[bigtrouble77]

I just bought this laptop:

http://secure.hypersonic-pc.com/scripts ... viator_AX7

I'm gonna be travelling quite a bit and need to hook this up to the car as the battery life is only 2 hours. I've tried hooking up inverters in the past with marginal success (some low power devices worked, most didn't). I ultimately want to snag a lighter adapter that goes straight to the laptop rather than use an inverter.

I was told by a honda dealer tech that hooking up a larger battery would be a problem because it would fry the wiring. Now I believe that many people here have upgraded to standard civic batteries so I don't really understand what the tech was talking about. Any help or links to high capacity batteries would be a HUGE help.

-BT

 

[Foxpaw]

I highly doubt that using a higher capacity battery would fry the wiring. The only scenario in which that would be the case was if the batteries internal resistance was greater than the resistance in the electrical system, meaning that the smaller battery could only supply X amount of current maximum, and that was being used as a safety limiter.

This scenario is extremely unlikely as not only would very few electrical engineers design such a system, but the lead acid battery can supply quite a bit of current and so the draw on the electrical system would have to be huge in order for such a safety mechanism to be effective.

Basically, a bigger, higher capacity battery can probrably cough up more current on demand, which could heat up the wiring more, but the keyword being current ON DEMAND, and I highly doubt that the Insight demands more than the stock battery can supply.

It is possible that when you said larger battery the tech interpreted that as "higher voltage battery." Since your laptop probrably has mothboard power levels of 12V, -12V, 5V, and -5V, you can probrably do that without stepping up, and then stepping right back down again - but it will depend on what sort of plug and stuff your laptop has.

Take a look at this and see if you could make use of it:
http://www.opussolutions.com/modules.ph ... name=News&

It's meant for connecting a DESKTOP computer in your car, but maybe it could work for laptop somehow.

 

[Rick]

Well if your going to depend on the 12 volt for any cyclitic use I'd recommend a deep cycle battery. As much as I'm not so much of a huge fan of optima's I think the civic sized optima yellow top might be your best bet for a drop in replacment. I think they're 41 amp hours. This will fill the whole battery tray so your not going to fit anything larger there without modification.

 

[bigtrouble77]

Thanks for the replies. I just discovered that I need an inverter. This is the one they suggest:

Linksys POWER2GO 140 Watt DC to AC Power Adapter
http://www.buy.com/retail/product_jump.asp?sku=10033740&SearchEngine=PriceGrabber&SearchTerm=10033740&Type=PE&Category=Comp&dcaid=15890

It's 140 watts. First, do any of you think the battery will have a problem keeping a charge if a 140watt device is drawing from it while the car is running? Second, will upgrading the battery have any positive effect in this situation?

 

[Guillermo]

I recommend a 400W or 600W DC to AC converter, it's more practical and can handle some current spikes. I went on road trip with a 150 Watt DC to AC converter I borrowed from work. The small video camera would sometimes crash the converter when it was turned on!
Next road trip we used a 400W DC to AC converter with no problems.

Bigger is better, 140 Watt converter is fine for cell phones but for your computer you might have problems sometimes, why risk it?

 

[bigtrouble77]

An Insight can handle a 400 or 600watt inverter? I had problems with a 250watt one, which worked fine in an acura. And if it does work will it drain the battery?

 

[b1shmu63]

Turning on the headlights draws 110 Watts. The key is to find out how much power your laptop actually needs, and sizing the inverter appropriately. Too big or too small an inverer is less efficient. A 600 Watt inverter with a 100 Watt load will probably draw about 140 watts from the 12 volt battery.

 

[dhammer]

skip the inverter

My dog just chewed thru my laptop power cord, so I bought this of necessity...but it is awesome! Remember your laptop takes DC power anyway, so why use an AC/DC inverter to plug in your AC adaptor to get DC power in the first place? Here is a link to a great universal power adaptor:

http://www.kensington.com/html/5406.html

Also, I use my laptop in my car so much I had to get a mount, but didn't want it installed....check this one out:

http://www.airdesks.com/CarDesk.asp

 

[lakedude]

Ok, I went to school to be an Engineer and am curretly an Electronic Tech. A higher capicity battery will NOT burn anything up. Heat is what burns things up and the amount of POWER a device uses determines how much heat it will put off. POWER = VOLTS times AMPS. Since the new battery is also a 12 VOLT battery the VOLTS would be the same. The new high capicity battery will have more available AMPS, but they will not all be used all at once. The amount of AMPS drawn out of the battery is defined by the load or RESISTANCE. If you put a high resistance load across a battery it will draw very few AMPS out of the battery. A lower RESISTANCE will draw more AMPS as defined by the equation AMPS = VOLTS / RESISTANCE. Remember that the VOLTS are the same in both batteries so the only thing that will increase the AMPS and therefore the POWER and therefore the the heat to burn up the wires is the RESISTANCE of the load. If there was a short (an unintentional lowering of RESISTANCE) a fuse would normally blow to protect the wiring from getting too hot. The only way (as has already been mentioned) that a bigger battery would burn up wiring is if the original engineers did not fuse the wires and there was short. There are rules about about such things that basically say that either wires must be fused or must be able to handle the full current (AMPS) of the source. Fuses or circuit breakers are normally used but on rare occations of a low available current source they are not. The only time I know of when wires are not fused is the wires coming out of a cheap "ice cube" wall transformer. Sometimes these wires are not fused because even if they are shorted the little transformer cannot put out enough current to burn up the wires.

Even the stock battery can put out more than enough current to burn up the wiring if a short develops so I'd bet a paycheck that the smaller wiring that goes the the 12 volt outlet or ciggerette lighter IS fused. A new battery is not going to burn anything up even if there is a short.

The bad news is that the new battery may not help unless there is something wrong with the old one. A 150 watt inverter is not much of a load to be putting on a even a small car battery especially if the engine is running.

The inverter they shipped with my old 2Ghz P-4 laptop did not put out enough power to run the laptop properly. The inverter works fine with the new laptop running a 1.5 Ghz mobile chip in the same car.

 

[bigtrouble77]

Thanks for all the suggestions and thanks lake dude for the info. The laptop should be coming in this week (possibly today).

They are shipping a direct DC power adapter with the laptop, not an inverter (As I originally thought).

I'll post my results when I get it all setup with the stock Insight battery. Being that this thing is an Athlon64 3700+ it's gonna be an interesting test. I'll be amazed if it works.