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paralleling NIMH batteries

M

Martin Riddle

I have an idea that requires a large capacity rechargable battery and NiMH
seems to fit the bill. I need to charge them quick.

The problem is I'll need 2 or 3 strings of SC or D size cells. From what I
can gather connecting to the load is straight forward, but charging will
require contrl circuits for each string and relays to connect them.

Any other gotchas with this?

Cheers
 
M

martin griffith

I have an idea that requires a large capacity rechargable battery and NiMH
seems to fit the bill. I need to charge them quick.

The problem is I'll need 2 or 3 strings of SC or D size cells. From what I
can gather connecting to the load is straight forward, but charging will
require contrl circuits for each string and relays to connect them.

Any other gotchas with this?

Cheers
not always
http://www.linear.com/pc/viewCategory.jsp?navId=H0,C1,C1003,C1037,C1078

this looks good
http://www.gpbatteries.com/pdf/GP1300FH_DS.pdf


martin
 
M

MassiveProng

I have an idea that requires a large capacity rechargable battery and NiMH
seems to fit the bill. I need to charge them quick.

The problem is I'll need 2 or 3 strings of SC or D size cells. From what I
can gather connecting to the load is straight forward, but charging will
require contrl circuits for each string and relays to connect them.

Any other gotchas with this?

Cheers

Unless you have watchdog circuits and charge individually, you will
end up with a "memory effect". Of course, it is easily solved by Ind.
charging again.
 
W

Winfield

Martin said:
I have an idea that requires a large capacity rechargable battery
and NiMH seems to fit the bill. I need to charge them quick.

I've come to the conclusion that Li-ion is the way to go.
 
A

Anthony Fremont

MassiveProng said:
Unless you have watchdog circuits and charge individually, you will
end up with a "memory effect". Of course, it is easily solved by Ind.
charging again.

He said NiMH, not NiCd. NiMH batteries are _almost_ never affected by
"memory effect". You don't have to go thru that much trouble. People that
fly expensive RC models may have different opinions on that. ;-)
 
M

martin griffith

I've come to the conclusion that Li-ion is the way to go.
have you seen the seiko stuff?
such as ftp://ftp.sii.co.jp/pub/ic/speed_dt/dt_sht_e/power/S8242_E.pdf


martin
 
W

Winfield

martin said:
have you seen the seiko stuff?
such asftp://ftp.sii.co.jp/pub/ic/speed_dt/dt_sht_e/power/S8242_E.pdf

Hmm, an 800-cell PowerPack for my Prius would require 400 ICs?
 
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