# current surge stalling engine

Discussion in 'General Electronics Discussion' started by davit, Jun 7, 2021.

1. ### crutschow

43
15
May 7, 2021
20,000Ω is way too high a resistance.
That will limit the current to a fraction of an amp.
Do you not know Ohm's law, which states that Current = Volts divided by Resistance?

This 50W resistor selected with 0.5Ω should work.
It should limit the maximum current to <10A with the battery attached (less than 5V across the resistance).

Last edited: Jun 10, 2021 at 1:22 AM
2. ### davit

37
0
Aug 16, 2017
@Bluejets sorry for any confusion, thought i had gave enough info uploading pics now, you can see in the pick i am using the isolator to connect alt to battery once the revs are very high, appologies for lack of alternator info i bought it new last year from a firm that has since stopped trading ( doh bang goes my warranty ) the little sw in the pic is the energize sw for the alternator,24vdc max 55amp
https://www.dropbox.com/s/c0pl4axinglr1e4/DSCN3145.JPG?dl=0
https://www.dropbox.com/s/ujroywaei0deofa/DSCN3142.JPG?dl=0

Last edited: Jun 10, 2021 at 10:28 AM
3. ### davit

37
0
Aug 16, 2017
sorry dont know any laws still learning which is hard at my age and part dementia, really appreciate the link for the resistor though will buy that i ,i just assumed the adjustable one i bought would adjust down to that low amp reading ,
my lack of knowledge is shinning through , we all started somewhere LOL

4. ### crutschow

43
15
May 7, 2021
Even if that were a 10W pot (which is not stated). the maximum current the internal wiring could carry would be 22mA, many orders of magnitude below what you need.

If you learn Ohm's law, plus the equations for power (P = V x I, P = V² / R, and P = I² x R) where P is power, R is the resistance, V is voltage across the resistance and I is current through the resistance, then you will be well along to understanding basic circuit operation.

5. ### Bluejets

4,748
999
Oct 5, 2014
What is the heatsinked device on the lower right connected directly across the battery.....?

Seems to be heavy leads connected to some kind of isolator but nothing on the alternator output pins.??

How about a sketch of the wiring you have done..??
Half of the info will get only half an answer at best.

Doesn't look right to me.

6. ### davit

37
0
Aug 16, 2017
the heatsinked device is a 24v - 12v reducer which works well ( recomened from an earlier post )
the isolater is between the batt and alternator, the electrics all work well its just the current surge can sometimes stall the engine
would be nice if it could be stepped, feel i am going round in circles now ,so will close this post now,
but i would like to thank you all for your reply posts they have been very helpfull and informative , what a wonderfull forum thank you admin,,

7. ### Bluejets

4,748
999
Oct 5, 2014
As I said previously, send a circuit diagram of what you have there.
Looks to me like you have nothing connected to the alternator output studs.