# [EVDL] BMS's something to look out for



## EVDL List (Jul 27, 2007)

> Steve Clunn wrote:
> > I just got back a car I'd worked on about one and a half years ago...
> > most batteries around .7v, the others between 5 and 10 v...All but 4
> > of the regulators burned out, the 4 good ones had fuses blown...
> ...


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## EVDL List (Jul 27, 2007)

Lee;

I had a different, but similar thing happen to me this past Saturday.
My truck sat for about 2 weeks, and the E-Meter drained my 16 ahr
accessory battery.
None of my other components are powered with the key off.
Had to disconnect it and charge it with a small 12V charger.
The DC/DC only kicks in when the key is on, so even when charging the
pack I am not charging the accessory battery.
When my truck would sit for a while, I would always check my pack
voltage every few days, to make sure there were no issues.
I could do this by waking up the E-Meter, without turning on the truck.
I didn't think to check the accessory battery analog gage, that only
comes on with the key.

I thought that I had this truck wired correctly, but now I'm having some
doubts.

What is the proper way to have these components wired to avoid these
kind of problems.


Thanks;
Dennis 
Elsberry, MO 
http://www.evalbum.com/1366 






-----Original Message-----
From: Lee Hart [mailto:[email protected]] 
Sent: Sunday, June 13, 2010 1:25 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] BMS's something to look out for



> Steve Clunn wrote:
> > I just got back a car I'd worked on about one and a half years ago...
> > most batteries around .7v, the others between 5 and 10 v...All but 4
> > of the regulators burned out, the 4 good ones had fuses blown...
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> >
> > ...All these devices
> > draw power even if they are in "standby". So now instead of killing a
> ...


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## EVDL List (Jul 27, 2007)

> mark at evie-systems wrote:
> >> ...All these devices
> >> draw power even if they are in "standby". So now instead of killing a
> >> cheap 12v battery, it kills the expensive propulsion pack!
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> >
> > Here are a few numbers that I have handy:
> >
> ...


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## EVDL List (Jul 27, 2007)

> mark at evie-systems wrote:
> > I have a P-FET that I'm using to "disconnect" the battery-monitors when the
> > key is "switched off", so the only resulting discharge current is 3.6v, 6v,
> > or 12v through 1MegOhm, which is still in the micro-amp range, so there
> ...


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## EVDL List (Jul 27, 2007)

Easy way to solve it, without just putting a big disconnect switch on the
accessory battery, is to put a small (5 watt or less) solar panel to keep it
charged. I've had to do that with a few newer vehicles that were only used
once a month. They tend to have much larger parasitic loads than older
vehicles did, and just assume that you'll drive them every few days to keep
up.

Z



> Lee Hart <[email protected]> wrote:
> 
> > mark at evie-systems wrote:
> > > I have a P-FET that I'm using to "disconnect" the battery-monitors when
> ...


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## EVDL List (Jul 27, 2007)

Ebay frequently has solar panels with cigarette lighter (oops, I mean 
'accessory power') adapters. Evidently Volkswagens ( I think it was) 
would drain the battery sitting at tlhe dock so they put these in them 
to keep the battery charged up.

- SteveS

On 6/14/2010 1:39 PM, Zeke Yewdall wrote:
> Easy way to solve it, without just putting a big disconnect switch on the
> accessory battery, is to put a small (5 watt or less) solar panel to keep it
> charged. I've had to do that with a few newer vehicles that were only used
> once a month. They tend to have much larger parasitic loads than older
> vehicles did, and just assume that you'll drive them every few days to keep
> up.
>
> Z
>
>


> Lee Hart<[email protected]> wrote:
> >
> >
> >> mark at evie-systems wrote:
> ...


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## EVDL List (Jul 27, 2007)

Check to see whether you have power to the "accessory power" plug when the
key is off. Most japanese cars it seems turn that off with the ignition,
whereas american ones don't. I have no idea on VW's, but guess they must be
more like american ones.

Z



> SteveS <[email protected]> wrote:
> 
> > Ebay frequently has solar panels with cigarette lighter (oops, I mean
> > 'accessory power') adapters. Evidently Volkswagens ( I think it was)
> ...


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## EVDL List (Jul 27, 2007)

VW accessory plugs are always hot. My Kia Sportage has one hot in the back
and the ones up front are off with the key. 

-----
If you don't understand, be patient, you will. Now I understand. 
-- 
View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/BMS-s-something-to-look-out-for-tp2253201p2254887.html
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## EVDL List (Jul 27, 2007)

Hi Dennis,

I use a Battery Tender Jr. to maintain my aux battery. When I have my 
car plugged in, it powers both the pack charger and the aux battery 
charger. The pack charger knows when to shut down, so I can leave it 
plugged in. The aux charger maintains the aux battery so I can leave 
that powered for as long as the car needs to sit. (I also use this 
system for my wife's porsche - a notorious eater of batteries).

Cheers,
Peter



> Pestka, Dennis J wrote:
> > Lee;
> >
> > The E-meter is my only load with the ignition off.
> ...


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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

> Bill Dube wrote:
> > I leave the DC-DC converter on when the ignition is off.
> 
> Or you can get a small Photovoltaic panel,
> ...


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## EVDL List (Jul 27, 2007)

Zilla Hairball ~50mA
The LCD CLOCK in my car - 20mA!
Alpine radio/CD player - 30mA

If I don't use my EV every 3-4 days I have to charge the 12V battery 
manually (or disconnect it).

-Adrian



> mark at evie-systems wrote:
> 
> >
> >
> ...


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## EVDL List (Jul 27, 2007)

> Adrian DeLeon wrote:
> >
> > Zilla Hairball ~50mA
> > The LCD CLOCK in my car - 20mA!
> ...


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## EVDL List (Jul 27, 2007)

Ha! You'd be wrong about the backlight. There is none! I'd have to check 
to see if it even gets lit at night with the rest of the cluster 
illumination.

The LCD clock is a standard gauge available on 70's and 80's VW vehicles.

I'd leave all the 12V stuff permanently OFF, but having the radio presets 
and settings blanked all the time is REALLY annoying.

-Adrian



> Lee Hart wrote:
> 
> > On 6/14/2010 10:40 PM, mark at evie-systems wrote:
> >> 20mA for a clock??? yikes!
> ...


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## EVDL List (Jul 27, 2007)

Or get a standard AM/FM car radio from the 70's... they use a mechanical
device to set the presets instead of an electronic one... no electricity
needed.

Of course, they leave alot to be desired as a radio compared to modern ones


Z



> Lee Hart <[email protected]> wrote:
> 
> > On 6/15/2010 12:12 AM, Adrian DeLeon wrote:
> > > Ha! You'd be wrong about the backlight. There is none! I'd have to check
> ...


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## EVDL List (Jul 27, 2007)

----- Original Message ----- 
From: "Zeke Yewdall" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Tuesday, June 15, 2010 9:13 AM
Subject: Re: [EVDL] BMS's something to look out for


> Or get a standard AM/FM car radio from the 70's... they use a mechanical
> device to set the presets instead of an electronic one... no electricity
> needed.

Yup! Easy to set, and operate, unlike the THINGS they sell as "Radio's" 
Today. Road hazards WORSE than texting, you have to LOOK at it to diddle out 
a selection! Top diss-traction going in todaze cars! Howbout a "Off-On" 
knob, controls volume all in ONE! A "station selector" nob, A Treble and 
balance one, a simple back light, lets ya know IF the damn radio is "On"I 
LIKE my 70's radio, although there is little worth listening to nowadaze on 
ETHER channels on the radio? Maybe Sattalite Radio is an improvement?Hence 
CD's which "Stick" when there is a wayward molecule on the disc, or 
Casettes, that get eaten, etc. The new solid state things, what? I-Pods may 
work better in EV's anyhow?
>
> Of course, they leave alot to be desired as a radio compared to modern 
> ones
> 
> You Bet; User Friendly!

Bob
> Z
>
>


> Lee Hart <[email protected]> wrote:
> >
> >> On 6/15/2010 12:12 AM, Adrian DeLeon wrote:
> >> > Ha! You'd be wrong about the backlight. There is none! I'd have to
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> >
> > mark at evie-systems wrote:
> >> I have a P-FET that I'm using to "disconnect" the battery-monitors when
> ...


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## EVDL List (Jul 27, 2007)

>> Have you tested your BMS with bad batteries?



> mark at evie-systems wrote:
> > Hmm, well, what's a bad battery? Over voltage? Under voltage?
> 
> Yes. As well as overtemperature, undertemperature, excessive internal
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> >
> > If "report" means turning on an indicator for the driver, it won't stop
> > an "impending doom". Unfortunately, the driver will either not see the
> ...


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## EVDL List (Jul 27, 2007)

Use a fiber connection to each battery. No noise, and if. The link drops you have a major issue.
Ill send more detail when I get back to my laptop.

Stub
Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: mark at evie-systems <[email protected]>
Date: Thu, 17 Jun 2010 06:31:59 
To: <[email protected]>
Subject: Re: [EVDL] BMS's something to look out for





> Lee Hart wrote:
> >
> > If "report" means turning on an indicator for the driver, it won't stop
> > an "impending doom". Unfortunately, the driver will either not see the
> ...


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## EVDL List (Jul 27, 2007)

> Collin Kidder wrote:
> >
> > Keep in mind that, in the case of a fault, communications could become
> > garbled, nonexistent, or sporadic. As such your charger shut off, charge
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> >
> > You might considering modularizing the system so a customer can't opt
> > out of the modules that *control* things.
> ...


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## EVDL List (Jul 27, 2007)

> mark at evie-systems wrote:
> 
> > But, if a module fails dead, then it can hardly send out any
> > messages...
> ...


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## EVDL List (Jul 27, 2007)

> Use a fiber connection to each battery. No noise, and if. The link drops you have a major issue.
> Ill send more detail when I get back to my laptop.
> 
> Stub
> Sent from my Verizon Wireless BlackBerry


<snip>

I have looked into this and using POF aka Plastic Optic Fiber, the stuff they use on the cheap audio equipment can make things
cheap, but the power requirements are high becasue they wnat high data and reasonable distance. Signal attenuation is high and
low-power was not a design issue with POF.

Glass fiber has much lower attenuation and so you could lower the power but the default is optimized for the most distance and
bandwidth you can get. You get more per watt, but still for a BMS it may be a hog. Connectors are still expensive but comeing down
fast and getting compeditive with multi-conductor copper. The tradeoff is more inteligence needed at both ends to multiplex data and
turn it into control.

I have seen multimode fiber in cars and machinery usually used between a resolver and a computer.

I haven't researched recently to see if this gap has been filled, but I think we have to create the low power short area network for
glass fiber.


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