DIY Portable Power Pack (aka solar generator) vs. Commercial off-the-shelf options

[1EPICFJ]

I've been doing some extensive research on the available options for a portable power pack / solar generator (whichever you prefer to call it) and the option of building it myself. I'm looking for something close to 100AH of available power and that comes with a Lithium Iron Phosphate (LiFePo4) battery.

Based upon my research, the only unit that comes close to this is the Renogy Lycan, but I've read reviews that the fan is extremely loud and the inverter puts out very low amounts (600w continuous, 1200w peak). I looked at others such as the Goal Zero Yeti Lithium or the Inergy Kodiak, but they use Li-Ion NMC batteries which aren't as efficient as LiFePo4 batteries. This has led me to wanting to build my own Portable Power Pack / Solar Generator. My plan is to buy the individual components and then house them in a Pelican Case. Before I go down this path, I wanted to see what others thoughts are on my proposed setup. Here's what I'm considering:

BATTERY

I'm undecided on whether I go with the Battle Born 100AH LiFePo4 12V battery or the K2 Energy Pro Series 111AH battery. The K2 is more expensive, but I was told that Battle Born uses Chinese parts and assembles the battery in the US whereas K2 uses purely American Made parts.

Battle Born - https://battlebornbatteries.com/shop/12v-lifepo4-deep-cycle-battery/
K2 Energy - https://k2battery.com/product/k2-auxiliary-battery-12-8v-111ah/

AC CHARGER

I came across the Progressive Dynamics 45A LiFePo4 battery charger on the Battle Born website. This should fully charge the 100AH battery in 2.2 hours. From what I've read these are great chargers.

https://battlebornbatteries.com/shop/progressive-dynamics-45-amp-lifepo4-battery-charger/

PURE SINE WAVE INVERTER

I'm not sure which one of these I'll go with, but 1500w continuous should be good for my needs. I'm more concerned with space and the ability to remotely switch the inverter on/off (this way I can mount a switch on the case and not constantly draw power to the inverter). Looking for any suggestions on this.

MPPT SOLAR CHARGE CONTROLLER

I have a 100W Renogy Eclipse Solar Panel mounted on my vehicle's roof that is currently fed to a Zamp Solar 15A Solar Charge Controller that is mounted under the hood. This is used to keep my Odyssey 31-PC2150 battery topped off (I run a Dometic Fridge/Freezer). My plans are to install a switch between the panel and the charge controllers so that I can direct the solar energy towards the main battery or a port in the rear that I can use to connect this portable kit to. I'm planning on putting an MPPT controller in because it's more efficient than PWM. I'll also probably want to add another panel (mobile/foldable style) and then link the panels in series.

I'm considering the BlueSolar MPPT 100/30 - https://battlebornbatteries.com/shop/bluesolar-mppt-10030/

DC CHARGING

I'd like the option to charge the power pack via a 12V connection in my vehicle. This way I can recharge it while driving. I could use something like a DC-DC Charger to keep the portable power generator charged while driving, but I've also thought about converting DC to AC via an inverter and then charging it through the AC Charging port (using the AC Charger mentioned above). Not sure which option is better/cost effective. Looking for inputs here.

MISC ITEMS

There are other various items that I'll need to get to complete this (Display, Fuses, Bus Bar, Cable, etc.) I haven't figured out which display I'm going to use to monitor voltage/amperage/wattage (open to suggestions). As far as the other items, I'll end up using Blue Sea components and Ancor Marine wire (have a lot of these items left over from an extensive wiring job I did under the hood of my FJ).

Please let me know your thoughts/suggestions on this. Appreciate the help and looking forward to this build!

 

[Hillbilly Heaven]

Why not combine the AC charger and Inverter in one device? DC charging can be handled by the solar charger. Just use DC input in place of the solar panel input.

 

[1EPICFJ]

Why not combine the AC charger and Inverter in one device? DC charging can be handled by the solar charger. Just use DC input in place of the solar panel input.

Can you post links to what you're suggesting for the AC Charger/Inverter in one?

Also - Are you saying just plug in 12V from the car to the Solar input that goes to the MPPT charge controller?

 

[Hillbilly Heaven]

To answer your 2nd question first, yes you can feed 12V from the car in place of the solar panels into the charge controller. Just be sure to fuse it properly.

Now to the inverter/charger. I noticed battle borne has one that is rated for LiFePO4 batteries that is pure sine wave. It is 2000 watt so will run almost anything but an AC unit. The battery charge section is 70 amps. I am not familiar with the brand name but specs look good although it is rather larger.
https://battlebornbatteries.com/shop/aims-power-2000-watt-pure-sine-inverter-charger/
Just make sure whatever inverter/charge you pick that it is designed to charge LiFePO4 batteries.

 

[1EPICFJ]

To answer your 2nd question first, yes you can feed 12V from the car in place of the solar panels into the charge controller. Just be sure to fuse it properly.

Got it, would make sure that nearly everything has the proper wire gauge and fuse for this setup anyways.

Now to the inverter/charger. I noticed battle borne has one that is rated for LiFePO4 batteries that is pure sine wave. It is 2000 watt so will run almost anything but an AC unit. The battery charge section is 70 amps. I am not familiar with the brand name but specs look good although it is rather larger.
https://battlebornbatteries.com/shop/aims-power-2000-watt-pure-sine-inverter-charger/
Just make sure whatever inverter/charge you pick that it is designed to charge LiFePO4 batteries.

From what I've read doing an inverter/charger all-in-one setup isn't as reliable as separating the two functions. AIMS is normally a good product, but it appears that there are several problems when combining the inverter/charger together in one unit.

 

[Hillbilly Heaven]

I was just concerned about packaging all this in a large Pelican case and how big it would be with all the hardware. Going to be a roll around rather than a tote and carry.

 

[1EPICFJ]

I was just concerned about packaging all this in a large Pelican case and how big it would be with all the hardware. Going to be a roll around rather than a tote and carry.

Agree that's the challenge here with this setup. I've got a Pelican 1510 Case (http://www.pelican.com/us/en/product/cases/carry-on-case/protector/1510) that's been sitting around for a few years (bought it when I traveled to the Middle East for work years ago). It's begging me to mount some electronics and drill some holes inside of it. Just gotta get it all to fit!

 

[Hillbilly Heaven]

With that size case rather than drilling holes in it for mounting devices, I would do some form of racking and stacking. Maybe some HDPE 1/2 inch thick sheets to mount to. Only holes to the holes to the outside would be for mounting connection points. It wouldn't be floatable but would at least be weatherproof.

 

[1EPICFJ]

With that size case rather than drilling holes in it for mounting devices, I would do some form of racking and stacking. Maybe some HDPE 1/2 inch thick sheets to mount to. Only holes to the holes to the outside would be for mounting connection points. It wouldn't be floatable but would at least be weatherproof.

Agree. The problem I'm running into is the whole cost/benefit analysis. Is it really worth it to ******** around with all of this? Does the cost outweigh the benefit or vice versa? The Goal Zero 1000 lithium should meet my needs, I just wish it would charge faster. The fact that I can get it from Costco and return it FOREVER if I ever run into issues is nice. I just wish I could get it to charge a hell of a lot faster. I'm torn on what to do...

 

[jonyjoe101]

For lifepo4 you will need a coulombmeter, the lifepo4 battery reads 13.1 volts almost all the time except when its almost full or almost empty. I been using the tk15 - {DC 8-80V 50A High Precision LiFePO / Lithium / Lead Acid Battery Tester Coulomb} you can find on ebay for 23 dollars for the 50 amp version (they have ones to handle larger amp use). You program the batterys AH rating and it counts all the amps going in/out of battery and lets you know percentage capacity left. For the price it works excellent, no need to spend a 100 dollars for a namebrand meter.

As far as solar controllers, for a 100 watt panel you won't get any extra amps using a mppt controller, unless the panel is a 36 volt one (but most 100 watt panels are 21 volts). You get 5 amps with either controller. Mppt needs the higher voltage to increase the amps.

You can make an overvoltage switch like me, so there is no way of ever overcharging your lifepo4. On mine it disconnect the solar panel from the controller if the battery voltage reaches 14.2 volts. But you can have it disconnect from any charge source, I have it controlling a 30 amp automotive relay but you can have it control a solenoid that can handle 100's of amps. This is to protect 12 volt devices from burning out if the battery isolates (bms triggers and stops charging) when a lithium battery isolates any charge controllers will continue to try and charge it and this cause voltage surges. Very bad for fans/lights connected to battery.

 

[pdavitt]

Got it, would make sure that nearly everything has the proper wire gauge and fuse for this setup anyways.



From what I've read doing an inverter/charger all-in-one setup isn't as reliable as separating the two functions. AIMS is normally a good product, but it appears that there are several problems when combining the inverter/charger together in one unit.

In my experience, six years in an off grid house with Inverter/Chargers (without a single problem), if you buy quality components they work very well. The trick is to buy a Pass-Through, Inverter/Charger designed for mobile use. I am partial to Victron Energy components, but I have no commercial relationship with them.

Below is an example system schematic for a 12VDC system. Please PM me if you have further questions.

Thanks,
Pat

 

[Hillbilly Heaven]

I don't know if that 60 amp current sensor will be enough to handle the draw of a 1000 watt inverter. I can not understand why companies that offer coulomb counting meters continue to use shunt based current sensors. When you get into the large amperage, which I consider anything more than 30 amps, you start to suffer with voltage drop due to the resistance of the shunt. Why don't they use Hall Effect current sensing? Easier to implement, and less prone to damage from over current conditions. Current shunts are a waste of battery energy when they reach the upper end of their range. Energy waste in the form of heat from the shunt.

Why the over voltage disconnect? Are you afraid of the quality of your charger not doing the job it is suppose to be designed to do?

 

[Hillbilly Heaven]

@pdavitt That is an excellent drawing. Very good representation of a combined energy system.

 

[pdavitt]

I don't know if that 60 amp current sensor will be enough to handle the draw of a 1000 watt inverter. I can not understand why companies that offer coulomb counting meters continue to use shunt based current sensors. When you get into the large amperage, which I consider anything more than 30 amps, you start to suffer with voltage drop due to the resistance of the shunt. Why don't they use Hall Effect current sensing? Easier to implement, and less prone to damage from over current conditions. Current shunts are a waste of battery energy when they reach the upper end of their range. Energy waste in the form of heat from the shunt.

Why the over voltage disconnect? Are you afraid of the quality of your charger not doing the job it is suppose to be designed to do?

I agree about the hall effect sensor. I have one in my Fluke 376FC AC/DC clamp meter and it works great. However, trying to find one you can install in a system with meters that can read it is, another story.

Pat

 

[pdavitt]

@pdavitt That is an excellent drawing. Very good representation of a combined energy system.

Thanks. Wish I could have figured out how I got two images on the post, or how to delete one of them.

Pat