Inverter Question...

[Olly]

JD ,
You raise an interesting point - about the state of charge . The New battery will in fact only be partially charged. So my recommendation is in fact the opposite of yours JD. Use the invertor to discharge the existing batteries to about half way - about 23.7 volts overall (45% charged) or for three good batteries batteries at 17.8 volts, and then change out the Bad battery( switching everything off of course) with the new one ! Charge them all up together.

This is one aspect that is often missed.

Olly

 

[cobraboy]

JD ,
You raise an interesting point - about the state of charge . The New battery will in fact only be partially charged. So my recommendation is in fact the opposite of yours JD. Use the invertor to discharge the existing batteries to about half way - about 23.7 volts overall (45% charged) or for three good batteries batteries at 17.8 volts, and then change out the Bad battery( switching everything off of course) with the new one ! Charge them all up together.

This is one aspect that is often missed.

Olly

Charging won't work that way. It will read overall internal resistance and charge accordingly. The internal resistance differential is more of a function of charging than discharging, since rarely will they me discharging at a high level equivalent to charging. The charger will always do a maximum charge...up to the very end when resistance is more critical. What happens is the new battery will never get fully charged...and THAT is where sulfur will accumulate on the plates. Because old batteries are used, the oomph for equalization won't be there.

Adding one new will seem to "work," but the system will always be operating below capacity and ultimately the batteries will fail much earlier.

I had 3 battery banks on my sailboat that had to be managed and had to learn the hard (expensive) way. It wasn't until I understood how the system worked that I got long life out of the battery system.

 

[Olly]

cobraboy,
Most boat systems are parrallel systems and not the series/parrallel arrangement of invertors. Your charging is mainly from engine alternators which I agree with you are voltage controlled not current control. In these circumstances I would agree with you but this is an invertor with complicated charging control.
So I am not sure the two systems are similar enought to draw any conclusion.

Well I am sure you are confused Jenny. But I will send you a pm with step by step instructions of how to do it. If you have someone who can help and an adjustable wrench you can do it yourself.

Olly

 

[Koreano]

So...
Is it true that most of the inverter will require you to buy in 4's? I have no knowledge on this... I have 4 and I might add extra if I feel the need. I don't know how long Trojan T-105 batteries last with just few items(LCD TV, internet modems, and maybe fridge) hooked up to it. I would like to add couple of fans and two lights one living room and others in bedroom.

 

[cobraboy]

cobraboy,
Most boat systems are parrallel systems and not the series/parrallel arrangement of invertors. Your charging is mainly from engine alternators which I agree with you are voltage controlled not current control. In these circumstances I would agree with you but this is an invertor with complicated charging control.
So I am not sure the two systems are similar enought to draw any conclusion.

Well I am sure you are confused Jenny. But I will send you a pm with step by step instructions of how to do it. If you have someone who can help and an adjustable wrench you can do it yourself.

Olly

Not correct.

Larger boats, especially sailboats, use 6v deep cycle batteries in series/parallel just like a home inverter. In fact they often have a much more sophisticated charging/monitoring system than a DR inverter. They also have both ground AC (dockside power) and engine driven charging underway which operates exactly like a diesel genset. My boat had both an deisel engine-driven 50w and 135w alternator (depending on needed load) with switches and sophisticated charging/analysis system far more complex and accurate than a home inverter/charger as well as a 3kw diesel genset. I had two battery banks with 8 6v deep cycle batteries, and one with two auto batteries for engine and diesel genset starting; they were all managed and monitored with sophisticated digital "smart controllers." Try replacing 16 batteries at a time because you didn't fully understand how it is supposed to work. Expensive tuition.

Mariners here know what I speak of.

The principles are the same.

It all comes down to personal choice: do you want to pay a little now and a lot later sooner, or more now, knowing what you have, and managing the system more efficiently for a longer period?

I suspect one battery died not because of the battery itself, but for another technical reason: charging rate (either/both voltage and amps), excessive discharge cycles, excessive discharge depth, excessive discharge rate, lack of equalization (cheap inverter), lack of battery maintenance (boiled out acid), etc. Replacing one or more batteries without investigating the root cause may create yet another short-term problem.

If it was me, I'd take a peek at the setup before making my decision. There are good technicians out there who know their stuff. Inverters are a part of normal life on this island. It may be complicated, but it's worth learning about because of the constant use.

But certainly the pedestrian solution is to just replace the one battery and hum a happy song...

 

[cobraboy]

So...
Is it true that most of the inverter will require you to buy in 4's? I have no knowledge on this... I have 4 and I might add extra if I feel the need. I don't know how long Trojan T-105 batteries last with just few items(LCD TV, internet modems, and maybe fridge) hooked up to it. I would like to add couple of fans and two lights one living room and others in bedroom.

A good 3.5 inverter with 4 T-105's will give you many hours of power with the items you mention.

We have a 3.5 with 4 batteries and have run out of battery on just 2-3 occasions when we had really long blackouts. I started a thread about my reseqarch, and another about how we hard-wired a remote 3.5kw gasoline genset into the home system just in case we had more long blackouts.

 

[william webster]

"And hum a happy song..." until the next one goes senos up.

 

[Olly]

Cobraboy - actually I am a mariner too?

Olly

 

[Olly]

Koreano,
Sort of getting away from the OP original question. Yes you do have to add in 4's for a 24Volt invertor.
With the load you describe -LCD TV 250 Watt, Modems 10 Watts, Fridge -medium size - 300 Watts when running - does not run all the time. If you have a modem then you have computer -80 Watts for Laptop.

This gives you a total load of about 650 to 750 Watts.

The four T-105 have a rated capacity of 205 amphours which gives you about 4.1 kWh stored so you should get about 6-8 hours out of them. Adding another 4 batteries in parrallel will give you probably 15 hours with the same load.

Adding fans are about 50 Watts each and low enegry lights about 12-15 Watts each. that will move you to about 900 Watts giving you 4.5 hours on your current 4 batteries and about 9 hours if you add another 4 batteries . You might get a bit longer since you have dropped the discharge rate for the batteries with two strings.

I think that answers your question - and guys this is ball park as the fridge is the key variable here. Oh and I always recommend at least a 3.5kW invertor if you have a fridge as it has a high start up current.

Olly

 

[Jenny429]

Wow.. Thank you all for so much information!! I have learned a lot.. I have another crazy question since you all seem so knowledgeable.. How is the inverter supposed to be hooked up? You see, I had the Inverter installed in the kitchen, then decided to put the batteries outside *inverter still inside*.. That's when the problem occurred.. And I always wondered if they hooked it up wrong.. Is it supposed to be negative to positive, linking each battery or is it supposed to be setup like a parallel series (I think) where All positives connected to the positive on the inverter.. all negatives chained to the negative side?

Thanks in advance..

 

[Olly]

Jenny - just sent you detailed instructions by PM - private message.


Olly

 

[cobraboy]

Cobraboy - actually I am a mariner too?

Olly

Then you know my comments are spot on...

 

[Olly]

Cobraboy -if you had 50w and 135w alternators I am not surprised you had problems - I think you mean 50 amp and 135 Amp Alternators!
So no your comments aren't spot on and I guess you paid a heavy price for believing what you do !
This is a complex subject and when you put in the marine environment even more so!
Olly

 

[cobraboy]

Cobraboy -if you had 50w and 135w alternators I am not surprised you had problems - I think you mean 50 amp and 135 Amp Alternators!
So no your comments aren't spot on and I guess you paid a heavy price for believing what you do !
This is a complex subject and when you put in the marine environment even more so!
Olly

Yes, amps, mea culpa.

I had problems because of poor maintenance and then just replacing damaged batteries.

The system never worked as it should until all the batteries were the same condition.

 

[SantiagoDR]

I would like to add 3 important side notes to this discussion:

(1) Best to add water to the batteries when they are charged, else you could over fill, and it will spill out upon charging.

(2) Battery brochures states that the water level should be 1/8" below the split ring when charged, just above plates when discharged.

(3) Keep the batteries AWAY from the Inverter, the fumes can damage the Inverter !!!!!!!!!!!!

The brochure I have is only in Spanish:

PS: I got $800 pesos credit for each used battery I traded in for new ones here in Santiago last year.

 

[Olly]

Jenny ,
Sent another pm .

Olly

 

[Casino127]

inversor question

Jenny ,
Sent another pm .

Olly

I have a 5.5k inversor with 8 batteries, 4 above and 4 below the shelves. The 4 below are getting hot. I disconnected the hot batteries on the below shelve hopping that this would work using the 4 above. It s not working.............What shall i do ? the all system is 4 years old. Are they getting to old ?? thanks for any answer.

 

[Criss Colon]

"4 Years" could be getting to the "End-of=the=line" for the batteries.
Depends on how mny "Apagones",and for how many hours,they have "Lived" through.
Also,were they maintained well,ie.,water level checked at least every week in the last year or two!
"Heat",and "swelling" means it's just about "OVER" for the batteries.
I say,"Time To Buy 8 New batteries"!
Then maintain them as if the cost a lot of money,Because They DO!
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC

 

[cobraboy]

"4 Years" could be getting to the "End-of=the=line" for the batteries.
Depends on how mny "Apagones",and for how many hours,they have "Lived" through.
Also,were they maintained well,ie.,water level checked at least every week in the last year or two!
"Heat",and "swelling" means it's just about "OVER" for the batteries.
I say,"Time To Buy 8 New batteries"!
Then maintain them as if the cost a lot of money,Because They DO!
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC

Yup. Good post.

A battery can only take so many charge/discharge cycles, the deeper the discharge, the shorter the life. That can be a year or seven years.

One issue is short charging. That happens when the charging cycle is disturbed before going into float mode, and causes the plates to sulfate. That can be common in the DR where the power goes off and on frequently, and batteries often don't get fully charged between discharge cycles.

Many cheaper chargers don't have an equalization phase and that will definitely cause batteries to die young.

 

[Casino127]

inverter question

"4 Years" could be getting to the "End-of=the=line" for the batteries.
Depends on how mny "Apagones",and for how many hours,they have "Lived" through.
Also,were they maintained well,ie.,water level checked at least every week in the last year or two!
"Heat",and "swelling" means it's just about "OVER" for the batteries.
I say,"Time To Buy 8 New batteries"!
Then maintain them as if the cost a lot of money,Because They DO!
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC

Thanks Criss