Looking for feedback on small/cheap MPPT controller for a 100w Panel

[baltik]

Looking for a little feedback on MPPT controllers

I have a VW Vanagon camper that has a Group 27 Flooded Battery (~100AH) this powers a small fridge (TF49) and under typical conditions is good for about 2 days. I would like to add a small solar setup to prolong that. I am not 100% sure whether the panel will be permanently mounted on the roof or deployable on a small stand. As such, partial shading will likely be an issue and it is my understanding that an MPPT controller will do better than PWM in that scenario.

So far I purchased a HQST 100w panel

https://www.amazon.com/HQST-Monocrystalline-Lightweight-Solar-Panel/dp/B017OMTAV6

The small.cheap controllers I am looking at are:
Victron 75/10 - well priced at $85 and I like that for an additional $50 I can get the bluetooth dongle that will allow me to monitor the voltage and reprogram it if needed

http://shop.pkys.com/Victron-Energy-MPPT-7510-Solar-Charge-Controller_p_4311.html

The other one that I stumbled on is the Genasun GV-10 - I like the small sealed design and the sub $100 price point but am a little concerned about lack of a digital readout,

https://genasun.com/all-products/solar-charge-controllers/gv-10-pb-10a-solar-charge-controller/

I am a solar newbie so would love to hear some feedback on my proposed setup, pros and cons of the two controller mentioned and if there are other ones I should be taking into consideration

thanks!

[SunEagle]

Hello baltik and welcome to Solar Panel Talk

There really aren't many low cost or cheap MPPT charge controllers. But unless you have more than 200 watts of solar panels or if you are using panels that have very high Vmp rating there really isn't a need for one. A PWM type CC should work fine for you.

[littleharbor]

An MPPT controller would only be beneficial to you if you were using a higher voltage panel. With a 100 watt 12 volt panel all you need is a conventional PWM type controller. As far as shade is concerned, avoid it.

[Mike90250]

a single 100w panel @ 13V = 7.6A Say you get really well aligned sun for 4 hours, you harvested 30ah into the 100ah battery, about 1/3 of capacity
Any extra charge will help prolong the service life of the battery,

[baltik]

Thanks for the replies,given the ~$80 price range of the mppt controllers I am looking at - the price difference vs PWM is negligible and avoiding partial shade will likely not be feasible if the panel is permanently mounted to the roof of my van (camping in redwoods etc). It seems that the performance in shade and extreme temperatures alone would warrant the ~$30 premium for going MPPT no? Also I have read reviews that people are getting as much as 18V from these panels on clear days...

[Amy@altE]

Outback Power also has a small 10A MPPT called the Smart Harvest SCCM10-100. It's $110 and has lights indicating panel and battery status. The Genasuns are terrific.

[PNjunction]

..It seems that the performance in shade and extreme temperatures alone would warrant the ~$30 premium for going MPPT no? Also I have read reviews that people are getting as much as 18V from these panels on clear days...

There is no magic cure for partial shading degradation. MPPT will NOT magically compensate for partial shading in any significant way - which sounds like something a sales or marketing droid told you that got stuck in your head.

18v is the normal ocv voltage of a nominal 12v panel.

Either controller in your situation is fine. Both are nice units.

[PNPmacnab]

The reason panels are 18V is they will drop in voltage dramatically as they heat up in the sun. Who da thunk panels are used in the sun? There really isn't any advantage to MPPT at this low power. Buy a $20 PWM and use the extra money saved to buy another panel. You will be way ahead.

[baltik]

Got it - thank you. Unfortunately 2nd panel is just not in the cards, Vanagons are pretty small so the surface area is rather constrained...

On a semi-related question - If I get 30 ft of extension wire for the HQST 100w panel - would 12AWG be sufficient? or do I need to go bigger.

I was planning to connect this with Anderson power pole as opposed to MC4, I presume that's not an issue

[PNPmacnab]

I use this calculator:

http://www.calculator.net/voltage-drop-calculator.html

to get voltage loss. Sometimes loss doesn't matter as with PWM controller, the reason PV panels are 18V. I like power poles, but they aren't waterproof.

[Brian53713]

Victron has 5 year warranty. Well respected European company. And great online & telephone support.