It's a start

[Zizzer_Zazzer_Zuz]

This is a tiny system for learning and as an emergency back up for my CPAP. It started with the intention of just an emergency pack when I lose power in the S&B's but now that I'm heading out on the road I am working to expand it just a little bit. I have found a great little charge controller and I am looking for a panel that I can use to charge this.

Please keep in mind that this is an emergency back up for a specific purpose, not a system designed to run my rig. Once I'm in a better place to build the larger system I may just keep this as a mobile backup or even sell it to someone just starting out like me.

I needed the entire thing to fit in a carry case that I can pick up and lug around. It all fits in this trolling motor battery box. The box has 2 12v outlets and screw posts.


A 40ah AGM gives me 2 days of CPAP use with no problem. If I set alarms and am willing to sacrifice the battery and a little sleep I could stretch it to 3 days. 


So far I've been charging and maintaining the battery with a Battery tender. This allows charging from AC. 
The starter batteries for the bus lose charge after about a 2 weeks without moving. Can anyone help explain if I can use the Battery Tender to float the starter batteries so I don't need to get a jump from my neighbor every time I want to start the bus? Yes, new batteries are high on the list but not absolutely critical right this moment. I will be buying 4-6 big ass batteries in the very near future but for the short term I'd just like to maintain the starters until I get this beast on the road.


I have some spare parts that I'm still working to install. I also have spare fuses and tie down mounts. The face plate has 2 12v outlets and 2 USB ports plus a voltmeter integrated in it which should help with monitoring the battery. The little jumpers are for charging directly from another battery such as a running car.


I do have a 300watt sine wave inverter. This is one mistake that I'm glad I made with a small inexpensive inverter and not a great big one, it's NOT PURE sine wave, just "sine wave" which I'm assuming means modified. I don't plan to use this much but it fits with the basic premise of the project and has proven useful.


The newest addition to this mini system is a waterproof, multi function (solar and wind) charge controller. It's too small for my main system but it should work swimmingly for this little solar geni and it will give me something to play with and experiment with without having to tinker with or modify my main house system. This is where the real questions start ...
 
Continued in first comment ...

 

[Zizzer_Zazzer_Zuz]

The newest addition to this mini system is a waterproof, multi function (solar and wind) charge controller. It's too small for my main system but it should work swimmingly for this little solar geni and it will give me something to play with and experiment with without having to tinker with or modify my main house system. This is where the real questions start ...


For anyone that saw my other thread, this is the controller from that post. I spent too much for it but I didn't get ripped off for the entire lot. Otherwise for the day I saved well over $200 on pickups for other required items for my build so it all works out. The seller was also knowledgable and we're keeping in touch about the build. He did a year and a half in a trailer a while back. So, the day all in all worked out well. For instance I got a Antennas Direct outdoors HDTV UHF/VHF/FM Antenna for $10, a bar sink for for $25, among others.

This is the Amazon add for it.

https://www.amazon.com/ECO-WORTHY-W...rd_wg=wOvfQ&psc=1&refRID=GATGCXWTVVMM88TFNJMJ

So maybe I'm making lemon aid out of a not so great deal but I'd rather make a $100 mistake on something that I can and will use rather than a $500 mistake on a larger system. The CT is waterproof which is kind of cool and it works with just small generating units like solar and or a wind turbine. It should work just fine for this little secondary system.

I have two additions that I want to make for this little system. Mounting the charge controller and the outlet faceplate with the USB outlets to the carry box and a single solar panel should complete this system. At that point I will be able to charge via AC (battery tender), DC (jumper cables), and solar. If I use a suitcase type or even roll up panel I will still be able to carry everything including my CPAP. Add a knapsack and I could carry enough to stay alive for 2-3 days with relative ease.

To get on the road I will need at minimum one panel to use to charge this 40ah battery. For short term I'm considering a mount for the side of the bus or even a panel that I can move around and set up outside of the rig. I'm thinking that 100watt would be more than enough to power this even on not so great days. Again this is for JUST for a DC powered CPAP and charging a cell phone once a day. Suggestions for the following items would be appreciated.

Wire to run from battery posts to face plate with USB ports, 12v outlets and voltage display
Adapter to run from CT wires to panel
wires to run from CT to battery posts
I'm confused about what sort of panel I can use with this CT. What are the specs I'm looking for in terms of output from the panel? Any suggestions on specific panels, especially roll (not stick on), panels or prebuilt folding suite case panels.

I foresee several possible scenarios for the future of this little system. As a stop gap until I can get the larger system spec'd, purchased and installed. Keep it running and charged as an emergency unit for use  if/when the larger system fails, needs repair, or I am away from my rig overnight. A system to tinker with and run smaller test and prototype electronics, Arduinos and Raspberry Pi's come to mind. Lastly, once the house system is up and stable I could donate or sell it to someone just starting out and in need of some basic solar.

If you made it this far, thanks.

 

[mayble]

I am just starting a similar project. A starter kit/ portable power pack to learn on.
I use this cart, so I can put a 40 pound battery in there and still move it

https://www.amazon.com/Mighty-Perso...78&sr=8-1&keywords=mighty+max+household+dolly


I'll be watching this thread, for sure. So far I have the trolling motor box and the cart. Looking for a cheap marine battery, and an AC charger, then a small solar kit. Baby steps!

 

[Zizzer_Zazzer_Zuz]

I am just starting a similar project. A starter kit/ portable power pack to learn on.
I use this cart, so I can put a 40 pound battery in there and still move it
I'll be watching this thread, for sure. So far I have the trolling motor box and the cart.  Looking for a cheap marine battery, and an AC charger, then a small solar kit. Baby steps!

There are some great examples of similar systems on youtube and instructables. I decided early on that this would just be a weekend warrior sort of thing and it needed to fit in my Hyundai and be easily loaded and unloaded. 


To round out the system I want to add a solar panel. Based on the calculations I've seen a 50watt panel should do the trick. I may need to tilt it and point it at the sun but would do the trick ... I think. A larger panel of course wouldn't hurt.

Since this project has been sort a learning curve I wanted to get some advice on the panel before I spent any more money on this.

Aside from the size of panel are there other details that I need to be aware of?

 

[SternWake]

Some of the lesser AGM batteries have maximum amperage limitations, generally 30% of the rated capacity.

A solar panel in theory should not be able to exceed the maximum amperage of such a battery.

But Solar exceeding 30% of the rated capacity of a battery would be a pretty big solar panel and a pretty small battery, but it is a consideration.

With AGM batteries, it can only be determined if they are fully charged, when they can only accept 0.5% of their rated capacity at absorption voltage.

Most low end solar controllers use a preprogrammed 'egg timer' that decides how long to hold absorption voltage after it has been achieved.
But this absorption voltage duration requirement changes as the battery ages, and changes depending on how many partial state of charge cycles have accumulated since the last full recharge.

Those wanting to achieve excellent battery life/longevity would be ensuring that at least once, every 5 or 7 deep cycles, that absorption voltage is indeed held as long as necesary, and not depend on the blinking lights or Egg timer.

Float, does not mean full.
Premature float voltage kills lead acid batteries, and is doing so every day all over the world, and a good % of the people who set up and use such systems are blissfully unaware of this, or think it is 'just fine' or inconsequential.

The power of a blinking green light is vast.

 

[Zizzer_Zazzer_Zuz]

It seems then that any 50 or 100 watt panel would suffice.

When the little green light goes on to indicate a full charge does the charger stop sending power to the battery?

In terms of charging via the Battery Tender should I leave the charger plugged in and attached to the battery for at least 4 hours after the green light goes? Are you saying I only REALLY need to do that every 5-7 charges?

I did some digging but can't find a manual for the CT. All I can find is this info below. That last line is interesting, it says something about MPPT but the body of the CT says PWM

Model: Double time model
Rated voltage: AUTO 12V/24V
Rated charge current: 10A
Over-load protection: 1.25 rated current 30sec or 1.5 rated loads current 3 sec, overload protection 3 rated load current,short circuit protection
Over voltage protection: 16.5V (×2/24V); keep working until drop to the point of Boost charge voltage action
Boost charge voltage:14.8V (×2/24V); Immediately stop charge,only applied when over discharge appears
Control mode: The way of Buck MPPT

What does all that mean?

If I can find a manual how do you go about programming these things?