New DPI Boiling Off Water

oldnavycdr

After 4 years of undercharging my 4 12V US Batteries I finally got a DPI charger to milk some life out of this pack. I started with an equalizing charge to balance the batts and bring them up to full charge. This consumed a lot of water so I refilled the batts post charge. Plugged the cart in again last night after a short 1 mile run with the cart. This morning, post charge, the batteries are still gassing while on trickle charge and water level is low again. The garage is filled with the rotten egg smell of electrolyte. I'm a little concerned about the high amount of gassing while on charge and even post charge trickle. Also, the amount of water being consumed during charge is quite high. I know this pack is coming due for replacement but can I continue to get the most out of these? Is the high amount of gassing unusual and the water boil off typical for 4 1/2 year old (long under charged) batteries? Are these conditions safe? I reinstalled the single point battery watering system because of the large volume of water required post charge. Also, can I refill the batteries while it is still plugged into the DPI or should I disconnect it, refill, and then reconnect?

BGW

__________________
This advertising will not be shown in this way to registered members.
Register your free account today and become a member on Buggies Gone Wild Golf Cart Forum

oldnavycdr

Also, with the green light of charge complete illuminated the meter is reading 6 amps. Seems a bit high for a maintenance trickle charge. The jumpers on the charger are set to Mode 1 for US Batteries.

cgtech

The batteries are already damaged, possibly beyond repair by the DPI. I think the DPI is working just right, for the crappy batteries. You can try, but I don't really think the situation is going to improve.

JohnnieB

The DPI float charges (Constant voltage) instead of trickle charging (Constant current or current limited). The constant voltage used is above the At-Rest 100% SoC voltage, but less than the gassing voltage.

Normally, there is very little, if any, gassing when on float charge, but any time current is passing through the electrolyte, gassing (electrolysis) can occur. By regulating the voltage to a fixed level and allowing the amps to float, the amount of energy added to the battery equals the amount of energy being consumed by self-discharge and energy lost to external battery drains, so there is no energy left over to decompose the water in the electrolyte (gassing).

The 6A seen on the ammeter while in float charge is mighty high. It might be due to the battery's poor health, or it could be something outside the battery pack is drawing amps. At a 6A rate, a fully charge 155AH battery pack will completely discharge in about 26 hours.

I'd make sure the DPI charger is putting out the correct voltage while in float charge.

The voltage at the end of the regular charge cycle can be 60V or more, so once the green LED comes on (Green LED only - if Yellow and Green are on, it is still the regular charge cycle), give it 3 or 4 hours to settle down to the float charge voltage level.

What is the battery pack voltage?
What are the individual battery voltages?

oldnavycdr

Pack voltage was 50.9 this morning. Battery voltages were roughly 12.7, 12.64, 12.6 and 12.74. There are no accessories to speak of on the cart beyond lights and a SOC meter. I figure this pack is about toast but as long as I can get 18 holes out them I'll limp along, unless this situation is dangerous. If so, then I'll buy a new pack and start off right with the DPI. AFTER verifying the float voltage is correct. Thanks for the help guys!

oldnavycdr

Been back on charge for about 3 1/2 hours now. Pack is at 52.4 (on charge), ammeter reading 15 amps. Gassing but not the rolling boil sound it was making the first couple of charges. I topped off the water prior to starting this charge.

JohnnieB

Need to be a little cautious adding water before charging. The electrolyte expands (grows in volume) as the SoC (State of Charge) increases and if it covers the air vents (vertical slots in the side of the wells), it will overflow.

The gassing will increase as the on-charge voltage increases.

Charging at 15A or more for 3.5 hrs might be warming the batteries quite a bit. If the get to 120°F, disconnect the charger, let the cool off and then reconnect charger.

oldnavycdr

Thanks, Johnnie. The cart had just come off charge when I added the water -- a LOT of water. I understand not to add water prior to charging but since it had just come off of charge and several cells were at the top or just below the plates I didn't want to risk charging them uncovered. I'll monitor the battery temperature.

JohnnieB

Yep, you don't want to charge (or discharge) with the plates exposed to air.

oldnavycdr

Yea, they got pretty warm. Stopped the charge to let them cool. Wondering if heat is where all the water is going?