<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yui_3_16_0_ym19_1_1460170703115_2643"><span>Thanks Steve,</span></div><div id="yui_3_16_0_ym19_1_1460170703115_2642"><span id="yui_3_16_0_ym19_1_1460170703115_2641">I'll wire it up with the resistor across the switch & see what amps the system is drawing</span></div><div id="yui_3_16_0_ym19_1_1460170703115_2654" dir="ltr"><span>once the capacitors are charged.</span></div><div id="yui_3_16_0_ym19_1_1460170703115_2656" dir="ltr"><span>Alan</span></div><div id="yui_3_16_0_ym19_1_1460170703115_2644"><span></span><br></div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1460170703115_2655"><br><br></div><div class="yahoo_quoted" id="yui_3_16_0_ym19_1_1460170703115_2660" style="display: block;"> <div id="yui_3_16_0_ym19_1_1460170703115_2659" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym19_1_1460170703115_2658" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym19_1_1460170703115_2657" dir="ltr"> <font id="yui_3_16_0_ym19_1_1460170703115_2661" face="Arial" size="2"> <hr size="1"> <b><span style="font-weight: bold;">From:</span></b> Stephen Fordyce via Personal_Submersibles <personal_submersibles@psubs.org><br> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <personal_submersibles@psubs.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Saturday, April 9, 2016 1:16 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Pre-Charge Resistor<br> </font> </div> <div class="y_msg_container" id="yui_3_16_0_ym19_1_1460170703115_2665"><br><div id="yiv9885648966"><div id="yui_3_16_0_ym19_1_1460170703115_2664"><div id="yui_3_16_0_ym19_1_1460170703115_2663" dir="ltr"><div>Hi Alan,</div><div id="yui_3_16_0_ym19_1_1460170703115_2662">Yes, basically resistance * capacitance == a time constant, which is a common theme in analog electronics design (RC = tau). So it's all nicely linear, ie. to double the time you double the resistance.</div><div><br clear="none"></div><div id="yui_3_16_0_ym19_1_1460170703115_2666">By my reading of it, the resistor won't actually flatten your battery - ie. when the capacitors are fully charged through the capacitor, there is no driving voltage so no current will flow through the resistor, thus it theoretically draws no power. But the capacitors will have a leakage rate that may draw a small current and as you pointed out, the LED on the controller may draw some current through to power the circuitry and indicator LED.</div><div id="yui_3_16_0_ym19_1_1460170703115_2668"><br clear="none"></div><div id="yui_3_16_0_ym19_1_1460170703115_2669">Probably best practice to isolate the batteries close to the source when not using for a while - and so the problem would still stand!</div><div id="yui_3_16_0_ym19_1_1460170703115_2670"><br clear="none"></div><div>Cheers,</div><div>Steve</div></div><div class="yiv9885648966gmail_extra" id="yui_3_16_0_ym19_1_1460170703115_2671"><br clear="none"><div class="yiv9885648966gmail_quote" id="yui_3_16_0_ym19_1_1460170703115_2672">On Sat, Apr 9, 2016 at 10:49 AM, Alan James via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span> wrote:<br clear="none"><blockquote class="yiv9885648966gmail_quote" id="yui_3_16_0_ym19_1_1460170703115_2676" style="margin: 0px 0px 0px 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;"><div class="yiv9885648966yqt5870709497" id="yiv9885648966yqt35103"><div id="yui_3_16_0_ym19_1_1460170703115_2675"><div id="yui_3_16_0_ym19_1_1460170703115_2674" style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);"><div id="yui_3_16_0_ym19_1_1460170703115_2673"><span>Thanks Steve,</span></div><div><span>I didn't know there was such a calculator.</span></div><div><span>The resistor Kelly supplied was 1K, the link I posted was misleading.</span></div><div><span>I would need to contact Kelly to find out about the capacitors in my controller.</span></div><div><span>I have seen figures elsewhere of anywhere up to 4 seconds delay.</span></div><div><span>The 1k resistor will run my test battery (48V 40ahr) down in about 800 hrs. if I </span></div><div dir="ltr"><span>don't disconnect the battery or resistor; unless there </span><span>is some electronics that I </span></div><div dir="ltr"><span>don't know about that monitors the state of charge of </span><span>the capacitors & turns their </span></div><div dir="ltr"><span>power supply off & on.</span></div><div dir="ltr"><span>Cheers Alan</span></div><div><span></span><br clear="none"></div><div><br clear="none"><br clear="none"></div><div style="display: block;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"> <font face="Arial" size="2"> </font><hr size="1"> <b><span style="font-weight: bold;">From:</span></b> Stephen Fordyce via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><span><br clear="none"> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> <br clear="none"> </span><b><span style="font-weight: bold;">Sent:</span></b> Saturday, April 9, 2016 10:50 AM<br clear="none"> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Pre-Charge Resistor<br clear="none"> </div><div><div class="yiv9885648966h5"> <div><br clear="none"><div><div><div dir="ltr">Hi Alan,<br clear="none">
Just putting it out there, it could actually take a while to charge a large capacitor bank through a 10k resistor - not sure if you've checked this but there are calculators on the web for that.</div>
<div dir="ltr">Cheers,<br clear="none">
Steve</div>
<div>On 9 Apr 2016 8:28 am, "Alan James via Personal_Submersibles" <<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><blockquote style="margin: 0px 0px 0px 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;"><div><div><div style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);"><div><span></span></div><div dir="ltr">OK figured out what I am doing.</div><div dir="ltr">For this experimental stage I will just have a circuit breaker on the battery + side of the main switch</div><div dir="ltr">& pre-charge resistor. I will trip this breaker when finished to take current off the resistor.</div><div dir="ltr">When operational on the sub I will have a relay to a solenoid switch.</div><div dir="ltr">When the relay is turned on, the pre-charge resister will see current & charge the capacitors</div><div dir="ltr">but there will be a timer circuit with a delay of 1 second before power goes to the solenoid switch.</div><div dir="ltr">Cheers Alan<br clear="none"><br clear="none"></div><div style="display: block;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"> <font face="Arial" size="2"> </font><hr size="1"> <b><span style="font-weight: bold;">From:</span></b> Alan James via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br clear="none"> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> <br clear="none"> <b><span style="font-weight: bold;">Sent:</span></b> Saturday, April 9, 2016 4:26 AM<br clear="none"> <b><span style="font-weight: bold;">Subject:</span></b> [PSUBS-MAILIST] Pre-Charge Resistor<br clear="none"> </div> <div><br clear="none"><div><div><div style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);"><div> Does anyone have any experience with pre-charge resistors.</div><div>I am wiring up my Kelly controller & they provide a pre-charge resistor similar to this one.</div><div dir="ltr"><a href="http://www.electricmotorsport.com/wirewound-pre-charge-resistor-5w-10k-ohms.html" target="_blank" rel="nofollow" shape="rect">http://www.electricmotorsport.com/wirewound-pre-charge-resistor-5w-10k-ohms.html</a></div><div>They are put across the terminals on a main power switch so that they charge up the banks</div><div dir="ltr">of capacitors that motor controllers have. Without them there is a large inrush of current to </div><div dir="ltr">the capacitors that can cause arcing to switches & damage to controller components.</div><div dir="ltr">However if you wire it across the power switch there is always some current going to the</div><div dir="ltr">controller. It probably only drives the ON LED on the motor controller, but I am not sure</div><div dir="ltr">of this. I can have another switch or circuit breaker up stream of the main switch, but you</div><div dir="ltr">would have to turn them on in the right sequence. I have heard of circuits that have delays,</div><div dir="ltr">so that when the power switch is turned on, power runs through the pre-charge resistor first.</div><div dir="ltr">Are there marine switches with built in pre- charge circuits?</div><div dir="ltr">Regards Alan<br clear="none"></div><div><br clear="none"></div><div dir="ltr"><br clear="none"></div><div><br clear="none"></div><div><br clear="none"></div><div><br clear="none"></div></div></div></div><br clear="none">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a href="mailto:Personal_Submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" rel="nofollow" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"><br clear="none"><br clear="none"></div> </div> </div> </div></div></div></div><br clear="none">_______________________________________________<br clear="none">
Personal_Submersibles mailing list<br clear="none">
<a href="mailto:Personal_Submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none">
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" rel="nofollow" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none">
<br clear="none"></blockquote></div></div></div><br clear="none"><div>_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a href="mailto:Personal_Submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" rel="nofollow" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div><br clear="none"><br clear="none"></div> </div></div></div> </div> </div></div></div></div><br clear="none">_______________________________________________<br clear="none">
Personal_Submersibles mailing list<br clear="none">
<a href="mailto:Personal_Submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none">
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" rel="nofollow" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none">
<br clear="none"></blockquote></div><br clear="none"></div></div></div><br><div class="yqt5870709497" id="yqt28013">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a href="mailto:Personal_Submersibles@psubs.org" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div><br><br></div> </div> </div> </div></div></body></html>