Thanks guys! I have a bag of in rush current limiters from many years ago that I never used and I like the halogen bulb idea. I have 400ah cells (4.8kwh) in our RV with 1kw solar and another 10kwh in our truck that I want to connect for more capacity. Trying to avoid sparks and melting and all that stuff. Since both are capable of very high current I am not sure what to expect when connecting at opposite SOC. On Jun 5, 2016 10:41 PM, "Mike Nickerson via EV" <ev@lists.evdl.org> wrote:
> Hi Lee, > > I don't think that is how in rush current limiters work. I use them to > protect my DC-DC converter caps so they don't get whacked with a high in > rush current when the connection is first made. > > https://en.m.wikipedia.org/wiki/Inrush_current_limiter > > Mike > > On June 5, 2016 10:19:55 PM MDT, Lee Hart via EV <ev@lists.evdl.org> > wrote: > >Mike Nickerson via EV wrote: > >> If the long term current draw will be less than 10A or so, you could > >use an in rush limiting resistor. That is a resistor with a negative > >temperature coefficient. When cool, they have a very high resistance. > >As they heat up, their resistance drops. > > > >This is probably the opposite of the function Gary wants. Inrush > >limiters have a very LOW resistance initially, so the peak current when > > > >you first connect the batteries is very high. As the inrush limiter > >heats up, its resistance rises -- so you wind up with quite a limited > >amount of current between them. > > > >Gary Krysztopik wrote: > >>> Does anyone have any cheap tricks for regularly connecting two large > >12 > >>> vdc packs together (one stationary and one mobile) and limiting > >inrush > >>> current when they are at different SOC? They both have huge current > >>> capability but I need it for energy vs power so one has small wires > >and > >>> fuses. > > > >The "cheap trick" is to connect a light bulb between them. Pick the > >bulb > >so your normal current is well below what the bulb normally draws on > >12v. For example, a #57 brake light draws about an amp, and a headlight > > > >about 4 amps, and a halogen spotlight around 10 amps. > > > >The bulb won't allow more than its normal rated current to flow between > > > >the batteries. If you try, it just lights up. But when the current is > >less than this (such as while on standby), the bulb's resistance is > >LOW. > >The bulb is out, and the two batteries are essentially connected in > >parallel for float charging, etc. > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20160606/f63eda4f/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
