vtmaps: A question, please.

ILFE

vtmaps wrote: »

Unfortunately, no. Not safe at all. Use a Midnite panel mount circuit breaker... they make great switches and are NRTL listed.

Those rotary battery switches are not listed for use in a home, even if you stay within their ratings.

read: http://www.amplepower.com/primer/burnt_sw/index.html

--vtMaps

I was reading your above reply in another thread. I decided to read the article at the link you posted, and found this early on:

First, if the battery selector is turned off when the alternator is charging, there will be bad consequences. The alternator and alternator regulator are likely to be destroyed, along with other electronics which happen to be turned on at the time. Electrical transient can reach several hundred volts for a few hundred milliseconds ...enough to fry all onboard electrical equipment.

If this is true, why do they have switches with field disconnects on them? I have used these types of battery switches before, with no issues. I have never lost a battery, an alternator, or a dual battery switch connected to my systems. I have had these in boats and Jeeps, in the past.

I will admit, I have never run more than 200 amperes through a dual battery switch. The brand name I used was Guest.

vtmaps

Re: vtmaps: A question, please.

ILFE wrote: »

If this is true, why do they have switches with field disconnects on them? I have used these types of battery switches before, with no issues. I have never lost a battery, an alternator, or a dual battery switch connected to my systems. I have had these in boats and Jeeps, in the past.

The field disconnect turns off the alternator. You don't want to disconnect the battery from the alternator while the alternator is charging the battery unless you first turn off the alternator.

read: http://www.jamestowndistributors.com/userportal/document.do?docId=100

Some companies make battery selector switches to switch from one battery to another. In this case it is important to have a make-before-break switch... in other words: you connect the second battery BEFORE you disconnect the first battery. You don't want the alternator to be unconnected to at least one battery for even a moment.

A make-before-break switch means that for a moment the two batteries are both connected in parallel. This can be stressful on the switch contacts because if the batteries are at different SOC (and therefore different voltage) there can be very high currents on the contacts.

--vtMaps