DC-DC converters experience

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Brett_celicacoupe
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DC-DC converters experience

Post by Brett_celicacoupe » Mon, 17 Sep 2012, 23:48

Wanted to offer feedback on my DC DC converter experience with my project.

1. i bought an ebay spec 144v-12v converter from a chinese supplier on ebay. the unit was very ordinary build quality. ie they claimed an IP5x rating or similar but when it turned up, the backing cover was loose and it was not something you would want to get wet. within minutes of letting the ebay seller know of this, they edited the listing and removed the IP rating claim.

further, when i first connected it, it blew the fuse. after replacing the fuse, it was no longer isolated from the traction batt pack.

I do not recommend this model be used on EV's

this is the model: http://www.ebay.com.au/itm/Votage-Reduc ... 0652082758


2. more searching led me to a supplier in vic or NSW of "meanwell" power supplies. i ended up purchasing a SP-320-12 model for $70 plus freight! very good price, very high quality and great service from the retailer. actually cheaper than the chinese version which was rubbish. the unit is actually an AC power supply but is happy with DC supply also. the output voltage has about +-10% adjustment which is perfect.

they have smaller and larger models with varying input and output voltages.

i cant understand why the ev suppliers havent caught onto this yet.


zeva
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DC-DC converters experience

Post by zeva » Tue, 18 Sep 2012, 01:14

Interesting, that eBay one has Chennic branding - they've been around for a while. Surprisingly that quality was so bad.

Quite a few people have Meanwell converters in their EVs. In fact back when I was with EV Works, we stocked them for a while. They did have a few problems though for EV use (just FYI)..

1) Some of them "backfeed" from the 12V side when the HV is off, i.e they slowly drain your 12V battery when not in use. Can be remedied with a big series diode.

2) 25A is not really enough to run all your accessories at once, especially if you have 12V power steering. Some people run two in parallel, e.g UWA's Lotus Elise has two SP-320-12s. You just have to tune their output voltages so they split the load evenly.

3) Not water/weatherproof, so they need to be installed somewhere protected.. not that the old ubiquitous IOTA DLS-55s were any better. But it would be nice to see more IP5x+ DC/DCs on the market.

4) We had quite a high failure rate from them, maybe 1 in 10 blew up.. but hopefully you won't have any trouble with yours.
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Simon
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DC-DC converters experience

Post by Simon » Tue, 18 Sep 2012, 03:24

I have a 500W Meanwell in my car, not sure what model number. It works OK but can't keep the voltage stable with the headlights on and indicators blinking. Noticed the issue with it draining the 12V battery but haven't fixed it yet.
Another thing to add on the "to do list".   Image

unheardofinstruments
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DC-DC converters experience

Post by unheardofinstruments » Sat, 22 Sep 2012, 06:55

Oh no I got the same one, I will let you know how it goes in my case, I am going to give it a LiFePO4 battery in series for help though as I wasn't sure 500W is really enough all the time which might be why it blew maybe?, were there lots of accessories on at the time?

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DC-DC converters experience

Post by roddilkes » Sat, 22 Sep 2012, 20:15

Brett_celicacoupe wrote:
2. more searching led me to a supplier in vic or NSW of "meanwell" power supplies. i ended up purchasing a SP-320-12 model for $70 plus freight! smaller and larger models with varying input and output voltages.

i cant understand why the ev suppliers havent caught onto this yet.


Well researched Brett. In fact I used one on my Mighty Boy for several years.

http://www.evalbum.com/preview.php?vid=1257

I also stocked them through EV Power for a couple of years.

Perhaps if you are having a good experience you could honor your NSW supplier with a small mention?
Last edited by roddilkes on Sat, 22 Sep 2012, 10:18, edited 1 time in total.

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Richo
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DC-DC converters experience

Post by Richo » Mon, 24 Sep 2012, 20:48

You have to becareful with electronic parts from e-bay.
They maybe cheap because they are not approved for use in Australia - or anywhere for that matter.

I recently purchased some soldering equipment from e-bay.
Found the earth wire was crimped to the insulation and not the wire.
The lug was screwed to a painted chassis/hole.
So any fault could have resulted in death.
So the short answer is NO but the long answer is YES.
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jonescg
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DC-DC converters experience

Post by jonescg » Mon, 24 Sep 2012, 21:24

My 200 W irons from eBay came with earth pins. The wire was cut off at the iron end Image In fact then tinning some copper I'd feel tingles through the length of solder ImageImage

I wear gloves when soldering now...
AEVA National Secretary, WA branch chair.

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