The practical effect is that the charge on the two batteries will be imbalanced, and should the charger ever get the more charge battery fully charged, the under charged battery will fool the charger into thinking the pair is not fully charged, resulting the in the fully charged battery being overcharged, and if not quickly damaged, then at least dramatically reduced in lifetime.
Some sort of converter is required to keep the load balanced across both batteries, and therefore the charge on the batteries balanced.. whether it be Xantrex or Astron. either will do the job and protect your batteries. _____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright Sent: Tuesday, March 25, 2008 6:04 AM To: [email protected] Subject: Re: [Repeater-Builder] Re: 24 vdc to 12 vdc Depending on the load connecting across one battery, the one connected to ground or the lower of the 2 12 batteries, will work. I would not do is load is heavy because I am sure the charging system is for both batteries and draining one much more than the other could upset things. Kirchhoff's current law says the sum of the currents will be zero. Kirchhoff's voltage law says sum of voltages will be zero. Not sure why revelant here, but I am sure Kirchhoff had something else to do with voltage and current sources. Would like to know. 73, ron, n9ee/r >From: Al Wolfe <[EMAIL PROTECTED] <mailto:k9si%40arrl.net> > >Date: 2008/03/24 Mon PM 04:36:54 CDT >To: Repeater-Builder@ <mailto:Repeater-Builder%40yahoogroups.com> yahoogroups.com >Subject: [Repeater-Builder] Re: 24 vdc to 12 vdc > >>This is a very common issue in aircraft. The most obvious question is >>does your jeep use 2 each 12 volt batteries? If so, simply connect >>your radio across one of 'em. > >This is done all the time but is a very, very bad idea. Ever hear of >Kirchhoff's law? Check it out. It's a very quick way to ruin two batteries. > >Get a real converter. The switching kind are much more efficient than the >linear voltage dropping kind. > >Al, K9SI > > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
