Battery Charger wires getting hot. at battery terminals

Link

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Has anyone had this happen before?<br />I haven't used the charger in a couple years and it never did this before.<br /><br />I'm pretty sure this is a common sense type problem and answer.<br /><br />The cause would be that the clamps are only crimped on and corrosion may have set in. (even though it doesnt look like it)<br /><br />The solution would be to cut the wires back a couple inches as needed, then clean everything and solder on.<br /><br />Any thoughts?
 

eurolarva

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Re: Battery Charger wires getting hot. at battery terminals

I have had this happen before. The problem for me was the battery was old and the charger wasnt very well regulated. I was charging on 10 amp setting and the battery wasnt taking a charge very well. I would look at the battery instead of the charger. Wait a couple of days after you charge it. Use a volt meter on the battery. If voltage is under 12.4 volts the battery is probably bad
 

rc581

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Re: Battery Charger wires getting hot. at battery terminals

link, i think your on the right track, either corrosion, or possibly not enough tension on your clips. possibly a btry problem, but i would suspect the charger leads. good luck.....bob
 

LubeDude

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Re: Battery Charger wires getting hot. at battery terminals

I vote for a bad battery. Been there, done that!!
 

roscoe

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Re: Battery Charger wires getting hot. at battery terminals

Bad battery. Current is running thru it, thus heating up the wire/clamps.<br /><br />If it was bad connection/corrosion, current would not flow, and the wires would not get hot.
 

dogsdad

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Re: Battery Charger wires getting hot. at battery terminals

Any of the answers could be correct, as far as what is causing the problem goes. <br /><br />But, I will clarify one point: in a circuit with current flowing, heat is a product of resistance. If ever heat is detected and determined to be originating AT the connection itself, then the connection is not good. In this instance it could be that the entire battery is getting hot, in which case it may be a faulty battery. But if it's just at the point of connection, I would try cleaning the point of contact. Also, make sure that the charger clamps are well connected to the cables themselves. Broken wires or a bad connection there will cause heat dissipation. And you are on the right track looking at the battery clamps and cables as well.<br /><br /><br />-dd-
 

Pascal

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Re: Battery Charger wires getting hot. at battery terminals

Link<br /><br />I believe you are right about the charger clamps.<br /><br />current flow through a resistance causes heat. If the current and resistance are just right, you got a light bulb.<br /><br />OTOH on open circuit = infinite resistance = 0 current flow = 0 heat<br /><br />low battery state of charge allows a higher charge rate and with the resistance at the clamp you get the heat at the poor connection .....<br /><br />12.6 volts on a battery (after you remove the surface charge) is fully charged. 12.4 is 75% charge.
 

eurolarva

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Re: Battery Charger wires getting hot. at battery terminals

Contact resistance is increased by a bad connection. If only 5 percent of the area is in contact due to corrosion you have high contact resistance. High contact resistance is going to reduce current flow and reduce heat. If battery has gone bad and is shorting out now you have low resistance, high current and high heat. Also a battery will take hours to go down to 12.6 volts after charge has been removed. If you test battery as soon as you remove charger you will probably read over 13 volts. To get an accurate reading, the battery should be tested the following day after the charger has been removed from battery.
 

Pascal

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Re: Battery Charger wires getting hot. at battery terminals

eurolarva<br /><br />I'm not sure I understand the correlation between the contact resistance example and the battery condition example.<br /><br />Current flow through a resistance = heat. I agree that less current = less heat but heat is still heat and there will be a tempurature increase at the point of resistance. <br /><br />If the battery post is corroded and you crank the engine, the post and clamp will heat up. <br /><br />This is a good quick check for resistance in the connection. Works every time.<br /><br />I agree about the surface charge removal. Quick way to take it off is turn on the headlightes for 5 minutes then let the battery recover for 10 minutes and check opencircuit battery volts.<br /><br />JD
 

eurolarva

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Re: Battery Charger wires getting hot. at battery terminals

The resistance of a 100 watt bulb is almost half of that of a 60 watt bulb. The 100 watt bulb will produce almost twice as much heat as the 60 watt bulb. If your contacts on your wires to your starter or battery are corroded only a minimal portion of the battery is able to pass to the starter which increases contact resistance. In order for your starter to crank you need a minimum of 10 amps at 12VDC which makes your resistance 1.2 ohms. If your contacts are dirty the resistance of the battery leads to the dirty battery can be in excess of 100 ohms. This means you have 1.2 ohms for the starter and 100 ohms of contact resistance. Because you only have 12 volts available you can only draw 120 Milli amps which is not enough to engage your starter. In this condition you can keep the starter engaged for an hour and not produce any heat. Now if the brushes in the starter have gone bad and have started to short the starter can not get enough current to start because of the short and you are creating a ton of heat.<br /><br />Another example is if you connect a 10000 ohm resistor in parrallel to your battery the heat will be minimal. If you put 1 ohm across your battery you will produce some serious heat. When a battery goes bad it can either act as a short or an open. If it acts as an open your charger will not produce heat. If it acts as a short the battery charger will try and push major current into the battery to try and equalize the voltage between the two sources and produce major heat.
 

Link

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Re: Battery Charger wires getting hot. at battery terminals

Thanks to all of you and in this case everyone is correct.<br /><br />I'm working with two exact batteries bought on the same day.<br /><br />After reading the replies on the 23rd I first went out to the storage shed and tried this to eliminate spring tension and bad wire connections on the clamps.<br /><br />First I moved both clamps back and forth with finger pressure to dig into the lead posts.<br />Then I put a vice gripe on each (now that took care of spring tension)<br /><br />Second I moved both pos and neg leads to the clamps while watching the amp meter on the charger. Both caused the amp meter to jump up and down.<br /><br />So I brought the charger in the house and cut the clamps off, cleaned and soldered both to the clamps. <br />"Link" Make mental note to never try this again with a 35 watt soldering iron again. Took awhile folks :eek: <br />Then re crimped and went out to try again.<br />This time moving the wires made no meter movement.<br /><br />No vice grips this time. And using a analog volt meter.<br /><br />Left the charger on battery (A) for 18 hours. It started off at 10 amps and went to Zero. No heat at all. Volts right at 14 minutes after taking off charger.<br /><br />Put the charger on battery (B) for 18 hours. It started off at 10 amps and was still at 8 amps. <br />No heat at all on the wires! Or the back of the clamps, but the battery terminals were so hot I couldn't keep my figures on them. Volts right at 12 minutes after taking off charger.<br /><br />I think after reading all the posts we can agree that I fixed a faulty battery charger and that battery (A) is good and battery (B) is bad for this test so far.<br /><br />Battery B goes to scrap<br />Anything else I should check on battery A ??<br /><br />Thanks again for your input. Sorry about the time lapse but I wanted to do the tests first before posting.
 

Link

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Re: Battery Charger wires getting hot. at battery terminals

^^Bump^^
 

eurolarva

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Re: Battery Charger wires getting hot. at battery terminals

I agree battery b is toast. Do you have a volt meter? What is the charged battery voltage of battery A? The meter bouncing around would have been a good clue to a bad connection. I am still suprised that the cables got hot. The charger must have been trying to throw all its current through only a couple of the stranded wires in the cables.
 

rwise

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Re: Battery Charger wires getting hot. at battery terminals

And if these batteries run in parallel, replace both of them.
 

Link

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Re: Battery Charger wires getting hot. at battery terminals

eurolarva: right at 13.8-14 volts with a analog meter<br />rwise: Not anymore :( Guess I'll just leave the good battery in the shed to run the 12V floresant lights and buy two new ones when I finish the boat and its ready for fishing again.
 
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