Inverter for portable computers

[westernman]

I have a Xantrex XPower 300 which is supposed to deliver 300W (600W Peak) of modified sine wave. It is hardwired with substantial wiring directly to big +ve and -ve bus bars in the boat (i.e. not through a silly cigar lighter).

However, it will not work with my portable computer mains charger (Dell 65W). I have also tried it with someone else's computer as well with the same results.

In both cases, the undervoltage alarm goes off in the inverter and the computer does not get any power.

What is going on? Does it really have to be a pure sine wave for these cheap chinese battery chargers that Dell uses????

 

[Quandary]

While I normally use a direct 19.5 volt converter to save power, our Dell laptop will also run quite happily off our 300w. inverter. The Dell charger label says 100-240v 1.5w so it should surely cope with your inverter output.

 

[fjarvis]

Does it work with the engine running (i.e. inverter at alternator voltage)? Could be that your battery is on the way out and the inverter senses too low a voltage on the battery when it's drawing a bit of current and shuts itself down...

 

[Playtime]

I have a Xantrex XPower 300 which is supposed to deliver 300W (600W Peak) of modified sine wave. It is hardwired with substantial wiring directly to big +ve and -ve bus bars in the boat (i.e. not through a silly cigar lighter).

However, it will not work with my portable computer mains charger (Dell 65W). I have also tried it with someone else's computer as well with the same results.

In both cases, the undervoltage alarm goes off in the inverter and the computer does not get any power.

What is going on? Does it really have to be a pure sine wave for these cheap chinese battery chargers that Dell uses????

I doubt it is the Dell charger that is the problem. As others have said, check the battery voltage when the Dell is plugged in. Does the inverter work OK with other loads of, say, 100W?

I have an old Dell laptop running off a 150W modified sinewave inverter without problem.

 

[westernman]

I doubt it is the Dell charger that is the problem. As others have said, check the battery voltage when the Dell is plugged in. Does the inverter work OK with other loads of, say, 100W?

I have an old Dell laptop running off a 150W modified sinewave inverter without problem.

It has only had problems with the lap top chargers - although the other stuff plugged in (several mobile phone chargers, MP3 players etc) is probably less total load than a lap top charger.

I have not checked when plugged into shore power or the engine is running. I will try that. I will also check try to check if the voltage is sagging.

 

[NorthUp]

a long shot..

try plugging in a table lamp with a 40 or 60 watt incandescent bulb as well as the Dell power supply.

 

[kesh]

While I normally use a direct 19.5 volt converter to save power, our Dell laptop will also run quite happily off our 300w. inverter. The Dell charger label says 100-240v 1.5w so it should surely cope with your inverter output.

Mine says 1.5A, so at 240 V this would be 360 watts. But I think this is over spec, particularly as the output is 19.5 V at 4.62A = 90 odd watts. I don't think the transformer is that inefficient.

So my guess is that the OP's boat's batteries are dropping a little too much voltage under load. Are they old or of not that high a capacity?

 

[charles_reed]

I have a Xantrex XPower 300 which is supposed to deliver 300W (600W Peak) of modified sine wave. It is hardwired with substantial wiring directly to big +ve and -ve bus bars in the boat (i.e. not through a silly cigar lighter).

However, it will not work with my portable computer mains charger (Dell 65W). I have also tried it with someone else's computer as well with the same results.

In both cases, the undervoltage alarm goes off in the inverter and the computer does not get any power.

What is going on? Does it really have to be a pure sine wave for these cheap chinese battery chargers that Dell uses????

My Dell charges quite happily from 150watt inverter.

Quoted, input is 1.5 amp 100-230vAC, output 19,5VDC 3.34 amps

In fact it only draws anything like this with discharged batteries and the computer on.

I'd suggest, as a test you put the computer switched off but with batteries requiring charging.

I'd also suggest using a direct current transformer - Maplins' 300watt version has a tip to suit the Dell and pulls about 60% of the current of the inverter/mains charger combination.

My inverter, however, is a Synaptics pure sine wave one, of considerable antiquity and cost. Pure sine wave is unnecessary for a battery-powered laptop.

 

[westernman]

Mine says 1.5A, so at 240 V this would be 360 watts. But I think this is over spec, particularly as the output is 19.5 V at 4.62A = 90 odd watts. I don't think the transformer is that inefficient.

So my guess is that the OP's boat's batteries are dropping a little too much voltage under load. Are they old or of not that high a capacity?

There are two banks of 260AH each. They were installed in 2004. Is that getting on a bit or should they still be going strong at that age?

 

[westernman]

I'd suggest, as a test you put the computer switched off but with batteries requiring charging.

Tried that - same result.

I'd also suggest using a direct current transformer - Maplins' 300watt version has a tip to suit the Dell and pulls about 60% of the current of the inverter/mains charger combination.

This is probably a good idea. Does the tip for Dell really work?

I tried one attached to a generic mains converter and although it supplied power to the computer and I was able to run the computer with discharged batteries, the computer complained that it was not a Dell charger and did not charge the batteries at all. Is this a new Dell thing?

Actually is was a real dell tip cut off a broken Dell mains charger and attached to the cable of the generic one.
So it looks like there is funny business going on. Also the computer complains if I plug in a Dell 65W charger - it knows it is not the original 95W one (although it does not complain about it not being Dell as in the previous case - how does it know??)

My inverter, however, is a Synaptics pure sine wave one, of considerable antiquity and cost. Pure sine wave is unnecessary for a battery-powered laptop.

That is what I thought.

 

[tel1]

There are two banks of 260AH each. They were installed in 2004. Is that getting on a bit or should they still be going strong at that age?

the amps have nothing to do with a batteries life. the amps is just how much power is stored.

you want the voltage drop. charge a battery up to full charge, disconnect everything, take a voltage reading, it should be well above 12v and not really anymore than 13.5v. then every 15 mins do the same again, if it goes under 12v in under a few hours then your batteries are shot. even if you top up to 13.5 v and it goes below 12.8v in 2 hours id say they are shot. this test must be carried with the battery disconnected from everything.

with all that in mind they tend to say batteries wont last anymore than 5 years max, and most people probably change theres every 3 years. so your batteries being a 2004 vintage would tell me and others that your battery is as dead as the dodo.

hope this helps

 

[kesh]

There are two banks of 260AH each. They were installed in 2004. Is that getting on a bit or should they still be going strong at that age?

too many variables to know. don't know how they've been used or what type of battery. but 6 years is a bloody good run and it would be no surprise if they are dying.

on the other hand that's a lot of amp hours and shouldn't produce much voltage drop under that kind of load if the batteries are even only slighty good.

 

[westernman]

the amps have nothing to do with a batteries life. the amps is just how much power is stored.

you want the voltage drop. charge a battery up to full charge, disconnect everything, take a voltage reading, it should be well above 12v and not really anymore than 13.5v. then every 15 mins do the same again, if it goes under 12v in under a few hours then your batteries are shot. even if you top up to 13.5 v and it goes below 12.8v in 2 hours id say they are shot. this test must be carried with the battery disconnected from everything.

with all that in mind they tend to say batteries wont last anymore than 5 years max, and most people probably change theres every 3 years. so your batteries being a 2004 vintage would tell me and others that your battery is as dead as the dodo.

hope this helps

Thanks for that.

So the next thread is, what do forumites recommend for battery type?

 

[tel1]

Thanks for that.

So the next thread is, what do forumites recommend for battery type?

depends on how much power you need. i live on a 38 footer, i have 3 120ah batterys and one starting battery. in a marina most of the time so they do me lovely. if i was going in a marina once every two weeks then id like the next size up. you also have to think about charging them. the bigger the amp hr the longer to charge. dont forget though, i calculate on a 60 to 70% loss on amps. you must never take the battery below 50% so my 360 amp hr batterys have allready been reduced to half of that at 155 amps. i tend not to use more than 100 amps, at this stage i either plug in or get the engine on. you then have to work out what you use, i have a fridge @ 2 amps an hour, normally lights can be as much as 1 amp, 5 lights = 5amps an hour. you can be surprised on how much power you use. choose wisely!

hopefully that hasent baffled you to much

oh and this laptop, running off my 500w inverter drains about 1 to 2 amps an hour!

 

[westernman]

depends on how much power you need. i live on a 38 footer, i have 3 120ah batterys and one starting battery. in a marina most of the time so they do me lovely. if i was going in a marina once every two weeks then id like the next size up. you also have to think about charging them. the bigger the amp hr the longer to charge. dont forget though, i calculate on a 60 to 70% loss on amps. you must never take the battery below 50% so my 360 amp hr batterys have allready been reduced to half of that at 155 amps. i tend not to use more than 100 amps, at this stage i either plug in or get the engine on. you then have to work out what you use, i have a fridge @ 2 amps an hour, normally lights can be as much as 1 amp, 5 lights = 5amps an hour. you can be surprised on how much power you use. choose wisely!

hopefully that hasent baffled you to much

oh and this laptop, running off my 500w inverter drains about 1 to 2 amps an hour!

I was thinking in terms of

1) normal car batteries
2) lead acid from a swindlery (any difference from a standard car battery?)
3) some of the more modern more expensive fancy types?

 

[tel1]

I was thinking in terms of

1) normal car batteries
2) lead acid from a swindlery (any difference from a standard car battery?)
3) some of the more modern more expensive fancy types?

well, i bought my boat 6 month ago, the batteries were shot. dident have the cash for new super duper fancy ones so went down to canvy island for some. i got three 115 ah batterys and the were £70 each, 6 months down the line and im wishing i bought the super duper ones. the ones i have a droping volts as if it was santa droping pressies on xmas eve. my advice, and advice is all it is, do some research and get yourself a good set of batteries, some that will last. i know i will be within the year!

 

[kesh]

the amps have nothing to do with a batteries life. the amps is just how much power is stored.

of course not. but they do have something to do with drop under load. and that is the issue here. a single 110Ah battery that's getting old is going to suffer worse drops than 4 such batteries equally old.

 

[charles_reed]

Tried that - same result.



This is probably a good idea. Does the tip for Dell really work?

YES

I tried one attached to a generic mains converter and although it supplied power to the computer and I was able to run the computer with discharged batteries, the computer complained that it was not a Dell charger and did not charge the batteries at all. Is this a new Dell thing?

MY DELL IS A 2000 8600 - IT COMPLAINS BUT GETS ON WITH CHARGING

Actually is was a real dell tip cut off a broken Dell mains charger and attached to the cable of the generic one.
So it looks like there is funny business going on. Also the computer complains if I plug in a Dell 65W charger - it knows it is not the original 95W one (although it does not complain about it not being Dell as in the previous case - how does it know??)

ON MAINS POWER THE COMPUTER RUNS AT A HIGHER VOLTAGE, X2 THE CPU SPEED AND FULL SCREEN BRILLIANCE, AUTOMATICALLY - WHILST CHARGING THE BATTERIES.
PUT IN LOWER AMPS & NOTHING LEFT FOR CHARGING.

LINUX ALLOWS FAR GREATER CONTROL OVER CHARGE RATES, SCREEN BRILLIANCE, CPU SPEED VIA THE ACPID APPLET





That is what I thought.

Apologies fro shouting - site shortcomings don't allow using a different colour and interleaving.

 

[westernman]

Apologies fro shouting - site shortcomings don't allow using a different colour and interleaving.

The cut off Dell tip on another charger did not charge the batteries at all with the computer switched off.

Why?

 

[charles_reed]

The cut off Dell tip on another charger did not charge the batteries at all with the computer switched off.

Why?

Without knowing the model and BIOS it's difficult to even hazard a guess.

Was the voltage set to the correct 19v?
Polarity?

As the two most obvious ones.