Multi input charge controller

BeauvilMD

Hi all
I m working on a project currently but I have one question.
Can t I find a charge controller that can hold different input ( Solar, car alternator and utilities) but not simultanoussly.
It's a battery power pack for rural and recreation uses and I need that people can charge in any of this type of source, from a solar panel, from the cigarettes light of their car or with a 12 utility volts charger. Any advice please?

Marckenson 

BB.

The problem is that you have widely varying input power sources... Some like solar panels can be turned on and off without damage. Others, like directly connecting a car alternator, will be damaged (or cause damage) if you use a "series controller" (like a solar charge controller) and just turn their output on/off.

And AC to DC power sources can have wildly differing output voltage/current/designs/requirements.

Can you tell us a bit more about what you are trying to do? The loads you want to drive (i.e., large or small power requirements), cost vs weight (use large heavy lead acid batteries or light weight/expensive LiFePO4 type), etc. We have had quite a few questions from people that want to run CPAP machines or other medical devices.

In general, the loads are very important--Because conservation of energy usage is almost always a better investment than using less efficient loads and designing a large off grid power system.

Will all of the power sources be brought with you and/or consistent interface (i.e., using a 10 amp 12 VDC lighter plug on car with the car running or stopped)?

How big/what voltage/what type of battery bank? How large of solar array (and voltage/panels you want to use)?

Just a ton of questions.

-Bill

BeauvilMD

Hi
Thank you very much for your feedback, let me try to answer some of your questions.
A small diagram is enclosed to give you a better idea.
First it will be a mobile system, with a 120 volts AC/ 12 volts DC charger, a 200 w/12 volts solar panel, and socket cable to hook up to the the truck lighter.

A universal DC-DC Charger controller to protect my battery. This is my request.

The  bank will be one battery 100 AH or two parralel batteries 50 AH optional. The inverter is 400 watts/12 Volts Pure Sine wave. For this system I m looking for DC/DC Charger controller that can hold even solar, truck and other 12 DC volts that's going to recharge the battery.

I don't want to use a selector for this three type of input charging source.

 I m not sure if I m so clear, but for other questions please feel free to let me know, and sorry for my old fashion english.

Marckenson Beauvil

BB.

If you plan on weekend use--Then you can get away with 5 amp (5%) rate of charge. However, if this is a daily use system, then I would suggest ~10 amp (10%) rate of charge.

If you have a 10 amp simple AC battery charger and 200 Watts of Vmp~18 volts at 11 amps total--Then you could use a simple PWM solar charge controller (DC from utility charger, or DC from solar panels) to regulate the average charging current to the AGM battery.

The truck lighter charging is a question... Typically, a 12 volt automotive type alternator charges around 13.8 to 14.2 volts. AGM batteries should not see more than 14.4 volts (typical) maximum charging voltage.

If the truck/car is not running, then you have ~12.0 to 13.0 volts (12.7 nominal) voltage and this will not recharge your battery bank.

For charging when the engine is not running, you would need a "boost" type battery charger to raise the votlage from 12.x volts to 14.x volts charge the AGM battery. Or, you can look for a buck/boost charger so that it can take any "reasonable" charging voltage from your vehicle to recharge the AGM battery (you could also probably move the AC to DC power source to this buck/boost charger).

Anyway, you have very different types of charging sources with a wide range of voltage/current profiles. It is difficult to give a generic answer--Each charging source needs to be defined and designed to meet those requirements.

Unless you want to make an electrics DIY project out of this--I would suggest that you may end up with 2-3 separate chargers connected to your one battery bank. It will be less complicated.

-Bill

BeauvilMD

Thank you very much bill, very useful your comments I will figure out what is feasable from your advices in my case and I ll keep you on tract.

Marckenson

peetee

Why can't you use DC power from solar panels to recharge the DC batteries on a electric car that is DC?? It would be just like a aux.alternator charging system why you driving the car

peetee

I'm almost positive it could be done or is it that the car companies and the charging companies wouldn't want to lose money

BB.

Welcome to the forum Peetree.

Yes, it is possible to to use solar panels to charge batteries on a car... A few cars even offer solar panels built into the roof. Presently about 10 car models in the USA have "solar roofs":

https://carbuzz.com/10-high-tech-cars-equipped-with-solar-panels/

There are multiple reasons why a mfg may not choose to build a solar roof into a car... I will try to quickly list a few reasons:

1. Solar panels are not that "efficient or capable" of gathering solar energy.... Just a quick back of the envelope math: An electric car draws around 250 to 300 Watt*Hours per mile of driving. A 1 meter * 2 meter solar panel * 1,000 W/sqmeter * 0.15 solar panel eff * 0.77 panel & charging eff * 5 hours of "good sun" per day = 1,155 WH per sunny day from a 3.3 ft * 6.6 ft roof panel... 1,155 WH per day / 300 WH per mile = 3.85 Miles per day of driving from solar).
2. A fair amount of electronics are required to connect a solar panel to a high voltage car battery bank... A typical solar panel outputs 0.5 volts per cell, or around 18-40 volts typical per panel... The vehicle motive battery bank is typically around 300-400 VDC... So need the electronics and charge controller to boost the 40 VDC from solar panel to 400 VDC to charge the battery bank. Is not difficult to do--But adds cost/weight/etc.
3. Vehicle needs to be parked under the sun "all day"... If there is any shade (trees, buildings, power lines, parking structure, etc.), the amount of solar power harvested can quickly drop to zero WH harvested. In real life, a stormy day can be 1 hour per day to >7 hours per day in in "perfect" conditions... 3 hours per day is "not bad" for winter for most places--And easily 1-2 hours per day in poor average winter day. Plus for "optimum" harvest that panel should be tilted towards the sun. "Flat" mounted solar arrays (car roof) harvest much less energy.
4. Solar is only available when harvested and used. Obviously, limits on access to sun, and amount of storage available (EV's do have a lot of storage available--But a full charged battery cannot store "more free solar"--Battery must be somewhat discharged and/or vehicle using power driving/AC/lights/etc.).
5. Energy Taxes... In most locations, there are no road taxes yet for electricity for electric vehicles. When EVs "few", the government was willing to forgo road taxes (fuel vehicles can have $1 to several $ per gallon of fuel taxes. But the government was going hammer and tongs against people using "untaxed" vegetable oil or "agricultural diesel" in their cars. And now there are multiple agencies (in USA) pushing for using GPS to charge ~$0.50+ per mile road taxes and/or adding $300+ per EV and even hybrid Vehicles per year license renewal taxes). And we have seen/used cameras and transponders/fast passes for for tolls/road taxes.

How much is a person willing to pay for 4 Miles per day of "free solar energy" that lives outside of (for example) the sunny South/West USA?

Here is an example of a person that added 9 solar panels to the top of his Tesla Model Y for 40 miles per day:

https://carbuzz.com/news/tesla-model-y-owner-makes-own-solar-roof-that-adds-20-miles-daily/

Things can be done... Should they be done? Will they be done?

-Bill