Most solar?

[rvlifer]

I hope this isnt me being dumb or getting senile but you will have to explain that one to me

 

[Gyrophoenix]

I had our HR Scepter completely refurbished, including a custom solar installation. The electric bay has eight 300 AH LiFePO4 batteries in parallel for a total of 2,400 AH, two 4,000 watt inverters, five 60 amp solar charge controllers, and 4,000 watts of solar panels up top. 2,400 of them are on the roof of the coach, and another 1,600 are on the roof of the trailer, hooked into the electric bay with umbilicals. That amount of power pretty much allows being able to live a fairly normal lifestyle. (The stove top is both induction and propane, allowing the flexibility to use whichever will best conserve electricity if necessary. The Dometic refrigerator is also electric or gas. Most of the time its on electric.) Today I ran the middle A/C (15,000 BTU Dometic) all day, it was cloudy most of the day, and the battery bank still had an 80% SOC at sundown. (For those wondering why the "overkill", it's because we're full-timers, and we almost exclusively boondock, and wanted to be able to live the same way out in the sticks as when we are plugged in.)

 

[DonTom]

The electric bay has eight 300 AH LiFePO4 batteries in parallel for a total of 2,400 AH

I am curious how you fuse that 2,400 AHs worth of batteries in parallel.

Here is the reason I am so curious about that.

-Don- Auburn, CA

 

[John From Detroit]

More batteries can equal either more watts or more hours

I looked at the link and commented there Wires overheat and burn due to one of two reasons

Too much current for the wire (Wire too small) Or Bad connections .

 

[Gyrophoenix]

I am curious how you fuse that 2,400 AHs worth of batteries in parallel.

Here is the reason I am so curious about that.

-Don- Auburn, CA

The key is utilizing the correct size fuses, breakers and cables. Also, since I have two inverters, all cables must be the same length to each, to keep everything balanced. Whoever installed system the you linked to didn't know what they were doing.

Every cable in my system was custom (hand) fabricated. All cables linking the batteries, and the batteries to the inverters are 0000 gauge. The inline fuses on the cables from the battery bank to the inverters are class T 400 amp. Each inverter, on the output side, feeds into a breaker box with two 20 amp breakers. The box on one inverter handles the rear A/C (one 20 amp breaker) and the other 20 amp breaker handles the kitchen appliances. The box from the other inverter handles the middle A/C (one 20 amp breaker) and the other 20 amp breaker handles all the outlets in the coach. (I can run both A/C units at the same time off the inverters, but to run the forward A/C, the generator has to be running or the shore line plugged in.)

I hope I've answered your question.

 

[NY_Dutch]

I haven't found a picture of it, and I don't know the wattage or battery capacities. The vehicle was a 54' van trailer with solar panels completely covering the top and sides. When parked, the sides were hydraulically raised and angled to automatically follow the sun. The rest of the trailer was a mobile showroom for a large solar dealer in Georgia.

 

[DonTom]

The key is utilizing the correct size fuses, breakers and cables.

IYO, is there any problem with using separate lower current fuses on each battery before it is paralleled with the other batteries?

IOW, instead of a single 400-amp fuse for a four-battery output, all in parallel, use, a 100-amp fuse on each battery before it is paralleled with the other batteries. Still a total of 400 amps.

While will be more expensive and a dead short will blow all four fuses, I somehow have a hangup WRT using extremely high current fuses if not absolutely necessary unless where such cannot be avoided. I would feel safer with the 100-amp fuses. But is there an issue there that I am not considering?

IYO, would that do anything useful, or would it just be a FWOTAM?

-Don- Auburn, CA

 

[Gyrophoenix]

IYO, is there any problem with using separate lower current fuses on each battery before it is paralleled with the other batteries?

IOW, instead of a single 400-amp fuse for a four-battery output, all in parallel, use, a 100-amp fuse on each battery before it is paralleled with the other batteries. Still a total of 400 amps.

My system has 8 batteries in the battery bank. If designed and fabricated correctly, the amount of current being drawn from the battery bank, regardless of if current is being drawn for one inverter or both inverters, is spread equally between all the batteries. Having fuses between batteries is fairly useless. The two 0000 cables for the two inverters are both connected to the same terminal on the same battery at one end of the battery bank. So there's only the need for one inline 400 amp fuse on those two cables between the battery bank and the inverters.

While will be more expensive and a dead short will blow all four fuses, I somehow have a hangup WRT using extremely high current fuses if not absolutely necessary unless where such cannot be avoided. I would feel safer with the 100-amp fuses. But is there an issue there that I am not considering?

IYO, would that do anything useful, or would it just be a FWOTAM?

-Don- Auburn, CA

I can't see that such a setup would accomplish anything useful. I hope the explanation above suffices.

 

[Lou Schneider]

IYO, is there any problem with using separate lower current fuses on each battery before it is paralleled with the other batteries?

IOW, instead of a single 400-amp fuse for a four-battery output, all in parallel, use, a 100-amp fuse on each battery before it is paralleled with the other batteries. Still a total of 400 amps.

-Don- Auburn, CA

Most lithium batteries have internal current limiting (overcurrent shutdown) in their internal BMS so adding a dedicated external fuse on each battery is largely irrelevant. Overcurrent shutdown is one of the things Will Prowse tests when he does his battery teardown and evaluations.

Here he's testing the overcurrent protection on a $155 12 volt, 100 a/h battery (it passed).

 

[DonTom]

Having fuses between batteries is fairly useless.

Less heat on the fuse sockets I thought could be helpful. But perhaps not a realistic issue. Just would make me feel a bit better to not have the large numbers for a current draw all at one place.

Especially after reading that message I linked to, but as you said, there were better ways to do such a job. Hindsight always makes such things a lot clearer.

-Don- Reno, NV