Battery Question

[Kit_Carson]

I hope this is the right place to post this question. My C has two batteries in parallel for the "house". I want to install a Battery Tender while in storage. The decal says to disconnect the batteries before using an outside charger. If I take off the main neg. and the main positive and leave the other cables intact as they are do I hook up the BT in place of the main cables? Any help will be appreciated.

[Bordercollie]

If you have 110volt "shore power" available where you store the rig, you might want to install a Trik-L-Start device that will keep the house batteries plus your engine starting battery fully charged. Most rigs have no provision for keeping the starting battery charged when connected to shore power.

Clarification: The Trik-L-Start device actually steals a little charging current from from the converter/charger and the house batteries and feeds it to the starting battery when you are connected to shore power.

[rehoppe]

You might want to check the specs on your power supply. It may have a 'charge maintenance' mode/level, that does the job of the tenders.

I replaced the power supply in my old 2000, when it went out. The now supply has the mode in it already.

Took the double ended cigar/power supply jumper from my portable air pump. Plugged it into the dashboard, and the socket in the 'house'. I just leave the coach plugged in all winter. Batteries (all three) stay charged, and the computer doesn't loose it's mind either. Win Win.

IIRC the supply was only $175 or so 'delivered'. But that's been a couple years ago now... The better news is that I haven't had to refill the batteries since, so they're not being overcharged.

[Kit_Carson]

DrewE, that is exactly the info I was looking for. I really appreciate you posting. I am familiar with the negative being first off and last on. I taught that to my two sons and now one of my grandsons. Thanks again...

[DrewE]

Leaving the two batteries interconnected is fine for the battery tender.

You only need to disconnect either the positive or the ground from the rest of the motorhome to isolate the batteries; it's not necessary to do both. Generally, the ground is the one to disconnect/disconnect first so that any accidental short from the positive to the frame won't cause a short circuit and the associated headaches. (This is particularly the case when installing or removing batteries and working with wrenches etc. on the terminals. Disconnect the ground first and connect it last.)

[Kit_Carson]

Thanks for the replies. I guess what I am trying to ask is if I disconnect the main cables but leave the connecting cables (parallel)hooked up and hook up the battery tender to the main post will the BT charge both batteries as one? I think it will but just trying to be sure. Don't want to mess up anything including the two new batteries.

[Oldme]

Note:
As I referred to above:
Parasitic Draw is always a problem.
Many Class C RVs tie, steps and the step monitors, O2 monitors
and other alarms to the Chassis Battery.
You would think house battery.

Good link here.

http://www.flashoffroad.com/electrical/Batteries/BatteryDrain.html

[Coach-man]

The problem with the factory battery disconect switches, even with them off, many items are still powered, steps, CO2 detector, Propane detector, etc.. If you want to, install a disconect switch leading from the negative terminal to ground. A marine type switch is my favorite, this way everything IS disconected. Only draw back, make sure your steps are stowed before turning the switch!

[Oldme]

Most Class C will also charge from the alternator.
What I did 3 years ago was buy a battery tender
that had a plug on the end that went into the
dash power outlet.

It has kept my 2 coach batteries and the starter battery
(Parasitic Draw is always a problem) charged and ready,
without problems.
http://www.flashoffroad.com/electrical/Batteries/BatteryDrain.html

A good diagram of RV electrical:
http://www.metrotrekkers.org/utility/electrical.htm

You should have a battery disconnect as in the diagram above.
If you are only concerned about the coach batteries you
should be able to disconnect them from the circuit.

Use the interactive functions in the diagram to see how the
system works at various times.

Hope this helps.