Another Noob Question about a portable system

[Eclipse90]

Im new to the forum and have been trying to do as much research as possible before asking for recomendations. I want to put together a very small portable system for camping and just for fun. It would really only be used to charge phones, recharge AA/AAA batteries for lights, and maybe plug in a small fan for a short period of time. I liked the idea of the Yeti 400 and wanted to mimic it, but have questions about the battery vs inverter sizing.

However, after reading Sunking's sticky about inverter size vs Battery size, I'm confused at how Goal Zero is running a 300 watt inverter with only a 33ah battery. According to the sticky, a 300 watt inverter would need a much larger battery. How is Goal Zero doing this without draining the battery too quickly? With a C4 discharge rate of an AGM battery, a 33ah battery would only be capable of a 99watt inverter.

Before reading Sunking's sticky, I was planning on 44ah agm battery with a 300w inverter, thinking it would be fine (since the Yeti 400 is only 33ah). Obviously that still does not seem like a good idea though.

Thanks for the help. And I am prepared for the harsh criticism in wanting to build a very small system to start with

[Logan5]

300 watts @ 12 volts is 25 amps, of a 33 AH battery only 17.5 AH is avail. before battery damage occurs. so at 25 amps your battery will be dead in 20 to 30 min's. draw 25 amps for 45min's and permanent battery damage will require frequent battery replacement.

[Eclipse90]

I totally understand that, which is why I'm curious how Goal Zero does that without people's batteries always being damaged. As well as the fact that the discharge rate would be extremely quick and damage the battery.

[Logan5]

not to mention, if you discharge to 50% you need to recharge it in a timely fashion, with solar a cloudy day or two, you better plug it in. depending on the wattage of the array, you should probably plug it in any way. so for a portable system, carry a tiny propane generator or you could consider a peltier junction, to heat with a camp fire to recharge the battery. Also for a portable system I would forego the inverter all together. every device you plan to plugh into the inverter can be replaced with a 12 volt native powered device w/o the need for the inverter at all.

[ElectroDolt]

Hi, sorry to jump in like this, but since I'm a total noob and have no clue what the heck anyone is talking about, please chalk it up to total noobness and accept my apologies.
Did you mean to say 12v negative device? Or is there something called a native device that allows you to power AC items without the need for an inverter? Sorry again, for butting in.

[SunEagle]

I am sure there is something in the Goal Zero manual about how big a load their product can run and for how long.

Rating a system on the inverter size instead of on the battery system is just wrong and very misleading.

[Mike90250]

[QUOTE=SunEagle;n321646...Rating a system on the inverter size instead of on the battery system is just wrong and very misleading.[/QUOTE]

You mean the ad with the fridge next to the 60W PV and suitcase is not going to keep the beer cold !!

[SunEagle]

You mean the ad with the fridge next to the 60W PV and suitcase is not going to keep the beer cold !!

Maybe if you drink it all very fast it would still be cold. But the milk in that frig will probably spoil.

[Eclipse90]

I wanted to original try and build something like this:

https://www.amazon.com/gp/aw/d/B00VJ429M8/ref=mp_s_a_1_5?ie=UTF8&qid=1467230291&sr=8-5&pi=AC_SX236_SY340_FMwebp_QL65&keywords=solar+generator&dpPl=1&dpID=41SvwquwSwL&ref=plSrch

But use a larger battery and solar panels. Would use a pelican case to house everything including solar panels that fold open. Looks like I have more research to do.

[SunEagle]

I wanted to original try and build something like this:

https://www.amazon.com/gp/aw/d/B00VJ429M8/ref=mp_s_a_1_5?ie=UTF8&qid=1467230291&sr=8-5&pi=AC_SX236_SY340_FMwebp_QL65&keywords=solar+generator&dpPl=1&dpID=41SvwquwSwL&ref=plSrch

But use a larger battery and solar panels. Would use a pelican case to house everything including solar panels that fold open. Looks like I have more research to do.

You can build your own system that can generate about 200 watt hours daily for ~$500. Use a 12v 65Ah Optima Blue Top battery, a 100 watt panel, 10amp CC and 250 watt inverter.

I did it for about $550.

[Eclipse90]

That's a good idea also, I think I just liked the idea of having something extremely compact that can all be carried in a pelican 1500 case. I could fit a 40ah battery and 4 10w panels that fold out in the pelican 1500. Charge controller along with everything else would also fit inside and mounted to allow access to ports on the outside of the case.

[SunEagle]

That's a good idea also, I think I just liked the idea of having something extremely compact that can all be carried in a pelican 1500 case. I could fit a 40ah battery and 4 10w panels that fold out in the pelican 1500. Charge controller along with everything else would also fit inside and mounted to allow access to ports on the outside of the case.

Just remember that both the charge controller and inverter require some type of way to cool off. Putting them inside a sealed pelican case will tend to keep the heat in and maybe reduce the effectiveness of that hard ware.

[Eclipse90]

I would defintley put a couple 60 or 80mm fans inside also to help with heat.

[MetricAmerica]

Why o why are you making ac power for 'camping'? Just to charge aa batteries? Agh, making me cringe... screw the aa and aaa's, get real 18650 lithium batteries! Look for good 10 w 6 v panels and you can buy several cheap lithium charger boards on Amazon and eBay, they charge upto 1 amp at 4.2 volts...
Best source for 18650 are out of laptop battery packs, you can't trust buying 'virgin' Chinese knockoffs, which are everywhere! Three 18650 will get your 12 v needs....
6 v or 5 volt panels can directly charge your 5v devices! And if not, you can get cheap lithium to 5 v charging boards, to get your iPhone charged. These boards can actually connect to the 6 volt panels instead and work just as well.

Way better solution then a crap wasteful ac invertes!

[SunEagle]

Why o why are you making ac power for 'camping'? Just to charge aa batteries? Agh, making me cringe... screw the aa and aaa's, get real 18650 lithium batteries! Look for good 10 w 6 v panels and you can buy several cheap lithium charger boards on Amazon and eBay, they charge upto 1 amp at 4.2 volts...
Best source for 18650 are out of laptop battery packs, you can't trust buying 'virgin' Chinese knockoffs, which are everywhere! Three 18650 will get your 12 v needs....
6 v or 5 volt panels can directly charge your 5v devices! And if not, you can get cheap lithium to 5 v charging boards, to get your iPhone charged. These boards can actually connect to the 6 volt panels instead and work just as well.

Way better solution then a crap wasteful ac invertes!

I agree. If the loads are all DC then using an inverter just wastes power.

I would caution giving advice to someone that may not be electronic or electrical circuit knowledgeable. Building your own system from parts takes some experience and knowledge. Not something most people without an electrical or electronic background can handle.