Charging with solar and alternator

Hi,

I just installed the 100W premium kit (20A MPPT controller) on our camper van.  I'm new to solar and I'm wondering, is it okay to keep the panel hooked up and charging the battery while driving?  In other words, can the battery be charged simultaneously from the panel and the van's alternator without damaging the battery or the charge controller?


Also, do I need to put an inline fuse between the solar panel and the charge controller for this set up?


Thanks. 

From what I've read and learned, as long as you don't ground the panel or controller to the vehicle it should be fine.

Hello,
Yes you can leave the controller connected while it is being charge by another source. The controller will sense another source is charging it and will go into float. For a 100 watt panel you can have a 10 amp fuse between the controller and panel.

I also have Renogy panels on my camper van and would like to hook my alternator to the battery just in case it gets low(northern calif and an el nino year...). Should I hook the alternator output to the charge controller input so it can control the charge out to the battery or should I hook the alternator directly to the battery with a manual switch so I can disconnect it when not needed?
Thanks in advance!

The alternator to the battery with a manual switch (to disconnect the alternator) is the way to go.

Generally, you want separate charge controllers for each type of power source for the batteries.  So, for example, you wouldn't feed solar panels AND wind turbines together into the same controller.  You'd have separate ones for each.  That way they can negotiate their outputs to the battery accordingly.

In your situation, the switch is necessary when you aren't running the alternator.  That would prevent the battery from possibly discharging back through the output windings.  But you can and should leave the Renogy controller connected to the batteries all the time (IE no switch).  The controller is meant to regulate the solar power to the battery regardless of whatever other sources may be charging the battery.

There's no way for a battery to be discharged through the charge controller; it also isolates the battery.  I know of an electrical engineer who wanted to rig up some house batteries to be charged exclusively from his vehicle, and the best way he found to do this was to hard wire the vehicle battery to a charge controller (using appropriate gauge wire, of course).  When the vehicle isn't running, the vehicle battery's voltage is too low to activate the charge controller, so discharging the house batteries cannot discharge the vehicle battery, and the house batteries cannot 'charge' the vehicle battery.  But when the vehicle is running, the alternator voltage is high enough to activate the charge controller, and it begins charging the house batteries.  It's a surprisingly simple, effective, and inexpensive solution.

I beg to differ.. My CC does it every 3 days if I haven't used enough power... I was astounded the first time I seen it...

So here it is two years later and I just want to say I hooked the battery into a switch and the solar panels into the same switch.  i move the knob to position one and the van alternator charges the batteries.  I move it to position two and the solar panels are routed to the charge controller which in turn charges the batteries.  I only needed to use the alternator once in two years.  Turns out it appears the Renogy panels provide a small amount of charging even on cloudy days and I don't have big power needs.  I have 250 amp hours of battery and three hundred watts of panels.  In a couple years, I hope to be retired and in a newer class B and gotta say l will have Renogy equipment in it.

There is a simpler way yet. It's called a B.I.R.D. relay, Bi-Directional isolator relay delay. It operates with a continuous duty solenoid to provide the isolator/battery charging functions of a RV. it actually senses voltage on the RV and chassis batteries., if the voltage on either one is above 13.3 volts, indicating the battery is being charged, it closes the isolator relay, paralleling the batteries, charging both. It operates in two directions, charging the batteries from the engine alternator and charging the batteries from the converter and/or solar controller. When active the system senses the level of voltage on the chassis 12 volt system. when the voltage goes above 13.3 volts for about 2.5 minutes, as happens when the engine is running normally, it will close the isolator relay providing charging current to the RV battery. It even allows a cold engine an opportunity to start and warm up before having the heavy load of a discharged RV (house) battery placed on it.

OK, so I'm looking at the Intellitec brand Bi-Directional Isolator Relay Delay. There are a couple of models, which should I get? I'm looking at a 00-00839-000 on eBay and I think it should work, but I definitely can't return it if it doesn't. 

What I'm doing is putting a solar panel on the front of my motorcycle trailer, to charge up a small battery (12-cell Antigravity Battery) inside- so I can charge phones, lights, etc., when I'm camping.  Then, the battery in the trailer gets charged from the bike while I'm rolling down the road, instead of the solar keeping it up when I'm stopped.  I envision it working a lot like a camper, where the tow vehicle charges the "house" battery while travelling, and the shore power or solar does it when camping.

I think it also might be a neat idea to be able to backfeed the motorcycle battery, if I ever needed to start the bike from the trailer for some reason.  That might save me from being stranded some day.  Thoughts?

daveking95

Go to Intellitec website,  intellitec.com/index.php/products/DC_Power_Management/Intelligent_battery_charging/The_BIRD_gas_with_Aux_start  

I have a diesel, they also have one for gas, check with their reps and get a qualified answer for your question. There are more questions to ask about your use and they are the one's to ask.

Sorry it took so long for me to get back, but I only check the forum every so often, besides there are several very knowledgeable people on line that have very good answers.