Impedance matching

[Forrest]

Hi forelle,

NOTES ON BATTERIES AND COILS IMPEDANCE MATCHING
• Ideally the impedance of each coil should match the C20 rate for the batteries.
• As previously indicated, the small 7.0Ah gel cell types have a C20 rate of 0.28A. That is the
maximum discharge rate allowed under the C20 rule. The coil specified on Peswiki comes
under this value and thus is well suited for new users.
• Obviously larger batteries with higher C20 rates will support larger coils or those with heavier
gauge wire or more than one coil (for now stick with the one coil). As a quick rule of thumb,
Roamer has suggested to buy 100ft of 18AWG twin speaker cable from Radio Shack and
make the coil for larger batteries.
• Basically, bigger wire coil implies higher RPM and more current. Multiple smaller coils imply
higher RPM and less current draw per coil but more overall than just one coil (see notes
below).
• All this depends on your rotor, the number of magnets, etc… with regards to where the
‘sweet spot’ RPM and amperage is going to be for a given coil size or number of coils running
at that ‘sweet spot’ RPM.
• As a further example a coil or coils that draw 1 to 3 amps (as shown on a DMM), will charge
a deep cycle golf cart size battery bank. This amperage draw does not even get close to the
C20 rating of the battery bank, so that the rest of the charge in the battery can be used for
other loads at the same time as charging the other bank(s).

Bud

[Forrest]

Hi forelle, The impedance question I am sure of yet. Do not have your answer but do have some very good info to read thru. SSG_STARTERS_GUIDE-Two.pdf

This was good enough for me to put into book form. It might give you the clues you need to the answer.

bud

[forelle]

Hello everybody,
It's allways talked about that the coils should match the impedance of the battery,but how is this made?
I hope somebody can help.
Thanks