Battery Charging off Inverter. Question

[BlitzBiker]

Hi there. I recently bought a cyc stealth gen 3 kit and installed on my 2014 Giant Trance and love it! I have a camper with a renogy 1,000w pure sine wave inverter. The inverter powers my 700watt microwave, 800watt heat gun without skipping a beat. It's wired to a 200ah 12v lithium batterry and solar. Works fantastic. However, I cannot charge my 52v ebike battery off the inverter. The inverter surges and stalls.

I plugged the charger into my wall watt meter tester and highest recorded watts I see it pulling are about 230watts. It charges the 52v batterry at about 4 amps. Im puzzled is this batterry charger really surging that hard on startup that my 1,000w inverter cannot handle it?

links to my charger, inverter, & battery

https://a.co/d/9e2xVbI

https://www.masterpiece.dk/uploadetfiles/11723/138/15534_Manual_23.pdf

https://www.electrifybike.com/collections/52v-batteries/products/52v-50amp-10ah-samsung-21700-50s-mini-max-e-bike-battery

[K442]

Interesting. Based on nameplate ratings, there should be no issues and you even say the inverter can run your microwave, so seems like it can supply at least a modest inrush current. Though I suspect both your inverter and possibly battery charger would have some form(s) of electronic monitoring / sensing, and probably sensing on the millisecond level, so they might be 'seeing' spikes/surges that a wall meter can't see, or would average out in its reading.

Two things I can think of:

1) Is it possible that your 52V charger has a large smoothing capacitor bank and the inrush into that is tripping the sine wave inverter somehow? Though I would think after a few cycles, things would balance out. (You'd eventually charge up the cap) If not already doing so, you might try plugging in the 52V charger with no battery attached to it, then add the battery once things become stable.

2) Maybe running two inverters 'back to back' is causing some sort of issue. Your main inverter is likely taking the 12V battery power, chopping that up into multi-KHz pulsed DC, then working to shape that back into a sine wave at 120VAC. Now this AC is flowing into your battery charger, which is rectifying it back to DC, chopping it again into multi-KHz pulsed DC and working to shape that into a "52V" charging voltage. So you're running a high frequency oscillator in each piece of equipment. Possibly some voltage spikes are leaking out on the 120V line and causing the inverter to momentarily sense this and shut down?

It would help to know exactly when things are happening, the exact set-up, etc. As a 'hack', I'd be tempted to try the charger with some other small appliance on the inverter. Does that seem to dampen out the surging? Another possible test would be to add a capacitor on the 120V output. This is also a 'hack', and a fairly dangerous one at that, so hard to recommend someone else try it.

[BlitzBiker]

Hey there k442, I really appreciate the input. this is very bizzare.

1) Is it possible that your 52V charger has a large smoothing capacitor bank and the inrush into that is tripping the sine wave inverter somehow? Though I would think after a few cycles, things would balance out. (You'd eventually charge up the cap) If not already doing so, you might try plugging in the 52V charger with no battery attached to it, then add the battery once things become stable.

I do this everytime i charge the 52v battery. when i plug it into my inverter without the battery attached, it seems to be fine. I've left it plugged in and powered up for about a minute I thought of this, but can try longer. as soon as i attach the 52v battery is when things start to pulse and i can see power pulsing on the charger. I've tested this exact same method on my work truck that has a 1000w Sensata pure sine wave inverter and it charges flawlessly without hesitation just as it behaves when I charge while on the grid.

If i were to plug in my 52v battery to this charger before plugging it into the wall outlet i actually get an arc. i suspect a fast inrush of power from the battery to the charger. perhaps I should try plugging in the 52v battery to the charger first then flipping on the inverter. Might be worth a test when I get home. I will also test what you've stated loading the inverter with another load while attempting to charge and report back what happens. I'm suspecting that this renogy inverter may not be pure sine wave as it's labelled or something is happening on that end. Weird how its behaved fine on all other appliances to date until this charger. I did see another post about a guy with a 2000W renogy having a similar problem.

[BlitzBiker]

update,

so this morning I attempted to charge the battery with the battery already connected to the charger, then plug it into the inverter, then flip the inverter switch on. havn't tried it like this. same result. I can see the 110 power pulsating instantly again.

I tried hooking up a small lamp to the second 110 socket of the inverter with the charger hooked up in the same configuration as above, flip the inverter switch on and it pulses and the light pulses as well. are these Renogy inverters just Junk? super weird, it powers everything else 700w microwave no problem.

I would just replace it with a better model/brand but the way I installed mine its not very easy to get the unit out, I may have to remove my entire sink in the RV lol. it's crammed in a small space.

[TwoTired]

Is the inverter high frequency or low frequency? High frequency inverters have problems with inductive loads, I'm not sure about chargers, but these days most chargers are switching regulators, so they may not like anything but pure 60 Hz. One thing that may help is a 110:110 transfromer, all that iron may filter out enough of the high frequency to work. Borrow, don't buy one, it may do nothing at all.

[BlitzBiker]

Is the inverter high frequency or low frequency? High frequency inverters have problems with inductive loads, I'm not sure about chargers, but these days most chargers are switching regulators, so they may not like anything but pure 60 Hz. One thing that may help is a 110:110 transfromer, all that iron may filter out enough of the high frequency to work. Borrow, don't buy one, it may do nothing at all.

I'm not sure but I found this on specs. Doesn't mention high or low freq.

Specifications


Continuous Power Rating: 1000W

Peak Power Rating: 2000W

DC Input Voltage: 12V

AC Output Voltage: 120V

Output Frequency (Nominal): 60 Hz ± 0.1%

Operating Temperature Range: -4°F - 158°F

Dimensions: 12.9 x 6.8 x 3.3 in

(Tips: Proper space needs to be reserved around for connection and use)

Weight: 6.0 lb

where would I look to get that 110:110 transformer you speak of? I mostly just see 110v step up transformers.

[TwoTired]

Low frequency inverters have big heavy transformers, and generally include charging circuits( inverter-charger ). If your inverter is not too heavy its probably high frequency. At 6 pounds it probably is HF.
Isolation transformers are 110 to 110, some autotransformers too. Check you charger specs, it may work with 220V so you can use a step up 110:220 transformer.

[K442]

Definitely sounds like something is not playing nice together. Based on the experiment with your truck, it sounds like the camper inverter is sensing something and trying to momentarily adjust, causing the surge.

The isolation transformer is a good thought. The iron core might filter out some of the high frequency noise. You might also try a "home power saver". In theory, these are a plug-in capacitor which would also help smooth any noise/ripple on the AC line. Though the "power saving" part is somewhat of a scam - unless you are running huge inductive loads. But for this application it's the smoothing/filtering you care about, so the capacitor should help there. It would just be important to get one which actually contains a capacitor - not just an empty box.

One other thought would be to try feeding your charger off a surge protecting power strip. The idea here is that the power strip should contain some circuitry to dump any overvoltage to ground. So, again, if you are getting any high frequency spikes on the line, it might help. (Of course then that also brings up a point of what is actual 'ground' on a floating / mobile system such as this?)

[BlitzBiker]

Thanks for all the advice. maybe I could even look to buy a different 52v charger. one that perhaps is known to work with an inverter like the one I have. removal of this inverter is not a very easy task given I sort of built a lot around it but could be done if necessary. I'll give the surge protector a shot. for the "home power saver" do i just plug it into one socket on the inverter and then plug my charger into the other socket? it doesn't seem to have a throughput type of plug on the power saver itself.

[73Eldo]

When you tried the light was it a old school light bulb or some sort of LED sort of thing?

[BlitzBiker]

When you tried the light was it a old school light bulb or some sort of LED sort of thing?

it was a lamp with an LED bulb.

[73Eldo]

Try it with an old school light bulb if you can find one. The constant 'dumb' resistance of a regular old light bulb may be enough to tame things down so that the electronics are not fighting each other.

I think even in CA you can buy old bulbs for appliances like ovens. The other option is they make a heater that screws into a light socket. They are made for use in things like reptile cages and should also do the job. I run into this issue when trying to dim LED bulbs. One regular bulb or one of those heaters stabilizes things. What ever it is has to be really dumb, can't even have an electronic power switch. If its got a switch it has to also be old school click click style.

[AZguy]

"Dumb" electric skillets or hot plates have much better load for battery testing - even a "high wattage" light bulb will only pull 10-20% of the rated power at 50V due to the high resistance of a cold filament and the low voltage...

[73Eldo]

I believe the issue in this case is his inverter is tripping when he connects his charger. I was thinking perhaps a small dumb restive load may help get the inverter online and stable so then maybe it will be able to deal with what ever noise and spikes may be happening when he plugs in his charger.

[AZguy]

Wouldn't surprise me if the inrush current to the charger would trip and inverter - these cheap chargers just use direct-off-line (DOL) that place some bulk capacitance on the other side of a rectifier so when they get plugged in they'll get a big inrush current and often an arc

*If* that's the case, the only reasonable "cure" for that I can think of is a negative temperature coefficient (NTC) thermistor also known as an inrush current limiter (ICL)... they are very cheap but just a leaded part and have to be sized so not just simple plug-and-play

[abwillingham]

I have a similar setup and the same problem. My 600/1200v sine inverter trips after a few seconds trying to charge my 52v ebike battery.
I put an inline amp meter between my 200ah house battery and the inverter. It was crazy high, > 60 amps.

Did you ever figure this out?
I would prefer to remove all the inverters and use a dc to dc charger.

Thanks
Tony

[BlitzBiker]

I have a similar setup and the same problem. My 600/1200v sine inverter trips after a few seconds trying to charge my 52v ebike battery.
I put an inline amp meter between my 200ah house battery and the inverter. It was crazy high, > 60 amps.

Did you ever figure this out?
I would prefer to remove all the inverters and use a dc to dc charger.

Thanks
Tony

No, no luck yet. I still need to try with an old school light bulb. at this point i'm kinda just looking for a new 52v charger. if anyone has any ideas or leads on a solid 52v 110v charger that will work well with this renogy 1000w inverter that would be awesome. or a charger that i can charge directly off of the 12v dc battery would work as well. anyone have any leads?