Tracking down a mystery drain

[Koobearpig]

I have a 2003 Thomas e450 5 window with a handicap lift. I didnt start it for 3 months so.it died. I have been charging the batteries and when I turn the ignition on it immediately drops to 8.5 volts. I've charged both batteries to 12 volts. Also the solenoid picture clicks on amd continues to buzz until the batteries are completely drained. Do I just have a bad solenoid? Also i pulled each fuse individually to see if one of them would stop the draw. I have a 75 amp jump box and cant get the motor to turn over even on jump start mode.

[mmoore6856]

load test the batteries

[Koobearpig]

That's was my next step to take them in to get tested but should that solenoid be acting that way

[magnakansas]

8.2 volts is not enough..... your engine battery system should be around 10volts at the lowest when cranking the engine. I dont know that you have a drain with out testing. but I know you dont have the voltage needed to get the job done.

william

[magnakansas]

Imagine this, the voltage hits the solenoid, solenoid activates, then more power is used through the solenoid, that causes voltage to drop and the solenoid deactivates, now the solenoid is deactivated, voltage goes back up, now we have enough voltage to activate the solenoid turn on, power flows, voltage drops again, solenoid deactive again... over and over and over...

the result is a solenoid buzzing, because it is on and off quick enough

yes solenoid could be bad, but start with fresh batteries that are capable of supporting the loads and test from there.


william

[john61ct]

Install a master switch, so when not being used, the battery is 100% isolated, otherwise will murder the new one too.

For good longevity even then, top up every few weeks, even quality lead self-discharges pretty quickly.

[Koobearpig]

Yeah I'm looking to put a switch on the main battery and the second one underneath for safety when I travel and or deploy. Batteries are getting tested right now I will let you all know what happens thanks for the info everyone

[john61ct]

Get a wattmeter that shows Ah drain per 24hrs, and you will see which parasites are causing the problem.

[Danjo]

Does it have two batteries? If it does, if one has a bad cell it can draw down the other in no time. Also, you can use a multimeter to do a parasitic draw test.

https://m.youtube.com/watch?v=KF1gijj03_0

[mmoore6856]

the batteries could be so bad that they wont jump start. when they are this bad they can explode if trying to jump start. all newer engines have a parasitic draw as the computer needs to remember its parameters. by using a shutoff switch you make it relearn these parameters every time you start it . sometimes it will run rough while doing this. a better idea would be a battery maintainer or starting it every 2 weeks

[mmoore6856]

do not waste your time on anything until you load test

[john61ct]

Your main valuable battery can be isolated, and the ECU programming and radio presets maintained with a cheap throwaway one, or one whose life is not shortened by sitting at PSOC.

As soon as the new battery is installed, do not procrastinate solving the problem, or you're just throwing good money away after bad.