AC Voltage Regulation / Stabiliser

[GRW]

Question for the Boffins.....

Anyone know what the various types of adjustable SCR / Voltage Regulator/ Voltage Stabiliser devices that are widely available (Chinese mostly it seems) - are like for running my Bosch Li-Ion E-Bike Charger (input 230V, 50Hz, 1.5A, output 36vdc, 4A)?

I'm guessing the Charger is some kind of Electronic Switch-Mode Power Supply - and concerned that some devices I might add in-line to try to look after the charger & battery pack - might have the opposite effect???

Application: I want the option to recharge my ebike while away off-grid in the van. I have an old Honda EX1000 portable generator, which DOES/HAS been tested powering the Charger once - but as it's a Capacitor Regulated generator, its Voltage regulation isn't special (rather high at 255-260vac at 53Hz off-load, but drops as low as 228 as you approach its upper load limit).
In case of possible damage to the Charger (despite it seeming to work just fine) I was thinking to add a suitable (ideally low-cost) adjustable regulation device, so I can "tweak" the genset output externally to 230v before it's fed to the Charger.

I might find other uses for a variable voltage regulator device also (such as being able to vary the speed of 1ph ac motors??

TIA for any responses.
G.

 

[EddyP]

I'd have thought the easiest way to achieve this would be a UPS, you then would have the option of having a charge off the battery when the generator isn't running too.
Alternatively find a nice pure sine wave inverter and power it from a couple of 12V batteries in the van which could be recharged from the alternator when you're driving. Your bike charger is only consuming 345 watts which is next to nothing really. Could even put a PV panel on the roof of the van to charge the battery too.

 

[GRW]

I'd have thought the easiest way to achieve this would be a UPS, you then would have the option of having a charge off the battery when the generator isn't running too.
Alternatively find a nice pure sine wave inverter and power it from a couple of 12V batteries in the van which could be recharged from the alternator when you're driving. Your bike charger is only consuming 345 watts which is next to nothing really. Could even put a PV panel on the roof of the van to charge the battery too.

345W yes (1.5A) off 230vac. But if using a UPS or an Inverter & batteries with a 12vdc source being 20x less volts, it'll take 20x the current off the battery.... so that 1.5A becomes 30A (near as makes no odds). Assume a 5-hour charge, that means I'd need a battery to sustain an output& voltage of maybe 150A over the charge period.
So buying extra batteries and solar to cover that, would need chunks of money and space I don't have in the van.
Hence the diddy generator.
So, a (full online, pricey) UPS might stabilise (IF it would accept the high genny voltage - unlikely), but it'd need a very bigger heavy battery store to do a stand-one charge. Non-starter.
Ditto an Inverter - it'd only do the business if I ran the van engine (driving or stationary) for up to 5-hours. It'd work, but cost lots in diesel just to produce 1.5A AC.

Hopefully the above explains why the genny, and ideally with some kind of inline better voltage regulation device that'll accept the genny voltage and correct it to a smooth 230vac.

 

[eddie49]

I agree with EddyP, a UPS - as used to stabilise and back-up the AC mains power supply to a PC - would do the job.

During a powercut, a typical small UPS would only run the mains output from it's internal battery for 10 - 15 mins, but that isn't the point. A "Line Interactive" UPS has a voltage stabiliser which will output a constant 230v regardless of voltage peaks or sags in the input. For example, this offline/line-interactive UPS is rated at 1kVA, which matches your generator capacity:

https://cpc.farnell.com/powercool/1000va/ups-1000va-3x-13a-plug-rj45-3x/dp/CS25751

The datasheet:

https://www.farnell.com/datasheets/1728871.pdf

shows that it will accept an input of 165 to 275 volts, while providing a 220v +/- 10% output.
You could probably run a UPS without the internal batteries and still benefit from the voltage stabiliser. When the batteries fail, they are very cheap:

APC Smart-UPS (1000 VA) - Line interactive - Tower (SUA1000I) UPS for sale online | eBay

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I am fairly sure that the UPS above would power-up and drive it's outputs from AC mains or from your generator, even tho' the batteries are missing.

At a higher price, an "Online/Dual Conversion" UPS rectifies the AC mains to DC, then inverts the DC back to AC, providing a simulated or pure sinewave output with a fully-regulated voltage and frequency.

However, as you said, your Bosch E-Bike charger is probably a switched-mode power supply. As such, it will immediately rectify the incoming AC mains to DC, then invert, transform, re-rectify, and stabilise that 300-ish DC volts to the required 36v DC, plus regulation to comply with the Li-ion charge curve. As such, it is probably very tolerant of the input voltage and frequency.

As for controlling the speed of a single-phase AC motor, a brush-type ( "universal" ) motor would typically use SCR or TRIAC phase control ( as in the trigger of a variable-speed drill ). Rather than the voltage, these light-dimmer-type circuits regulate the amount of each half of the sinewave that gets passed through.

 

[GRW]

Thanks very much for that detailed reply
Sounds very much like actually as the charger is a SMPS - that I don't need to worry about my genny voltage starting a bit high (say 260vac or a bit less) to 230+ under the one-third or so total load the charger represents.
So - maybe I should just run directly off the genny as per the successful test I've done once and not worry about it.

Interesting that the UPS you mentioned tolerates such a wide voltage input range! I thought outside +/- 10% UPS would switch to battery backup - but clearly the one you mention stabilises over a wide V-range as well..... but if I read you right I don't need one anyhow.

 

[eddie49]

The Bosch battery charger may specify what range of input voltage it will tolerate. I'm fairly sure there will not be a problem with your genny. Perhaps the price of replacing that charger may be significant in deciding whether to risk it...

The idea of using a secondhand battery-less UPS as a cheap but accurate voltage stabiliser is tempting. As you suggested, the UPS has to be able to withstand deep troughs in the input without needing to switch to non-existent batteries! Depending on what kind of loads you typically use with your generator ( e.g. angle grinder vs. complex electronic device ), adding a UPS may be a cost-effective upgrade.

 

[GRW]

The Bosch battery charger may specify what range of input voltage it will tolerate. I'm fairly sure there will not be a problem with your genny. Perhaps the price of replacing that charger may be significant in deciding whether to risk it...

The idea of using a secondhand battery-less UPS as a cheap but accurate voltage stabiliser is tempting. As you suggested, the UPS has to be able to withstand deep troughs in the input without needing to switch to non-existent batteries! Depending on what kind of loads you typically use with your generator ( e.g. angle grinder vs. complex electronic device ), adding a UPS may be a cost-effective upgrade.

The charger doesn't state on its label - it just says 230vac, 50hz (but it charged the e-bike OK off the genny the one time I tried it).
I got the genny for nowt as it was abandoned on the scrap/ferked pile, and tinkered with it for a while and managed to repair it. I did so specifically so that I might be able to recharge the e-mtb if I was away for a weekends riding off-grid - so don't really have any other regular/planned use for the genny tbh.

I too though liked the idea of being able to smooth/stabilise the genny output so it could run a sensitive load without spending lots - and a UPS like you can up with might just do that very well indeed.
(I've seen so many fragile/pointless suitcase inverter-gens that I simply don't trust any of the Chinesium cheapies to be worth the outlay for a glorified boat anchor. Only the genuine Honda Eu10/20/30i range seem robust.... but they aren't cheap so you've really got to need one..... hence the basic old Honda EX1000 skip-dive special )

 

[Matrixx]

All electrical appliances have to be able to run on a + / - 10% voltage variation.

 

[GRW]

All electrical appliances have to be able to run on a + / - 10% voltage variation.

Yes, I know this, but that's a range of 207 to 253vac (from the std 230vac base). The genny was off-load just a tad over the upper.

The good news though is that I was away with a group and used the genny in Saturday pm to recharge 3 e-bikes at the same time - and it all went perfectly with all the chargers and battery packs happily charged off the genny source with no issues - so all is well

 

[Matrixx]

Yes, I know this, but that's a range of 207 to 253vac (from the std 230vac base). The genny was off-load just a tad over the upper.

The good news though is that I was away with a group and used the genny in Saturday pm to recharge 3 e-bikes at the same time - and it all went perfectly with all the chargers and battery packs happily charged off the genny source with no issues - so all is well

It should have a 5% Hz droop on a mechanical governor. the voltage should follow close behind. as you using a switch mode power supply you should have no issues on a variable V/Hz power supply.

 

[GRW]

It should have a 5% Hz droop on a mechanical governor. the voltage should follow close behind. as you using a switch mode power supply you should have no issues on a variable V/Hz power supply.

It's only a dinky ex1000, 1kva set, and far from new (1998) with an unknown working life before I rescued it from the "dumped" pile... so the frequency variation is more than 5% (more like 5hz). Luckily the SMPS charger (on my ebike and both the other Levo chargers that got connected) - doesn't seem to care about this or the wide voltage range (capacitive voltage reg).