it and tell me what it means. Let me go back to my basic question though. First of all, I purchased the single 100w panel because I simply want to use it as a trickle charger to keep my batteries topped up, because i dont have shore power where i normally park it when not in use. It seems to do that quite admirably; ie it'll take 70% batteries up to 100% in 4-5 hrs or less. (I've never seen it charge at much over 13v) My real problem, and the obvious reason (to me) to have the controller is too prevent it from overcharging my batteries. The controller (HP 2410) is giving me different readings on battery level, depending on whether the panel is plugged in or not. The readings are much lower when plugged in, and seem more accurate wen its unplugged, because its consistent with the trailer's monitor panel. Is the controller the problem or am I misunderstanding the readings?

The controller may be providing the voltage it is putting out to the battery and not the battery voltage. Just something to think about. The measured voltage is not a perfect way of knowing the battery State Of Charge (SOC). The only way I know to get that data is to use a temperature compensate hydrometer to measure the acid content of each battery cell. It's more work but provides more accurate data.

Since I don't have a manual for the HP 2410, I can't comment much on it's readouts and operation. Generally, a CC is connected first to the battery and allowed to boot up, then connected to the PV. I don't know of any controller where that boot up sequence is illegal.

Interpreting the readout sometimes takes having the manual in hand to understand the display.

The points Secessus brought are valid, but extremely rare. It's much more common for a poster to appear here with circumstances like yours - 100w panel and a controller that makes no sense of what is happening. Or the ever popular MPPT sticker on a PWM controller.

The Gensun controllers are the only brand I have ever heard of that provide boost to charge a battery


Secessus - if you would like to start a thread in Off-Grid about reliable, low cost MPPT or PPT controllers, that would be a welcome addition, and we can refer questions to it.
with so many counterfeit products on amazing and allibabba , I can't keep it all straight.
Question, will gensun Boost controllers ( say for 12V battery) also perform MPPT tracking on higher voltage panels, or only boosting to battery voltage ?

I'm not a solar guru or much of electrical wiz. I do have a 100 watt solar panel on my van that runs the interior lights, furnace or fantastic fan depending on the season and chargers for laptop, kindle and phone. If I have any kind of sun it will keep my two 35 AH batteries charged. I have a Renogy PMW controller, no meters but lights, while charging(volt meter on the battery reads 14.1-3 v) the lights are on steady, when fully charged it goes into float mode one light blinking(meter reads 13.5) and when the sun goes down it is fully charged at 13.1 v. As long as the sun is shining I can stay indefinitely. The battery meter usually reads 12.1v in the morning if the furnace has run all night, it is a very low draw furnace for a vanagon that I installed in my ford van. After three years my batteries started losing power and would drop into the 11.? v range by morning and fully charged at 12.8v, I changed batteries and we are back to normal I use two 35 AH wheel chair batteries in parallel and my controller has a SLA setting.

I have a suitcase panel for the motor home(100 w) and a PMW control, the load consists of lights, 12v c-pap machine all night we still have enough power to run the furnace in the morning and the 100w panel will have the house battery(single small deep cycle) topped off 1-2 in the afternoon. stove, refer and water heater are all propane. I've changed out all the lighting to LED

I'm planning a panel for my trailer to charge my trolling motor batteries, I have two one in the canoe and the other on the charger. I'm going to use the suitcase panel for now to charge them.

First, I hope your EE son can answer the electrical questions better than my Computer Science Major kid, who every question I get seems to be outside her area if study.

Second, I just finished my first test of my batteries and with them supposed to be charge to a specific gravity of 1.277 to be 100%, mine were charged to a temperature corrected 1.285, with very little difference between the cells. So I got .008 overcharged or about 105% charged. Now, I had two chargers on these batteries, one which had the electrical readout between 50 and 75 for all four batteries, and the other had the readout between 75 and 100 for all four batteries.

Right now I trust the responses I get off this forum more than from the battery shop and more than the one or two word responses I get when I E-Mail the battery manufacture's tech dept.

Since I think there is some "art" involved in this, to ensure my batteries don't overcharge:

1) I am going to remove them from the 600 watts of Panels when I store the RV. I thought about either putting one bank of 300 watts of panels on it, or even installing a second 100 watt panel just to charge the batteries but I opted against it.

2) I have a set of shelves with a charging and measuring station I built to keep my 270 LBS of Batteries charged. Now that they are charged, I am not going to leave the float charger connected. I will take specific gravity measurements every week to determine their health, and put them on the charger.

3) If there comes a point where I get sick of lugging 270 LBS of batteries between the RV and my house, I will start with rigging a 100 Watt panel to my MPPT charge controller, and take hydrometer readings and check water levels every month. I see myself going to this option sooner than I hope. Those batteries are heavy, and I'm really not sure if they're mode to be moved around a dozen times a year.

So basically, if it comes to option 3, I will be doing something similar to you, but I will check battery health with a hydrometer to make sure they're not overcharging or undercharging.

With flooded batteries & solar & being idle.
1) it's harder to overcharge than you think. If your hydrometer was reading 105% charge, something is off. Once all the sulfur has been driven into the electrolyte from the plates, you can't overcharge. You can still pump power into the cells, and you are now electrolizing water to gas, creating lots of bubbles of Oxygen and Hydrogen. This can raise the tempature a bit and that causes the electrolyte to expand in volume. If you had recently topped off the electrolyte with distilled water, this can sometimes cause the cell to overflow, which many people think they are boiling over. They aren't likely to be boiling with only a couple hundred watts. But if they are full, and sitting on a solar charger, that goes thru a Bulk and a 120 minute Absorb (or Boost) cycle, they will use a lot of water and some unnecessary plate material shedding, but it's preferable to being sulfated. Some chargers you can set the controller to a Float Duty, like exit signs, which only come on once a year. Then a day or two before you activate the RV for a trip, re-set to Cycle Duty, which changes the voltage back up.

The other thing is maybe you are reading 105% full because the temp compensation was off, or at some point in time, electrolyte was added to refill, instead of distilled.

But you don't want to be doing a daily Absorb for very much time, while the bank is idle, it just wastes water.

To avoid hijacking the OP's thread with my learning points, I've put my response in my "https://www.solarpaneltalk.com/forum...charger-to-buy" Thread