[Repeater-Builder] Re: Kenwood battery back-up
> WHAT excellent battery backup provisions? It's a simple > changeover circuit, and the Kenwood internal trickle > charger is a joke. Actually it works pretty well for what it is and claims to be... a battery trickle charger. > >with a Wal-Mart marine battery. > You'll be sorry. A marine battery is a just a starting > battery - a variation on an automotive battery. You want > a true deep cycle battery (think "golf cart"). At typical x-times the cost of a standard auto battery... I buy auto batteries and replace them after a few years of operation working well or not. Much more cost effective for the budget minded operator... and much better than having no battery backup and the dollar value is very good. > So the battery lasts half as long (powering both repeaters) > and takes twice as long to recharge (being charged by one). An added low voltage disconnect is a great idea. Even a single battery for short term back up is better than none. In a generator backed location it's often more than enough. There would be no reason he couldn't enable both repeater trickle charge circuits but the addition of a proper size single diode and resistor will help more quickly bring the battery back up to near full charge. > Float the battery across a good high quality after-market > charger that is designed to keep a standby battery alive, > and maximize the life. Look at those sold for RVs and for > standby generators. > > Warning - a GOOD charger will not be cheap. > > Then run the repeaters as 12v loads. Don't even hook up > the AC power to them. Run the controller off the battery > as well. Works as described but does cost much more money. If you already have a typical dc power supply there's no reason you can't use it with the internal Kenwood circuit. If rapid recharge of a drained battery is a major concern... add a properly sized series diode and resistor and get on with enjoying the new equipment. cheers, s.
[Repeater-Builder] Re: Kenwood battery back-up
> Our club has recently acquired a TKR-750 and a TKR-850, > to replace an aging hodgepodge of repeater components. > Both the TKR's are co-located and share a Link RLC controller. > We want to use the excellent battery-backup provisions of > the TKR's, with a Wal-Mart marine battery. We plan to connect > the one battery to both repeaters' battery ports in parallel, but > activate the charging jumper on only one repeater. > I guess we just want reassurance that there are no problems > with this arrangment; any comments will be appreciated! There shouldn't be any problems but you might want to consider some type of low voltage disconnect to ensure the equipment doesn't drain the battery down to an early death when the power fails (goes away) for extended periods of time. The selection and addition of a proper size diode and resistor from your power supply + terminal to the battery (direct) (+ terminal) will help more quickly recharge the battery from a depleted condition (versus trusting the trickle charge internal to the Kenwood Repeaters). The diode to prevent reverse current flow and the resistor to limit the charging current to a safe value (for the power supply capacity while still operating the repeater). The wrong selection of the resistor or direct diode to power supply wiring can kill or disable the power supply... so a little thought is required (and advise available upon request). Remember (a big deal) The Low Voltage Disconnect will save your bacon... (battery wise). cheers, s.
