not having a good day - my batteries are boiling again now

Your inverter is sending to much charge to them I believe. Resolve that issue first.

I'm sure you'll day will get better. Anyway, you always have tomorrow. Good luck with your battery.

Hi JR I beleive what Chip said.Your inverter is charging too much.Once the batteries are full charge,your inverter should cut to a trickle charge just to maintain it.If you can get a voltmeter,test the voltage on the batteries with the inverter off (street power off).The reading should be close to the voltage of your installation, 12V..24V..or 48V on full charge batteries.Then,turn on the inverter and test again.the reading should be the same or very close.

On low batteries,it's normal that the voltage coming from the inverter will be one or two volts above your installation rating until the batteries are fully charged,then,it should cut off.

Regards

Mike

When older batteries get hot, they get into a thermal runaway condition where the inverter cannot reach the state of full charge. They never reach the proper voltage for the inverter. So it just keeps pumping in current because the voltage does not rise high enough to go to absorption and/or float states of charge. If you can, disconnect the batteries and let them cool. It might help get more time out of them.

As batteries age they reach a point where the plates are damaged by loss of material that falls to the bottom. At that point they will never reach the proper state of charge and need to be changed. I just bought a new set of batteries today at LH in Moca. Mine had become permanent space heaters and were simply wasting energy. By the way, EDTA will NOT fix this kind of problem because it is not sulfation that is the problem.

One more point. If your inverter has a battery bank size, turn it up to the largest bank size. That will help them get to float faster and waste less energy. Also you can switch the setting from 7 to 6. That will turn of the first stage of charging at a lower voltage hopefully reduce the heating. This is only for older batteries that are acting up and overheating.

From the very beginning when I bought my first set of batteries and inverter the batteries boiled. I changed everything after two years and have had no problem. An expert in inverters needs to dial down the charge imo.

Indeed, the proper settings of battery charge rate in amperes, correct battery type selector switch position and battery bank size are all important to battery life. A battery charge rate for lead acid deep cycle batteries is typically 1/10th to 1/8th of the bank size or capacity. For example charge one 225 AH bank of 4 batteries between 23 and 28 amps. Two banks of 225 AH batteries add up to a 450 AH bank that can be charged between 45 and 56 amps. Three banks of 225 AH batteries will have a bank size of 675 AH that can be charged at 67 to 84 amps.

That said, if your electricity is almost always on, you can charge at lower than those rates and help to prolong battery life. On the opposite end, if you have a poor supply of electricity which is only on for short periods each day, you will have to push up the charge rate or fear losing power when the batteries run out.

I know of one person completely off the grid that charges a large bank of batteries from a generator at the maximum rate his inverter/charges can supply every day in just 2 hours and then they drain down to 30% of capacity. Going from 30% charge to full in 2 hours should be a battery killer, but he gets 2 to 3 years from his batteries doing this very harsh method.

I just purchased Trojan Red T105 225 AH batteries from LH Internacional. They were 5,000 pesos RD each and LH will give you 800 pesos each for the old batteries you trade in. I go to LH because they are a major importer of batteries and supply many other shops. They give you batteries that are all from the same batch from the factory and they have not been sitting on the shelf of months. Both of which are important when buying new batteries.


Trojan Red batteries are the best normally available in the DR and are probably the most economical in the long run despite being the most expensive. Note that Trojan black batteries are only 208 AH so beware of that. US Battery brand is also a good choice. US Battery also has a 225 AH and and 208 AH version for sale here.

We have not established that the OP has an inverter with all of the settings I described in this thread.

It would only take one warped plate in the battery bank to cause the inverter to think more charge is necessary with other batteries are full, because the inverter reads that the overall float level has not been reached and continues to charge.

One check would be to turn off the inverter and check the voltage of each battery individually. If one is low that could be the culprit. 'Course, then the real decisions have to be made: replace the one, or replace them all. Tough call if the bank is only a year old...

A decent voltmeter should be in every expat toolbox.

jrh, do you have a 12 or 24v system?

CB, you got that right. And another item is a battery hyrdometer. If the readings differ by more than a slight amount, it is time to equalize the batteries. If equalization doesn't help bring a cell back to the correct reading, then that cell is failing.

EZ Red S101 - Battery HYDROMETER

If the battery bank is a year old and you try to replace just one failed battery, it will probably not work out. Been warned against doing that, tried it anyway and the other batteries quickly started to fail. The batteries have to all be in similar condition to play nice with each other like a good team.

windeguy said:

If the battery bank is a year old and you try to replace just one failed battery, it will probably not work out. Been warned against doing that, tried it anyway and the other batteries quickly started to fail. The batteries have to all be in similar condition to play nice with each other like a good team.

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I'd replace the one bad battery with a good used on of approx. the same age...if I could find it. They need to be in approx. the same age/condition...

Most inverters, and certainly good quality ones have a "Battery Sense" port, into which you can plug a temperature sensor that you jam between your middle batteries. This then cuts down the charging current when the batteries get hot. The sensors are available through Trace or off eBay in the USA. I certainly worked for me, I've had my sensor now for about 5 years

jrhartley said:

apparently one of my cells is defective, no cheeky remarks please........the batteries charge has been reduced so that they are no longer continually charging and seem to be working ok for now- I dont know how long they will last in a power outage with the reduced charge though

also one of my cables had come loose apparently they gradually come loose over time , so you should tighten then periodically when checking the water level

thank you to anyone that tried to help
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That is exactly the situation where substituting a battery of the same age and brand as the one with the bad cell could help. Hard to do.

Slightly off topic but here goes- can anyone tell me :
Are the electrical items that are covered by the inverter (ie still work when the mains power is down) only wired up to the converter?
If so does that mean if the inverter stops working or is disconnected or stolen then those appliances will not work even when the mains power is OK?

Inverters have a switch inside them(called a relay) that switches between the power being supplied by the batteries when there is no utility power or the utility when utility power is on. If the inverter is disconnected then you will have no power from the utility without making that connection manually between utility power and the power supplied to the line formerly serviced by the inverter. CAUTION: Never make that connection with the inverter still in the circuit because you will almost certainly blow up the inverter.

If the relay fails, it may not pass utility power correctly.

On the Trace inverters that I own, if you disconnect the batteries then the utility power will not pass through the inverter, which I have always considered a strange way to design the circuit. I would have expected the design to default to street power if no batteries are connected.

My villa is maintained by a local management company. The transformer to the house which supplies the street electricity blew up but has now been replaced. The inverter was stolen by the outgoing tenant. The management company are telling me because most of the equipment in the house is covered by the inverter then they cannot check that equipment without a new inverter and batteries being installed. My question is - can all the equipment in the house be checked without installing a new inverter? I would like to only install a new inverter once a new tenant is found for the house. That might be quite a long time given the current (excuse the pun!) economic climate.