Keeping ones starting battery charged.

Desert Captain wrote:
Once again I just don't get it. I think a lot of folks are searching for a solution for which there is no known problem.

How can keeping your starting battery charged be a problem? Unless you have a failure of the engines charging system a starting battery can sit for weeks without losing its ability to start the engine. Drive a few miles and you are back to square one. Even if the starting battery did die, say you left your headlights on, most motorhomes come with an emergency start switch that allows you to tap into the house bank to boost the starting battery back into full operation.

It is a problem.

Perhaps you don't understand issues with RV batteries including parasitic battery drains and charging. Parasitic drains are battery drains that occur even when the RV is sitting and not being used. These may include gas detectors, refrigerators, radios with clocks, TVs, etc. Even many RV's with house battery disconnect switches, don't disconnect everything.

There can be parasitic drains to both the chassis and house batteries. Sometimes house batteries are dead in a week of sitting due solely to parasitic drains. So if both sets of batteries are dead, the emergency switch isn't going to be helpful.

Also, driving a few miles isn't going to fully recharge any battery. It takes 4-6 hours to recharge my house battery on a 20amp portable charger. Granted, a RV alternator is going to be putting out more amps, but it still isn't going to be enough to recharge the batteries in a few miles--more like a few hours of driving. Also, charging at a lower amp rate is better for your batteries.

Another point--chassis batteries are generally not deep cycle and thus they are easily damaged by discharging. So, just because they can be recharged doesn't mean that you shouldn't be concerned about them being discharged. Even a couple of discharges could permanently damage the battery.

Although the Trik-L-Start works, it isn't an ideal solution. From their website:

HOW DOES TRIK-L-START™ WORK? TRIK-L-START™ is a "diversion charger" - Basically, it "steals" a little bit of current from your house battery charger, diverting it to keep your engine starting battery(s) charged.

So, the Trik-L-Start only charges the chassis battery when the house battery is getting charged. This would work best when the house battery discharges at a greater rate than the chassis battery (which, granted, is probably the most common). So, when the chassis battery is run down and the house battery isn't, it could take quite some time for the chassis battery to recharge--perhaps several days.

Proper battery charging is complicated. Ideally, each battery bank should be charged with a 3-stage smart charger. These chargers customize the charge depending on the state of the battery bank and possibly on the type of battery (starting or deep-cycle).

So, the Trik-L-Start isn't going to perform as well as independent 3-stage chargers for both the chassis and house batteries would. However, as is evidenced by other posts here, it is working well enough for many folks.

For more detailed info see:

BATTERIES--AND OTHER ELECTRIC STUFF


The 12v Side of Life