Posted: Sun Jan 23, 2011 8:16 am Post subject: charging both batteries at once
What would be the proper way to charge both batteries at the same time? Can I simply connect a pair of jumper cables: POS-POS & NEG-NEG, then attach a 12v charger as with a 12 volt system? I an seriously considering coverting from a 24v to a 12 v system in the future. Is there a good 'sticky' or comprehensive list of items required to perform such a conversion? I'm SURE there's more to it than the obvious... bulbs, generator, regulator, starter/coil/distributor, etc. Thanks for all the great info on this site!!!
Joined: Feb 14, 2006 Posts: 18 Location: the Netherlands
Posted: Sun Jan 23, 2011 10:18 am Post subject: charging both batteries at once
It is better to seperate the 12V batteries to charge, so the cable between the two batteries one pole disconnecting.
What you can do, place a batterie disconnect switch between the batteries and you do a half turn the knob to the left and the disconnection is broken.
Also good to use when the jeep is parking in a garage.(see my pictures)
Regards from the Neterlands, Chris
There is een problem with download the pictures, I try to sent private. [/img]
Last edited by sinrisnekaf on Sun Jan 23, 2011 10:26 am; edited 2 times in total
Joined: Feb 14, 2006 Posts: 18 Location: the Netherlands
Posted: Sun Jan 23, 2011 10:19 am Post subject: Re: charging both batteries at once
sinrisnekaf wrote:
It is better to seperate the 12V batteries to charge, so the cable between the two batteries one pole disconnecting.
What you can do, place a batterie disconnect switch between the batteries and you do a half turn the knob to the left and the disconnection is broken.
Also good to use when the jeep is parking in a garage.(see my pictures)
Regards from the Netherlands, Chris
There is een problem with download the pictures, I try to sent private. [/img]
The proper way is with a 24 volt charger connected as shown below. The alternate methods are also illustrated.
The reason it is preferred to treat them as a matched pair is they are meant to be changed and serviced as a matched pair. Batteries hooked in series will never be a perfect match and it is this slight mis-match that causes the batteries to chase each other down when stored for long periods and connected together in series. The greater the mis-match the greater the rate of discharge chasing and the shorter the battery life.
M38A1 / M170 Note: It is important that when charging with a 12 volt charger you disconnect the precise terminal I pointed out.
M38 Note: It is important that when charging with a 12 volt charger you disconnect the precise terminal I pointed out.
24 volt systems in these jeeps can be a challenge but the jeep's value is increased significantly by retaining the 24 volt system.
If battery run down is an issue and they run down below the ability to start the jeep in less than a month then something is wrong with the jeep. Usually it is current leakage thru the kick starter switch which is notorious for internal corrosion and leakage. A battery disconnect switch will prevent the long term discharge. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Wes... You are right... You "talked me off the 12v conversion ledge" I would like to spend the $ and get a good 24-v maintainer and work to improve the integrity/reliability of my OEM 24v system and components. I looked at the following link to shop for a 24v battery maintainer, but am not sure what Amperage I should be shopping for:
Any thoughts or recommendations... I drive the vehicle only occasionally, and intend to keep it on a bat. maintainer 90% of the time so I can get better starting performance.
Any quality made (prefer US) 2 thru 5 amp with the float function.
The key to enjoying the use of a 24 volt system is having the proper tools and tech data to maintain it. The GI issue harness adapter kit and the TM 9-1825B (Dated 1954) for Auto-Lite equipment and TM 9- 8627 (Dated 1953) for Delco equipment is the minimum. TM 9-1825E (Dated 1952) Bendix equipment helps with the assembly of the connectors and receptacles.
Pin and shell kits and crimpers are also nice to have and a digital VOM is an absolute necessity. A quality 24 volt service charger in the 10 to 15 amp range is more than adequate to charge a dead set of batteries in 3 hours or so enough to get you running. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Nov 16, 2009 Posts: 47 Location: Ridgeland, MS
Posted: Sun Jan 23, 2011 8:45 pm Post subject: Checking for curretn draw?
Wes,
I have the slow batt discharge you mention. I use the 24 v chrager method BTW.
There is a small spark when connecting the ground to battery with all switches OFF. Per your comment suspect the stater? Could possibly the fuel indicator as it jumps around?
Is this trouble shooting in the TM?
Thanks,
Jim
Joined: Jul 05, 2009 Posts: 136 Location: Mooresville, North Carolina
Posted: Sun Jan 23, 2011 9:44 pm Post subject:
I posted a reply on the other site about the battery maintainer - I have used the Battery Minder model 24041 for two years and have it wired in so that hook up is a simple matter plugging it in to the battery circuit. Don't know about other folks, but I like it - Sonny _________________ 1951 M38, 1952 M38, 1952 M100,1946 Bantam T3-C, RT-66/GRC, PP-112/GR, MT-299, DT-44 Mine Detector, MVPA # 33068, PMVPA CO
There are a few troubleshooting pages in the operator's manuals but not enough thoroughness to get all aptitude levels through a serious problem.
The Army manuals are written to be used by a certain group. The operator's manuals were meant for the drivers and as such kept the level of troubleshooting as low as possible. If you look at the manuals geared and written for the upper echelons of maintenance they offer very little troubleshooting info at all. That's because they were written to be used by trained, experienced mechanics.
The place to find detailed troubleshooting info is the Army's mechanic's training syllabus guides. Also the Army TM5- series manuals offered a lot of guidance. Another very handy manual is a mid 50's edition of TM 9-8000 Principles of Automotive Vehicles.
Now back to your problem. If you have the stock military 24 volt system with the 25 amp DC generator and the old mechanical voltage regulator it is common to get a spark when you disconnect the regulator but it is not common to get a spark when you connect the regulator. When you disconnect the regulator the spark you see is caused by the radio noise filter (capacitor) discharging. When you see a spark connecting the regulator that indicates there is now a current draw somewhere in your jeep. If all the switches are off then you have a problem.
This is an ancient problem and is usually troubleshot the same way on just about all vehicle electrical systems. You disconnect the battery ground cable that is actually fastened to the frame at that battery's negative terminal. Now you connect a 24 volt test lamp to the end of the cable you disconnected and the other lead of the test lamp you connect to the battery's negative terminal. With all switches off and the lamp does not glow then you have no current draw. If the lamp glows (even dimly) you have a problem with a current draw. To find the culprit you must isolate one circuit at a time and when the lamp goes out you have located the bad circuit. With stock M series vehicles the culprit is usually a deteriorated, corroded and burnt contact inside the kick start switch on top of the starter. Common sense says disconnect the switch and let's see if the lamp goes out. Now here's where you should have remembered to have the wiring diagram in front of you. There are two wires on the switch terminal. The fat one (wire #82) from the battery and a thinner one (wire #4) that goes to the regulator. If you disconnect both then you are actually removing power from the entire jeep's electrical system. Your test lamp would go out and you would assume you need a new switch. Wrong assumption. You must keep the fat wire #82 and the skinny wire #4 fastened to each other and insulated or protected from grounding out on anything. Now if you lamp goes out the starter switch is bad. If the lamp is still on the starter switch is good and the problem lies elsewhere. So now you connect the two wires #82 and #4 back to the switch. Now go to the voltage regulator and remove the connector that does not go to the generator. If the lamp goes out the regulator probably has a problem. To be sure you must insert a small jumper wire across the two pins in the plug from wire #4 and Wire # 10. If the lamp is out the regulator does have a problem. If the lamp stays on the jeep's electrical system has a problem. Now follow wire # 10 up under the dash. You will have to disconnect one circuit at a time from wire #10 to determine where the culprit is. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Has anyone tried making a 'slave cable' plug-type adapter to hook their 24v battery maintainer to? I think I would like to use that feature, unless there is some reason that it would not be advisable to do so...Thoughts?
It would be easier to use the radio power plug at the right side of the passenger seat.
Personally I would mount the charger/maintainer under the glove box out of site and run it's positive lead to the cowl battery positive and it's negative lead to a firewall ground. Keeps the whole shebang out of site. There are several options for routing the AC plug. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
I don't have the radio power plug. I soldered wires to 3/8" copper tube and taped with electrical tape two short pieces about 2" long. I plug them into the slave receptacle and connet them to the 24volt maintainer. Of coarse it something that has to be unpluged and removed when using the jeep. _________________ Tropical Veteran
35th Inf. Reg. "CACTI" 4th I.D. VN
Amateur Radio K5XOM
Joined: Aug 11, 2014 Posts: 12 Location: Montreal Canada
Posted: Sun Nov 30, 2014 9:34 am Post subject:
Hello Wes you talk about a pic of how to charge a batterie .... i cant see it would you be so nice to repost the image
thank again
Gilles _________________ M38a1 1967
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[/img]
!! I wish you lived near Me!
would you be so nice to repost the image
