Golf Cart Batteries

I have done quite a bit of*research online and have seen differnet numbers for the safe discharge level on golf cart batteries, from 50% to 80%. What is the safe level to take golf cart batteries down too?

This is one of many sites that I have read.
http://www.yachtsurvey.com/boat_battery_basics.htm

The DM post got it right , the question is better how deep a discharge are you willing to PAY for?

With deep cycle (not start or "marine") batts a real contemplation can be how large a set , vs how long they will last.

At 70%SOC limit (state of charge , 30% removed) the set will run 5 or 8 years , if kept up and a quality desulfator is used.

At 50% SOC the service life will be 4 -5 years for most folks , and dragging them down to 20% is really hard on the set.

And even harder if the set is allowed to stay discharged and not recharged to 100% fairly soon.
Think 2 maybe 3 years.

If a boat can stand the weight , having 2x as many batts may not cost more over the years.

For most folks the math will need to be done for the refrigeration system , as on most cruisers , its the biggest juice user.

Outfitting is one of the great compromises.

FF

***** ... if kept up and a quality desulfator is used

OK - what's a desulfator??* Is it an additive to the electrolyte, or something in the charging process?

Also - I contacted Rolls about life vs discharge on their (very expensive) batteries.* Mr. Surette himself replied with graphs of cycles vs depth of discharge.*

They claim that their high end 5000 series will do about 4000 cycles at 30% discharge (70% remaining), a bit over 3000 cycles at 50%, and a bit under 2500 cycles at a 70% discharge (30% remaining).

I dunno what a "desulfator" is, but I do know that with conventional flooded-cell, lead-acid, non-sealed batteries you can equalize them, which is in essence pumping a real high charge into them--- say 16 volts--- for a period of time to "boil" them. This removes the buildup from the plates and also mixes up the acid and water real good. If this is done on a regular basis--- we try to do it about once a year--- battery life can be extended signficantly.

Some smart chargers have this capability built-in, or you can buy stand-alone battery equalizers. Our Heart Freedom 25 has an equalization mode you can select with the remote control unit.

Very important to make sure the batteries are topped up when you do this, that all echo chargers are disconnected, that the battery area is well ventilated, and that you don't turn on any of the boat's 12vdc systems or equipment during the equalizing process.

I don't know if this is what FF meant by "desulfanator" or not.

Thanks for the info,*that clears up some stuff for me!

Eric--- You should put your post back up. You had good information about the effects of sulfide buildup on battery plates that some people--- including me--- didn't know.

Google it... Here is an example:

http://www.solarhaven.org/BatteryDesulfator.htm

I just bought a couple of new desulphators for Christmas. One for a friend of mine for his farm truck / equipment, and another one for me, for my truck. I've had one on the boat battery bank for years and swear by them. This is the one I use, but they lots of others on the site:
http://www.batterystuff.com/battery-restoration/12-volt/BM12v117.html

No, you don't have to turn anything off. They work well with large battry banks, but of course take longer. Mine is automatic... when you plug it in it trickle charges up to full charge, then turns on the pulse feature. OR you can push a button and turn the pulse feature on manually. Very simple and inobtrusive. Mine stays on in the engine room all the time. I just move it from one battery bank to the other occasionally. It runs while your normal charger is working as well. Couldn't get any simpler.

One difference is that the equalizer process can only be done (according to our Heart Freedom 25 manual) on conventional flooded-cell, non-sealed batteries. It cannot be used on gel-cell or sealed batteries. Perhaps the devices shown in Keith's link don't heat up the batteries to the point where there is a lot of gas venting, which as I understand it is the reason equalizing should not be done with sealed batteries.

-- Edited by Marin at 14:12, 2008-01-05

The so called "de-suphators" do not produce a spike but rather have an output that is actually AC but at a much higher frequency than what shore power has and it is produced generally in pulses of a few milli-seconds duration. The theory is that this high frequency pulse causes the sulphate to resonate and crumble off the plates and then gets dissolved into the electrolyte. They should not cause any problem with connected devices except for a "buzz" in some radios or stereos.

I have used these devices on commercial two-way radio installations for years where the back-up batteries are "on charge" continuously but the batteries are not discharged until there is a power failure. I also had two of them on the boat with clip lead cables and periodically moved them among the battery banks. On the commercial installations they definately caused the batteries to give a longer service life and I believe that was the case on the boat as well however the batteries from the boat were disposed of when I started the re-fit knowing they would require replacement by the time the boat goes back into the water so I can't say for certain their life cycle was improved.

John Tones "Penta"

Equalization is a controlled overcharge , nothing more.

De sulfation is quite different ,

www.pulsetech.net is the brand we have been using for a decade or so on coach conversions and cruising boats.

FF

I found this on ebay

http://cgi.ebay.com/ebaymotors/BatteryMINDer-Battery-Charger_W0QQcmdZViewItemQQ_trksidZp1638Q2em118QQcategoryZ6755QQihZ017QQitemZ270002142078QQrdZ1QQsspagenameZWD1V

Keith,
Do you know if the one you purchased is better than this one?
BatteryMINDer has two models, 12112 and 12117, the only difference I see is one has a 1.3A charge and the other has 1.0A charge.

-- Edited by troy994719 at 10:22, 2008-01-06

Don't know... maybe the one on E-Bay is an older model, and he bought the closeout inventory from Battery Minder? I can't find the ebay one's model on the batterystuff website.

If a modern , Smart batt charger is not used the use of Hydrocaps will reduce the watering drill.

FF

A short technical description of what happens and how the desulphating works is at

http://www.rollsbattery.com/Bulletins/501.htm

I think the pulsing achieves the same effect as the 2.6 to 2.7 volts/cell described in the bulletin, but without having to worry about overheating - so you can connect the desulphator and let it run unattended like a lot of y'all are doing.

Good discussion guys - this was something that I didn't know that I didn't know about.

" but without having to worry about overheating - so you can connect the desulphator and let it run unattended like a lot of y'all are doing."

Most any system will operate unattended and do a modern job of batt maint.

We have no shore battery charger , as the boat is a cruiser, and batt maint is done with solar.

A 75W solar panel is connected to a Trace C-10 that charges to full , then cuts the voltage back to float , when the sun shines.

It keeps track and will equalize every 30 days automatically.

So far it did well for 2 winters in CT , even shadowed a good part of the day by trees in the yard , and weeks of snow cover , at times. Summer months on a mooring is easy, as the solar will usually make up for any inverter power tool use.

In most conditions on the summer mooring nothing is on but the bilge pump, which would hardly care if it got 15V while operation.
Today most cautions on operating during an equalization cycle is to preserve the light bulbs , which DON'T like excess voltage.

FF

Installed desulphators on all seven batteries on Ancora with no difference in life expectancy.
right now I have two disconnected dead golf cart batteries sitting in the boat while I wait for the other two to go south so I can change all four of them at the same time. The boat is over-batteried so I can afford the loss of two house batteries. The desulphators turned out to be just "snake oil" for this user.

Well, I have a house bank of 8 GC's, Exide E-3600's. I've used the Batterminder de-sulphator since they were new, 6 1/2 years ago. At about the 5 1/2 year mark mine still tested about the same as when new. I have a Freedom 25 (2500 watt inverter with 130 amp charger) and a Link 2000 monitor panel. My test simply consisted of anchoring out and watching how many amp hours I could draw before draining the bank down to about 12.06 volts, which according to the*schedule I have is 50%. I thought that was wonderful so I figured I could improve on that,*and decided to try to equalize them with the Freedom. I did and guess I killed the bank, or at least something. I haven't gotten around to testing them to see if I just have a bad cell, but looks like if your batteries are that old, and you haven't been doing the equalize thing, this ain't the time to start. Instead of getting over 400 amp hours before the 12v mark, now I only get about 150.
Of course I haven't tried to use this same type of bank without the Batteryminder, but sure looks like it was doing what it was supposed to until I screwed with it.
By the way, is there a better way of testing individualy cells than just with a hydrometer? (If that is even the right name for it)

-- Edited by Brent Hodges at 22:58, 2008-01-08

"By the way, is there a better way of testing individualy cells than just with a hydrometer? (If that is even the right name for it)"

The hydrometer is it for single cells,

But for $400 or so the newest battery checkers will look at a charged or discharged bat and asses its useability.

Mostly used by battery stops and golf courses that have hundreds of carts and tons of batts.

Probably pricy for a boat owner .

FF

Brent,
You can take the probes on your VOM and go cell to cell- inserting the probe in the electolyte/ or start at one post and "add" a cell at a time to your test. Each cell has a 2 volt value, but should show slightly over when charged.
Steve