View Full Version : Charger Boils 6 x 8D Batteries

10-03-2011, 12:59 AM
My 2000 rig is fitted with a Heart Interface Freedom 25 inverter/charger and a Link 2000 controller. I think the system is applying too much juice to charge the batteries (my house battery bank consists of 6 x 8D batteries) because I am getting a lot of liquid coming out of the batteries which is messing up the compartment. I am sure that the batteries were not overfilled.

I noticed this problem when the storage warehouse where I store my coach started offering power for coaches to maintain batteries. It is only 120V, 15A max so I set the charger to the lowest setting (5 amp). This feature is called Charge Sharing in the manual (avoids tripping the source breaker by limiting current). The charger transitions from Charge to Accept to Float but even in float the batteries emit a lot of liquid out of the vent caps.

In my mind, the batteries on float should not do this. I have checked the settings (set for wet cell batteries) and they seem OK. I did notice that the battery bank capacity was set to 220 Amp hours. It seems that since I have six 8d's, the capacity should be set to something like 1200 AH (6 x 200). According to the manual, this setting is only for estimating the amount of power remaining in the bank under load. It does not appear to affect the charging process. Any ideas, suggestions?

10-03-2011, 02:23 AM

I have the same setup you describe. You are totally correct about the amp-hour setting. It just effects the estimated hours remaining at present load, and should have no effect at all on the charging of the batteries. Your Link2000 should give you quite a bit of information about the charging voltage and current in the float state.

As point of reference, mine float between 12.90 and 13.0 at about 1 amp. I would be very concerned if floating voltage was much above 13.3 or it took a lot of amps to hold the floating voltage.

I think battery manufacturer recommends filling to about 1/8" below the point where the electrolyte meets the bottom of the filling ring. I always thought that was strange and am guilty of filling to the bottom of the ring on occasions.

There has always been some corrosion and cleaning involved with the wet cells I have used as house batteries. Maybe someday I will have AGMs, but for now I have to save my money for tires :-)

Richard and Rhonda
10-03-2011, 05:12 PM
Your setup may be different than mine, but I discovered that dip switch 1, which is used to equalize the batteries was in the wrong position on my inverter/charger. Meaning, each time the power was interrupted to the charger, it would start an equalization cycle again. Ouch!!!
Not a good thing.

It might be something to check. In hindsight, I knew something was fishy in that everytime I powered up, the amps and voltage would go up indicating a heavy charge, even if the batteries did not need charging.

10-06-2011, 06:40 PM
Check your batteries with a hygrometer. You may have a bad cell or two. If you find you have a low acidity number you may try equalizing.

10-26-2011, 01:31 AM
Thanks for all the suggestions. To Richard and Rhonda, the Link 2000 control panel I have does not control equalization with dip switches, it is selectable with button pushes. To Busnut, I have not checked the batteries yet with hydrometer. Based on group comment to this email, that will be my next step. To better understand how the charging system is behaving, I let the batteries set for a few weeks and then started the charging cycle again keeping a record (see table).


Bank 1 is the house batteries, Bank 2 is the chassis batteries. The charger cycles through three modes during the charging process, Charge, Accept and Float. I set the charger to a 5 amp maximum charging rate initially. You can see that the charger remained in the Charge mode for several days. I upped the max amp setting to 20 and the system almost immediately rolled over to the Accept mode. First lesson learned, limiting the amperage can inhibit the normal charging process. The system finally moved to the Float mode with an amperage of 10. Subsequent measurements in Float have also been around 10 amps. I wonder if that is too high. The manual lists the amperage in the Float mode as 2% of the maximum battery capacity which makes no sense to me since the battery capacity in measured in amp hours, not amps. For those that have the same system (Heart Interface Freedom 25 charger/inverter) does this appear to be normal operation or is the float amperage too much leading to excess loss of battery water?

10-26-2011, 02:12 AM

I think your float current is too high. The following is cut from my Link 2000 manual:

"If the battery is 100% charged, and the LINK 2000 is in sync with the batteries, overcharge amp hours are displayed as positive. Some accumulation of overcharge amp hours is normal and harmless with systems continuously connected to a charger. For example: a 100 AH battery at the float voltage will normally have less than 0.1 amp flowing into it. This means that a maximum of 2.4AH of overcharge would accumulate in a 24 hours period. If your battery system is larger, there will be proportionately more current flow and positive amp hour accumulation."

Your 10 amps of float current is 100 times that of the example. I am sure your battery bank is not that large.

As to the confusion on amperage in float mode as a percentage of battery capacity my manual states it differently.
Under Summary of Factory Default Values is says:
Charged Current % = 2% ( of battery capacity )
The units are both in percent.

I suspect battery problems.

Good Luck!


10-26-2011, 03:52 AM
OK, I will break out the hydrometer and report my findings. Thanks for the advice.

Richard and Rhonda
10-26-2011, 12:45 PM

You probably have a shorted out plate in one of the batteries. Your float amperage is way too high as others have said.

Here is how I would identify the culprit Remove the cables from the batteries. Remember negative first off and last back on. Remove the cableing that connects the bank of batteries together. Wait 24 hours. My guess is one of those batteries will have a much lower voltage.

That one is the devil

I had this exact same problem with cooking the batteries. Found one of them had croaked.