The simple way is with one of Rich's PFC50's or a PWM controller, but these=
both cost money. =
Dump charging on the cheap requires a bit of trial and error. Basically yo=
u are using the higher voltage of the larger pack to force current through =
the smaller pack, and the larger the difference in the packs the more curre=
nt you will get. I played with it on my motorcycle a bit, but decided it d=
id not fit my needs. It's easy to dump charge through the bulk charge phas=
e, but dangerous during the finish charge. It is fun to charge at 100's of=
amps though
Here is what happens. When you first start you will have the highest curre=
nt as you will have the largest voltage differential. The current is deter=
mined by this voltage difference and the totally resistance in your charge =
circuit. I just used 2 large cables and a beafy contactor. The voltage on=
the pack you are charging starts coming up and the voltage on the pack you=
are charging from starts to sag so the current drops off. To overcome thi=
s you can break the circuit and add another battery on the charging side, b=
ut this is when things start getting tricky since you now have unequal batt=
eries that you are charging from. The next tricky part comes when the volt=
age on the battery you are charging starts to fill up. If you are still pu=
shing big current, things can go bad in a hurry.
The two packs you describe below seem like they might work well together. =
It's easy to test, you just need some beefy cables and a nice big switch/co=
ntactor. I would guess that it will work fairly well through the bulk phas=
e, but not be quite enough to bring everything up to 14.7 volts. You might=
need one more 8 volter for that.
damon
> Date: Thu, 20 Sep 2007 12:32:31 -0700
> From: [email protected]
> To: [email protected]; [email protected]
> Subject: [EVDL] Dragster question2
>
>
> How can I =91dump=92 charge a small pack from a big pack,
> is there a simple way to do that?
>
> If I have 16 8v 190ah flooded lead acid batteries
> which when fully charged are about 133v then could I
> divide that amongst 9 12v 28ah high output AGM
> batteries to charge at 14.7 volts each?
>
>
> harry
>
> Albuquerque, NM
> http://geocities.com/hendersonmotorcycles/blog.html
> http://www.austinev.org/evalbum/1221
> http://geocities.com/solarcookingman
>
>
> _________________________________________________________________________=
___________
> Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user pan=
el and lay it on us. http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.as=
p?a=3D7
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
_________________________________________________________________
Gear up for Halo=AE 3 with free downloads and an exclusive offer. It=92s ou=
r way of saying thanks for using Windows Live=99.
http://gethalo3gear.com?ocid=3DSeptemberWLHalo3_WLHMTxt_2
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
both cost money. =
Dump charging on the cheap requires a bit of trial and error. Basically yo=
u are using the higher voltage of the larger pack to force current through =
the smaller pack, and the larger the difference in the packs the more curre=
nt you will get. I played with it on my motorcycle a bit, but decided it d=
id not fit my needs. It's easy to dump charge through the bulk charge phas=
e, but dangerous during the finish charge. It is fun to charge at 100's of=
amps though
Here is what happens. When you first start you will have the highest curre=
nt as you will have the largest voltage differential. The current is deter=
mined by this voltage difference and the totally resistance in your charge =
circuit. I just used 2 large cables and a beafy contactor. The voltage on=
the pack you are charging starts coming up and the voltage on the pack you=
are charging from starts to sag so the current drops off. To overcome thi=
s you can break the circuit and add another battery on the charging side, b=
ut this is when things start getting tricky since you now have unequal batt=
eries that you are charging from. The next tricky part comes when the volt=
age on the battery you are charging starts to fill up. If you are still pu=
shing big current, things can go bad in a hurry.
The two packs you describe below seem like they might work well together. =
It's easy to test, you just need some beefy cables and a nice big switch/co=
ntactor. I would guess that it will work fairly well through the bulk phas=
e, but not be quite enough to bring everything up to 14.7 volts. You might=
need one more 8 volter for that.
damon
> Date: Thu, 20 Sep 2007 12:32:31 -0700
> From: [email protected]
> To: [email protected]; [email protected]
> Subject: [EVDL] Dragster question2
>
>
> How can I =91dump=92 charge a small pack from a big pack,
> is there a simple way to do that?
>
> If I have 16 8v 190ah flooded lead acid batteries
> which when fully charged are about 133v then could I
> divide that amongst 9 12v 28ah high output AGM
> batteries to charge at 14.7 volts each?
>
>
> harry
>
> Albuquerque, NM
> http://geocities.com/hendersonmotorcycles/blog.html
> http://www.austinev.org/evalbum/1221
> http://geocities.com/solarcookingman
>
>
> _________________________________________________________________________=
___________
> Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user pan=
el and lay it on us. http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.as=
p?a=3D7
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
_________________________________________________________________
Gear up for Halo=AE 3 with free downloads and an exclusive offer. It=92s ou=
r way of saying thanks for using Windows Live=99.
http://gethalo3gear.com?ocid=3DSeptemberWLHalo3_WLHMTxt_2
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev