 |
|
|
| |
Subject |
Author |
Date Posted |
Forum
|
 |
RE: Square wave inverter to LFP battery?
Most batteries hate heat. MSW inverters do cause batteries to get hotter when charging at least on my laptops.
What sort of wattage do you want to run? I got a very nice 700 watt psw inverter from Victron for $109.00 about 5 years ago. They may be cheaper than that now.
Here is a 375 watt:
https://www.amazon.com/Victron-Energy-Sinewave-Inverter-VE-Direct/dp/B01N0W4H34/ref=sr_1_3_sspa?crid=31YUZ7H28E0TD&keywords=500%2Bwatt%2Bpsw%2Binverter&qid=1682215042&sprefix=psw%2Binverter%2B500%2B%2Caps%2C514&sr=8-3-spons&ufe=app_do%3Aamzn1.fos.f5122f16-c3e8-4386-bf32-63e904010ad0&smid=ALRPFGEN62HZC&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzUjlSQ0ZYVlVURFZXJmVuY3J5cHRlZElkPUEwNjg5NjA5M1BPTUFPMVlQREtLSCZlbmNyeXB0ZWRBZElkPUEwMDIyNjUxMzQzVUxHWEY3QkhSNCZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU&th=1
Point about heat is taken, thank you Don. I would be interested in something over 1000W if I get around to adding a residential fridge and possibly a separate small freezer. I hear that compressor start-up wattage could exceed 600W - and if both machines start at the same time and I happen to run a small microwave at this exact moment (1400W input), I don't even know what could be the total wattage, 3000W?
|
Almot
|
04/23/23 09:57pm |
Tech Issues
|
|
RE: Square wave inverter to LFP battery?
I was mostly concerned about battery charging with MSW. LFP battery in laptop and phone, NiMH in cordless drill. I am not running any electronics on MSW. The only piece of electronics that I've been running on it was a corded electric shaver, it has an AC-DC converter hidden in massive 110V plug.
|
Almot
|
04/22/23 06:22pm |
Tech Issues
|
|
Square wave inverter to LFP battery?
I've been charging small electronics with a small $20 SQ for years. Laptop, phone, toothbrush. Don't have much use for a bigger/better one. Other than slower charging due to intermittent DC, is there a reason why this might be a bad idea?
Small motors like electric shaver or water flosser do work on SQ wave, but quieter and "rougher" - it's like I can almost hear intermittent work at 30 HZ pulses.
|
Almot
|
04/21/23 11:36am |
Tech Issues
|
|
RE: LFP battery absorption and float - report
Victron MPPT won't start Bulk charging again until it can't sustain 13.2 Float anymore - which is usually the last few minutes before sunset - doesn't make much difference.
As a result the battery was getting lower every day, with plenty of sun.OK so I would expect the re-bulk to start about 30 minutes earlier each day if the state of charge was dropping each day.
Didn't notice, not saying yes or no. With my very low draw any sun, even minutes before sunset, results in keeping the battery above 13.2. It has to drop below Float for at least a minute for Victron to start re-Bulk.
What I did notice was progressively lower pre-dawn voltage day after day, as witnessed both by checking voltage on the app before dawn, and Victron records of "minimum voltage" for each day.
|
Almot
|
02/10/23 07:01pm |
Tech Issues
|
|
RE: LFP battery absorption and float - report
Don, input for Victron was 60V from 490E solar.
Also the controversial Float matter with LFP. It might not be strictly necessary but in camping there is always discharging going on, at least 1A standby current of fridge, radio, LP detector. I consider Float a continuous (in daytime) charging of battery that is being discharged continuously and thus is never really full. By setting Float to 13.5 I am getting 1 or 2 amps above the standby current in daytime only, ensuring SOC close to upper 90s by the evening.
3 tons - yes, the harvest was less than daily draw, because with zero Float current the controller stops charging shortly after the Bulk is reached. I set it up this way according to the LFP manufacturer recommendations - zero or short Absorb time, zero Float current. This is not a controller defect. Just wanted to note that contrary to the manufacturer's promise this LFP was not getting fully charged just by reaching Bulk 14.2V (my mistake, it was 14.2 not 14.4). Not even close to full. After reaching Bulk it was drawing same 8A for almost 2 hours when I set Absorb time to longer.
Again, Victron factory pre-set for their "Victron Smart LFP" is 2 hours Absorb time and 13.5 Float so I can't blame my particular LFP either. Makes me wonder about the popular mantra "no Absorb time, no Float".
|
Almot
|
02/10/23 09:57am |
Tech Issues
|
|
LFP battery absorption and float - report
Bought this 120AH LiFePO4 a while ago https://www.lynaclithium.com/wp-content/uploads/2022/03/12.8V-100Ah-True-Series-Quick-Sheet-USA.pdf. 120AH marketed as 100AH.
Don't see this now but on the older page (and most other LFP manufacturers) recommendations for LFP are - very short or zero Absorb time, no Float or set ~13V (for 14V battery). Now I see them recommending Tail Current 2A-5A, this is where you should completely stop charging, be it Bulk or Float or whatever but I doubt this would work for me (see below).
Set Victron MPPT to Float 13.2, Absorb time 10 min, controller wouldn't accept values <10 min.
Was drawing ~ 30-40 AH a day. Was harvesting slightly less, because it wasn't fully charged upon reaching Absorb 14.4, and there was zero Float current. When loads kicked in, Victron increased Float current to slightly below the load demand - ex. fridge thermostat 2A, Float 1.5A , pump 10A, Float 8A etc - so no joy here.
Victron MPPT won't start Bulk charging again until it can't sustain 13.2 Float anymore - which is usually the last few minutes before sunset - doesn't make much difference.
As a result the battery was getting lower every day, with plenty of sun.
Interestingly, Victron pre-set mode for some "Victron Smart LFP" is 2 hours Absorption time and 13.5 Float.
Set Absorb to 3 hours to see how long it takes to bring tail current to zero. After a few days when battery was finally fed well and was getting some charge during Float to compensate for Loads draw during the day, it took 1 hour 45 minutes to stay in Absorb to drop the current to roughly what loads demand. Well, at parallel 28 it's still winter, max 20A current from a modest array (8A when it became getting full charge every day).
Same story with Renogy DC-DC converter - when set to Li, it was getting lower every day with 6-7 hours driving and the only load - 4A fridge at 60% cycle. Set Renogy to Led Acid battery. Hopefully it won't try running equalization.
|
Almot
|
02/09/23 06:23pm |
Tech Issues
|
|
RE: Norcold fridge - clogged drain tube?
... try pouring some hot water in the tray. Might melt the blockage.
Richard
Bingo. Boiled some water, poured in - very inconvenient, can't get to it with a cup, had to feed it with a table spoon, melted ice in the tray, removed icy cold water, poured more hot water. Blockage opened, next day closed again - slightly - but now I know how to deal with it.
Could've been ice and dust too.
Doug - cooling unit has not been replaced. I'm just pushing the limits of this machine. Hot and dusty. But at least it's sunny. I'm missing and a normal compressor fridge of huge capacity, not measly 6 cu.ft, and a separate chest freezer.
|
Almot
|
12/17/22 03:54pm |
Tech Issues
|
|
RE: Norcold fridge - clogged drain tube?
Doug, my freezer will not get to 0F when the outside coils can't cool well, i.e. hot sun on this wall. It will struggle keeping it at 4, cycling almost nonstop. Fridge would fare better, cooling down to 40, but to keep it cycling almost nonstop - in order to achieve near-zero in freezer - I have to set thermostat to Max, and then fridge goes to 32 and below, causing icing of the fins and freezing water in the tray. If I set it to 1 or 2, it will stop cycling when fridge is 44 -46 and freezer 5-6. This is my reality. In the morning I set it to 3-4, as it gets freezer to 0, in the afternoon I set it to Max to get somewhere from 0 to 4.
Yes, better ventilation at the back of the fridge is needed, and possibly fan inside the fridge - to spread the cold air from those 22F fins around so that it would not freeze the food near fins.
About check valve. It's just a plug on the tube, with a small hole so that something (insects?) wouldn't get in. It's tiny, don't see any one-way mechanism. I removed, anyway. It's not the culprit here.
|
Almot
|
12/16/22 05:00pm |
Tech Issues
|
|
RE: Norcold fridge - clogged drain tube?
Thank you, people. Likely the ice. Can't defrost it now, fridge is full. Will have to clean the tray daily so that it wouldn't overfill.
Doug, will all due respect to your knowledge in this area, ice on the fins and in the tray is related to freezer temps, albeit indirectly. Thermostat is in the fridge as I understand. It cycles when fridge temp rises to whatever the thermostat is set to. In warm weather with sun shining on the fridge side of trailer, I have to set thermostat to Max to keep freezer below 4. This causes fridge to cool below 32 and freeze water in the tray, and sometimes to grow an impressive ice fur on the fins before it starts dripping to the tray.
|
Almot
|
12/14/22 11:17am |
Tech Issues
|
|
Norcold fridge - clogged drain tube?
Under the fins inside the fridge there is a tray to collect dripping water. There is a hole at the back of the tray, with a flexible tube going to the outside.
Somehow it stopped draining. No water comes out on the outside, the tray got filled with water, then it froze - I tried to keep freezer at 0F as it should, this required the fridge bin to cool down to low 30-ish. Now I'm checking it every day and manually remove pieces of ice from the tray - VERY awkward under the fins.
Tried to run 1/16 wire through the tube from inside - it hits some hard obstacle within a fraction of inch from the entry. Tried to push wire from the outside - same thing, wire stops after approaching more-less the spot where the tube goes into the fridge back wall. Tried to blow the tube by mouth from the outside - nothing, air doesn't go in. The tube terminates outside with a plastic plug and a tiny hole (to stop insects from coming?), removed the plug, no help.
Tray seems to be glued to the "holed" fitting in the fridge wall, or some caulk, can't pull out the tray to inspect the hole.
There were some dust winds in my absence, but to push the dirt all the way up the tube, and to pack it so hard that steel wire can't go through?
Any suggestions or comments on how to clean the passage or remove the tray, are welcome.
Model N611L, if this matters.
|
Almot
|
12/13/22 07:12pm |
Tech Issues
|
|
RE: Did anybody tried Victron MPPT warranty?
Thanks, Don.
|
Almot
|
11/04/22 05:35pm |
Tech Issues
|
|
RE: Did anybody tried Victron MPPT warranty?
Don, what small controller - 20-30A range - would you think is the best for low-light conditions?
|
Almot
|
11/04/22 09:08am |
Tech Issues
|
|
RE: Did anybody tried Victron MPPT warranty?
Almot,
This behaviour reminds me of Mac laptops--where static electricity would sometimes build up on the mother board.
Try shorting out the input then wait a few moments and return power.
I think I see a shipping box in your future if the device is still under warranty.
Don, do I need to disconnect it from the battery while shorting the input?
Yes, warranty for a few months more, plus 1 year topped up by credit card though this could be more pain, have never tried this route.
|
Almot
|
11/03/22 09:03am |
Tech Issues
|
|
RE: Did anybody tried Victron MPPT warranty?
Victron has 5V "threshold"? Mid-tier Chinese boxes (meaning not a complete ju.nk) - Epever and Renogy, both open at the panel voltage 2-3 V above the battery voltage, frommy experience.
The fact that it no longer can switch to User Defined mode is still unexplained and inconvenient.
|
Almot
|
11/02/22 11:44pm |
Tech Issues
|
|
RE: Did anybody tried Victron MPPT warranty?
I thought about battery BMS, will check it later with another controller.
But I think Victron gone crazy. Today it refuses to start at all, even at 18.5V. Battery is 13.5V, this corresponds to ~80% SOC.
It also refuses to switch to User Defined mode in the app (yesterday in attempts to revive it I switched the mode to one of factory presets, namely AGM. So I can now switch between AGM , Victron Smart Li (low 14.4 Absorb in this one), and a few Gel variations - but not User Defined. And it doesn't start charging. Uninstalled and reinstalled the app - didn't help.
Will call Canadian dealers after Christmas, don't have time for this now.
|
Almot
|
11/02/22 02:04pm |
Tech Issues
|
|
RE: Did anybody tried Victron MPPT warranty?
Well, Don, it does behave weird.
Just to remind, this is a bench test with regulated 15A DC supply. I didn't pay attention to it in field, in summer.
It opens at 18.4V. I don't know why yesterday it opened at 15V - maybe it was after I cranked it up to 18, got scared that nominal 15V DC supply will blow up and lowered it to 15V. Once it opens, input can drop to 14.6V and it still pumps undetectable current, batter reads "On". Shuts down at 14.3V, says "goodnight", battery reads "Off" and won't wake up again until V input rises to 18.4.
When simulated "sun" goes down, controller is clinging to MPP curve very well. At 15V "evening" it outputs 6A, at 14.5V - 0.1 A (heavy rain?), and if "rain" stops and V input rises to 15 again, it outputs mere 0.2A - not 6A. Then it wakes "for real" at ~16V, at which point current jumps to 10A and V drops to 15-something - MPP tracking at work, but not as smooth as in the "evening".
Reached Absorb at 14.6V - as per my setting. Current tapered to zero. I pulled the plug, then decided to let Li batt fry a little more, plugged DC supply in - nothing. With charger disconnected and zero load my Li reads 14.3V fully charged, this isn't new, it drops by 0.3V from 14.6 observed at the end Absorb. Cranked input up to 18.5V - nothing. Isn't it supposed to re-start Bulk again, quickly rise to 14.6 and go to Float? My "Re-bulk" is set at 0.1V, this means it should start Bulk again if V drops to 14.5.
Somebody with Victron MPPT, please enlighten me. Maybe it's normal not to open until sun gets high and V input =18.5, and not to at least "try" to resume charging at 14.3 after 14.6 Absorb has been reached.
|
Almot
|
10/31/22 08:10pm |
Tech Issues
|
|
RE: Did anybody tried Victron MPPT warranty?
Follow-up: let it sit disconnected for a few hours, now it works. Don't know what happened. Probably new firmware took time to settle down. (While disconnected? A mystery).
Turned it On, began increasing input V, it woke up - veeery slowly. Opened at 15-something, for a minute was running 0.1A current, then jumped to 10A (DC power supply can't do more). Victron opens at a higher voltage than a couple of other controllers, this isn't new, but it used to open up and jump at once to maximum possible current. Must be new firmware, fine with me. As before, once it opens, input V can go a bit lower, it will still charge. Love new firmware. They added "Adaptive absorption time" and "Tail current". Something akin Morningstar and (defunct) US-made Rogue. Too bad they didn't at the same time upload three-line display and on-board interface with buttons like in Rogue.
|
Almot
|
10/30/22 08:27pm |
Tech Issues
|
|
Did anybody tried Victron MPPT warranty?
After a few months of inactivity - disconnected from battery, loads and solar - it doesn't pass any current through. 20A model with Bluetooth.
It's home now, on regulated DC supply. When connected to battery, it downloaded firmware upgrade, reads V input/output but zero current. Bulk LED - blue - is blinking every few seconds, the app reads 13.1V battery - about 50% discharged Li, zero current, 16V input, I increased input to 18V - nothing.
I might have mistreated it, momentarily connecting Pos of power supply to Neg of MPPT or vice versa, don't remember. Getting old I guess. It was only one lead, not both. Fuse is fine.
Did anybody try manufacturers warranty?
|
Almot
|
10/30/22 04:24pm |
Tech Issues
|
|
RE: Can you mount solar above vents?
2 reasons not to mount above the vent lid: 1) if y want to be able to open it a little, you'll mount it high and there will be more air resistance when driving,
and 2) it will block the lid from fully opening, less air flow for you when camping.
#2 will be TAD countered by the shade the panel provides.
There is no reason not to mount it directly above the tank vent - I did. The roof slopes downwards there, and while the panel is ~6" above the roof at this point, it is just barely higher that the crown of the roof. You need to leave a few inches between the panel and roof anyway. Make sure there is a few degrees slope on the panel, to shed rain water and dust.
|
Almot
|
10/30/22 04:04pm |
Tech Issues
|
|
|
|
|
|
