Ben Bragg Loc: Dayton Ohio

It’s that time of year again
Breaking out the boats and other outdoor equipment
When dewinterizing my boat earlier this week. I discovered my cranking battery dead.
Volt meter showed 4.6 volts
Charger showed an F1 fault, and wouldn’t charge.
What was happening was the battery had fallen below the output level expected by the charger. Modern Chargers won’t work on “Dead “ batteries

If this happens to you , try this

1. Connect jumper cables to a known good battery and the dead battery. Pos to Pos. Neg to neg

2. Connect battery charger leads to good battery. Let this sit a while . A few hours at least.

Charge will pass thru good battery to dead battery and restore output voltage of the dead battery to a level that is in range of the battery charger

3 remove jumper cables if you have a volt meter , check the output voltage. It should read somewhere around 12 V

4. Try the charger on the dead battery. It should charge normally.
If not reconnect cables and repeat steps 1 and 2

Once the charger is functioning, allow full charge. When charge is complete disconnect charger and check output voltage. It should read 12.7 V or more

5 let battery sit for 24 hours. Reconnect charger to top off. Chances are good it has retained full charge and your charger will read Full after a short while . If not leave connected to fully charge.

If successful , your battery should be fully recovered.
If not. It may be Time for a new battery . You can go to a local auto parts store for a battery check and advise

You can Google this topic for a more detailed description of how to do this procedure

Danger25 Loc: Philly/ Cape may New Jersey

Good to know...thanks Ben

bknecht Loc: Northeast pa

Ditto, wasn’t aware of that. Thanks Ben. I’ll probably forget it when it’s time for me to do the same and if so,you can expect a PM if that’s ok with you.

Danger25 Loc: Philly/ Cape may New Jersey

Not a mechanic by any means but wondering why that works....your basically putting a charge into a dead battery but with a good battery in between.

And how the hell did you figure this out Ben?

Ben Bragg Loc: Dayton Ohio

You are tricking the circuitry in the charger.
For some reason a charger won’t work on a battery that is less than a certain level of charge.
Don’t make sense to me either.
You would think a charger that works on a drained battery is a good thing.

I went on line years ago and found this procedure . I was facing replacing a $300 battery. Was willing to try anything.
I just did this on my Optima cranking battery and it worked like a champ.
After the second top off charge I’m still holding 12.7V . I was at 12.5 V a day after the first charge.

Ben Bragg Loc: Dayton Ohio

I’m hoping Jeremy jumps in.
If anyone can explain this , I’m sure he’s the guy

Danger25 Loc: Philly/ Cape may New Jersey

Good enough for me....like a lot of things...i dont know how it works just glad it does.

audigger53 Loc: Severn, MD

Just a note for you. Sealed non gellcell batteries do require Distilled water over time. The "Sealed" Battery has 1 or 2 plates that you can pry up with a flat blade. If the water is below the plates add until at the top of the plates. Then charge the battery or start the car, if in the car. It is normal for batteries to loose water. part of the discharge and recharge process. When the H2SO4 is to strong the battery will have problems.

Blindman Loc: Wisconsin

Great information. Thanks Ben!

Mike

kfsrmn Loc: Lake Havasu AZ

I have an old battery charger. Find an old charger at a garage sale or a 2nd hand store. The new chargers are designed to protect electronics. Do not use the old style chargers on a battery that is hooked into a newer car or anything with electronics. Disconnect the battery before charging with an old style battery charger.
I have a Noco GB40 booster I keep in the car. It will start a car or boat with a dead battery.

hacksaw Loc: Pasadena, Texas

Thanks Ben, I think my kayak battery is low or dead so I’ll try this. Hope it works those Marine batteries are high dollar.
Hack 🇺🇸🍺🍺

MJWheeler23 Loc: Los Angeles

What you can do as well is bring a small charger out with you and with a separate power source, hook it up to the battery. Let it run for an hour and then plug the boat in with both chargers running. The on-board will get tricked into starting and then when your remove the portable charger, the ob will stay on. Let it run as long as you can...
PS- I've owned a electric boat repair company for 33 years and work on "Duffy" type boats since '87....

woodguru Loc: El Dorado Ca

I was going to say when my high tech chargers won't "engage", I put an old school low tech charger on it and juice the battery up for awhile then put a desulfate charger on it. I put a full charge on it, then leave it on a trickle disulfate mode for a week or so. I bought a boat ten years ago that had two Trojan deep cycle group 31m batteries that listed at $275 each, the guy had used the boat and left it sit without charging the batteries for a year, they seemed to be toast. I did the old school charge, and put two chargers on the batteries so that they were always used and charged equally as a pair, and got five years use off of them on a 24v MinnKota. The guy who bought the boat from me killed them by using it and letting them sit for over a year.

woodguru Loc: El Dorado Ca

Home Depot has Exide deep cycle marine batteries that are $89 for the group 27 and $109 for group 31, use and charge them right and they will give excellent service for years. I think the group 31's I got are rated at 115ah.

hacksaw Loc: Pasadena, Texas

Ok, thanks so much guru. I’ve had this one for six years so maybe it’s time to get another.
Hack 🇺🇸🍺🍺