DC Charging

[midlandsman]

Hi folks,
Can someone advise me..?
I want to charge my i167 from a 24v vehicle source and I reckon a 250 watt inverter should do it. Is it safe to use a modified sine wave inverter or should I go for the true sine wave inverter? i.e. does the charging circuit tolerate a less than pure 50 Hz supply ?
(The TSW inverters are about 6 times the price of MSWs in the UK).
Thanks
Peter

[bystander]

quote:Originally posted by midlandsman

Hi folks,
Can someone advise me..?
I want to charge my i167 from a 24v vehicle source and I reckon a 250 watt inverter should do it. Is it safe to use a modified sine wave inverter or should I go for the true sine wave inverter? i.e. does the charging circuit tolerate a less than pure 50 Hz supply ?
(The TSW inverters are about 6 times the price of MSWs in the UK).
Thanks
Peter
Here's some old posts:

http://www.google.com/custom?&sitesearch=segwaychat.com&q=modified+sine+wave+inverter

Most anecdotal evidence suggests MSW is OK. However, most of us are making 120vac, 60hz here in the states. I understand the HT should take "100 to 240 V, 50 to 60 HZ", according to the reference manual.

I have used a MSW inverter on my I-167, as far as I can tell everything's fine.

[fredkap]

Ground Loop has previously writen in this forum:

Many of the cheaper power inverters are a bit 'overrated', to be kind. They sometimes rate them with the peak "surge" output instead of real capacity (like cheap audio amps). If your inverter costs less than $50, check the packaging carefully for weasle-words and warnings. It needs to be able to sustain a real ~150W for an extended time.

In a pinch, you can guess a little based on the design. A good inverter will have quite a bit of heatsink and fins. A cheapie unit will have almost none and likely overheat.

Keep an eye on it for the first charge and see how hot it gets. If it smells stinky or it's too hot to keep your hand on, then take it back and get a higher rating.

--------------------------------------------------------------------------------

I'm waiting for someone to explain why a sine-wave inverter is better or necessary. I can't think of any reason why it would be one whit better for the HT than a total square-wave or "modified/step" sine wave inverter that costs much much less. Isn't the HT charger using a switching power supply anyway? This would have been a perfect question to pose in yesterday's chat.

As for power demands, my Segway HTi draws surges of 155W during the pulse charge. This is measured RMS power at the mains, so it's a very real consumption. If your inverter is set to trip to quickly overload at anything less, it may shutdown. In my experience, the price of an inverter is directly proportional to the accuracy and integrity of the specs on the box. The cheapo units usually claim some baldfaced lie about handling jiggiwatts of power for $19.99 and will blow after a few hours of rated-power use. The expensive mounted units for RVs and trucks have more honest ratings.

A full HT charge from totally dead to trickle consumes 550Whr and takes about 4hr 45min. During fast-charge, the HT draws a continuous 115W. Again, this is my unit -- yours may be different, but I'd be surprised if it's by much.

----------------------------------------

Peter, a lot of us have $28 400 watt inverters that can handle one Seg from the cigarette lighter.

Fred

[midlandsman]

Thanks for the advice, my 167 draws 140W on fast charge and I shall buy a 400W MSW inverter. I've considered using my generator but I have a horrible fear of a 240+ voltage spike taking out the processors. I can't afford a spike like that!
I guess it's sensible not to run the vehicle engine when Segway charging, I would think the vehicle alternator can also be spikey. Am I being paranoid?
Regards
Peter

[bystander]

quote:Originally posted by midlandsman

Thanks for the advice, my 167 draws 140W on fast charge and I shall buy a 400W MSW inverter. I've considered using my generator but I have a horrible fear of a 240+ voltage spike taking out the processors. I can't afford a spike like that!
I guess it's sensible not to run the vehicle engine when Segway charging, I would think the vehicle alternator can also be spikey. Am I being paranoid?
Regards
Peter
In my experience, I have traveled on the highway while charging the HT for around 2 hours (at a time) at highway speeds. I did not encounter any problems. I wasn't worried about spikes. I suppose it depends on the condition of your vehicle's electrical system and the quality of the inverter used.

You're probably OK. But it's OK to be cautious too. There's not much anyone can do for you if your vehicle causes your HT's charging circuit to break down. So be as cautious as you need to be.

If considering a generator for charging, perhaps a reputable surge suppressor between the generator and the HT would make things less uncomfortable. I recall a couple of Segway chatters in years past recommending this, even when just plugged into the mains.

[Red Seg]

This is from Segway's FAQ page:

Can I charge my Segway HT from my car or boat?

Yes, a Segway HT can be charged while driving in your car or boat by using a suitable DC-to-AC power inverter. Each Segway HT typically consumes approximately 140 Watts of power while charging. However, due to charger startup requirements, we recommend that inverters have power capacity of at least 350 Watts for each Segway HT being charged. Power inverters that produce either square or sinusoid waveform output are suitable for charging the Segway HT.

http://segway.com/faqs/faq/answer=1046776590&id=1012478135&subject=General%20Questions