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.
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.
Just leave the generator off with settings above. The PV will surge in with no 120v input.
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
Replied to these questions 2 posts earlier with a pic of my settings.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
Thank you
Yea... a high voltage drop under full load would mean the battery is smaller and load is larger. For example, if an 18650 battery drops from 4.0v to 3.6v 'instantly' on a load, I'd say the load is extreme for the battery size. Can you increase the size of your battery or lighten the load?
Based on my basic calculations I am pulling about 3kWh AC so about 120A DC and it shouldn't be more than 1.5A per cell peak(I think there are about 180 cells in series assuming I haven't blown too many cell level fuses yet). I am actually thinking a not insignificant part of the voltage drop is from wire losses. Most of it I am sure is do to the bad cells drawing down the pack but I currently only have two parallel 10AWG wires from the batteries to the inverter and while the distance isn't long I am pushing past the design specs of the wire and it does get warm(but not hot) to the touch when at peak load. Again that whole "temporary" thing but I plan to have 1/0AWG wire for my new packs and inverter so that should handle 250A.
1a / cell is pretty hefty for regular laptop cells - most are more in the 0.5a standard discharge range. What cells are you planning to use?
Just take your load and divide it by the number of cells in one of the series packs. For example, let's say you have 7s100p and you're max load is 3000w. 3000w/24v = 125a. 125a/100p = 1.25a/cell. Unless a cell has specs for this (standard discharge) it will pull down the voltage.My current setup is one I inherited form a fellow hobbyist and I don't plan to keep up the design and am retesting all the cells since they have sat at full charge for a couple years since the last testing and there are lots of ones I would consider B grade for my standards, Under 1800mAh, Sony cells... I haven't done supper detailed tests since this current setup is "temporary", I think we all know how that goes
PIP is a (loose) short-hand term for an MPP Solar Off-grid unit. https://www.mppsolar.com/v3/pip-series/
Neutral in my thinking is one of the single-phase 120v wires - e.g. the white one. The black is the other wire.
I don't have any codes or alarms.
In my case, the grounds are all wired together and all go back to the 'grid provider' ground. When plugged into the house, its the main panel where ground is tied to neutral (per US code). At camp grounds, I don't know what they do - but hopefully the ground is wired to a ground somewhere.
Grid (generator) 20a * 120v = 2400watts. 2400w/48v battery = 50. You might want to use 50a instead of my 40a for "Max charging current" as a permanent setting.
The "Max AC charging current" has no affect on PV with the other settings above.
My MPP Solar is 25a max. My 120v grid circuit at the house (and typical campgrounds) is 20a or 15a. At 2a (the minimum) 250w are directed toward battery charging. At 10a then 1200w are directed to charging - which doesn't leave much on a 15a or even a 20a to run mini-split, microwave etc. So I typically bump AC amps when I'm ready to charge and not run much else.
The "Max AC charging current" has no affect when boondocking as there's no incoming Grid.
Then it's off and settings don't matter.
Cool! Thanks for the kind words.
