Trailer - Disable PIP for long term storage

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prepared1

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Jan 17, 2021
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OGITC: if you switch the system off during a time when the PV panels are still getting input, will that damage the panels? It is a concern with typical hot water solar panels, so people put in some sort of dump load or a cover. Just curious. I have considered doing something similar to your project, would like to know.

Thanks for the interesting posts...
 

OffGridInTheCity

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Dec 15, 2018
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OGITC: if you switch the system off during a time when the PV panels are still getting input, will that damage the panels? It is a concern with typical hot water solar panels, so people put in some sort of dump load or a cover. Just curious. I have considered doing something similar to your project, would like to know.

Thanks for the interesting posts...
Thank you for the thought. The 2s2p panels go to thru standard circuit breakers, are combined, and then on to the MPP. The disconnect procedure not only re-routes the AC around the PIP but also includes turning off the battery bank and disconnecting the PV input.
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OffGridInTheCity

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Lately the sun is high enough to reach the 4 x 300w panels on the roof of the trailer. Mid day - there is band of shadow from the roof of the house, killing optimal performance but beginning and ending 1/3 of the day they are in full sun ....
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and producing pretty good power. Here's the kwh vs hours of the day from the PIP logs for yesterday. The dip in the middle is the shadow from the roof in the pic above. They're wired 2s2p length-of-trailer-wise - so 1 string is full sun and the other has shadow on both panels.
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With the dip I'm getting 2kwh/day (June 2) and would expect to get 3kwh/day in full sun. I've been running the 9000 BTU heat pump maintaining 75F/24C 24hrs/day on a 48v@260ah 18650 battery bank and its keeping up.

The temp spiked this week to a few days of 100F/39C but will be back down to 80-90F/29C'ish soon. The system looses some ground at 100F but gains just a bit of ground at 85F. The trailer is 14x7 with 1" insulation + radiant tape *everywhwere* (ceiling, wall, floor, in the tail-gate, and all the nooks-crannies.

I'm really pleased at how well heat-pump / 1200 watts of panels / PIP / 14kwh battery is performing. With modest power management and good sun - this thing can actually run on Solar.

The DIY 18650 14s88p battery made of RING cells is performing very well. Sat for the last 4 months and just turned it on... and balance is holding at 20mv max difference same as 4 months ago.
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**Lessons learned.
1) FLAT mounted panels means the rain/water pools on them due to the frame lip all around them and when the water evaporates the dust/dirt is caked on and is not washed off the way tilted panels are. Hadn't considered that... and would warn others to allow for some tilt for better self-cleaning.

2) The Honda EU3000is generator was converted to support Propane and it turns out you can still use Gasoline. The Gasoline mode will produce 2,200watts of continuous charging. The Propane mode will only produce 1,800watts... the motor isn't quit as powerful under load. and that's 20% less charging power.
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OffGridInTheCity

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I've been experimenting with the 120v is disconnected and the Trailer/PIP 3048LV has been running on solar + battery only. The mini-split has been maintaining a reasonable temp 24/7 - all good. However we've hit a hot patch - 106F/41C yesterday and projected 115F/46C today.

At these temps it can't maintain and the 48v (14s88p) battery is down to 51.8v this morning.

QUESTION: You can see my PIP settings below - what happens when the battery hits cut-off-voltage. with no 120v input?
I assume it will require external battery charge? and that it won't resume AC output until it hits "Back to discharge voltage"?
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R

robinkyle11

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Yes. I have a few scenarios with the trailer and I just need to know what to set for different modes. For example:

1a) One mode is using the onboard generator to charge the batteries while driving - e.g. the generator goes to the ATS / PIP sees 'grid' and I want it to do the 20a max charging.

1b) An Alternate to this is just using the solar panels while driving to charge. The trailer is in shade so I can't test this very well right now - and surprised to see 2a charging (10a max) when when the panels only creating 100w in "Solar->Utility->Battery" mode. The 2a must be coming from the grid but why 2a instead of 10a?

2) Another mode is boondocking with sun and I want the solar panels to have priority - but maybe run the generator an hour or 2 to assist (with max amps flowing).

3) And bypass - where I have grid at a campsite (or just parked at the house) and bypass the PIP/batteries and leave it all turned off ---
*You're 3-position switch advice has solved this for me - thank you again for that!*

The good news is I can adjust parameters - but want to work out the minimum set of adjustments :)
 

OffGridInTheCity

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I've got mine down to 1 setting for all the below.
1st up - I have Charger source prioirty = SBL&UCB + Output source priority = Utility->Solar->Battery. This works when AC input is off + when AC input is on it will still let the PV thru if I throttle the Max AC charging current so that Max AC charging current + PV <= Max charging current (to the batteries). In my case 2a + PV = 13a = 15a and is <= 40a.
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I have a honda eu3000is and discovered that Max AC charging current = 20a (in conjunction with Max charging current = 40a) is the max the generator can sustain before the engine overloads / runs erratically. This gives me ~ 2,200w of continuous AC charging.

The reason I have Max AC set to 2a (right now) is that if I left it at 20a (for max generator charging) it would be 20a + load = overload on the 15a circuit I have the trailer plugged into at home. This might be true at a camp-ground as well. But with 100% generator = I can set it up to 20a for max charging.


Yes. I have a few scenarios with the trailer and I just need to know what to set for different modes. For example:

1a) One mode is using the onboard generator to charge the batteries while driving - e.g. the generator goes to the ATS / PIP sees 'grid' and I want it to do the 20a max charging.
I only need to alter the Max AC charging current from 2a to 10 or 20 or xxx till I reach the max the generator can do. But remember - its Max AC charging current + load - so you're situation may vary. While driving, you're load should be minimal so max AC amps your generator can handle.

1b) An Alternate to this is just using the solar panels while driving to charge. The trailer is in shade so I can't test this very well right now - and surprised to see 2a charging (10a max) when when the panels only creating 100w in "Solar->Utility->Battery" mode. The 2a must be coming from the grid but why 2a instead of 10a?
Just leave the generator off with settings above. The PV will surge in with no 120v input.

2) Another mode is boondocking with sun and I want the solar panels to have priority - but maybe run the generator an hour or 2 to assist (with max amps flowing).
Since you'll likely have load, you might want to pull on Max AC charging current - to 50% of your generator max to both charge and leave room for active loads.

3) And bypass - where I have grid at a campsite (or just parked at the house) and bypass the PIP/batteries and leave it all turned off ---
*You're 3-position switch advice has solved this for me - thank you again for that!*

The good news is I can adjust parameters - but want to work out the minimum set of adjustments :)

I hope that helps and I'm not sure this is the 'only way' - its just what I'm doing so far :)

A side note - I took the 7,000lb trailer out for a 1st 20mile run the other day. It only weighs 3,800lbs (good) and the PIP / mini-split ran just fine the whole time. The mini-split is silent inside and out. The surprise was the PIP is not that noisy - perfectly OK for inside the trailer!
 
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OffGridInTheCity

Active member
Joined
Dec 15, 2018
Messages
1,712
I have a few scenarios with the trailer and I just need to know what to set for different modes.

For example:

1a) One mode is using the onboard generator to charge the batteries while driving

e.g. the generator goes to the ATS / PIP sees 'grid' and I want it to do the 20a max charging.

1b) An Alternate to this is just using the solar panels while driving to charge.

The trailer is in shade so I can't test this very well right now

and surprised to see 2a charging (10a max) when when the panels only creating 100w in "Solar->Utility->Battery" mode.

The 2a must be coming from the grid but why 2a instead of 10a?

2) Another mode is boondocking with sun and I want the solar panels to have priority

but maybe run the generator an hour or 2 to assist (with max amps flowing).

3) And bypass

where I have grid at a campsite (or just parked at the house) and bypass the PIP/batteries and leave it all turned off

*You're 3-position switch advice has solved this for me - thank you again for that!*

The good news is I can adjust parameters

but want to work out the minimum set of adjustments :)
Replied to these questions 2 posts earlier with a pic of my settings.
 

Korishan

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They were a spammer, they've been removed.
 

OffGridInTheCity

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Dec 15, 2018
Messages
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After a year of work - "The Trailer" took it's maiden overnight voyage! Used 5-6kwh in 24hrs for full 24hr mini-split comfort + dinner (full range of appliances). The 14s88p (260ah) battery went from 56.0v down to 50.0v low (52% DOD per my chart) and back to 52.0v with a bit of sun on panels during travel home.

Overloaded the MPP Solar 3048 at one point (mini-split + hot-water + hot-plate + microwave) and had to turn it off + back on to reset as I didn't know what to do - but that worked. The system has 30amp AC circuit breakers (10awg wire) - so the the PIP overloaded before they tripped as it tops out at 25a@120v.

Really happy with the 18650 battery and the PIP :)
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