Restoring or Recharging Dead Batteries

[Russ]

IMHO, cool and dry is better than warm and humid for battery storage. I could be wrong.

Yea, I'm no battery expert, but I would agree. The humidity might speed drainage. Dry is better.
But COLD, as in freezing battery cold is when I've had battery failures.


--Russ

[kmclemore]

OK, so nobody has yet answered the question....

...how come somebody hasn't made a device that does just exactly that? i.e., you plug it in, connect it to your battery, and it automatically cycles every 3-4 hours between trickle charging and applying a load? Seems pretty simple to make.

??

[DaveB]

I agree, Wet Deep Cycle Batteries in North FL. can discharge between 1-3 % per Mo. If batteries were fully charge and disconect terminals than 7 Mo. would only discharge at Max. 21% well above the 50% discharge you can go. Even at 3% I doubt you will see that and more likely at 1% and that would only be 7% discharge.
Batteries can slightly sulfate over long periods of time such as 7 Mo. but very lightly and a quick 10 amp recharge should desulfate the batteries.

Dave

So many great battery experts with good advice.

Okay.. so is the boat in Florida? If so you don't have cold freezing temps to kill the batteries. Just normal sitting around without being charged discharge right?
I wouldn't sweat it. 7 months, most of which are mild climates doesn't seem like a battery killing environment. Get back, charge 'em up and see what happens I say. If they are totally run down, maybe take some of the wise words above. But if it were me, I'd put them on a slow charge for a couple of days and see what gives.


--Russ

[c130king]

Excellent info Dave, Thanks. Hopefully you are spot-on and the batteries will be no worse for the wear so to speak...or at worst lightly worse for wear.

Cheers,
Jim
Sailing on König

[DaveB]

I use a builtin 10amp Battery charger from Pro Bass and it is hooked up to Starter battery and other wire to twin group27 wet deepcycle house batteries, the charger charges them seperate and one cannot drain to other. Deepcycles are 12.8 fully charge and starter battery is 13.2 volts fully charge.
The charger will charge both sets at diffrent voltage and will completly shut off when batteris meet the fully charge condition and will turn back on when voltage drops. This is completely safe for long term battery life.
Ideal would have replace all 3 batteries with 27 group deep cycle and used them in a series if need be than switch to house if starter battery got down to 12.3 volts and still be able to start my 50 hp Honda . I have installed a combiner that didn't work because I found out my Rectifier/regulator didn't work and putting out 17.5 volts, than I found out my 1 year old selector switch wouldn't turn over engine in the #1 starter switch (bad switch) .
I really hate this and just my luck when it comes to elect. fixing.
Dave

OK, so nobody has yet answered the question....

...how come somebody hasn't made a device that does just exactly that? i.e., you plug it in, connect it to your battery, and it automatically cycles every 3-4 hours between trickle charging and applying a load? Seems pretty simple to make.

??

[waternwaves]

lets see.......here are some of the things you want in this device......
temp sensor
isolation transformer
desulfator power supply and switch.
smart charger
40 watt dummy load
2 cycle timers
battery type selector switch
Battery capacity display indicator?



anything else you want in this device??? small size?? cost under 30 dollars??? waterproof??, under 8 lbs......

wireless internet connection to report back your battery condition half way around the world?


tell ya what....... I am between jobs....... I will design and patent this and build 10 prototypes for the first person that sends me $8,000 and I might even split the royalties.

integrated solution

[DaveB]

No worries Jim, next time get a 5watt solar panel for single or a 10 watt for double batteries and attach wires direct to battery. No other regulator or Diodes needed. Harbor Freight $15 for 5 watt,$25 for 10 watt.
I used the 10watt on my CP19 duel Golf cart batteries and Potter19 duel Gel battery and the 5 watt on the CP16 single battery.
Solar is great if you don't have shore power.
Dave

Excellent info Dave, Thanks. Hopefully you are spot-on and the batteries will be no worse for the wear so to speak...or at worst lightly worse for wear.

Cheers,
Jim
Sailing on König

[DaveB]

Just one other thing,
Most auto supply places carry battery acid. Use this instead of distilled water.
Only fill the battery fill holes to bottom of plastic fill hole, this will cover the plates with approx. 1/2 inch fluid over the plates.
If you fill higher or go to top you can sulfate batteries and also disrupt chargeing causeing damage to batteries.
Dave

No worries Jim, next time get a 5watt solar panel for single or a 10 watt for double batteries and attach wires direct to battery. No other regulator or Diodes needed. Harbor Freight $15 for 5 watt,$25 for 10 watt.
I used the 10watt on my CP19 duel Golf cart batteries and Potter19 duel Gel battery and the 5 watt on the CP16 single battery.
Solar is great if you don't have shore power.
Dave

Excellent info Dave, Thanks. Hopefully you are spot-on and the batteries will be no worse for the wear so to speak...or at worst lightly worse for wear.

Cheers,
Jim
Sailing on König

[Love MACs]

That purchased from HarborFreight must have been a while ago Dave as the price on the 15 watt is now $60, I just checked. Was going to buy one myself for the price you mentioned

This may be a difficult question given all the variables but can a 15 watt keep two batteries charged, while using minimum electronics (that's the variable) under sail I am talking chartplotter, depth finder, VHF radio and maybe a few hrs of stereo radio. At night anchor we use our LED's Cabin lights albeit sparingly and maybe a movie ( 2 hours) on our 12v DVD player.

I know I can motor a couple of hours to get them back up but wondered if you, or anyone had a thought on the 15 watt solar being sufficient for my needs

Allan

[Russ]

lets see.......here are some of the things you want in this device......
temp sensor
isolation transformer
desulfator power supply and switch.
smart charger
40 watt dummy load
2 cycle timers
battery type selector switch
Battery capacity display indicator?



anything else you want in this device??? small size?? cost under 30 dollars??? waterproof??, under 8 lbs......
wireless internet connection to report back your battery condition half way around the world?

Bzzzzt.... Thanks for playing.


All great ideas. Under $30 bucks. I got some swamp land.....urm.. I mean great real estate to sell ya.

But if we market this properly.....in the $500 plus $25/month subscription price. We might have a product.

[Hamin' X]

Do not add battery acid to batteries that are low on water, unless they have been tipped over and spilled. Sorry, but it is an old wive's tale and will mess up the specific gravity of the battery, when charged. Only add battery acid to "dry charged" batteries. You will run across things like this and things like not leaving batteries on concrete. Same thing: Not true.

~Rich

[seahouse]

Dave - I respectfully dissagree. Never add acid to a battery unless you spill some out. Add only distilled water to replace that lost through evaporation, otherwise you will be changing the design concentration of the electrolyte.

Hamin'X- you're correct on both counts! The concrete one is a real "beauty"!

c130king- leaving a battery sit like that is a classic battery killer. But you have some things going for you. A deep cycle battery has thicker, less spongy lead plates (the +ve ones) than a starting battery so they are hardier at handling discharging, which is good. You disconnected the terminals which will prevent parasitic drain (some diodes in place to prevent this will still "leak"current) , so your discharge rate is restricted to only the internal discharge of the battery (might be up to 10% range) high if hotter, humidity will not have much role. And you charged it before you left it, good.

An idle battery should be trickle charged after checking the electrolyte level to be above the plates (inter alios to prevent explosion), and the same in all cells. Contrary to what you might think, top the acid level the rest of the way up after it's fully charged, not before. Note that even a new battery will not reach its rated capacity until a few dozen charge/discharge cycles anyway. The charge rate should be enough to cause bubbling in the cells so there is vertical mixing and no stratification of acid density, (unless the wave action is helping that).

You can tell whether or not to buy a charger by lifting it. If it's heavy don't buy it. It means it has a big clunker of a transformer in it, and relies on the charge current being raised and lowered as the internal resistance of the battery "pushes back". The harder the charger tries to amp the power to it the harder the battery pushes back, and as the battery voltage goes up, the amperage goes down. That's not really "automatic" and it's not the best thing for the long-term health of the battery. At least you do not want to leave these connected to your battery for any length of time.

The good ones are lighter, solid state, fan cooled, and will automatically feed exactly the amount of amperage that the battery can easily take. They will then switch over to a maintenance mode that will trickle current only when it senses the voltage drop in the battery. Might be under $100 for a good one in the USA.

next post>>>

[seahouse]

Cont'd >>>

All lead-acid battery charging happens in 3 stages, bulk, absorption, and float. The so-called "intelligent" or "smart" chargers are logic-controlled and will take continuous feedback from the battery and only give the current and voltage the battery can safely take, which will vary at each stage of charging. They will charge faster than the "automatic" clunker chargers because the clunkers will slow down as the battery get to a higher charge (the absortion stage) , putting out much less amperage than the battery will accept because the battery's voltage is higher (even if it's a "20 amp" charger). The smart charger will sense this and increase the voltage output during the absorption stage when it's safe. When the charge is complete the smart charger then switches to float with a switching lower or zero voltage to maintain the battery over long periods.

The intelligent charger will give digital readouts on charging current, charging amperage, % battery capacity (estimated based on voltage - you really need a hygrometer to accurately know this, or a load test) and automatically goes through desulfate cycles on a battery if it determines it needs it. Will also tell you if the battery is toast after trying several times.

If you wanted to you could easily put one of these on a timer as well!

c130king - check the voltage of your batteries when you start out - you might luck out if they haven't fallen much below 12 volts, which would be around a 50% discharge, but hopefully above 10.5V, which is 0%.

Bite the bullet and get one of these intelligent chargers for your batteries - they're the best thing and you'll know you've treated them well in the charging department. But charge them outside the boat.

- Brian.

[c130king]

Guys,

All great info. Thanks for teaching me (and hopefully others) all this great battery info. My specific circumstances are probably fairly unique and most don't have this issue as you can get to your boat more often or you have solar or you have it plugged up to shore power of some sort. A solar trickle charger of some sort is in my future.

But hopefully once I get back to the U.S. I won't have these issues any more as I plan to use my boat MUCH more often...can't wait. And hopefully since my batteries were fairly new and have been disconnected from everything while sitting in the boat...they won't be in too bad off and hopefully will be above 50% with very little loss of liquid.

Brian, can you recommend a good charger like you are recommending? For the garage...not for the boat. An in-boat charging system is fairly far down my list for now.

Cheers,
Jim
Sailing on König

[DaveB]

I bought them over 2 years ago and I mentioned the 10 watt for $25 and I am sure it was on sale.
15 watts equal approx. 1amp @12 volts and you would have to have perfect conditions (live in S.Florida,sun high,clear skys) and even than a 15 watt doesn't really put out that 15 watts most of the time. It won't keep your electronics going, will charge phone batteries and VHF on standby with the 5 watt setting.
I am getting a 45 watt and only expect average 15amps per day in S. Florida,enough to run my Refig. 8hrs during the heat of the day.
Doing this will allow me to cruise 5-6 days in 90 degree temps. and haveing my twin 27 group house batteries 40-50% discharged. If I run the engine than can expect approx 6-7 amps per hr out of my 10amp honda 50.
I now get 4 days with 40% discharge in last week 90 degree heat.
We don't have a lot of juice burners but we do watch CD movies on our 15.6 laptop and have 200 watt sterio and depth sounder. The two interior lights are being changed to LED's. My anchor light is a Walmart $5 LED with 2 Recharge AA on the 3 bulb setting good for 72 hrs before recharge, also head is battery LED's.
We carry 2-60, 1-75 and 1-125 watt inverters that plug into cigarett fixtures thruout the boat. We have two 12volt fans ceiling and gally mounted and another 12 inch AC fan for sleep rear berth.(the laptop runs on the 60 watt inverter)
Dave

That purchased from HarborFreight must have been a while ago Dave as the price on the 15 watt is now $60, I just checked. Was going to buy one myself for the price you mentioned

This may be a difficult question given all the variables but can a 15 watt keep two batteries charged, while using minimum electronics (that's the variable) under sail I am talking chartplotter, depth finder, VHF radio and maybe a few hrs of stereo radio. At night anchor we use our LED's Cabin lights albeit sparingly and maybe a movie ( 2 hours) on our 12v DVD player.

I know I can motor a couple of hours to get them back up but wondered if you, or anyone had a thought on the 15 watt solar being sufficient for my needs

Allan