charging problem

[bubba_got_you]

[FONT=&quot]Ok all the tm’s for the 5ton are down and I have a charging problem. I know you can’t find the problem for me obviously and that’s not what im looking for. What im looking for are ideas of what to look for. The small wire has 24v with the switch on and with the truck running the gen has the same voltage as the battery but the voltage is not going up. The gauge in the truck shows yellow or less. So I need trouble shooting ideias. [/FONT]

 

[area52]

Put a multi-meter on the batteries to see what the generator is putting out, should be higher than 24 volts ( maybe 27or 28?) to charge the batteries. If it is not higher than 24 volts, I would suspect the generator. or voltage regulator if its separate.

 

[Warthog]

You can get the manuals at JATonka's site.

JATONKAM35s HOME ON THE WEB

Sounds like your alternator died

 

[bubba_got_you]

yes i tested the bats they stay around 24.5 unless i turn on the lights. i tested it continuous for about a minute. thanks warthog but thats where they are not working.

 

[area52]

You tested the batts with the engine running? or off?

If its 24.5 running then its your generator or regulator.

 

[bubba_got_you]

motor on
i was hopping there was something i was not checking

 

[bubba_got_you]

i replaced the gen with what i thought was a good one so i was hopping that was not it

 

[area52]

Do you have an external regulator? Might be bad if you replaced the generator.

 

[bubba_got_you]

it is an internal regulator. i changed out the regulator with a different one (dont know if it is good or not) but it is doing the same thing. so i tried disconnecting the battery wire from the back for the gen and the gen is reading 0.58v but when i put the battery wire back the gen humms and the voltage from the battery goes down from 24.35 to about 24.11.
this makes no sense to me.

 

[Wildchild467]

with it running check to see if there is a voltage between the ground on the generator and the ground on the battery.... it should be close to zero volts... if there is over say 1 volt, i would check all your grounds. my deuce had a loose final fuel filter bracket and that was causing the batterys to not stay charged as they should have been. i put new bolts in and tightened it up and all is happy now. you can also adjust the voltage regulator with a screw driver if you need to. but seeing you put another generator on that might have been good, i would double check all the connections. i cleaned all of mine up and put some oil on all the connections just to prevent corrosion. another thing, make sure you have power at the wire to the generator when the accessory switch is on... this is the excitation wire to get the alt to charge. with no power there the alt wont do anything.

 

[cranetruck]

Here is the M809 series charging system, if it helps...note the action of the polarity protection relay.

 

[ed_watts]

If the battery voltage drops when you hook the "BAT" lead to the [running] generator (alternator), one or more of the diodes in the alternator -- a three-phase, full-wave bridge with six diodes -- is/are shorted. There are three "positive" and three "negative" diodes; they all do the same thing, but three are grounded and three are not. If the diodes are shorted, the battery will generally discharge when the truck is not running.

You might be able to buy the correct diodes to fix it yourself, but they have to be pressed out of and into their heat sinks. It's quicker, less frustrating, and, usually, cheaper to have the alternator repaired by an auto electric rebuilder; many of them can do the larger "truck" stuff as well.