Zamp 160 watt portable solar

[dznf0g]

OK, I have been asked how my portable solar project is going and I have some performance numbers to share.

NOTE: We all know the benefits and drawbacks to rooftop permanent solar installs vs. portable. This is NOT a thread to debate those pros and cons, please.

For many of us who camp most of the time in deep deciduous temperate forest, rooftop solar just doesn't work, from a cost/benefit analysis (and observation). Many of us have no choice but to "chase" the sunspot around the campsite if we stay in the same place more than a couple days. Also, for me, I camp in Wisconsin often and they have a generator ban all state owned lands.

So I made the decision to go with a portable solution. I chose the Zamp 160 watt unit. I considered the 200 watt unit, but the extra size and weight were a factor. My own power usage stats, at least, supported the 160 watt
unit. The newer Gen 5 system has some improvements over the prior models: better support legs and a much better PWM controller than before. They call it a 5 stage, but the first stage is a slow ramp-up from 3 - 10V utilized only with deeply discharged batteries. And the 5th stage is an equalization stage utilized only if the unit is hooked to the AS for 28 days (not likely in my need set). So it is really a 3 stage; bulk, absorption, and float. Bulk ranges from 10V - 14.0V; Absorption is at 14.7 and float is at 13.6V. Amperage varies during the absorption stage as status requires.

I knew when I purchased it, I was going to have to do some mods. I needed more cable length than the wimpy 16' battery cable with alligator clips. I purchased 50' of 6awg marine stranded and tinned cable (about $3/foot!) and several Anderson connectors.

Everything stows inside the folded "suitcase".



The orange bag contains 50' of 1/4" winch cable with eyes on either end and a padlock to at least slow down a "walk-off". I drilled a hole in the panel frame for the padlock.

The experiment and data gathering were done 9/2 and 9/3. Both days were very similar in sun-load. Both days had partly cloudy to mostly sunny conditions and varied from morning to evening.

The pic shows the initial setup with the controller still mounted at the panel....knowing full well that the voltage drop off would be relatively substantial. But it was at my calculated level per research, at 3%. Numbers looked like this: There was a .4v drop between the controller display and my Trimetric display inside the AS. Amperage is around 6.5 in morning and evening and during the 4 hour "peak" (11am to 3pm here) averaged around 8.6A, with brief peaks at 9.1A . So, the performance with this configuration is all around the advertised peak output of 8.94A. (perhaps a bit lower with my 50' of cable) All in all, pretty satisfactory performance.

[dznf0g]

However, I knew that performance could be increased by moving the controller closer to the AS and taking advantage of 17V panel voltave running through the 50' cable.



The numbers, predictably, changed. With the controller at the batt compartment, I saw a 1% (.1V) drop between the controller display and the Trimetric. Amperage went to an observed average (peak times) of 8.8A - 8.9A and some peaks at 9.4A!!!! Better than advertised.

Day one, I was hard pressed to get 50Ah back into the batts; day two, it was no problem to get 50Ah, and I took it down at 4PM. Probably would have gotten 53 - 54Ah, had I left it up.

More pics:

[Tincampers]

So, how do you connect this to the batteries?

[dznf0g]

I knew someone would ask. I chose a setup somewhat different than Lewster and I discussed through PM. For the negative, I really had no choice but to attach to the shunt for my Trimetric, if I wanted to monitor activity....and Lew agreed. This, however does introduce several more feet of cable and several connections between it and the batteries.

Lew suggested that the positive go directly to the positive post on the batt you see in the pic. I chose differently, for several reasons. My batteries are in the standard locations and have about several feet of cable running to the positive buss bar. If I were to hook to one batt post, the juice to the second batt would have to pass through about 6' of additional cable and I don't like batts being charged at different voltages. (This would be slight, but that's just me) Also, because I have a pigtail permanently mounted in the batt box, I was concerned that it needed protection from a chafe and short. I had an empty 30A breaker in the breaker bar that serves the positive buss (not to be confused with the fuse block). This buss has both batt + cables directly attached to it, so both batts get the same juice, but it does add a couple of mechanical connections.

[Tincampers]

I don't recognize your battery enclosure. Would it be ok to run a pigtail from the batteries to outside the box and connect the controller there and then another pigtail to the solar array? Like you have it but without the Trimetric?

[dznf0g]

It's a classic with the battery doors on either side of the tongue.
Like this:




Yes, you can go directly to the batts...just make sure you protect with a 30A fuse on the positive. (the wimpy cable that comes with it has a 30A fuse in the cord assembly). Fuse size, of course depends on which size panel you are working with.

[Tincampers]

The wimpy cable would be history. That was what turned me off on the Zamp, but your project confirmed what I thought I might do.

[dznf0g]

Yeah, if I were to get really picky, I would run 6awg between the panels and to the first marine cable connection by panels as well as the short lead from the controller to the other end of the marine cable. But I don't think it would make a measurable difference. I believe those sections ate 12awg.

I went ahead and put an Anderson connector on the wimpy cable in case I want to use the panel remotely...for a boat batt or something else.

[Tincampers]

Very nice work. The cable you are using looks to be fairly flexible. Does it try to kink up?

[Gringo]

Thanks for the writeup. I am waiting for delivery of the Zamp 200 system, and I just bought a couple bigger batts yesterday. Similar situation to yours. We just simply don't want to have to always park the trailer in direct sun when there's a shady spot available. Also, I suspect there are some major technologies coming shortly on photovoltaic technology, and I don't want to mount a bunch of soon to be obsolete hardware on the trailer. Gluing the flexible panels directly to aluminum with no cooling seemed to be another bad idea, so the portable way is a good start for now.

[mefly2]

We have a two year old Zamp portable 60 solar briefcase charging system (purchased for our non-solar Bambi) that provides 22 volts to the charge controller. With a 25' heavier cable we only see a drop to 20volts at the charge controller - which is relocated to the end of the cable near the batteries. We use upgraded alligator clips directly to the batteries. With the factory solar on the EB, the Zamp provides marginal extra power (maximized in the winter sun with clear weather) while actually camping, but is fine to maintain charge when stored; we will likely just sell the Zamp.

[dznf0g]

Originally Posted by mrprez

Very nice work. The cable you are using looks to be fairly flexible. Does it try to kink up?

No, being stranded marine cable, it is VERY flexible and coils easily....so flexible it will stay in the coiled state shown just sitting on the floor. Much more flexible than your fresh water hose, for example. Great stuff....at a premium price, but I would never try to handle anything else for this application.

[dznf0g]

This is the wire I got. I can't tell you how many strands per conductor, but they are maybe twice the size of human hair...maybe three times.


https://gregsmarinewiresupply.com/Ze...49a3cb49bc2188

[cwf]

Awesome!

[Tincampers]

How have your Anderson connectors held up? All of mine broke right where the wire goes into the lug. I think they were soldered and not crimped.

I also moved my controller inside and the entire system works much better. I am planning phase 3 which will include Trimetric monitor and charge controller. Mine is not programmable. I also updated my batteries to 2 6v golf cart in series. Plenty of juice.

[dznf0g]

Mine have held up fine so far. Crimped and soldered.

[Tincampers]

I'll have to redo mine that way.

Someone tried to steal my solar panels and bikes last night. Something scared them off. They did get a Honda 2000 from another camper though.

[wareaglewalt]

Can you post a picture of where you drilled for your padlock?

[KJRitchie]

I used a flexible 30' cable that hand loops already made at each end.

http://www.amazon.com/gp/product/B00...ilpage_o06_s00

There were already holes drilled into the frame. I found a padlock that fit the holes and then ran the cable loop onto the padlock. The other end I looped through the trailer rim spokes then attached the other end to the panel frames with the padlock. It's not 100% fool proof but I take the panel in when the sun sets.

Kelvin

[roperlaw]

Thanks for all this very helpful information. It helped me decide to buy a Zamp 160 watt portable kit for our Airstream 23fb.