# [EVDL] DCP dc/dc overload and Karmann Eclectric update



## EVDL List (Jul 27, 2007)

Howdy Folks, 

Need to ask about a little issue I'm having with my DCP dc/dc converter. The old unit has taken a lot of abuse, but has a ***** in the HV armor, namely it's ACG 250V 10A input fuse. Mine keeps eating them, and roadside replacement is not fun. Issue seems to be that when my nicad 12V 'house battery' falls off it's voltage cliff (hits the knee on discharge), it has an insatiable appetite for current below the 14.5 V setting, and the DCP either blows the ATO 12V 30A output fuse, or lately, the 10A input fuse. Now even I can calculate that the 2500W rating on the input fuse means that the 300W converter should almost never blow that input fuse! Are the fast-blow fuses I'm using the wrong type? I've got a ceramic 10A fuse upstream that has never blown. Is there a circuit breaker that I can wire in upstream of it that's more compact than this? (And would the MidNite Solar MNEPV10-300 provide proper protection?)

Being simply a constant voltage device, the DCP doesn't provide a proper nicad charge profile, and my house battery is chronically undercharged. When attempting to set the DCP for a 15.5V standby voltage for nicad charging and 14.5V "run" voltage, it seems to default to the higher option at all times. Bright lights and fast fans are nice, but I don't wanna damage my stereo or instruments. (or is that not an issue at 15.5 to 16V?) It would seem that anyone using a Lithium house battery would have similar issues on the discharge knee, even with a BMS. I've taken some pride in getting the lead out, but have resorted to carrying a small SLA 12V for reserve purposes. Please say I don't need to make that permanent...

Secondly, I've finally excercised the parallel fields option on my Jim Husted special, the Gamera Nine. The surplus of low-end torque is reduced, but that just means my 3000lb pressure plate no longer chatters and the 8' wide tires have a better chance of maintaining traction, even though first gear launches are now useful instead of a pure time waster. The real story is in the upper rpm region. I finally got to test Zilla's rev limiter, as the motor now enthusiastically winds up to the 6000 rpm redline in gears 1-3 (awaiting an opportunity to wind out 4th gear) and the super-balanced motor/flywheel combo stays smooth even at such speed. Full revs at load was not much of an issue in series mode.

-Jay
www.karmanneclectric.blogspot.com
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## EVDL List (Jul 27, 2007)

Hi Bob,

I was just wondering if you could expound on the increased needs for 12V
power in the winter. I had my conversion last year, but parked it most of
the winter. I hope to drive it this year over the winter. I have an Elcon
30A DC-DC and was assuming that would be sufficient.

I see my 12V needs are:

- Contactor and Solid State Relay - Year around
- Radio - Year around
- Headlights and tail lights - Year around but more in winter
- Ventilation fan - Year around but more in winter
- Rear window defroster - Winter only
- Heater circulating pump - Winter only (Heater is MES-DEA running off
the traction pack with a 12V enable and 12V water pump)
- Power windows - Summer only. Leave them closed in winter.

The car is garaged at night so would always leave defrosted in the morning.
It might need defrosters and heaters to run on the way home. My drive is
about 30-45 minutes so a reasonable amount of time to recharge after the
initial load.

I don't see 30A continuous here. I'm sure the load would be higher with
things like electric seats, but I don't have those. I see increased loads
for lighting, small water pump and rear window defroster.

What am I missing here?

Mike

P.S. Just to be clear, I'm trying to charge the 12V lead-acid that came
with the car. Not a NiCd like the original poster.

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On
> Behalf Of Bob Bath
> Sent: Tuesday, September 06, 2011 9:34 PM
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] DCP dc/dc overload and Karmann Eclectric update
> 
> Jay,
> I used a DCP DCDC for my first few years of EV ownership, so allow me
> please the following observations:
> - Don't know your climate, but aux. line needs increase like crazy in
winter.
> As a result, your aux. batt. will not stay topped off, and die an early
death as
> your voltage sags.
> - 35 A is not (in my experience, see above) enough. I'd move to a 60A
model
> that _doesn't_ eat fuses.
> - Damon Crockett, founder of DCP, is still in business under AllTrax.
While it's
> possible he'll say, "Sorry, I don't give a rip about my old stuff," he is
firmly
> committed to EVs, especially on-road. He used to race a Mazda RX-7 EV.
The
> least you could do is give a call, and see if his staff is interested in
overhauling
> it. Prepare to be w/o a DCDC or an EV for 3 weeks (shipping & repair
time).
> Barring that, ask if you can have his ear for 5 mins., and describe the
> symptoms. He may be able to diagnose it over the phone, as he is _wicked_
> smart.
> Just my 0.02, based on experience working with him.
> Stay charged, bro!
> 
> Thinking about converting a gen. 5 ('92-95) Honda Civic? See
> http://home.budget.net/~bbath/CivicWithACord.html for DVD and tons
> more info!
> ____
> __/__|__\__
> =D-------/ - - \
> 'O'-----'O'-'
> Would you still drive your car if the tailpipe came out of the steering
wheel?
> OR Lic. "LCTRNS"
> 
> 

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