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EFV-8 Club Forum / General Ford Discussion / Jump start 6V with a 12V?

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Posted By Discussion Topic: Jump start 6V with a 12V? -- page: 1 2     Flatbob 01-07-2010 @ 12:12 PM reply profile send p.m. Member Posts: 437 Joined: Oct 2009 Would it damage an Optima 6V battery or dist./coil if a 12V battery is used for a jump start? supereal 01-07-2010 @ 3:36 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 The short answer is yes. For all of their advantages, the spiral wound Optima batteries are sensitive to large voltage changes. That is why they must be slow charged. Lead acid batteries are more resistant, but each year we see lots of battery failures from improper jump starting or those high voltage machines used by towing companies. Almost always, the battery will have to be replaced very soon. If the battery has run down enough to allow the electrolyte to freeze, the battery can explode with disastrous results. It is always better to remove the battery, bring it into a warm place, and attach a good low amperage charger. Proper jump starting requires that the battery of the donor car and the one needing a charge to be interconnected, with the donor car running for 10-15 minutes, then disconnected. Trying to turn the stalled car over immediately can fry the diode trio in your expensive alternator in your donor car, and possibly other components, such as the ECM. Stroker 01-07-2010 @ 3:48 PM reply profile send p.m. Senior Posts: 1460 Joined: Oct 2009 I'd like to add one more caveat to Supereal's excellent advice; and that is to remember that our cars are positive ground. So, if you have a car club buddy that is willing to jump start your car with his 6V GM, Chrysler, or other negative ground car, just be sure your bumpers aren't touching. JebNY 01-07-2010 @ 5:59 PM reply profile send p.m. Member Posts: 44 Joined: Nov 2009 I don't like to jump any 6 volt system with 12 volts. 6 volt lead acid batteries sometimes blow up when jumped with 12 volts also. What I do, assuming there is at least enough charge left to run the ignition, is to turn on the key, transmission in neutral and jump to the starter side of the solenoid. Nothing see the 12 volts but the starter. Jim... 1950 F1 Stake Flatbob 01-08-2010 @ 8:38 AM reply profile send p.m. Member Posts: 437 Joined: Oct 2009 Thanks everyone, I won't try that in the future! 39Fordfan 01-08-2010 @ 9:06 AM reply profile send p.m. Member Posts: 202 Joined: Oct 2009 Lots of good information here, especially on what not to do. However, this topic begs the question, what is the proper or best way to jump start a positive ground 6V? I've got a lead acid battery now but will be moving to an Optima when my current battery dies. Is there some sort of converter I can buy to carry around with my jumper cables just in case there isn't another 6V car around and I'm stuck with jumping from a 12V? My car always starts but I've almost had to help some friends with their cars and with a 6V positive ground system I wasn't sure what to do. ford38v8 01-08-2010 @ 9:19 AM reply profile send p.m. Senior Posts: 2764 Joined: Oct 2009 Fan, the best way is to not jump it, but rather, to push and pop the clutch. Even a dead battery is usually sufficient to supply enough spark for the ignition to get home on. You may recall that during your youth, you often did this, and could not use accessories such as headlights and radio, or the engine would die? I know I'm not the only one who remembers those days! Alan supereal 01-08-2010 @ 11:56 AM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 Just be sure that your cables are clearly marked Positive (red) and negative (black). Good advice about being sure that there is no contact, other than the cables, if the donor car has the common negative ground when jumping a positive ground car. As said earlier, unless you are in an emergency situation, avoid jumping at all. Determine why the battery is low in the first place. lightflyer1 01-08-2010 @ 10:34 PM reply profile send p.m. New Member Posts: 107 Joined: Oct 2009 In my '35 2 Optimas fit perfectly. I installed them and connected to one. I keep them both charged and have my own jump if needed. 37RAGTOPMAN 01-09-2010 @ 5:55 AM reply profile send p.m. Senior Posts: 1962 Joined: Oct 2009 NO WAY, you want more problems ???? I thought about one of the optima batterys,special chargers exta cost,for a special battery, the cost and the looks, but I think the neg's out weigh the positives,the cost on the optima is about $130.00 I just bought a 6 volt battery for about $65.00 and that will last me about 4-5 maybe more years,for my 1931 MODEL A,have the same one in my 37 I got 7 years out of one of the FORD SCRIPT BATTERY'S DO your self a favor... charge the battery, and see if it starts, and if not find the problem and correct it, these cars are not hard to repair, this is my 2 cents worth, 37RAGTOPMAN

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