10UHCSEL Posted November 7, 2015 Report Share Posted November 7, 2015 1st post, and I've searched several times but unable to find the answer to my question. Got a '13 Cmax SEL back during the summer for the wife, she likes the car alot and is still figuring out the differences with a hybrid and a ICE only car. I want to install a 12v battery charger to the car but cannot quite figure out how to accomplish this seemingly simple task. I have found the + post under the engine hood, but where do you make the negative connection? I don't want to make a wrong connection and fry the wiring, etc. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
ptjones Posted November 7, 2015 Report Share Posted November 7, 2015 (edited) I believe everyone that is charging they're 12v battery is doing it at the batt. posts in the trunk, under the cover. Here is a Pic. :) Paul Edited November 7, 2015 by ptjones Quote Link to comment Share on other sites More sharing options...
Bill-N Posted November 7, 2015 Report Share Posted November 7, 2015 The under-hood negative connection isn't obvious. From the positive connection, look about 5 inches toward the front and then down in about 6 inches. It's a post that sticks up quite close to one of the big orange cables. Cheers. Quote Link to comment Share on other sites More sharing options...
10UHCSEL Posted November 8, 2015 Author Report Share Posted November 8, 2015 So far I have not been able to find the negative post on the battery itself in the rear hatch area, so will have to look harder I guess. I did find the metal post mentioned in the engine compartment and was able to get a VDM reading using it. I prefer to use quick disconnect type connectors and did not see an easy way to make the connection in the engine compartment. More digging and looking. Thanks for the replies. Quote Link to comment Share on other sites More sharing options...
plus 3 golfer Posted November 8, 2015 Report Share Posted November 8, 2015 So far I have not been able to find the negative post on the battery itself in the rear hatch area, so will have to look harder I guess. I did find the metal post mentioned in the engine compartment and was able to get a VDM reading using it. I prefer to use quick disconnect type connectors and did not see an easy way to make the connection in the engine compartment. More digging and looking. Thanks for the replies. So far I have not been able to find the negative post on the battery itself in the rear hatch area, so will have to look harder I guess. I did find the metal post mentioned in the engine compartment and was able to get a VDM reading using it. I prefer to use quick disconnect type connectors and did not see an easy way to make the connection in the engine compartment. More digging and looking. Thanks for the replies. The negative terminal of the battery is not readily accessible likely because the negative cable has sensors as part of the cable. The Battery Control Module uses the data from the sensors. Connecting load or supply across the battery terminals may affect the monitoring function of the BCM, There is a chassis ground lug that can be used in the rear hatch area for connecting a charger. So by connecting load or a charger across the + battery terminal and the ground lug, charging current or load current will flow through the negative battery cable with the sensor and provide the BCM with appropriate data. The negative post under the hood is connected to chassis ground. ptjones 1 Quote Link to comment Share on other sites More sharing options...
Kelleytoons Posted November 8, 2015 Report Share Posted November 8, 2015 Um, now all this talk has me wondering (and worrying): what do I do if I just want to jump start my car? (Using that little portable battery jump-start thing I bought when I was worried about having battery problems Haven't needed it yet but I had better well figure this out before if/when I really do need to do this). Should I just attach under the hood to the positive and the negative post under the hood? (If so, I guess I had better identify them now). Quote Link to comment Share on other sites More sharing options...
WNY Posted November 8, 2015 Report Share Posted November 8, 2015 (edited) Yes, the jumping of the vehicle i believe in the manual (pg 260) states to use the (+) post under the hood and the (-) neg post near it that hooks to the frame. There are connections in the trunk for the battery that you can find for both the + and - directly to the battery. The negative post is hidden under the cover for the high voltage batteries, hard to get to without taking it off, but it does have some frame ground screws readily accessable next to the battery. Edited November 8, 2015 by WNY Quote Link to comment Share on other sites More sharing options...
10UHCSEL Posted November 8, 2015 Author Report Share Posted November 8, 2015 I've seen one ground connection in the rear hatch area that is visible when I removed the very 1st layer of cover but was not sure that was an appropriate negative connection to make. Will look some more. Thanks for the advice. Quote Link to comment Share on other sites More sharing options...
ptjones Posted November 8, 2015 Report Share Posted November 8, 2015 Here's a pic of Positive and Negative terminals under hood with the gray long bolt being the negative terminal next to large black cable with yellow strip. You can use alligator clips to connect to posts. :) Paul C-MaxSea 1 Quote Link to comment Share on other sites More sharing options...
C-MaxSea Posted November 8, 2015 Report Share Posted November 8, 2015 (edited) and another view: Previously posted/created by someone else here I believe - with captions. Edited November 8, 2015 by C-MaxSea ptjones and Louder North 2 Quote Link to comment Share on other sites More sharing options...
Bill-N Posted November 8, 2015 Report Share Posted November 8, 2015 and another view: Previously posted/created by someone else here I believe - with captions. Thanks for finding this picture. I looked yesterday but couldn't find it. Kelleytoons, you definitely want to use the underhood connections because the hatch can't be opened if the 12V battery is dead. Cheers. ptjones 1 Quote Link to comment Share on other sites More sharing options...
BERK7574 Posted February 29, 2016 Report Share Posted February 29, 2016 this is a joke. 3 jump starts (2 this week). The tow guy looked for a while and I am not sure if he just found something to ground it to or what. Quote Link to comment Share on other sites More sharing options...
ptjones Posted February 29, 2016 Report Share Posted February 29, 2016 Sounds like you need a new 12v battery. ;) Paul wab 1 Quote Link to comment Share on other sites More sharing options...
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