I just finished a Samlex pure sine wave PST 3000-12 inverter install. I ran 00/2 cables because that was recommended in the user manual. I added a Renogy 30 amp transfer switch with the charger wired to the shore power connections so the charger stays off when shore power is off. It is practically next to the battery compartment under the dinette seat. I also installed the remote at the entry wall so I can see the readings without bending over like with reading the Victron meter (when not using Bluetooth) or the surge protector which I ordered without the remote by accident. So my first test was to run the microwave for 1 minute. I was kind of shocked to see the time remaining plunge from 9 hrs to 27 min in power left after only 1 minute. The 14.6 capable batteries were not fully charged reading 13.37 volts at start. Not sure why they were at that level as they are on shore power so the progressive dynamics 9160L should have them a bit higher. The voltage dropped to 12.87 in a minute. The Victron reads 98% charge but only 27 min remaining power. Maybe there is something wrong with my meter settings. Start:End after 1 minute of microwave power used:Does this amount of power draw seem about right for this inverter?

It shows that your battery bank (as entered in AH for capacity at the 20hr rate) will only last half an hour at 124 amps draw. After the MW has run its five minutes or whatever. the battery bank will bounce back quite a ways and still give you lots of time at ordinary amp loads like 10 amps for the furnace and a light.Your idea of battery voltages seems muddled. Your converter is set at 14.6 but the battery will take time to reach that voltage (Bulk Stage) then it is still not full. Now it stays at 14.6 with amps tapering until the battery is full. Now you drop that voltage to 13.6 for floating.

Right I may be muddled. I have read that explanation of battery charge and I must not fully understand it. The RV is usually plugged in to a 20 amp outlet with a 40ft outdoor extension cord. I think it’s a 14ga. So since it’s been constantly plugged in the charger should be in float mode and the battery somewhere between 13.8 and 14.6. I believe 13.8 is the highest voltage I’ve seen on the meter. I started the inverter just after disconnecting shore power and the meter only read 13.37 which seems a little low. 27 min left using the microwave would be great but the time left was dropping like crazy while the micro was on. From 9 hours to 27 min in a minute. I guess I should test again using the microwave until the battery power drops below11 amps. I thought that I could use the microwave with the inverter for short bursts of time without pulling that much power.

Your 9160L converter will keep the whole Rv at 14.6 when on shore power. the battery voltage will drop to its voltage that goes with being full once the converter is disconnected That is 13.6ish for an LFP.The monitor does not know how long you plan to run the MW so it is playing catch-up the whole time for time remaining, so you see that fast drop in time remaining the longer you run the MW.Seems like it is all behaving as it should. If you intend to be on shore power very long, you might consider shutting off the converter and only use it to recharge the battery as required. LFPs don't like to be on that 14.6 float for long periods. You still want 12v in the rig. You can use the battery for that or else get a second converter that floats at 13.6 and just use the 9160L when you need to bring the LFP to full.PD has a newer version of that converter that has a 13.6v float stage for LFPs.You can run the MW in bursts so your battery does not hit bottom all in one go. Some recovery between bursts is good.

batteries 12V in parallel, or GC2? GC2 do NOT like high current draw, way to much internal resistance so the inverter will kick out on low voltage pretty quick.12V, assume you have at least 2, they (a) share the current, so each battery supplies 1/2 the load current unlike a GC2 pair where each battery must supply total load current and (b) have much lower internal resistance, hence less voltage drop with high current load.The 125A draw is in the ballpark for a microwave, the AH consumed is reasonable for a 1 minute draw. I suspect that the display is calculating looking at the voltage drop over time and going from full charge and then drawing a high load for a short period of time the voltage tapered faster than it will over time hence messing up the remaining time.I think you will get a better indication by running the microwave for at least 5 minutes, better 10 minutes and see what it shows for remaining time. It could still be in the 30 minute range with a 200AH + battery bank

I still recommend 400+ amp hours for an inverter of that size. Victron seems correct. Although is it set for LFP? If set to lead-acid the Peukert calculation will reduce the expected capacity a bit faster. Did I miss the battery set up?Otherwise seems normal.Could be the photo angle but the ventilation seems a bit tight.

Samlex Inverter Power Draw Question | Good Sam Community

ktmrfs
Explorer II
Jul 08, 2021
theoldwizard1 wrote:
ktmrfs wrote:
batteries 12V in parallel, or GC2? GC2 do NOT like high current draw, way to much internal resistance so the inverter will kick out on low voltage pretty quick.

12V, assume you have at least 2, they (a) share the current, so each battery supplies 1/2 the load current unlike a GC2 pair where each battery must supply total load current and (b) have much lower internal resistance, hence less voltage drop with high current load.

I disagree completely !

Golf cart batteries are designed specifically to handle "high" loads and at 125A that is only 1/2C ! A pair of GC-2 batteries will live longer than a pair of 12V marine/RV batteries and cost less !

GC2 have many advantages, and can handle hundreds of cycles down to 25% SOC, but high current draw is NOT repeat NOT an advantage nor something GC2 do well. Myself and several other posters to this thread have seen the voltage drop and how quick a inverter will drop out when drawing 100A from a pair of GC2's.

Even trojan will tell you if you want high current draw use their 12 deep discharge. Thick plates and few of them do NOT play well with high current draw.
EMD360
Explorer
Jul 08, 2021
GC batteries are too large for my space anyway. I had more room in the old RV and could fit two group 27 batteries. But I ended up using only one group 29 because I burned them out too quickly. I tried Walmart SLA batteries and they didn’t last more than a season or two. I tried Autozone marine and kept losing one cell. Finally went back to Interstate and sold the rig with one group 29 rather new inside. I even tried used agm batteries and a double battery bank with a blue sea switch but they only lasted a season or two. Thus my willingness to invest in lithium batteries.
3_tons
Explorer III
Jul 08, 2021
Microwaves are relatively cheap…It makes little sense to try and run a stick house 1500w microwave from an battery starved inverter when a 800-850w works perfectly well in a camper…

3 tons
ktmrfs
Explorer II
Jul 08, 2021
3 tons wrote:
Microwaves are relatively cheap…It makes little sense to try and run a stick house 1500w microwave from an battery starved inverter when a 800-850w works perfectly well in a camper…

3 tons

if your shopping for a new microwave for the RV get a panasonic true inverter microwave. doesn't cycle between 0 and 100%, but stays at a fixed % you set and at 50% power will do most of what you want but draw about 1/2 the full power current, Works great with an inverter setup. Doesn't take twice as long at 50%, maybe 25% longer
3_tons
Explorer III
Jul 08, 2021
ktmrfs wrote:
3 tons wrote:
Microwaves are relatively cheap…It makes little sense to try and run a stick house 1500w microwave from an battery starved inverter when a 800-850w works perfectly well in a camper…

3 tons

if your shopping for a new microwave for the RV get a panasonic true inverter microwave. doesn't cycle between 0 and 100%, but stays at a fixed % you set and at 50% power will do most of what you want but draw about 1/2 the full power current, Works great with an inverter setup. Doesn't take twice as long at 50%, maybe 25% longer

Agreed 100% :)

3 tons
pianotuna
Nomad III
Jul 08, 2021
EMD360 wrote:
The bigger test would be to somehow continue a high load until the battery charge shuts off the inverter. Maybe the air conditioner. Waiting to hear from pianotuna though I know he’s not a lithium convert.

Hi EMD360.

Thanks for the compliment.

Li are EXCELLENT batteries but they do require more fuss than some folks care to admit, especially if one wants a high number of cycles.

Because I rv in extreme cold, only one formulation of Li would suit my needs--and it is 4 times as expensive as lifepo4.

DO add the cooling grill Li batteries do not love heat. I'd go farther and add a computer fan on a thermostat.

The big inverter is a good plan.

I would not use the air conditioner for the load test. Use a 15 amp heater instead--if the heater dies it is no big deal. If the compressor on the air conditioner goes out--well who wants that sort of trouble?

I think, from what I read that your system is behaving normally. Peukert hardly applies to Li at normal loads.
3_tons
Explorer III
Jul 08, 2021
PT, says “ Li are EXCELLENT batteries but they do require more fuss than some folks care to admit, especially if one wants a high number of cycles.”

This comment is a prime example of why I choose not to comment on a battery type that (I admittedly…) have absolutely no experience with (e.g. SiO2’s), and points to the importance of reader discernment…

3 tons
time2roll
Nomad
Jul 08, 2021
pianotuna wrote:
Li are EXCELLENT batteries but they do require more fuss than some folks care to admit, especially if one wants a high number of cycles.
The fuss is all during the set up. Then they just work.
pianotuna
Nomad III
Jul 08, 2021
3 tons,

Your comments help the OP in what manner?

time2roll, Yes they work--where it is not -30 or if in a full time situation where there is a way to keep them warm.
KJINTF
Explorer
Jul 08, 2021
No Fuss at all!
I highly recommend the LIFE cells
They just work - even in the winters/summers of Montana
Had my 4 LIFE 200amp cells for going on 7 years now
No BMS - just four 200amp LIFE Cells strapped together
Use a simple $15 Cell Log 8 to monitor cell performance
They all track <30mv difference all the time from full charge to full discharge
They easily supply enough for a 2KW psw inverter which powers my 1Kw Microwave

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