After reading the other thread about starter wiring/disconnect switch location I want to start a new topic covering the type of disconnects available four our applications. I would like to know what type of disconnects are rated for bus use and what might be the "ideal" set-up. I just replaced the batteries in the bus and need to install a disconnect of some sort.
Here is one rated at 400 amps continuous and 2000 amps starting. I think this is the one MCI uses.
http://www.delcity.net/store/Heavy-Duty-Disconnect-Switch/p_4873.a_1 (http://www.delcity.net/store/Heavy-Duty-Disconnect-Switch/p_4873.a_1)
Or this one with alternator field switch included
http://www.delcity.net/store/Extra-Heavy!duty-On:Off-Diesel-Switch/p_789172.a_1 (http://www.delcity.net/store/Extra-Heavy!duty-On:Off-Diesel-Switch/p_789172.a_1)
Further along the disconnect subject, would you think a battery charger should go directly to the batteries or through the disconnect?
I bought a switch from these folks:
http://shop.pkys.com/batteryswitches.aspx (http://shop.pkys.com/batteryswitches.aspx)
Remember to have a fuse rated lower than your switch so the fuse will blow before the switch welds itself together. Just in case.
Jerry
Cat has the best switches for 50 bucks not your made in China junk
good luck
Quote from: Lin on June 07, 2010, 08:19:23 AM
Further along the disconnect subject, would you think a battery charger should go directly to the batteries or through the disconnect?
This is one of those questions that does not have an easy answer. Just as whether the alternator should be connected before or after the switch became a somewhat contentious discussion in the other thread, the location of charging sources in general needs to be well thought out.
Disconnect switches can serve several functions, and which or how many of those distinct purposes you have in mind will have a bearing on the decision. Also, the make, model, and type of charger might have a bearing -- some chargers are not designed for full-time connection, and can actually draw a small amount of current from the batteries when not in charge mode.
Here are some pros and cons:
Connecting charger directly to batteries:
- Allows charging of the batteries even when loads are disconnected. For long term storage batteries will need to be charged periodically due to self-discharge.
- Precludes charger from energizing the loads without the buffer of an attached battery.
- Requires the batteries to be physically disconnected in order to work on the charger and any wiring between them.
- Can accelerate depletion rate in storage with low-quality chargers.
Connecting charger across the disconnect from the batteries:
- Ensures that the disconnect switch completely de-energizes all wiring, so long as the charger is not running.
- Eliminates the charger itself as a potential source of discharge (for example, any meters or battery status indicators on the charger will now be disconnected).
- Means the disconnect must be closed to charge the batteries (or an external charger must be used).
- Creates the possibility that the charger, if energized, may power up the loads without the benefit of a battery in the circuit; with some chargers, this can damage the load and/or the charger.
Many folks will be using a charger that is built-in as part of an inverter, and in this case it is more clear-cut. Because the inverter/charger is a load as well as a charge source, it should be across the disconnect from the batteries. Many inverters, to avoid exactly the situation I described earlier, will not energize, even if 120vac is available, unless battery voltage is present on the DC side.
Lastly, I will reiterate my assertion from the other thread: if the "charger" is actually an alternator, whether it is being driven by the main engine or by its own pony motor ("DC generator" setup), it is recommended to connect it on the battery side of the disconnect to reduce the chance of alternator damage.
Hope that helps with your decision.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
There are several choices for charging and each has it's own need I use Solar panel to charge so have a seperate switch to connect to any of the battery banks. The engine driven Generator is on line once the main didconnect is closed. and I have and AC charger that puts out 24 volts so I can elect when to connect it up too. Jerry