# shopping for 120v nominal dc-dc convertor



## frodus (Apr 12, 2008)

Iota, Vicor, Meanwell.... 

here's a couple on ebay
http://cgi.ebay.com/Power-One-LWR-1...emQQptZLH_DefaultDomain_0?hash=item414a04abdf

http://cgi.ebay.com/DC-DC-Converter...emQQptZLH_DefaultDomain_0?hash=item3a5977fb20


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## dtbaker (Jan 5, 2008)

frodus said:


> Iota, Vicor, Meanwell....
> 
> here's a couple on ebay
> http://cgi.ebay.com/Power-One-LWR-1...emQQptZLH_DefaultDomain_0?hash=item414a04abdf


this is only 6a output....



frodus said:


> http://cgi.ebay.com/DC-DC-Converter...emQQptZLH_DefaultDomain_0?hash=item3a5977fb20


[/quote]
spec sheet says this is ac-dc charger/converter, not dc-dc....


but when the time comes I will sift thru ebay. I was looking for personal recommendations mostly. I seem to recall the iotas having significant draw in standby being mentioned...

I went and poked around the evolveelectrics.com website for more info on the iotas and they say they are intended to be used with either 120vac or dc input, but the product spec sheet only shows ac.... I am confused. 

Anyway, why are the iotas so much less expense than the curtis, zivan, and others I have seen so far?


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## frodus (Apr 12, 2008)

dtbaker said:


> this is only 6a output....
> 
> 
> this is ac-dc charger/converter, not dc-dc....
> ...


oops, hadn't had my coffee yet.....sorry about that. There's always stuff on ebay, check every day for new stuff on there.

I use vicor for everything I do, they're nice, over-current protected, wide input ranges available and they're sealed. Just bolt them to a heat sink and they're good to go.

And most of them have a Gate input, when you ground it, the converter is disabled.


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## Dave Koller (Nov 15, 2008)

dtbaker said:


> spec sheet says this is ac-dc charger/converter, not dc-dc....
> 
> Anyway, why are the iotas so much less expense than the curtis, zivan, and others I have seen so far?


There is not much to them Dan, but they are used by a lot of EV'ers - I ran cl-30's to cushion the inrush - look at the last pages of my thread below - I also have the IQ Smart Controller installed internally... 


AND paid a whole lot less than that.....
Look at some of the solar dealers like Arizona Sun and Wind...

Oh one more thing Iotas are famous for running your battery down if output is left connected with no input.... Hence a relay there...


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## dtbaker (Jan 5, 2008)

Dave Koller said:


> There is not much to them Dan, but they are used by a lot of EV'ers - I ran cl-30's to cushion the inrush - look at the last pages of my thread below - I also have the IQ Smart Controller installed internally...
> 
> 
> AND paid a whole lot less than that.....
> ...



you're over my head with cl-30s (whats that?!) I just want something that will last and put out 30+amps at 13.6v from my 120v DC main pack, and hopefully not drain much when left sitting.

I drive the EV almost every day, so a little drain is probably not noticable. I guess if I were leaving it for a week I could pop the main circuit breaker. Only reason I want the dc power always on is to keep the radio settings, clock, and door lights. 

Do more expensive dc-dc units like the Curtis or Vicor have any substantial differences? i.e. any real reason they cost more?


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## Dave Koller (Nov 15, 2008)

dtbaker said:


> you're over my head with cl-30s (whats that?!) I just want something that will last and put out 30+amps at 13.6v from my 120v DC main pack, and hopefully not drain much when left sitting.
> 
> I drive the EV almost every day, so a little drain is probably not noticable. I guess if I were leaving it for a week I could pop the main circuit breaker. Only reason I want the dc power always on is to keep the radio settings, clock, and door lights.
> 
> Do more expensive dc-dc units like the Curtis or Vicor have any substantial differences? i.e. any real reason they cost more?


You read this?

http://www.evdl.org/pages/iotamods.html

GE Sensors CL-30 inrush limiters are cheap AND really it is an easy MOD think of them like a pre-charge.. (Fact I would like to try them as a super fast pre-charge for the controller ! - would be nice if someone has tried them and would comment!) 

The other mods are common sense .. Neat thing is they can be plugged into AC also and charge.. ( BUT the mod done in the above URL was for DC only ) I guess the price is the attractive part of IOTA - and there is a lot of them being used on EV's!


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## Dave Koller (Nov 15, 2008)

http://www.evalbum.com/dcdcr

and note the number of IOTAS ... 

20 to 1 lol!


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## dtbaker (Jan 5, 2008)

Dave Koller said:


> You read this?
> 
> http://www.evdl.org/pages/iotamods.html


I just did... and can now see why they are cheaper... (because they are BUILT cheaper) and that explains why people using them might hesitate to use a dc-dc without aux battery backup. Also explains why some of the more experienced resellers like KTA don't even offer them if they are notorious for failure.

....I guess I will stick with a more solid reputable dc-dc designed and intended for this type of use. so.... what are the options? Curtis, Zivan, Vicor ? In the $500 range instead of $150-ish for an iota?


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## david85 (Nov 12, 2007)

Rctous (Brian) sold me a nice unit. So far its worked perfectly.

Not sure what you expect for pricing, but see for yourself if any of these are good for you.
http://new.tanicpacks.com/index.php?cPath=76_53

And FYI, Brian explained to me that these can accept AC or DC input voltage. The internal electronics handle the seamless transition without you having to change anything.


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## dtbaker (Jan 5, 2008)

frodus said:


> I use vicor for everything I do, they're nice, over-current protected, wide input ranges available and they're sealed. Just bolt them to a heat sink and they're good to go.


what model vicor do you use? where do you get them? how much do they cost?


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## dtbaker (Jan 5, 2008)

david85 said:


> Not sure what you expect for pricing, but see for yourself if any of these are good for you.
> http://new.tanicpacks.com/index.php?cPath=76_53


looks like the 45amp unit retails for $200, which is not bad at all... after reading the 'review' of the Iota internals though, I am wondering if any of the EE types here in the group have looked under the cover of this brand to review its quality?

The spec sheet looks good (to me), but I did note that it has an overvoltage setting of 140v, which would trigger during a 120v pack charge cycle (at 3.68v per cell with a typical 38 cell Li pack)... Does anyone have any experience with these units? I found more info at
http://www.cascadeaudio.com/power_converters/power_converters.htm


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## frodus (Apr 12, 2008)

dtbaker said:


> what model vicor do you use? where do you get them? how much do they cost?


I got mine off ebay, its a VI-251 series, only 250W for my motorcycle.... but I do know people use them in their vehicles with the larger modules..... I think they're the MegaMods which most people use. 

I've been familiar with Vicor for about 10 years. They always tested well when I was working at GE Energy, and the ones I've used for my bike stuff have all been great.

For pricing, find the model you want and look on vicor's website, they're pretty responsive.

Look at the Maxi line with a 15V output (trimable) and 110Vin (66-154V) and 400W.
http://vicr.com/cms/home/products/brick/mini-maxi-micro-converters


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## dtbaker (Jan 5, 2008)

frodus said:


> Look at the Maxi line with a 15V output (trimable) and 110Vin (66-154V) and 400W.
> http://vicr.com/cms/home/products/brick/mini-maxi-micro-converters


that sounds about right.... although a safety margin of up to 600w output would be even better if it didn't cost a lot more. A 120v nominal pack is going to see 144 to 150v at the top of the charge cycle, so i wouldn't want to over-volt the dc-dc with every cycle...


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## frodus (Apr 12, 2008)

dtbaker said:


> that sounds about right.... although a safety margin of up to 600w output would be even better if it didn't cost a lot more. A 120v nominal pack is going to see 144 to 150v at the top of the charge cycle, so i wouldn't want to over-volt the dc-dc with every cycle...


they have 100-200V range too, chose based on the total range of your pack. The 100-200V version will work down to ~85V before shutting down.

600W is only available in a few voltage ranges, look here:
http://vicr.com/cms/home/products/brick/mini-maxi-micro-converters/Maxi_Mini_Micro_Datasheet_Listing


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## Dave Koller (Nov 15, 2008)

david85 said:


> Rctous (Brian) sold me a nice unit. So far its worked perfectly.
> 
> Not sure what you expect for pricing, but see for yourself if any of these are good for you.
> http://new.tanicpacks.com/index.php?cPath=76_53
> ...


David isn't TANIC MADE by IOTA? They Look the same (slight case difference no top venting)! And one really does NOT have to modify IOTA - they work on AC or DC -- Since Brian is back he could relate more on that.. Many of the 180 plus users have NOT done anything to the IOTA but hook it to the pack.. they have not shown much to complain about (at least not anymore than other DC/DC that have given up the ghost ).. They DO NOT work under about 108 volts and that may be the worst part.


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## dtbaker (Jan 5, 2008)

frodus said:


> they have 100-200V range too, chose based on the total range of your pack. The 100-200V version will work down to ~85V before shutting down.
> 
> 600W is only available in a few voltage ranges, look here:
> http://vicr.com/cms/home/products/brick/mini-maxi-micro-converters/Maxi_Mini_Micro_Datasheet_Listing


a 85v lower limit would probably be fine for a 120v nominal LiFePO4 pack, right? even under full load.... but I dunno exactly what the sag is under a 3C load toward the lower end at say 80% or 90% DOD.

I am not seeing any Vicor listed in the evcomponents.com site, or kta-ev.com, so I am wondering why and where I COULD get them...

looks like this unit is the best fit, puts out 400w.
http://cdn.vicorpower.com/documents/datasheets/ds_110vin-maxi-family.pdf


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## frodus (Apr 12, 2008)

dtbaker said:


> a 85v lower limit would probably be fine for a 120v nominal LiFePO4 pack, right? even under full load.... but I dunno exactly what the sag is under a 3C load toward the lower end at say 80% or 90% DOD.
> 
> I am not seeing any Vicor listed in the evcomponents.com site, or kta-ev.com, so I am wondering why and where I COULD get them...
> 
> ...


depends on your lifepo4 and how many cells. Are you doing a 40 cell pack?

Off a charge, you'd probably be around 3.7V a cell. Under load you could be anywhere between 2.5 and 2V a call depending on what cells you're using.

we don't sell vicor at EVC, as I said before, go to the vicor website, go to "purchase" and they'll email you back with a quote.


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## JRP3 (Mar 7, 2008)

I just ordered one of the Chennic's from Sharon on this forum, $99.99 delivered. Jack Rickard tested one running steady at 30 amps and likes it much better than the Iota's for lower voltage systems. From what I can see 120 volts looks a little low for the Iota's.


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## Dave Koller (Nov 15, 2008)

JRP3 said:


> I just ordered one of the Chennic's from Sharon on this forum, $99.99 delivered. Jack Rickard tested one running steady at 30 amps and likes it much better than the Iota's for lower voltage systems. From what I can see 120 volts looks a little low for the Iota's.


That looks interesting! And outwardly tough......... Price is right...


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## dtbaker (Jan 5, 2008)

JRP3 said:


> I just ordered one of the Chennic's from Sharon on this forum, $99.99 delivered. Jack Rickard tested one running steady at 30 amps and likes it much better than the Iota's for lower voltage systems. From what I can see 120 volts looks a little low for the Iota's.


30amps is plenty for me, and $99 sounds like a killer deal. Sharon WHO ? can you post a link?


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## Dave Koller (Nov 15, 2008)

I'm not sure but this is the manufacture site....

http://www.chennic.com/index.asp

but you probably found that ...


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## JRP3 (Mar 7, 2008)

Thread: http://www.diyelectriccar.com/forum...-brand-newisolated-dc-dc-converter-39567.html


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## Dave Koller (Nov 15, 2008)

JRP3 said:


> Thread: http://www.diyelectriccar.com/forum...-brand-newisolated-dc-dc-converter-39567.html


Is it shipped from china?


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## EVfun (Mar 14, 2010)

JRP3 said:


> I just ordered one of the Chennic's from Sharon on this forum, $99.99 delivered. Jack Rickard tested one running steady at 30 amps and likes it much better than the Iota's for lower voltage systems. From what I can see 120 volts looks a little low for the Iota's.


I would be curious to learn how that works out for you. I have a couple of 120 volt EVs. The Iota indicates the standard 120vac 45 and 55 amp converters have an output that pretty much drops from full rated output at 130 volts DC to about 1/2 amp at 95 volts DC. They are supposed to be low voltage safe though.

Another option, if you can find one, is an old (discontinued) "LV" model Todd AC to DC converter. They lack low input voltage protection so they may fail if the input volts drop below about 90 volts DC. They are usually not hard to repair (either the MUR460 diodes or the IRF740 fets fail, or both.) These are less likely to fail if there is a good load on the output when the input voltage goes low. If the Todd converter doesn't end with "LV" it is really only suitable for a 156 volt EV.


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## JRP3 (Mar 7, 2008)

Dave Koller said:


> Is it shipped from china?


Yup. I don't expect to see it for a while.


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## Dave Koller (Nov 15, 2008)

JRP3 said:


> Yup. I don't expect to see it for a while.


Lol I will be waiting to see how it flies !


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## JRP3 (Mar 7, 2008)

Just checked the tracking info and it's at my local post office! I guess it should be in my mailbox this afternoon.  Ordered March 30, shipped April 2.


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## Dave Koller (Nov 15, 2008)

JRP3 said:


> Just checked the tracking info and it's at my local post office! I guess it should be in my mailbox this afternoon.  Ordered March 30, shipped April 2.


WOW! Tracked from China that fast.... Let us know what it looks like that is fantastic!


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## dimitri (May 16, 2008)

Dave Koller said:


> Lol I will be waiting to see how it flies !





Dave Koller said:


> WOW! Tracked from China that fast.... Let us know what it looks like that is fantastic!


I guess this confirms that it does in fact FLY..... 

I'm also interested in good options for DC-DC, but it would be better if US based EV retailers carried them instead of direct purchase from China.


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## JRP3 (Mar 7, 2008)

I guess I needed to sign for it  Note in the mailbox saying it's at the post office and I need to pick it up.


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## Dave Koller (Nov 15, 2008)

JRP3 said:


> I guess I needed to sign for it  Note in the mailbox saying it's at the post office and I need to pick it up.


So they actually cost 69.95 LOL cause with all that certified mail there has to be a fewbucks in "flying" it here with return receipt ....

Dimitri:
YOU can be the first to handle them Stateside!
*AFTER* JRP tests it......

P.S. they have many models!


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## david85 (Nov 12, 2007)

Wow, that looks like a great unit!


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## Dave Koller (Nov 15, 2008)

david85 said:


> Wow, that looks like a great unit!


this one is interesting:

*Isolated DC-DC Converter 800W (JCDI60)JCDI61* 




The DC-DC converter will accept a maximum input voltage range of 60VDC to 100VDC, 100VDC to 200VDC 200VDC to 400 VDC, and 60VDC to 400VDC super wide input range.


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## dtbaker (Jan 5, 2008)

dimitri said:


> I guess this confirms that it does in fact FLY.....
> 
> I'm also interested in good options for DC-DC, but it would be better if US based EV retailers carried them instead of direct purchase from China.


if these units look reasonable, we can SUGGEST they stock up!


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## Dave Koller (Nov 15, 2008)

dtbaker said:


> if these units look reasonable, we can SUGGEST they stock up!


Yep, they have a few Knock-offs also in Meters


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## JRP3 (Mar 7, 2008)

So I'm all excited and run up to the post office and give the lady my slip, she says: "This is from today, it's still out on the truck". D'oh  of course it is!  Hopefully I can get up there tomorrow.


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## david85 (Nov 12, 2007)

Seems to be standard proceedure here too for pick up the next day but in some rare cases, I was able to get mine earlier (afternoon of the same day).


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## JRP3 (Mar 7, 2008)

Picked it up, looks as if it got a bit beat up in shipping They need better packaging, one corner of the heat sink is pretty bent over. Funny thing is if you look closely at the picture in Sharon's original thread the exact same corner in her picture has similar damage. I haven't had a chance to hook it up as I need a relay to switch it on.


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## dtbaker (Jan 5, 2008)

ouch, that took a hit! perhaps if you email Sharon and suggest better packing?! 

What do you suppose the deal is on needing a relay? Why not just plug it in?

Or.... in my case the dc-dc will always be 'on', so the only time it would power on/off would be if I flip my main circuit breaker. That should work, right? basically just a big switch that only gets flipped once in a while....


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## JRP3 (Mar 7, 2008)

I just sent her an email with that suggestion. There is a green power wire that gets switched to the pack positive line that turns it on since there is no need for it to be on when the vehicle isn't in use. I guess I could just wire it always on temporarily. Or I guess I could just wire it to my main contactor so it gets powered with the key switch. Don't know why I didn't think of that sooner


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## dtbaker (Jan 5, 2008)

I have had mine 'always on', upstream of the contactor, but downstream of the main circuit breaker. I do NOT want it off with key-off, because I want my clock, door lights, and radio to have constant power.... unless I flip the 'kill everything' main circuit breaker.


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## JRP3 (Mar 7, 2008)

I'm planning to run a small battery as well as the converter so I don't have that issue.


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## dtbaker (Jan 5, 2008)

I am zeroing in on what to order, and strongly considering the Chennic 400 watt unit. After careful review of the under/over operating volt range though I am thinking that I will order the 108v nominal model instead of the 120v nominal because the operating voltage range is a little lower (84-146) versus (94-162).

If the pack sagged to 84v, that would be 2.21v per cell, at which time I would be ok with the dc-dc cutting out, which would open my main contactor, and sort of be a low charge fail safe... maybe a little like a 2x4 in the face if it happened at a bad time. But, a momentary rest would raise the v, and everything would come back on I think. 

At the high end, my charge cycle (shouldn't) go over 146v, and will certainly drop to 120-125 once i am on the road for a minute....


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## dimitri (May 16, 2008)

JRP3 said:


> I'm planning to run a small battery as well as the converter so I don't have that issue.


See my poll on DC-DC setup, I did the same originally and now I'm redoing it to be always on.

When you hook it up, check for any current leakage on both sides to see if it could drain either main or aux battery if left connected for very long time.

As for damage, its possible it was hit even before it left the factory, perhaps its was tested to withstand collision. At least it doesn't have any holes from AK-47 bullets, does it?


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## JRP3 (Mar 7, 2008)

dtbaker said:


> I am zeroing in on what to order, and strongly considering the Chennic 400 watt unit. After careful review of the under/over operating volt range though I am thinking that I will order the 108v nominal model instead of the 120v nominal because the operating voltage range is a little lower (84-146) versus (94-162).


The specs I've seen, including the sheet that came with it, show 76-145V range for the 120 volt unit.


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## JRP3 (Mar 7, 2008)

dimitri said:


> See my poll on DC-DC setup, I did the same originally and now I'm redoing it to be always on.
> 
> When you hook it up, check for any current leakage on both sides to see if it could drain either main or aux battery if left connected for very long time.


I don't think my Fiero has much that would drain the 12 volt battery even if it sat for a while, but I'll keep an eye on it.


> As for damage, its possible it was hit even before it left the factory, perhaps its was tested to withstand collision.


They must have tested it in the packing box as there was cardboard and foam jammed into the bent heat sink fins.


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## dtbaker (Jan 5, 2008)

JRP3 said:


> The specs I've seen, including the sheet that came with it, show 76-145V range for the 120 volt unit.


I must have found a different unit? I am looking at the JCDI42-10813.5
http://chennic.com/show-products.asp?id=49&JCDI42

d


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## JRP3 (Mar 7, 2008)

Yes I got the JCDI30-12012 which has much more pronounced heat sink fins. The one you linked has a higher output voltage, 13.5, and is 35 amps as opposed to 30 amps. I would guess it's also more expensive than the one I got.

Compare them here: http://chennic.com/products.asp?anclassid=2&nclassid=9


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## dtbaker (Jan 5, 2008)

JRP3 said:


> Yes I got the JCDI30-12012 which has much more pronounced heat sink fins. The one you linked has a higher output voltage, 13.5, and is 35 amps as opposed to 30 amps. I would guess it's also more expensive than the one I got.


yeah I looked at that one too.... I decided that the extra output for $10 more was a good thing, and having 13.5 output, which probably drops to 12.5 under load, would be better in case I do put a small aux battery in. Besides the smaller fins are less like to get crushed in shipping!

running direct output to my ICE at 13.0-13.5 should be fine, thats what my current little 300watt Curtis is doing....

The price is hard to beat if these things are decent.... $78+34 shipping
d


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## Dave Koller (Nov 15, 2008)

Did you guys get prices somewhere as I did not see them on the site?


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## dtbaker (Jan 5, 2008)

Dave Koller said:


> Did you guys get prices somewhere as I did not see them on the site?


it took several email exchanges.... the chinese method of sales does not include posting prices...


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## Dave Koller (Nov 15, 2008)

LOL - thanks Dan.... It was as I figured ... So Shipping was about 34 bucks .. Still a bargain if they work well... Your EV setup will be a good test (not having an AUX battery) .... Hope it comes WITHOUT the extra fin damage !


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## JRP3 (Mar 7, 2008)

Sharon's original thread mentioned the 99.99 price including shipping. So at least she put it out there without prodding.


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## JRP3 (Mar 7, 2008)

JRP3 said:


> Or I guess I could just wire it to my main contactor so it gets powered with the key switch. Don't know why I didn't think of that sooner


Well that didn't seem to work, gave me a "failure to precharge" error from my controller, so I just wired it always on, seems to be working well, keeping my battery at 13 + volts, though I haven't checked it under load. I should add, be prepared for the large spark when you first hook it up as the caps charge. Gave me a good scare as it was larger than I was expecting.


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## david85 (Nov 12, 2007)

JRP3 said:


> Well that didn't seem to work, gave me a "failure to precharge" error from my controller, so I just wired it always on, seems to be working well, keeping my battery at 13 + volts, though I haven't checked it under load.


haha, I had a similar experience with mine. It will go into precharge, but it just takes much longer than the usual 10 seconds when the DC/DC is hooked in. All the 12V accessories in the car also have to be powered off or it won't turn on at all and the main relay for the ECM will simply cycle on and off.

I'm thinking to do the same as you and hard wire the DC converter to always be on. If you think about it, there is always some 12V drain for the clock and radio memory anyway. It can always be disconnected if the car has to be stored for long periods.


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## dtbaker (Jan 5, 2008)

david85 said:


> I'm thinking to do the same as you and hard wire the DC converter to always be on. If you think about it, there is always some 12V drain for the clock and radio memory anyway. It can always be disconnected if the car has to be stored for long periods.


I think I already said that. 
Mine is 'always on', but downstream of the main circuit breaker/kill. If something really goes south I can pull the plug on EVERYTHING with the kill cable to the circuit breaker.


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## EVfun (Mar 14, 2010)

This is a good time to mention that nothing should be connected between the main contactor and the controller except the precharge wiring. Anything connected between the two is also precharging when the controller is trying to precharge. This will slow or prevent the controller from precharging.


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## Dave Koller (Nov 15, 2008)

JRP3 said:


> I should add, be prepared for the large spark when you first hook it up as the caps charge. Gave me a good scare as it was larger than I was expecting.


http://www.diyelectriccar.com/forums/showpost.php?p=170432&postcount=73

Add a couple of CL-30's to soften that initial charge-up.... Save the DC/DC caps and front end...


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