Jump starter not starting newer AGM equipped cars

[MattPersman]

So what I do is try my JNC770 first if that doesn’t work. Which like you it may not. I bring out my lokithor and hook it up as well. Go into override on that unit and they start. I can then pull off the small lokithor and leave the JNC on for a while just in case it is one of those vehicles that dies when you take off a jump starter initially.

I have a gooloo too I use at times instead of the lokithor. Both good Li units. Many times those have a better chance than the JNC by themselves

So TLDR version get a good Li pack and use that to supplement your JNC at times.

 

[bullwinkle]

Jump pack is kept in a heated cab and always plugged in to charge when not in use. The pack is maybe 2-3 years old. I’ve gone though 3 in the last month. Boss just swaps one out for another

You can replace the battery in a JNC-660 with a higher capacity one-mine actually got weak, Home Depot actually had a decent bolt-in replacement for less money than the Clore replacement one. They’re limited in what they can do,though, a completely dead battery will suck up enough amps to stop an engine from cranking fast enough. Have had to pull a battery & recharge it to get it strong enough to start.

 

[bullwinkle]

So what I do is try my JNC770 first if that doesn’t work. Which like you it may not. I bring out my lokithor and hook it up as well. Go into override on that unit and they start. I can then pull off the small lokithor and leave the JNC on for a while just in case it is one of those vehicles that dies when you take off a jump starter initially.

I have a gooloo too I use at times instead of the lokithor. Both good Li units. Many times those have a better chance than the JNC by themselves

So TLDR version get a good Li pack and use that to supplement your JNC at times.

The addition of the lithium pack gives the extra added power to get a completely dead battery going, I’ve put the Gooloo on with the JNC-660 on the F-450 before-but it doesn’t have the big $ electronics to fry…

 

[Jetronic]

Peak amps is a useless, fantasy specification. It is favored by marketing departments because the numbers look very impressive.

I alwats understood that to mean short circuit amps....

 

[KE7JFF]

When I did roadside work (I may get back into that on the side...) I actually wanted to build my own jump box after running into the same issue with some AGM batteries, it was in particular the factory installed batteries where they just are dead. The idea I had was actually a semi-luggable box with three 18aH 12V lead acid batteries wired together in parallel with an LED voltage display, an easy throw switch.

One of the tow yards I worked out of for a bit, someone on the auction side actually took a shopping cart, wired up several random car batteries in parallel, then found an old dumb voltmeter gauge like something you find in an evil scientist's lab and that cart could jump anything.

 

[michaelluscher]

My Gooloo pack lights off stone dead OE H/K AGM batteries, and happily jumped my Duralast AGM

Maybe I just had good luck

 

[M1Accord]

If I was jumpstart cars all days for living (actual a dream post retirement job for excuse to crisis around on someone else gas) I would get 2 Gooloo GP4000, and 40-ft jumper cable, and maybe a JNC 1224. The JNC1224 packs two normal JNC660 into one package but it is heavy. I would most likely rigged up some sort of inverter and run an extension cable to attempt to recharge the customers’ cars if I want to make sure they can restart themselves once I am gone. We’re talking Cadillac service now but OP is also a battery seller so I am assuming there is some potential serious conflict of interest there.

Time is money when we’re talking about Americans actually having to do work, especially when places like AAA don’t necessarily pay much for service calls such as jumpstarting. So a decent lithium jump pack to backup a standard jump pack is ideal. I had seen road side repair guys let their vehicles idle while spending 15-30 mins on a jump job and I always shake my head. They should turn off their vehicle unless they plan to use it ti jump the car. This should be a quick 5 mins job and 5 more mins to let the customer car recharge their own battery then get them to shut the car off for 1 minute and restart themselves. If they can’t and the battery reads less than 12 volt, they probably should be advised to go to auto part stores for a second check and battery replacement. If the road side derive people also sell battery, I can’t see how much premium they can charge; $50 extra over what AAP or AZ charges? Those places already have about $50 premium over Wally because of all the free checks they do all days. That is why Costco battery is the cheapest, they don’t do checks and they don’t install battery. Thst free install from AAP and AZ are already in the price and I would be nervous about letting Wally ward install battery.

 

[M1Accord]

My Gooloo pack lights off stone dead OE H/K AGM batteries, and happily jumped my Duralast AGM

Maybe I just had good luck

My Gooloo GP4000 just jumpstarted a backhoe/tractor at the local dumpster last weekend. The operator forgot to turn the amber light off and we have been having sun-freezing temperatures at night so that thing was dead. I saw him struggle while I was dumping recycles so I offered to jump his rig. The look on his face when that little lithium pack jumpstarted that giant Caterpillar rig was priceless.

 

[avacado11]

If I was jumpstart cars all days for living (actual a dream post retirement job for excuse to crisis around on someone else gas) I would get 2 Gooloo GP4000, and 40-ft jumper cable, and maybe a JNC 1224. The JNC1224 packs two normal JNC660 into one package but it is heavy. I would most likely rigged up some sort of inverter and run an extension cable to attempt to recharge the customers’ cars if I want to make sure they can restart themselves once I am gone. We’re talking Cadillac service now but OP is also a battery seller so I am assuming there is some potential serious conflict of interest there.

Time is money when we’re talking about Americans actually having to do work, especially when places like AAA don’t necessarily pay much for service calls such as jumpstarting. So a decent lithium jump pack to backup a standard jump pack is ideal. I had seen road side repair guys let their vehicles idle while spending 15-30 mins on a jump job and I always shake my head. They should turn off their vehicle unless they plan to use it ti jump the car. This should be a quick 5 mins job and 5 more mins to let the customer car recharge their own battery then get them to shut the car off for 1 minute and restart themselves. If they can’t and the battery reads less than 12 volt, they probably should be advised to go to auto part stores for a second check and battery replacement. If the road side derive people also sell battery, I can’t see how much premium they can charge; $50 extra over what AAP or AZ charges? Those places already have about $50 premium over Wally because of all the free checks they do all days. That is why Costco battery is the cheapest, they don’t do checks and they don’t install battery. Thst free install from AAP and AZ are already in the price and I would be nervous about letting Wally ward install battery.

The batteries I sell on roadside are $10 less than AZ and AAP for the comparable warranty(3 year). But it seems like most folks have already made up their minds when calling in. They either want a battery or they just want a jump. Very seldomly do I actually need to pitch a battery sale.

But ever since I picked up a cheap HF jump box I haven’t actually needed to use it. Temps have warmed up and the 660 has been working fine. Built in air compressor is slow but handy for stuff that I can’t get my truck to. It’s about all I use the box for these days.

 

[Brad_C]

Where I worked we made submarine batteries. They were single cells grouped together, usually for 240V or so. But each cell was a typical lead acid 2v nominal. One test they came up with on the Seawolf cell was to short one out. These were about 1500A for 8hr rated. A dead short would be tremendous surge.

So they got a solid copper bar about 3" square and long enough to reach both +- terminals. Rigged a means to drop it on the terminals to short it out remotely. We all stood back and hit the switch and nothing, not hardly even a spark. It did indeed short it out but no catastrophic melting failure. Didn't even get the copper bar hot.

Something was wrong with the test or a result of single cell short. I've witnessed both tools being turned into blobs of molten metal with 3-12 cell shorts; cells exploding and sending sulphuric acid all over the space. I've thrown out holed clothes as a result of acid dripping from structural beams. I'd suggest your test was a damp squib or had too much resistance for a single cell. Lead acid batteries can and do explode under catastrophic short.

 

[SHOZ]

Something was wrong with the test or a result of single cell short. I've witnessed both tools being turned into blobs of molten metal with 3-12 cell shorts; cells exploding and sending sulphuric acid all over the space. I've thrown out holed clothes as a result of acid dripping from structural beams. I'd suggest your test was a damp squib or had too much resistance for a single cell. Lead acid batteries can and do explode under catastrophic short.

No nothing was wrong. The buss bar and terminals were up to the task of delivering all the amperage. Something very important in submarine batteries. I have seen plenty of battery explosions over the years.

 

[4WD]

Completely dead AGMs take a long time before they really start taking a charge. Sometimes days if it's been like that awhile.

Even my lawn tractor AGM takes waaaaayyyy longer than B4

 

[SHOZ]

Even my lawn tractor AGM takes waaaaayyyy longer than B4

I think it is because after they are completely discharged, the liquid that is trapped in the fiberglass nanotube separator material is all water. Water does not conduct electricity anywhere near as good as acid. So it is very slow to initially push enough current through to start the release of the sulfate ion from the plates to mix with the water and bring the local specific gravity up.

A flooded battery has much more solution to start with and can take a heavy charge right off the bat, up to the point of gassing.

 

[4WD]

I think it is because after they are completely discharged, the liquid that is trapped in the fiberglass nanotube separator material is all water. Water does not conduct electricity anywhere near as good as acid. So it is very slow to initially push enough current through to start the release of the sulfate ion from the plates to mix with the water and bring the local specific gravity up.

A flooded battery has much more solution to start with and can take a heavy charge right off the bat, up to the point of gassing.

Sadly the battery was killed by someone leaving the key on - it was time to mow (been out of town) - so $100 bucks for a new one …
(Then 2 days to charge the old one) …
Was also blessed with a bunch of engine hours that never happened !

 

[SHOZ]

Sadly the battery was killed by someone leaving the key on - it was time to mow (been out of town) - so $100 bucks for a new one …
(Then 2 days to charge the old one) …
Was also blessed with a bunch of engine hours that never happened !

I did that to my new mower the second time I used it I think. Left the key on and had the battery down to nothing.

 

[JHZR2]

I once had a shorted cell in a battery. Even a tow truck couldn’t start the thing! If that’s the failure mode, a funky jump starter won’t help. Those things are ok if you left the lights on too long.

 

[John105]

Yes the issue is probably the protective circuitry inside the lithium jump starters refusing to engage on a fully dead battery.

Almost all of the handheld lead acid jump packs have the same 18 AH battery inside. The amp ratings are hype. You might do better carrying a fully charged full size AGM and a good set of jumper cables. Also if this is a garage full of cars that the same company owns, consider hoping that the car next to the dead one can start and be used to supply a jump start.

The interesting thing is when that popular YouTube channel rated jump
Packs, mine was rated as not usable at all. And it cost like $100 with a lightning deal (NOCO). So I decided to try to start a car that had been sitting 6 years and had no battery. Worked.

Someone here said if I were you I’d return it, so I did.

Then I got a better rated gooloo. Did my same test. Couldn’t start. Oh. Press boost. Now it started. Again, no battery. I’ve seen neutral drop do the same. But, it also shut down after repeated tries and had a countdown timer.

Flash forward 1 1/2 years. Take it out, shows 99% charge.

I wanted to use it to hold my car while I swapped batteries. Because the clips and cables are conducive to positioning without them falling off (last time I used my RV power supply and my jumper cables slipped).

The unit was powered on, said ready, and no, my car didn’t have power and the ECU reset.

I say yes the circuitry. Somehow it’s designed to provide temporary current and a lot, but not a steady 12V.

Just me I don’t like the ECU to reset, going beyond the emissions and memory settings. Just don’t like it. There are many hidden things that got reset. For example, on my wife’s, the external thermometer. It matters. It takes a long time to work again and if winter, it’s needed to tell the vehicle whether AC must stay off etc., ie for defrosting.

Anyway back to the point, owners manual does state 20% charge needed. But how about no battery at all? I did it on the car that was sitting 6 years because it had no battery, and this worked with the NOCO and the gooloo. I’d actually be afraid of the alternator being damaged but this car was going to be junked.

 

[SHOZ]

A completely or really low battery would be a big load when trying to jump start.

 

[meep]

I just learned (by accident) that the NOCO has a mode where you can defeat the safety nanny. This is useful if the battery is stone cold dead, like a dome light left on for for 2 days, completely flat where the NOCO can’t see it. In this case, after finding the button for it by accident after all else failed, the v6 Hyundai with flattened battery crawled up a mid-strength crank to start.