Ok to power cheap 12V inverter with 4s Lipo pack?

[John in CR]

I need to put together a quick and dirty battery + solar charged power setup to output 110V AC running small loads continuously and intermittent 500W loads. I already have a common 12V 1000W inverter, and I have lots of batteries. While I have lifepo4, the far simpler solution would be to use 4 or 6 of my Nissan Leaf modules, which are each 500wh of LiMn. The resulting series/parallel combination puts the battery bank at 16.8V top of charge. Is it reasonable to think the inverter can handle the higher than lead acid voltage? Could a UPS with a dead battery be a better candidate? In the case of a UPS I'd add a fan for ventilation, since 5hrs of continuous use isn't typical.

If I really need to knock the voltage down by a couple of volts, does anyone have any slick ideas? I don't have any low enough voltage brushed motor controllers, even if the inverter could accept the PWM'd input. I also don't have enough DC/DC converters to handle the peak current, or a sufficient supply of high power diodes either.

 

[Nobuo]

as the max voltage difference between SLA and 4s 16.8Vmax is ~2V, I doubt you will have any issue.

 

[Gregory]

I agree, they would have designed & built it to be safe up to at least 15V, and the components (mosfets, capacitors) will have some decent margin of safety on top of that for voltage spikes etc.

 

[Harold in CR]

Solar panels typically have 17-19 Volt output, so, I'm about to do the same as you.

I did some research, and found 3000W-5000W inverters that would work inside the parameters of Lipo batteries High volt limit and low volt limit.

 

[John in CR]

Solar panels typically have 17-19 Volt output, so, I'm about to do the same as you.

I did some research, and found 3000W-5000W inverters that would work inside the parameters of Lipo batteries High volt limit and low volt limit.

My solar is a non-issue for me as I can output to batteries any voltage I want from my solar modules to charge batteries, from 3.5V up to 220 and tune any cutoff voltage in between...even balance charging if I want.

Did you see those inverters locally? A more sure way to go might be to use my larger APC UPS. It has 2 lead acids in series, so 3 Leaf modules in series for 6s is a nice match. It starts beeping and has auto shutdown somewhere in the 20-21V range, so my batteries would be well protected from over-discharge, though I'll have 40-50% excess capacity as primary protection.

I found my 1500W invertor, and it says 10-15V input. Now to put my hands on my 500W inverter to be the sacrificial guinea pig for 16.8V test from the battery.

 

[Harold in CR]

Did you see those inverters locally?

No.
I have been watching an Aussie, on another site, redoing Chinese Inverters and others have asked about this particular brand. The Chinese have been doing upgrades, as the Aussie spreads the info on this other site, and he has years of experience with this particular brand.

He explains the good and the bad features of them, and explains how to rework them to become very good and reliable inverters. The one I am going to buy is a 5000W continuous and 15000W peak. Can be purchased for $300.00 & up, if you watch for sales.

I have 3--1400KVA Ups's that I bought years ago to use as cheap inverters. I have a 500W I believe it is, that has a manual switch wired in to turn it on and off, that I use as a portable inverter for drilling and such, remotely on the farm.

I plan to try to wire a switch into one of the 1400KVA units, as well.

Hope you get something to work, but, I believe that 15V is High Voltage shutdown from the battery on the 500W inverters. It's been a while since I messed with them, though.