Community Forums

NealC · 09-15-2017, 07:41 AM

It's an interesting balance in cost over function. Gen power vs. Solar/Batt power vs. Tank durations.

NealC · 09-15-2017, 11:28 AM

Quote:

Originally Posted by C.Martin

You really need AGM or better yet...LiFePO4 batteries to take advantage of the really large array on a coach. Lower resistance allows them to take much higher charging currents. A large array will top up your bank quickly...and would seem to be a waste...but they also help with fast recovery after using daytime loads such as the convection/microwave, instant pot mini duo, or Rocket Espresso machine...

Marvin caught my attention when he upgraded the system for wheelingit's rig. They can run an air conditioner and do laundry with thier system. Impressive...(also not cheap).

I am hoping that the weather in ABQ for the Balloon Fiesta will be mild enough to not need air conditioning. If so, I'll be giving the solar a good workout...running oasis for hot water, convection/microwave, fans, Water pump, espresso machine, Dish/Stereo/TVs...we'll probably have some prepared meals,,,that just need to be heated up. From photos of past years...I won't be able to take advantage of tilting panels...due to the orientation they use to park the coaches. At least in the lot they have us in.

For grey water...the 4-wheeled 42gal Barker tank reigns supreme. If you have to ferry long distances...putting it in the back of your toad...and using a macerator oump to transfer the grey water would be useful. I am looking to add a 60 gallon drinking water blivet and transfer pump to bring fresh water back the other direction.

I emailed Marvin - this is your fault again Charlie

I looked at the Dutch Star mod, I certainly don't want to give up storage/basement space, it's already at a premium as I take everything almost up to a spare dog with me! :( So I'm probably going to look at what you did i.e. max solar panel coverage to support my 8 x GC2-ECL-UTL batteries and existing inverter. I'm also looking at the Barker tank, thanks for the lead on that. I would enjoy secluded camping from time to time and seeing what I can do off of solar and added tank support. Sounds fun.

4x4 · 09-15-2017, 01:22 PM

My 2¢...

I had 8 new high quality AGMs with 600 watts solar and the Magnum 3000w hybrid inverter. Even with 8 new AGM batteries with 880 ah (440 usable) the Magnum would VERY quickly drop the voltage on the AGM's when playing around trying to run one AC. In the morning before the solar panels had a chance to fire up, the microwave, or induction stovetop or hot water tea maker would drop the voltage below 12 and even below 11 volts. If you really want a system that works, go Lithium. My coach is currently getting upgraded (again) and I will report back the difference between what was 8 new 8 AGMs and a bunch of Lithiums.

On another note, IMHO if you are installing Lithiums put them inside and not in the storage bays. I had a temperature probe in there and it was consistently 10+ degrees warmer than inside and that was without any A/C running and while parked! Imagine how hot your storage bay will get when running in just 90º weather! The asphalt is basically unshaded on most western roads so it can get to 120º or more basically reflecting that heat back into your storage bay. lithiums do not like warm temperature for cycle duties.

The other thing I would say is keep your inverter in the storage bay away from the batteries. This will make for a significantly longer cable but if sufficiently heavy the loss can be under 2%. This will keep the heat generated from the inverter away from the batteries and as a bonus will also keep any fan noise from the inverter from bothering you.

4x4 · 09-15-2017, 03:33 PM

This is interesting for this discussion... lead vs. lithium batteries...

https://www.linkedin.com/pulse/lead-...s-robert-bean/

NealC · 09-15-2017, 04:50 PM

I think I just lost interest in solar again [emoji853]

4x4 · 09-15-2017, 05:32 PM

Quote:

Originally Posted by NealC

I think I just lost interest in solar again [emoji853]

My bad... sorry

C.Martin · 09-15-2017, 05:53 PM

I guess I shouldn't follow that link???

NealC · 09-15-2017, 06:18 PM

Here's my uneducated opinion:

Green energy is all backed by batteries. Whether solar, wind, or hydro. It's all about storing the harvested energy into batteries to then be consumed or sold back to an electric company. If you don't have great batteries why spend thousands on the system to capture it. Batteries are half of the equation. If I'm going to do solar right then the right batteries are equally as important. Why buy a great audio receiver if you don't have great speakers? I would want to replace my lead batteries with the best, lithium it sounds. I don't want to add batteries or probably even change the inverter. Just put in 8 great batteries.

OverDo · 09-15-2017, 07:36 PM

Neal,
Absolutely correct. Back in the day I did some work on one of the college solar powered race cars. You of course needed efficient solar panels, charger and motor(s). Turns out it was really a battery race not a solar panel, charger, or motor race at all. The best batteries won the race then and still do today. Power storage is the key to success with solar or any other form of energy storage and redistribution.
Vern

FlaRider · 09-15-2017, 08:46 PM

So if you had a 40' say a 4018, any recommendations on where to put the lithium batteries inside?

NealC · 09-15-2017, 08:53 PM

I would replace the house batteries with lithium. Same location.

4x4 · 09-15-2017, 10:06 PM

Quote:

Originally Posted by NealC

I would replace the house batteries with lithium. Same location.

That would be a mistake. Heat kills lithium and you can't recharge them below freezing. The best place is inside as even the bays get too hot.

NealC · 09-16-2017, 07:11 AM

Quote:

Originally Posted by 4x4

That would be a mistake. Heat kills lithium and you can't recharge them below freezing. The best place is inside as even the bays get too hot.

What are your options? Put them in the coach and let it be your year round internal heater? And smell probably?

Put them in a basement where there is no ventilation and it takes up storage?

Put them where your house batteries are so they are ventilated, if needed then add a cooling fan(s) in that bay.

Can batteries like electronics handle the temperatures? They are probably designed and expected to handle it. What are the manufacturer ratings on high and low temps?

Think of R/C planes that are electric or real cars, yeah, the batteries get very hot when they are serving the juice. But that's expected.

Seems to me the answer is save a lot of money, run the generator when you need electrical demands, use the inverter with rationed power when you don't need it. Diesel consumed would take 8,000 years to cost what the solar setup would cost. I'm all for solar if it's a good fit, but is it? That's what I'm vetting now.

4x4 · 09-16-2017, 08:40 AM

Lithium batteries do not vent so they don't smell. They have low internal resistance so they don't get hot in and of themselves. They should be put in the most temperature controlled environment possible. The inverter/charger should be as close as possible but not in the same space as it generates both heat and noise so I would put it in the basement as close to the batteries as possible.
If your looking at solar from a purely financial angle then you'll probably never make it back.
If you're looking from the peace and quiet point of view while boondocking than solar is priceless.
It all depends on what's important to you.