ak2handr Posted January 23, 2023 Share Posted January 23, 2023 Hiya, all. The chassis battery master is somewhat mechanically sloppy; it can turn from 90° (on) CCW past 0° (off) to about 300°. As I'm having chassis-side electrical issues, (covered in separate post) and I've read that the stock switches are kinda cheesy, I was going to replace at least this switch, and probably the house side as well. I've read references in this forum to Blue Seas Systems switches and have found a couple of vendors. Question: which model have folks here been using? There are switches rated for 300A, 450A, and 600A. The largest rating shows a 30-second crank spec of about 1,760A. My engine is a Cummins 300 ISB, and I don't know how much current the starter should typically demand. . From the 300A version to the 600A is only about $60 difference -- each. I don't mind purchasing the higher-rated unit, but if this engine & related chassis circuits will never draw anywhere near 900A short-term loads, nor over around 300A, I could use those $60 for two or three gallons of diesel ..... So which version do y'all folks (they talk like that here) recommend? Related battery issue follows in separate post. Many thanks & 73, Barney KL7HNY/4 Link to comment Share on other sites More sharing options...
cbr046 Posted January 23, 2023 Share Posted January 23, 2023 While our Endeavor (R8RR chassis, Cummins ISC) is substantially different I'd bet your starter is connected directly to the battery, bypassing the cutoff switch. Hence, engine starting current is irrelevant. I can't comment on how much current runs through the master switches, or which brands are more reliable. But curiosity is killing me . . . . what is the /4 after your call sign? Licensed in zone 7 but operating in zone 4? - bob FWIW WD4BMV Link to comment Share on other sites More sharing options...
HammerGeek Posted January 23, 2023 Share Posted January 23, 2023 Now I'm going to jump in with @cbr046 as I am a retired Navy Submarine communications guy and am curious about your comms background as well. I never got into the HamRadio stuff but always wanted to. Link to comment Share on other sites More sharing options...
Solution Tom Cherry Posted January 23, 2023 Solution Share Posted January 23, 2023 17 hours ago, ak2handr said: Hiya, all. The chassis battery master is somewhat mechanically sloppy; it can turn from 90° (on) CCW past 0° (off) to about 300°. As I'm having chassis-side electrical issues, (covered in separate post) and I've read that the stock switches are kinda cheesy, I was going to replace at least this switch, and probably the house side as well. I've read references in this forum to Blue Seas Systems switches and have found a couple of vendors. Question: which model have folks here been using? There are switches rated for 300A, 450A, and 600A. The largest rating shows a 30-second crank spec of about 1,760A. My engine is a Cummins 300 ISB, and I don't know how much current the starter should typically demand. . From the 300A version to the 600A is only about $60 difference -- each. I don't mind purchasing the higher-rated unit, but if this engine & related chassis circuits will never draw anywhere near 900A short-term loads, nor over around 300A, I could use those $60 for two or three gallons of diesel ..... So which version do y'all folks (they talk like that here) recommend? Related battery issue follows in separate post. Many thanks & 73, Barney KL7HNY/4 OK....first.... The Chassis Switch only turns OFF the Battery. It does NOT carry the actual Starting Current. Look at your prints. You need the Blue Seas 6006. That is the RED one. https://www.bluesea.com/products/6006/m-Series_Mini_On-Off_Battery_Switch_with__Knob_-_Red If you go to Amazon, they are there....but they have different options. in the select box....the top right one. DO NOT GET (you don't need it as you have NOTHING TO HOOK UP) the Dual Circuit. That is for the more sophisticated Dyanasties and above. SO....YES this is the SWITCH. https://www.amazon.com/gp/product/B00445KFZ2/ref=ppx_yo_dt_b_asin_title_o00_s01?ie=UTF8&th=1 Next up. That is the SAME switch to use for the HOUSE. Depending on how your MH is configured and such....you may be able to turn OFF the House Batteries and they will be disconnected from the INVERTER. BUT, some are directly connected and you can't shut them off.....that means that the Inverter is always ON (in Standby...on a Magnum....no matter how many buttons you push.) It is PULLING a parasitic load and will eventually, without the charger on, drain them. Folks say... I TURN 'EM OFF. Well if the switch IS controlling the main power to the batteries and the INVERTER....YES. BUT, if the Inverter is connected (usually through a 300 A Fuse) then, yes, all you are doing is turning off the CHARGER and then the drain continues. SO...it doesn't matter....they were the SAME when new....they need to be the same...not upgraded unless you are planning on running something like a high powered 2,000 winch or such.... You will NEVER need more than the 300 Amp rating. BUY THESE....the SINGLE CIRCUIT and replace one or both. It is THAT SIMPLE.... 1 Link to comment Share on other sites More sharing options...
ak2handr Posted January 23, 2023 Author Share Posted January 23, 2023 7 hours ago, cbr046 said: [Snippage ensueth] But curiosity is killing me . . . . what is the /4 after your call sign? Licensed in zone 7 but operating in zone 4? - bob FWIW WD4BMV WD4BMV de KL7HNY R R FB OM, es tnx fer help. When I left Alaska in 2002 after more than 30 years there, I heard consternation & confusion on hams' voices on VHF/UHF repeaters in San Francisco area, then Spokane, and now NC. I started appending the "/4" here (and /6 in CA, /7 in WA) so as to squelch the idea that I was being heard via Internet linked repeaters, tropo ducting, or just outright magic. And when I'm working DX or popular HF Special Event stations, it *seems* as if the extra second or so after my call to speak "stroke four" functions as a sorta tail-ender call. I frequently hear the station respond with, "The stroke four, go ahead." My other reason is so that some station that needs Alaska for some award doesn't spill his/her/its container of coffee/soda/beer into his/her/its new YaeKenCom rig that just cost them an amount equal to the GDP of several eastern European nations in his/her/its haste to swing their Yagi-Uda towards 60°N, 151°W & load up his/her/its Blastmaster 6000 amp in time to catch me. I've kept current with Da Gummint as I've explored the Lower 48, and am up-to-date on QRZ.com 😉. Amateur radio has been my longest term hobby over the years since my Novice in 1961 as a chubby little 9-yr-old. When I was about 20 I learned I could make a living with a 2nd Phone. Amateur radio was my entry into the world of actually knowing what I was doing at a tower site or screen room at a two-way shop. 73 for now, and thanks for the call. Oh, and the wiring info 🙂 diddly dahdidah dit dit Link to comment Share on other sites More sharing options...
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