by Michael Packard – Motorcader
The “Boost Switch” is the subject, which we will cover in this issue. What I want to accomplish here is to give you a better understanding of this important feature in your Foretravel motorhome. We have used this for several years, beginning in 1979.
Until 1984, this was a momentary switch that enabled the coach and chassis batteries to both be engaged, to aid in starting the engine when the switch was depressed.
Since then, however, we have designed this as a “charge/boost” switch to function either on momentary or constant. By depressing the switch fully to the left with the light “ON,” the system is constant. What this means is that if 110-volt power is supplied, (generator running or shoreline plugged in) you will be charging all of the batteries. This is accomplished through the power converter.
Conversely, if the switch is turned “OFF” and 110-volt power is supplied, then only the coach battery(s) is charging. When driving, it is not necessary to keep the switch turned “ON” because the alternator will recharge the weaker battery system first and this is accomplished through the battery isolator.
In the event that our alternator would not be charging our chassis battery while driving (due to an alternator failure or the loss of a belt), we can turn the “boost switch” to constant “ON.” Then start the generator and leave it running in order to help recharge the chassis battery until we can correct the alternator situation.
IMPORTANT: Don’t forget to turn the switch “OFF” if you are going to dry camp and NOT be plugged into shore power or have the generator running. The reason for this is that you could discharge the coach AND engine batteries simultaneously with enough 12-volt components operating.
A good practice and habit would be if your batteries have been in a low-state of charge. due to “dry camping” or heavy use, without being plugged into shore power or with the generator running. It is important to plug the coach into shore power or turn the generator on and let it run for several hours. This is due to the fact the alternator for the engine is not really a “battery-charger,” and it can actually harm the batteries and alternator if you begin to get underway with batteries in a low state of charge. Simply by supplying AC power with the boost switch in the “ON” position. it will help to increase the charge-level of both the coach and engine batteries.
The Boost Switch has a tiny bulb that can burn out. That does not mean the Boost switch is not working. It simply means if you are having problems and are not sure, you need to have it checked. It could be just a burned-out bulb.
To replace the bulb for a 2002 and later dash is to get inside the dash and pull the top connector straight off and find the bulb inside. On older coaches you open up the dash and pull the socket out from inside – just a gentle pull does the trick. The bulb number is “NAPA # LMP73” and is a common bulb for turn signals, ashtrays, high beam indicators, etc.
Thus, this important feature can be used effectively to always ensure that we have ample power available whenever we want it. by Michael Packard – Motorcader