Baffeling Batteries.

Chaz · August 24, 2009, 10:32:34 AM

Hey guys,
A couple months ago I bought a couple new start batteries (not 8D's but I think you call them 30's ?) for my 4108 and I went to start her and they were basically dead (4 and 7 volts). There is a large disconnect switch above the batteries that I always throw, and it was off, but the batteries were down. How can that be?

Thanx,
Chaz

DaveG · August 24, 2009, 11:03:55 AM

You may want to start by checking the water level in your batts and fully charging them...disconnect at least one of the cables to each battery.

One of two things are going on here...1) you have something else still connected to the system electrically that is causing a draw on the battery/batteries...or 2) you have a couple of bad batteries.

One bad battery I could see, both...I dunno...

lostagain · August 24, 2009, 11:42:12 AM

Same happens with the hockey team's bus. I know of at least the Webasto timer that stays on with the main batt. switch off. They might be other fantom loads that I don't know of... If it is parked for more than a few days, I take the cables right off the batts.

I don't have that problem with my converted Courier 96, because of the solar panels keeping the batts. charged all the time.

JC

Chaz · August 24, 2009, 03:14:49 PM

Thanx guys,
The bats are basically brand new - only a couple months old. They are also maintenance free so I'm not sure about prying them open.

The main power cable is the only thing connected to them and that goes thru the main cut off switch. This one has me stumped.

Altho when you turn the switch off everything goes off but could there some how be some sort of draw thru it somehow?? I'm grasping for straws here.

Chaz

Sojourner · August 24, 2009, 03:57:24 PM

Do a drainage test. Remove a battery cable from the battery. Measure voltage drain between cable end and battery post. It should never be over point 5 (analog) volts for 12v system. Double that for 24v system.
Otherwise you do have a bad drainage problem.

Sojourn for Christ, Gerald

Chaz · August 24, 2009, 05:28:51 PM

Thanx Gerald. I may do that for the heck of it but I am pretty sure I found the problem. It is in that disconnect. I measured with it on and off a few times and got different readings sometimes a full 24v when it was supposed to be off. Time for a new switch I guess. But it still seems odd.
Do you guys think the little green knob disconnects would be ok for now?? I want to eventually connect the house and start batteries with a remote disconnect. I just ned to "get off the pot" and do it.
Thanx for the help and suggestions!
Chaz

JackConrad · August 24, 2009, 06:05:56 PM

Make sure the little green knobs are rated for the amount of amps required by the starter. I think around 900-1000 amps? Jack

DaveG · August 24, 2009, 06:36:22 PM

Good point.

Chaz · August 24, 2009, 06:54:03 PM

Thanx Jack. I will tear into the old disconnect to see if I have what it takes to maybe rectify the problem first.

If not............. plan B. And I'm glad you mentioned what to size it for.

I did like that disconnect tho. But...........I have been thinking...... (scarey) .............that maybe I might as well do a remote disconnect from the drivers seat while I'm at it. Any suggestions on how to do that or better yet, what to use?? I might get up to the new millennium yet!

Later,
Chaz

pvcces · August 24, 2009, 07:49:22 PM

Chaz, those little green knob switches that I have seen are pretty light duty. They will handle surges pretty well but they overheat when runnin any serious current through them for a while.

Tom Caffrey

buswarrior · August 24, 2009, 08:27:21 PM

take note of lostagain's post, busnuts of the future...

The battery disconnect doesn't always disconnect the batteries.

All manner of new equipment, both highway and transit, does not go completely dead when the "battery switch" is turned off.

With the temperature hovering somewhere south of 0 degrees Fahrenheit, (or is that north of?) I do not sleep well knowing a wonky coolant furnace can drain my coach batteries while I sleep, battery switch position being irrelevant, preventing me from delivering the service that has been paid for in the morning. I'm old school, and pull the coach battery switch when on an away charter. Trouble is, I'm not "pulling the battery switch" anymore. There's still stuff connected!

With the age and condition of the systems that a busnut inherits, and our long periods of vehicle inactivity, a reliable method of cutting the power to all parts of the coach in a single switch might be critical for stopping an electrical fire at worst, and confirming good batteries when we return to start up the coach after an extended parking at best.

The coach is ours, and we may wire it as we see fit.

I expect this will become a standard busnut "adjustment" in the years to come.

happy coaching!
buswarrior

luvrbus · August 24, 2009, 08:29:53 PM

Chaz, The Cat equipment have a nice disconnet switch that will handle high amps the last one I bought was around 30 bucks I don't know what it will cost today good luck

Chaz · August 25, 2009, 06:55:50 AM

Thanx luvrbus. I will be looking around for a good remote switch and I would not have thought to look there. My battery disconnect is on the only wire/cable that comes from my battery. So unless my batteries can discharge thru the case they should stay up.
I think I will steer clear of the "little green things".

Thanx guys,
Chaz

Sojourner · August 25, 2009, 08:06:29 AM

Chaz...For information...if the main disconnect cutoff switch is fried around the contact (inter) post even though it still starts engine, it will drain battery because of the burned plastic is now carbon which is no longer insulated.

Weak or dirty switch will do that as well eating away the contact's posts.

Sojourn for Christ, Gerald

BTW...to have a peace in mind about the battery holding charge is to disconnect both pos & neg cables from the bat. Next morning, compare voltage reading to the day before.

belfert · August 25, 2009, 09:40:14 AM

My coach is a 1995 and the battery disconnect certainly does not disconnect all drain on the battery. Some items like the radio, overhead clock, DDEC, and other items have their own connections to the battery bypasasing the main battery cable.

In the winter I have to use a Battery Tender or charge the batteries periodically so they don't go dead and ruin the batteries. Batteries hold their charge much better in the summer and I start the vehicle more during the summer.