Renogy DC-DC charger with MPPT

[2Big2B]

Seems like a pretty decent deal.



If you can afford the price now, I'd prefer to not risk it going up.



It is not uncommon to see 200W panels @ 12V. All appear to be 12V panels, so you would need two in series.

What I can't find is what they way, or their physical size. I would count on at least 35# each. This may be a lot to manage.



What do you want to spend? Do you want the awesomeness of Victron? You wouldn't need more than a 100/20 or similar. You could get away with a PWM as well, and those are dirt cheap.

Personally, given your physical limitations, I would look at 3X 130W flexibles. They claim 4.4 lb, and that's 390W for about the same $ as 2X 200W. 3S would require a 100V MPPT though. A Victron 100/20 with bluetooth is $90.

=============================
Specs: "ECO-WORTHY 200 Watt Bifacial Solar Panel Mono PV 12V"

Brand JJN
Material Monocrystalline Silicon
Product Dimensions 30.3"L x 1.4"W x 53.7"H
Item Weight 25 Pounds
Efficiency 200W
==================================

I could probably handle a couple of these.



Which 3X 130W flexibles are you suggesting that I could get for the same cost? These?
With the 20% off with code HOT20DEALS, they are $190 for three.

=====================================================================

============================================================


My impression from listening to Will Prowse about flex panels in general is, they all suck. Very exaggerated claims of efficiency and outputs. It looks like they are very unpopular on this forum. I do like their light weight though. I have seen you give the opposite advice to a guy with an RV along the same lines as what everyone else has been saying. But perhaps in my case though, because of how I want to use them, it is qualified advice. So, Maybe. I will mull on it.

As for my budget, a $300 indulgence for something I might never use is about my max.

Let me further investigate if these flex panels would fit the bill.

I also need to know more about the charge controller best suited for this...

This one (open box!) ?

=======================================================





====================================================

Putting this all in the Cart, it would cost:


Items (4)$292.91ShippingFreeDiscount-$2.40Tax*The state of Virginia requires eBay to collect sales tax and applicable fees from buyers. eBay will pay the collected tax to the tax authority.$17.43Gift cards, coupons-$47.51

​

Order total: $260.43​

That could work... But I probably still need some connectors and such?
=======================================================

Thank you Sunshine!

 

[sunshine_eggo]

Yes, the 130W panels in that same ebay listing.

You know your physical limits better than I do. My only reason for flexible is weight and ease of deployment.

The 75/15 would be marginal for 3S flexible panels, but good for 2S fixed.

 

[2Big2B]

Yes, the 130W panels in that same ebay listing.

You know your physical limits better than I do. My only reason for flexible is weight and ease of deployment.

The 75/15 would be marginal for 3S flexible panels, but good for 2S fixed.

Now looking at youtube reviews on those panels. Maybe not so bad!

I think I should pull the trigger on this deal. I don't think it gets much better... Agree, or shall I keep studying it?

 

[sunshine_eggo]

Now looking at youtube reviews on those panels. Maybe not so bad!

I think I should pull the trigger on this deal. I don't think it gets much better... Agree, or shall I keep studying it?

3S 130W flexibles needs the 100/20. 2S 200W rigid can use the 75/15.

Neither are bad choices, and pricing is reasonable for all components.

The decision is yours.

 

[2Big2B]

3S 130W flexibles needs the 100/20. 2S 200W rigid can use the 75/15.

Neither are bad choices, and pricing is reasonable for all components.

The decision is yours.

Done. Trigger pulled on the 3 flex panels and 100/20 open box Victron as you recommended!

Thank you.

That, with my three 24v 100ah battery packs and Samlex 600 & 1500 inverters, and a bottle of something 90 Proof, I think I might survive a rough hurricane season!


======================
Opps, I ordered the BlueSolar, not the SmartSolar w/BT... Let's see if I can reverse it.

Can I get away with a SmartSolar 100/15 with there 3 panels?

or do I need to go up another notch to SmartSolar 100/30 ?

 

[sunshine_eggo]

Done. Trigger pulled on the 3 flex panels and 100/20 open box Victron as you recommended!

Thank you.

That, with my three 24v 100ah battery packs and Samlex 600 & 1500 invertes, and a bottle of something 90 Proof toxic, I think I might survive a rough hurricane season!

The smartsolars have some pretty cool features. They track total energy produced in Wh, Max power observed, PV max voltage observed and min/max battery voltages, and load Wh used, and will list them for 30 days on the history tab also recording the amount of time spent in bulk, absorption and float for each day. This gives you a really good measure of how much energy you have available for use per day.



Additionally, they will log and graph (2 at a time) multiple controller measured values: battery voltage and current, PV voltage and current, PV power, load current (if present) and battery temperature (if it's receiving battery temperature from another device) for 46 days in the TRENDS tab of VictronConnect. Short term live graphing is updated every second, but logs granularity get increasingly more coarse the older the data is.



Yes. I'm an unpaid shill for Victron.

 

[2Big2B]

The smartsolars have some pretty cool features. They track total energy produced in Wh, Max power observed, PV max voltage observed and min/max battery voltages, and load Wh used, and will list them for 30 days on the history tab also recording the amount of time spent in bulk, absorption and float for each day. This gives you a really good measure of how much energy you have available for use per day.

View attachment 219619

Additionally, they will log and graph (2 at a time) multiple controller measured values: battery voltage and current, PV voltage and current, PV power, load current (if present) and battery temperature (if it's receiving battery temperature from another device) for 46 days in the TRENDS tab of VictronConnect. Short term live graphing is updated every second, but logs granularity get increasingly more coarse the older the data is.

View attachment 219620

Yes. I'm an unpaid shill for Victron.

So what is the minimum Victron SmartSolar model that I can use?
75/15, 100/15, or 100/30?

Well, I decided to go with this one. I probably can't go wrong it... Right?






Or, for less value @ Amazon, but why would I ?:

 

[sunshine_eggo]

So what is the minimum Victron SmartSolar model that I can use?
75/15, 100/15, or 100/30?

3S 130W flexibles needs the 100/20. 2S 200W rigid can use the 75/15.

I forgot there was a 100/15. That would work too for the 3s 130W. The 100/20 is special as it will also work on 48V, so I'm kinda partial to it.

For every 100W of panels, you'll need

100W/28.8V = 3.5A

3.5A of MPPT output per 100W of panels, so a 15A will work up to 400W.

When you buy Victron, you're buying the seller as it's the seller's front-line responsibility to support the product. InvertersRus is a known good seller.

Not sure why they're claiming 6 year warranty. Standard is 5 year with an option 10 year for 10% more. They may be carrying a year of the warranty.

 

[2Big2B]

I forgot there was a 100/15. That would work too for the 3s 130W. The 100/20 is special as it will also work on 48V, so I'm kinda partial to it.

For every 100W of panels, you'll need

100W/28.8V = 3.5A

3.5A of MPPT output per 100W of panels, so a 15A will work up to 400W.

When you buy Victron, you're buying the seller as it's the seller's front-line responsibility to support the product. InvertersRus is a known good seller.

Not sure why they're claiming 6 year warranty. Standard is 5 year with an option 10 year for 10% more. They may be carrying a year of the warranty.

I don't mind spending a couple of more bucks and oversize up a step. I think Will would agree that bigger in this case is better; for a safety margin and later expansion options, like adding another panel. This one runs 12/24/48 too, so it is a step above that 100/20 that you like, and Victron is a known quantity and holds value. I think I got a good price on it. If I was so worried about spending another dime and found some cheaper wonder controller, it would cost metwice as much in peace of mind.

So, That's what I decided to do!

So, for about $350 I put this together with your help.
All told: $250 for the panels, $95 for the Victron SmartSolar MMPT 100/30... Yep, $350 is just about as deep a hole I can dig out of!

That said,

We had Damn Well Better get a hurricane this season or I will be really pissed.

Thanks!

 

[sunshine_eggo]

So it shouldn't hurt to spend a couple of bucks more and get the 100/30, right ?
I figured that bigger is better for safety and other options later, and Victron is a known quantity, and this one does 48v too.
That's what I decided to do.

It won't hurt, but they are typically 2X the price of a 75/15. I wouldn't purchase open box unless you get the full warranty from a true Victron reseller.

Unless it's a brand new model that wasn't announced by Victron, the 100/30 won't do 48V. I have one I purchased a couple weeks ago from Pike Industries on Amazon sitting 8 feet from me. It only does 12/24V. Also, if you ever want to use load ports, the 100/30 does not have them.

If you ever have questions about a specific piece of Victron hardware, you can download VictronConnect on PC, Mac or Smartphone and use their Demo Library to see the settings and capabilities of any listed products.

 

[2Big2B]

I forgot there was a 100/15. That would work too for the 3s 130W. The 100/20 is special as it will also work on 48V, so I'm kinda partial to it.

For every 100W of panels, you'll need

100W/28.8V = 3.5A

3.5A of MPPT output per 100W of panels, so a 15A will work up to 400W.

When you buy Victron, you're buying the seller as it's the seller's front-line responsibility to support the product. InvertersRus is a known good seller.

Not sure why they're claiming 6 year warranty. Standard is 5 year with an option 10 year for 10% more. They may be carrying a year of the warranty.

Actually, if I were to be a Pollyanna', I think the correct equation would be:

For every 130W of panels, you'll need

130W/28.8V = 4.5A
4.5A of MPPT output per 130W of panels is

... I haven't a clue ... so a 15A will probably work over 400W, I guess.

(what's a mppt... )

I am trying to remember a lesson about adding up the mppt totals and adding a 15% gratuity or something... or was it total load plus tip, I forget...

 

[2Big2B]

It won't hurt, but they are typically 2X the price of a 75/15. I wouldn't purchase open box unless you get the full warranty from a true Victron reseller.

Unless it's a brand new model that wasn't announced by Victron, the 100/30 won't do 48V. I have one I purchased a couple weeks ago from Pike Industries on Amazon sitting 8 feet from me. It only does 12/24V. Also, i
For every 100W of panels, you'll need



100W/28.8V = 3.5A



3.5A of MPPT output per 100W of panels, so a 15A will work up to 400W.
, the 100/30 does not have them.

If you ever have questions about a specific piece of Victron hardware, you can download VictronConnect on PC, Mac or Smartphone and use their Demo Library to see the settings and capabilities of any listed products.

Geeze, you are right. I don't know where I picked that up - maybe it was some youtube I watched. In see the 12/24/48 label in my minds eye from something I saw... Not that I would ever need to run a 48v system or load ports really. I just want simple, but robust. Victron, Samlex ... they seem overbuilt and more rugged. I like that. I am old fashioned that way.

 

[2Big2B]

Aha! I just figured it out.

My order was actually the one you suggested:

Victron Energy SmartSolar Bluetooth MPPT Charge Controller, Every Size Available
$89.25Unit price $89.25

Item number: 324948358287
SCC110020160R ⋅ SmartSolar 100/20 12V-48V


Sorry about that.

==============================================================


============================================================
I am just a confused old man who likes High Voltage...

zzz High Voltage zzz High Voltage zzz zzz High Voltage zzz High Voltage zzz zzz High Voltage zzz High Voltage zzz zzz High Voltage zzz
.


...

 

[sunshine_eggo]

Actually, if I were to be a Pollyanna', I think the correct equation would be:

For every 130W of panels, you'll need

130W/28.8V = 4.5A
4.5A of MPPT output per 130W of panels is

... I haven't a clue ... so a 15A will probably work over 400W, I guess.

(what's a mppt... )

I am trying to remember a lesson about adding up the mppt totals and adding a 15% gratuity or something... or was it total load plus tip, I forget...

I was simply trying to establish an easy relationship to remember. The 10W difference doesn't matter between 390W and 400W in any real sense. Given your described conditions, you are not receiving unobstructed solar exposure between sunrise and sunset.

An MPPT (Maximum Power Point Tracking) is the type of charge controller you've bought. They allow you to use much higher PV voltage than is needed for the battery, and they find the optimal voltage/current draw to capture the maximum amount of power available. MPPT are sophisticated DC-DC converters that seek to output the maximum available power from the input.

A PWM (pulse width modulation) controller MUST have the suitable "12V" or "24V" or suitable combination of panels attached to achieve the approximate 1.5X system voltage discussed earlier. These controllers operate by shorting the panel to the battery thus forcing the panel, which is most efficient at Vmp, to operate at battery voltage. This may yield a 20% performance hit due to the lower voltage. Once absorption voltage is hit, they start "pulsing" the connection on and off hundreds/thousands of times a second to maintain an "average" voltage and since it's not connected 100% of the time, the average current is reduced.

 

[2Big2B]

I was simply trying to establish an easy relationship to remember. The 10W difference doesn't matter between 390W and 400W in any real sense. Given your described conditions, you are not receiving unobstructed solar exposure between sunrise and sunset.

An MPPT (Maximum Power Point Tracking) is the type of charge controller you've bought. They allow you to use much higher PV voltage than is needed for the battery, and they find the optimal voltage/current draw to capture the maximum amount of power available. MPPT are sophisticated DC-DC converters that seek to output the maximum available power from the input.

A PWM (pulse width modulation) controller MUST have the suitable "12V" or "24V" or suitable combination of panels attached to achieve the approximate 1.5X system voltage discussed earlier. These controllers operate by shorting the panel to the battery thus forcing the panel, which is most efficient at Vmp, to operate at battery voltage. This may yield a 20% performance hit due to the lower voltage. Once absorption voltage is hit, they start "pulsing" the connection on and off hundreds/thousands of times a second to maintain an "average" voltage and since it's not connected 100% of the time, the average current is reduced.

That is so cool!

Sounds like I did good! It sounds sort of like a high frequency inverter works, no?

I have some studying to do on all of this now, to try to better understand all of this and cut through some cobwebs....

Watts/Volts = Amps...
Amps x Volts =Watts ...

Sticking with a simple 100w panel example - which is probably somewhere near what a 130watt flex panel will do, so lets assume my panels will produce 100w each in optimal conditions.

"For every 100W of panels, you'll need
100W/28.8V = 3.5A
3.5A of MPPT output per 100W of panels, so a 15A will work up to 400W."

This is where I get stuck...
(3.5A x 3 panels) = 10.5A x 28.8V = 302.4 Watts

15A x 28.8V = 432 Watts. Where did you get 15A ?

3 (panels) x 3.5A ea = 10.5 ... are you adding 15% for safety, or am I way off ?

I'm gettin' there ...

So, assuming 15A, theoretically I should expect to harvest about 432 watts per hour for every hour of optimal conditions for battery storage.
True?
Assuming 4 hours of usable daylight = 1,728 Watts.
A 24v @ 100A battery packs (100A x 24v ) = 2400 watts.


And how does that relate to the SOC of a 28.8v LifePo4 battery if it charges within its operating voltages between 25v - 29.2v ?
Does that throw off the math?

I am trying to get some sense of how how long I can run on battery with this solar charging setup replenishing it, in ideal conditions. I can use that to help estimate my energy budget until power is restored.

My impression is that realistically I can probably refresh half of a battery pack in a day.

Without replenishment, I figure that I should be able to budget my total 7.6kwh available in my batteries before a blackout event, getting several days or more out of it if I am judicious in what I use it for.

So how much time have I bought with this set of panels. What amount of peace of mind have I afforded myself? That's what I am really after.

12.8v x100ah = 1280 x2 = 2560wh per pack.
Theoretically I can harvest 1,728 wh per average day with optimal conditions. Probably unrealistic, but..
That is 0.675, or about 2/3 the way for a full charge from 0v to 29.2v.

But it is actually charging between 25v and 29.2 v.
Do I need to figure that into the math, or can I ignore that?

Or am I just on some kind of a Power Trip ???

 

[sunshine_eggo]

If you want to become a whiz, click Spoilers in my signature and read the resource in line #6.

 

[2Big2B]

So, will I want to put all 3 panels in series, or is there any advantage running 2 in parallel, then in series with the third?
No doubt you have a name for that, like 2P1S or something...?

 

[sunshine_eggo]

So, will I want to put all 3 panels in series, or is there any advantage running 2 in parallel, then in series with the third?
No doubt you have a name for that, like 2P1S or something...?

3S is your only option. 2S in parallel with 1S would be like putting 24V and 12V batteries in parallel. You can imagine the badness.

Since all components in a series circuit must pass the same current, 2P in series with 1 means the 1 panel would restrict the current from the 2P "panel" and would thus be no different than omitting one of the 2P panels/

 

[2Big2B]

3S is your only option. 2S in parallel with 1S would be like putting 24V and 12V batteries in parallel. You can imagine the badness.

Since all components in a series circuit must pass the same current, 2P in series with 1 means the 1 panel would restrict the current from the 2P "panel" and would thus be no different than omitting one of the 2P panels/

 

[2Big2B]

Wow! What a great way to make fire out in the wilderness when you are out of matches !

 

[2Big2B]

I wonder if I need to anticipate not having enough length of mc4 pigtail from the panel to the charger... I should probably anticipate that.

I am speculating getting a set of 10awg extention cables with mc4 connectors on one end, tinned bare end on the other. Eco-Worthy sells 20' made up extention cables for $30, and there are several other vendors on ebay that will sell in various lengths for about $1 per foot. I might need more like 35' for comfortably doing of what I am planning.

Before I order anything, are there special considerations about wire guage, length, and how much current it needs to carry with the least loss, but appropriate to 3 x 130w Flex panels?

I may decide later to get a 4th panel so as to go 2 x 24v parallel, but I don't want to get ahead of myself until I tackle using panels first to see how that works.

That said, should I be ok with say, 35' of 10awg? What about 12awg, too light for longer runs? It's probably cheaper. What would you use?

I don't yet have any sense yet of what kind of power is going to be going through those wires. I am no stranger to meatball electronics. I used to take apart radios and tvs as a kid, and them CB followed by a General Ham licence years later. But solar is foreign to me. Not for much longer though.

Anyway, that's where I am going next. Any advice?

I live in ground floor 2 story apartment with a back patio. It is one of very few apartments that have access to the large back lawn. My back patio, which happens to face south, is on a a 15' x 10' concrete slab. The upstairs neighbor's wooden deck above serves as my patio's ceiling - eg its underside of just roughly finished decking..

In my mind's eye I am thinking of hanging a long pole horizonally at the entrance like a curtin rod and hang the panels in a string, a curtain of mats facing out.

Hanging straight down, perpendicular to the ground, the panels wouldn't be in direct sunlight. It is always bright out there, with bright flood lights back there at night as well. It is so bright that I use a blackout curtin in my bedroom. So, the ambient light alone actually might be enough to passively make some level of power 24/7. It wouldn't surprise me and I look forward to finding out.

With a little bit of light framing and, a short rope and a couple of wooden props or gas filled auto shock absorbers as found in auto cargo doors, I could deploy the panels by swiveling them up skyward together, forming a sort of extended canopy extending out beyond my patio, facing the sky at whatever angle I choose to keep it for for charging, if weather permits.

Then, I can swing it back in and fold it up against the deck ceiling's underside, out of the way and out of sight. All of this is why Im will probably need a long enough extention to accomodate connecting it. But I haven't taken any measurements yet.

The Victron mmpt 100/20 has shipped and will arrive next Tuesday. The panels haven't shipped yet. It would be nice to have everything I need to slap something together in a pinch.

Where I will set up the controller is another detail I am trying to decide on.

What I want the end result to be, is a solar powered battery charger for my wheelchairs.

I would probably mount the controller on a square piece of plywood and wire a male xlr connector as its output. It is what my wheelchair uses for its charge port. Hence, I could simply plug it directly into my chairs to charge their batteries, and my portable spare pack too. That would be ideal. The chair's charge circuit wiring is rated for a 10A charger, which I could beef up if needed to, and the batteries are a pair of 12.8v Power Queen Lifepo4s in series, with a 10A balancer beween them. I attached 2awg 175 Anderson pigtails to each battery of each chair, nicely tucked away, but available to plug the inverters into.

I am already prepared without the solar, but now I will have a solar charger for my chairs - as well as my spare 24v 100ah Lifepo4 portable pack, that I can tap into. In the event of an extended Hurricane power failure I will start out with 7.6kwh of available battery power, and ride it out for as long as possible. With any luck, I could probably keep going for weeks. Its a romantic notion that may, or may not be realistic.

After hurricane season I would probably take the panels down and store them for next year so as to keep them young...

Sound like a plan?

 

[sunshine_eggo]

I wonder if I need to anticipate not having enough length of mc4 pigtail from the panel to the charger... I should probably anticipate that.

I am speculating getting a set of 10awg extention cables with mc4 connectors on one end, tinned bare end on the other. Eco-Worthy sells 20' made up extention cables for $30, and there are several other vendors on ebay that will sell in various lengths for about $1 per foot.

I regularly buy MC4 patch cables because I've misjudged something. I also have a MC4 crimp tool for when I get too much and need to make a shorter cable. Most of what I've bought is from windy nation on Amazon.

Before I order anything, are there special considerations about wire guage, length, and how much current it needs to carry with the least loss, but appropriate to 3 x 130w Flex panels? I may decide later to get a 4th panel so as to go 2 x 24v parallel, but I don't want to get ahead of myself. But it is possible. That said, should I be ok with say, 25' of 10awg? What about 12awg, too light for longer runs? I don't yet have any sense yet of what kind of power is going to be going through those wires. I am no stranger to meatball electronics. I used to take apart radios and tvs as a kid, and them CB followed by a General Ham licence years later. But solar is foreign. Not for much longer though.

Anyway, that's where I am going next. Any advice?

Most PV specific wire is 10, 12 or 14 gauge. With 3S, you don't even need 14, but I don't think MC4 connectors typically go on less than 14awg.

I live in ground floor 2 story apartment with a back patio. It is one of very few apartments that have access to the large back lawn. My back patio, which happens to face south, is on a a 15' x 10' concrete slab. The upstairs neighbor's wooden deck above serves as my patio's ceiling - eg its underside of just roughly finished decking..

In my mind's eye I am thinking of hanging a long pole horizonally at the entrance like a curtin rod and hang the panels like car mats facing out. It is always bright out there, with flood lights lighting the are at night. I use a blackout curtin in my bedroom because of it. So, the ambient light might be enough to passively make some level of power. In that position though it wouldn't be in direct sunlight. With a little bit of light framing and, a short rope and a couple of props I could then swivel the panels together in an arc to form a sort of extended canopy, putting them outside the patio at whatever angle I choose to tie it off in, and leave it that way for charging, if weather permits. Then, I can swing it back in and fold it up against the deck ceiling for sealth and storage. i will have to be able to have it connected by a long enough extention to accomodate that. I haven't taken any measurements yet.

Where I will set up the controller is another detail I am trying to decide on. This is to be a quick makeshift sort of situation where I will probably just make a charge station inside where my living room is, wire snaked through the sliding patio door. For the controller's output I could probably wire up a male xlr connector (like a microphone connector) which is what my wheelchair uses for its charge port. Hence, I could simply plug it directly into my chair to charge its battery. The chair's charge circuit wiring is rated for a 10A charger, which I couold beef up if need be, and the batteries are a pair of 12.8v Power Queen Lifepo4s in series, with a 10A balancer beween them. I attached 2awg 175 Anderson pigtails from the batteries of both chairs, nicely tucked away, but available to plug the inverters into. I am already prepared without the solar, but now I will have a solar charger for my chairs - as well as my spare 24v 100ah Lifepo4 portable pack. In the event of an extended Hurricane power failure I will start with 7.6kwh of available power, and ride it out for as long as possible. With any luck, I could probably keep going for weeks. Its a romantic notion that may, or may not be realistic.

After hurricane season I should probably take the panels down and store them for next year so as to keep them young...

Sound like a plan?

I don't see any issues beyond the sliding glass door cutting wires.

Since it's temporary, anything sensible works.

 

[2Big2B]

I regularly buy MC4 patch cables because I've misjudged something. I also have a MC4 crimp tool for when I get too much and need to make a shorter cable. Most of what I've bought is from windy nation on Amazon.



Most PV specific wire is 10, 12 or 14 gauge. With 3S, you don't even need 14, but I don't think MC4 connectors typically go on less than 14awg.



I don't see any issues beyond the sliding glass door cutting wires.

Since it's temporary, anything sensible works.

I was thinking that too, but I can also park a wheelchair out there to charge, as well as the portable spare pack, so that doesn't have to be an issue. A pitbull attached to the chair might be a good idea though. That way, they'd just steal the dog.

 

[2Big2B]

So after looking around at extention cables I came up with an interesting compromise. Alibaba: a short mc4 to common SAE automotive connector, and then a couple of 15' 14awg cables with those connectors. So, for the $35+ I would have spent on a 25' solar extention, I have an adapter and a twoof 15' SAE cables runs I can join together and use as a quick spice for the sliding glass patio door. I can use them, cut them up, or do anything I will ever need to, along with that adapter: All for $20.


My 12vdc Survival Kit

... lives in a box next to some old 12v AGM batteries on life support with battery minders.

I typically wire up stuff to my almost dead 12v AGM battery collection. I have a box with stuff I can plug in during a blackout, tried and true. I can run my cpap with its accessory car adapter (available from Resmed or 3rd party), as well as whatever led lightbulbs I have, a radio/scanner, maybe my ipad, and even a 2 meter mobile rig - as if anyone ever works the band these days, and an old dashboard 12v fan. Its good stuff to keep in the toolbox. Keeping tools in a toolbox is another matter.

Now I can run a fridge and a microwave...

 

[2Big2B]

Update:

I got with Eco-Worthy and was able to upgrade to a "520 Watt kit", eg 4 panels with the extra cables, and their dicey looking charger that I would never want to use on my first experience.

Here's their 390 w kit. I added a 4th panel to make a 520w kit:


-> 4 x 130W Flexible Solar Panel
24V/36V/48V/60V/72V MPPT Boost Controller
5m Solar Cable with Connectors
Controller-Battery with Connectors
2* Y-Branch Cable

By description their charge controller is a VOC booster which perhaps I will find a creative use for. From its description It boosts the voltage so that, theoretically I probably could generate enough voltage to charge a 24v battery with a 130w single panel. I doubt it would have much current though.

MPPT Boost Charge Controller​

Display：LED digital
Input Voltage: DC 13-50V
Input Power: 450W
Working Current: 12A
Output Voltage: 24V/36V/48V/60V/72V
Battery Type: Lead-acid/Lithium/GEL/Flooded
Working Temperature: -20℃~60℃(-4℉~140℉)
Heat Dissipation: Cooling fan(Auto-turn-on at 131℉)
Size: 133*87*52mm (5.2*3.4*2.0 inch)/Weight：420g (0.93 lbs)


After I understand what I am doing better, perhaps I will experiment making a second system, either 12v or 24v... It gives me something to experiment with using my mostly dead AGM 55ah battery collection, and my HP variable amp/voltage power supply that I used to balance my battery build.

Meanwhile I plan to use the Victron MPPT 100/20 to get my feet wet. Essentially I got Eco-Worthy to give me the spare "Kit" for free.

So I pulled the trigger on a forth panel which I expect will fit my plans, and I bought the 3 year Allstate warranty for $7.99, with the object of being able to return one of the panels them if one goes bad out of warranty... a 3 year warranty is probably a good bet. It is rare for me to pay for an extended warranty, but in this case it will probably be worth it.

I am thinking that there might be a benefit to having a pair of 24v strings in parallel. It may give me more options. Besides, the sale on them is almost over... My expectation is that in reality these panels will live in the closet once I have tested them. That way they will last forever until I need them.

My application to invent a solar charger for a power wheelchair is a bit oddball, but with a south facing patio it is rather elegant and straight forward. I will remember to post my results. Even with crappy ambient light I bet I could still get my battery to benefit using 4 x 130v panels no matter how exaggerated their 130w ratings are... The kit will be sent after Tuesday because of the Dragon Boat Festival. (???)


Hi,
We can send you controllers and wires for free.
But it will have to wait until next Tuesday.
Due to the weekend and Dragon Boat Festival, I may not be able to get back to you in time!
Please don't worry we will take care of it!
Best wishes!
Icey

Nice folks!