Portable solar question

[Scalf77]

It is not a question if you can hook it directly to the house battery. The question is what will the charging rate be? Let us say the existing house system is giving you 6 amps and the portable can give you 2 amps. Best case is you them together and you get 8 amps, but.

Another option is one shuts down as it sees that there is another charge source.

House stays on 6 amps, portable shuts down 0 amps - No gain in performance over house alone
Portable stays on 2 amps, house shuts down 0 amps - Worse performance then house alone.

So you can see that you can hook it up, but that does not mean that it will give you better performance. I know of a couple of controllers BlueSky and Morningstar that will shut down if they sense a another source. In most cases this is a Alternator or Charger, but another solar charger would do the same. In that case they are doing it by design, another case would be to be confused by the voltage output of the other controller, and go into float mode. I just do not think you will get the results you are expecting. You best option would be do ditch the portable controller and wire the panels into your existing panels in parallel. And do that only if the specifications of the panels match up Or use it as in but only when the van is in the shade and the portable panels are out in the sun.

[Carl]

Latest suggestion is from Zamp, to hook their portable panel and controller, to the house battery. Both systems charge, then one shuts off, the other trickles.

Another suggestion from a solar guru is to take out the Zamp controller and go direct to house battery, and use only when camping and needed. (this would produce a better/stronger charge)

thoughts?

[Scalf77]

My first thought would be to return the unit to ZAMP. Second I would ask for the specification of the solar panel. Key PV module specifications;

PMAX Maximum power in watts (PMAX = VMP x IMP)
VOC Voltage with module open circuit (typically ?20 – 22V for 12V nominal modules)
VMP Voltage where module produces Maximum Power (typically ?17 – 18V for 12V nominal modules)
IMP Current where module produces Maximum Power
ISC Current with module Short Circuit

If they can't give you that kind of data, I would really return it. You would then need the specification for your existing House panel and the house controller. Then we could make a reasonable conclusion what you could do with the two systems

Good luck

[Carl]

Seems there are many people trying to understand the whole solar issue.
My question should be simple, which is, if I hook my Zamp 80 watt panel with its own controller, direct to house battery, what if any negative things happen to my charging of the house battery due to any conflict with the installed Kyocera 130 system with Blue Sky controller?

I seem to be getting one camp saying this is less than ideal, others saying just do it and you're fine?

My goal is just to increase my ability to charge the house battery better than by just using the stock 130watt system. I assumed this may happen because there may be advantages of having the portable in sun at times when the vehicle may be in shade. Also that 130 + 80 =210 which should be better.

Thoughts?

[daveb]

It isn't gonna "hurt" anything but may be less efficient as the batteries peak. If the 130w controller or the portable see's either as a shore power charge it will send one or the other into a float mode and shut down the bulk charge. It depends on the controller. As Greg mentioned this is a possibility. My guess is the portable has a more gereric controller and would shut down the 130's controller.

Larger RV solar system often use a smaller array for the starting batteries (because the bank is smaller) and the bigger system is tied to the house batteries. There is no seperator to tie the batteries together because of what is posted above but may have a jump buttom for an emergency start during dead battery situations.

You should do like I did and that is to get a small panel that has similar specs to the 130 and add a plug to the van that runs to the existing controller. When you need it it's there which isn't often; I've used mine maybe twice in 4 years. The 130 will do fine for a single 4-D. If you think you can run things on solar panels you're barking up the wrong tree. An 80w panel might get you a couple extra amps if it's tied into the 130's controller.

[Tapatio]

It isn't gonna "hurt" anything but may be less efficient as the batteries peak.

+1

[Carl]

Great points!
Just to clarify then. If my portable is currently wired to starting batteries, and I do not connect to house, is it worth even using?

Seems that if I run lights, fridge/freezer, microwave, etc... that I can go several days without starting the van as it is. It is after a few days without running that I drain more than ideal.

What would you suggest using only what I have?

thanks,

[daveb]

Originally Posted by Carl

Great points!
Just to clarify then. If my portable is currently wired to starting batteries, and I do not connect to house, is it worth even using?

Seems that if I run lights, fridge/freezer, microwave, etc... that I can go several days without starting the van as it is. It is after a few days without running that I drain more than ideal.

What would you suggest using only what I have?

thanks,

If you have two "fixed" solar systems, one for the house and one for the chassis system then you don't want a battery separator. You just need a tie switch for those times that you might need to jump start the vehicle. The idea behind a battery separator is to protect the starting batteries from over discharge while you sit in the back and suck down power. However, it also allows you to use a single solar array to keep both battery systems up to par. If you're running out of battery reserve you need a larger house battery system. Even two 4-D batteries will charge somewhat quickly with a single 130w panel. Don't try to run things off the solar, even two 130w panels won't put out the high amps needed when a heavy amp item or multiple items are running. The main draw is your fridge and it pulls about 3 amps when it cycles. So even a panel that puts out 5 amps is gonna charge the system for the most part...it will just take longer to charge. There is a rule of thumb for how much solar you need for the size of your battery reserve. We only have a limited amount of space for panels and space for batteries. 100 watts of solar for every 200Amp Hours of battery is OK. Sure 200 watts would be better but might be overkill. I installed two 135 watt panels because I have two 4-D batteries worth 440AH. Could I get by with 130watts? Yes, but in times of less sun I get a little more and in good sun I'm charged up faster. AGM's should not be brought down below 50% or 12.2 volts at rest. So I don't have a deep discharge to deal with. If my two batteries are say at 12.4v, I'm charged by 9AM provided I'm not using much except the fridge and maybe my Espar.

[daveb]

Well I just talked to a solar outfitter I know and they say they have designed hundreds of solar systems that use multiple controllers with mismatched panels and they claim that is the way to do it. I brought up "one fooling the other" idea and they said it won'y pose a problem. If the batteries are so close to the float level it doesn't matter if one shuts down the other. So in their view, just plug the Zamp onto the house battery system and be done with it. If the batteries require a bulk charge, both controllers will work together to charge quicker.

Seems Zamp said the same thing. You might ask other dealers especially the solar controller manufactures and see what they say. It will be easy to test. Just unplug the Zamp and see if the other system changes.

Please post back what you find.

Dave

[Carl]

What it sounds like is that having my rooftop 135 watt panel/controller and "adding" the Zamp 80 watt connected direct to house battery will only give me a quicker charge. Is this correct?
My issue started one trip when parked without running for 4 days. That trip I ran the normal fridge, coffee pot, microwave, lights, but I also brought an additional portable fridge/freezer. Several days in, my 110v clicked off from what I presume to be low power in battery.

If the Zamp hooked up direct to house battery "adds" some speed in charging, I may have been ok another day or so?

thoughts?