H3-45 batteries dead. Help?

Seangie · January 12, 2015, 02:06:03 AM

If you have a plug in the back keep in mind it may be for an engine block heater and not for a battery charger. I'd spend a few minutes and see where the plug is coming from. If it goes to the engine block then its a block heater.

-Sean

luvrbus · January 12, 2015, 06:54:20 AM

If it is located by the battery box on a H - Prevost it will be the charger

kemo3ce · January 12, 2015, 05:26:42 PM

ok just got back from out of town.. i got the batteries charged still haven't put them in yet.. here what i got, the plug on the back goes to a black box inside the battery compartment. then out of there a red and black wire come up to the jump posts on the side of the wall.. then from there cables run to the batteries. heres my idea, i want to disconnect the wires that run to the batteries so the cables that come from the black box die on the posts i want to then plug in the ac extension and see what i can read with a multimeter on the posts.. my question, what should it read? 24v 12V or what would i be looking for? thanks for all the help guys if this works its bonn solve this problem from ever happening again.. i also talked to provost.(nice guys) they said that there are 2 master switches... one thats a switch like a blade he said and another thats like a knob... the blade cuts lights and main things but the knob cuts the batteries from the bus.. does anyone know about that?

Ace · January 12, 2015, 05:48:32 PM

My guess is the leads coming from the black box are 24v and if properly charged the reading should 27v or close.

As for the switches? One is your 12v feed and one is your 24v feed that actually starts the bus. All your lights and accessories are 12v. The bus starts on 24v
Keep in mind that even turning off the switches, there is still going to be current flowing from your batteries to items like your vanner and your ecm because they are hard wired directly to the batteries!

luvrbus · January 12, 2015, 06:18:50 PM

It does have 2 switches but they are hooked up in series with both turned off you will still have power to the Ecm,Ecu,vanner,and if you have preheater it will have power along with the recirculating pump and I believe the door and the sound systems will still have power I check the voltage at the cut off switch

eagle19952 · January 12, 2015, 09:42:45 PM

I guess I'll say it again...

a DC clamp on meter at the batttery will better tell you if there is a draw....with and without the master on/off.

There are techniques to make any amp meter read down to milliamps.

This will tell you how much draw is on the batteries with the switches off....and it will tell yo how much the charger is charging...knowing the voltage is only half of what you need to know....

Tony LEE · January 13, 2015, 03:27:00 AM

Quote from: eagle19952 on January 12, 2015, 09:42:45 PM
I guess I'll say it again...

a DC clamp on meter at the batttery will better tell you if there is a draw....with and without the master on/off.

There are techniques to make any amp meter read down to milliamps.

This will tell you how much draw is on the batteries with the switches off....and it will tell yo how much the charger is charging...knowing the voltage is only half of what you need to know....

Perhaps to assist the OP, who may not have the experience and knowledge to use your advice, could you provide some links to a DC clamp meter that will read milliamp currents in large battery leads. Also links to the techniques for increasing the sensitivity of less sensitive clamp testers, particularly those with zero reading errors that aren't able to be eliminated and how you would implement that in a typical starting battery system..

blue_goose · January 13, 2015, 04:47:45 AM

Most clamp meters only read AC amps. You need to make sure you are using a DC clamp meter.
With the battery connected and the charger plugged in you will have 27 to 28 volts when the batteries are charged. If you turn the charger off you will see a drop in voltage. If you get the drop in voltage don't worry about anything else the charger is working.
Jack

The test for voltage is made with at DC volt meter. You don't need a clamp meter to make this test. See what Ace said below.

Ace · January 13, 2015, 05:29:54 AM

I simply use my greenleigh volt meter! 😊

eagle19952 · January 13, 2015, 05:50:31 AM

http://www.amazon.com/MASTECH-MS2108A-Current-Clamp-Meter/dp/B009CNYJG2/ref=sr_1_1?s=industrial&ie=UTF8&qid=1421157521&sr=1-1&keywords=dc+amp+meter&pebp=1421157524218&peasin=B009CNYJG2

a technique often used is to take one lead of your circuit and wrap several turns of wire around one of the legs of the meter. For example if you wrap 10 turns of wire then the meter reading will be 10 times the actual current. So a reading of .500 amp would show for an actual current of. 050 amp. If you need a better reading use 20, 30 or 40 turns or more. Then just divide the reading on the meter by the number of turns. Most high sensitivity current probes use this technique.

eagle19952 · January 13, 2015, 06:07:31 AM

google is your friend.... dc parasitic load test.

http://www.w8ji.com/battery_and_charging_system.htm

Boomer · January 13, 2015, 07:50:17 AM

You should have two master switches; one on the dash and a toggle in the battery compartment. There is no knife switch on your model unless someone added one. Sounds like you need to break out your manual.

luvrbus · January 13, 2015, 08:14:42 AM

Mine works off relays 12/24 V there is no blade switch, he can download the manual from Prevost free with the vin number

kemo3ce · January 13, 2015, 11:30:38 AM

Thanks guys for the help and I'm sorry i wasn't clear on my earlier post.. the plug that i was referring to is an AC plug thats outside of the bus.. the wire runs to a black box next to the batteries.. my question was how do i check it to see if that box is working.. i finally got time to go out there today its a vanner 3 stage battery charger has three LEDS one over temp one bulk and one float.. i would like to know how to find out if it work.. i disconnected the cables from the unit so it isn't going anywhere.. current wise.. but i can't get a reading on my multimeter my guess is it need the battery to start going?? but the light does blink... green float one.. gonna put in the batteries around 3 o clock.. although one of them might be bad... which is why I'm going to wait until 3 to see if it says its ok... let me see if i can load pics

https://www.dropbox.com/sh/qbvcusdb24z7y6s/AACKUNG9jsHJsbV_z4ZRKUQ9a?dl=0

luvrbus · January 13, 2015, 11:46:04 AM

You need to have battery power if it doesn't sense 18 volts it won't charge at least mine will not,if the green light blinks you have a wire that is not connected or no power that is a 42 amp charger @ 24v it will do the job so the reading will be around 28 volts.
Is the remote readout no longer there or maybe it wasn't there to begin with some have one some don't