# [EVDL] DC battery charger



## EVDL List (Jul 27, 2007)

<<< Part of the trouble is that 370V is quite high. Not very many DC
converters or 12V battery chargers support that sort of input. >>>

I can see 370V being a problem - your fully charged pack may get 
higher than some HV converters (even a Vicor for that voltage is 
200-400V, with cut-back above that, but at least it protects itself).

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## EVDL List (Jul 27, 2007)

> On 11 Nov 2009 at 16:04, Collin Kidder wrote:
> 
> > Part of the trouble is that 370V is quite high. Not very many DC
> > converters or 12V battery chargers support that sort of input.
> ...


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## EVDL List (Jul 27, 2007)

Hello Collin,

I use a separate on board Smart Charger by Schumacher Model WM-6000A to 
charge and/or maintainer for my 12 volt deep cycle battery. It goes on every 
time I plug in the main AC plug. It is protected by a 20 amp circuit breaker 
from the equipment panel.

It has a ampere range of 30, 10, and 2 amp. Battery selections are regular, 
deep cycle, AGM and Gel Cell. It automatically bulk, equalize and then goes 
to a maintainer charge. It also indicates voltage and state of charge.

I have a 12 volt deep cycle 135 AH Trojan battery on this charger since 
April of 2002 and still going.

The IOTA DC-DC converters go off line when I turn off the ignition. These 
units would under charge this battery at 13.5 volts or over charge it at 
14.5 volts.

Every time I plug in the AC, I just fold down the rear gate and push the 
switch for 12 volt deep cycle and what ever ampere you want.

See http://go-ev.net/pics/011.html how this charger looks like.

I got this charger from Wal-Mart for about $40.00 back in 2002.

Roland




----- Original Message ----- 
From: "Collin Kidder" <[email protected]>
To: <[email protected]>
Sent: Wednesday, November 11, 2009 1:04 PM
Subject: [EVDL] DC battery charger


> I've got a car with lithium ion batteries in a 370V pack. I've got a DC
> converter to go from that to 13.5V for the normal car stuff. I'd like to
> also put a 12V battery in as well to allow for better surge support,
> running acc while the car is off, etc. My DC/DC converter is not meant
> to be used as a battery charger. If I never let the 12V battery get very
> low I could possibly cheat and just send 13.5V to the battery and let it
> charge. But if the battery ever gets low it would overload the DC
> converter. So, is there a good option (and hopefully cheap) option to
> add a DC powered battery charger? (12V output. Amp output doesn't need
> to be very high)
>
> Part of the trouble is that 370V is quite high. Not very many DC
> converters or 12V battery chargers support that sort of input.
>
> I have thought about using diodes and a 6ohm power resistor to make a
> sort of makeshift 2A charger and source isolation circuit. It'd be crude
> but I think it's workable with only 2 power diodes and one power
> resistor. Is there any reason such a simple solution to the problem
> would be undesirable? I could draw something up real quick in a
> schematic editor if it would help to visualize what I'm thinking of
> doing here.
>
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> 

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## EVDL List (Jul 27, 2007)

Ok, so put in the 12V. battery, also an automatic charger from 120 ACV to
recharge that battery when you are charging your pack. Now connect the
output of the DC/DC and the 12V. battery to a "Combiner" like the RV guys
use to isolate two 12 V. sources (Basically two suitable Schotkey Diodes) so
which ever 12v. source is higher voltage will supply the load. And the DC/DC
won't try to recharge the 12 V. battery, and it gets recharged when you
charge the pack. I'm thinking this is an inexpensive and viable way to
accomplish your desired effect. [call me if the description doesn't make
sense.]
Regards,
Dennis Miles, (Director)
Electric Vehicle Technical Institute Inc.
Tampa Bay Region, Florida, USA
Phone (863) 289 - 0690



> Collin Kidder <[email protected]> wrote:
> 
> > I've got a car with lithium ion batteries in a 370V pack. I've got a DC
> > converter to go from that to 13.5V for the normal car stuff. I'd like to
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC Battery Charger*

(hopefully this threads right. I'm posting from the forum interface and it
didn't have my thread in it for some reason...)

Thanks for the suggestions. I thought about going that way. Maybe I still
will use a dedicated 12V charger off of the AC. A potential problem is that
this car is dual 110/220 on the charger so I cannot just hook up a 110
charger unless it auto adjusts for 220V. However, I don't think 12V chargers
normally do that.

Instead, I still kind of want to do what I originally thought of. Here is a
schematic I quick drew up. Please warn me if it wouldn't work for some
reason. 

http://n4.nabble.com/file/n607107/Batt_scheme.png 
-- 
View this message in context: http://n4.nabble.com/Re-DC-Battery-Charger-tp607107p607107.html
Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.

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## EVDL List (Jul 27, 2007)

Bryan at Belktronix will build you one for any voltage - belktronix.com .

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [email protected]


----- Original Message ----- 
From: "Collin Kidder" <[email protected]x.xxx>
To: <[email protected]>
Sent: Wednesday, November 11, 2009 1:04 PM
Subject: [EVDL] DC battery charger


> I've got a car with lithium ion batteries in a 370V pack. I've got a DC
> converter to go from that to 13.5V for the normal car stuff. I'd like to
> also put a 12V battery in as well to allow for better surge support,
> running acc while the car is off, etc. My DC/DC converter is not meant
> to be used as a battery charger. If I never let the 12V battery get very
> low I could possibly cheat and just send 13.5V to the battery and let it
> charge. But if the battery ever gets low it would overload the DC
> converter. So, is there a good option (and hopefully cheap) option to
> add a DC powered battery charger? (12V output. Amp output doesn't need
> to be very high)
>
> Part of the trouble is that 370V is quite high. Not very many DC
> converters or 12V battery chargers support that sort of input.
>
> I have thought about using diodes and a 6ohm power resistor to make a
> sort of makeshift 2A charger and source isolation circuit. It'd be crude
> but I think it's workable with only 2 power diodes and one power
> resistor. Is there any reason such a simple solution to the problem
> would be undesirable? I could draw something up real quick in a
> schematic editor if it would help to visualize what I'm thinking of
> doing here.
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC Battery Charger*



> Collin Kidder wrote:
> > (hopefully this threads right. I'm posting from the forum interface and it
> > didn't have my thread in it for some reason...)
> >
> ...


----------



## EVDL List (Jul 27, 2007)

You can also try Absopulse.com, they make DC/DC converters for industrial 
and railway use. I purchased a custom voltage (114V in, 13.8V out) BAP319 
converter for about $700 US. A lot of their converters can be ordered for 
higher input voltages.

-low input voltage protection
-inrush current limiting
-output overvoltage protection
-output overcurrent protection
-conformal coating & ruggedizing
-output diodes available
-150,000 hour MTBF @45C
-etc.

-Adrian



> Collin Kidder wrote:
> 
> > I've got a car with lithium ion batteries in a 370V pack. I've got a DC
> > converter to go from that to 13.5V for the normal car stuff. I'd like to
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC Battery Charger*



> Collin Kidder <[email protected]> wrote:
> 
> >
> > (hopefully this threads right. I'm posting from the forum interface and it
> ...


----------



## EVDL List (Jul 27, 2007)

How about one of these Vicor units. It will take up to 425V input, and 
I think that can be paralleled if you need more than 600W output.

http://vicor.industrialpartner.com/other-industrial-v/v375a12c600a.htm

Bill

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC Battery Charger*



> Collin Kidder <[email protected]> wrote:
> 
> > Now, that will taper the charge from 8A down to zero as the battery
> > charges. There is a potential issue though. If the battery were allowed
> ...


----------



## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC Battery Charger*



> Collin Kidder wrote:
> > Replying to myself just to clarify this in case anyone else wants to try
> > it to make sure I'm not totally crazy.
> >
> ...


----------



## EVDL List (Jul 27, 2007)

370V nominal as in 100 cells in series? 
That is a bit higher than most factory conversions
which typcally have around 312V pack voltage.
Most European power supplies (and wide-input units
with high frequent switching conversion) may reach
up to 400V DC (up to 260V AC with safety margin so
400V components are used) but if you charge 100
Lithium cells you could potentially reach 420V or so.

There are power supplies that survive this level,
but they are more difficult to find than units below 400V
To what voltage level are you charging your Lithiums?

I have been experimenting with Dell server power supplies
which (like many other larger power supplies) consist of
a PFC front-end that switches the incoming AC to 400V DC
while loading the AC with an AC current (PF=1)
then a second stage takes the raw 400V DC with ripple
and switches it to the required 3.3 5 and 12V outputs
at some 30A or so.

I have not checked the voltage ratings at the secondary
stage, but I know that the 400V front-end can go to 420V
when the load is too light, that is why it uses 450V caps.

Success,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Collin Kidder
Sent: Thursday, November 12, 2009 2:35 AM
To: [email protected]
Subject: [EVDL] DC battery charger

I've got a car with lithium ion batteries in a 370V pack. I've got a DC
converter to go from that to 13.5V for the normal car stuff. I'd like to
also put a 12V battery in as well to allow for better surge support,
running acc while the car is off, etc. My DC/DC converter is not meant
to be used as a battery charger. If I never let the 12V battery get very
low I could possibly cheat and just send 13.5V to the battery and let it
charge. But if the battery ever gets low it would overload the DC
converter. So, is there a good option (and hopefully cheap) option to
add a DC powered battery charger? (12V output. Amp output doesn't need
to be very high)

Part of the trouble is that 370V is quite high. Not very many DC
converters or 12V battery chargers support that sort of input.

I have thought about using diodes and a 6ohm power resistor to make a
sort of makeshift 2A charger and source isolation circuit. It'd be crude
but I think it's workable with only 2 power diodes and one power
resistor. Is there any reason such a simple solution to the problem
would be undesirable? I could draw something up real quick in a
schematic editor if it would help to visualize what I'm thinking of
doing here.

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