Any battery experts here? Using an inverter safely while the engine is off.

DJPepper · May 22, 2020

So I'm living out of my truck now while I save some funds to by a houseboat in San Diego. I just bought a cheap inverter from walmart to run my laptop and I'm wondering what implications this has for my battery. I have an ACDelco silver line (30 month) that's about a year old and has never had excessive drainage. So I guess my question is what exactly is the excessive drain limit? I mean is there a minimum voltage I should keep in mind to avoid premature battery failure. Obviously I want to avoid a no start condition. What voltage could that occur at? I'm just charging my laptop with it (130w charger) and am assuming running it while the engine is off is fine for a while. I tried to google and youtube for some answers but was inundated with garbage results so hopefully this question is fine here. Any other inverter related advice that might not be obvious to consider would be appreciated too. And inverter recommendations. I'm pretty sure this is a modified sine wave (cheap, Everstart plus 400w), are the true sine wave models worth it?

sefiroxx · May 22, 2020

Gambling. . .

Get a second battery and a solar charger

You might even get a battery charger to plug into the inverter when driving around.

What you can be assured the truck will start when needed and have a spare on hand for that of hand mIstake of leaving something on when living inside or talking a walk.

swathdiver · May 23, 2020

On 5/21/2020 at 10:46 PM, DJPepper said:

So I'm living out of my truck now while I save some funds to by a houseboat in San Diego. I just bought a cheap inverter from walmart to run my laptop and I'm wondering what implications this has for my battery. I have an ACDelco silver line (30 month) that's about a year old and has never had excessive drainage. So I guess my question is what exactly is the excessive drain limit? I mean is there a minimum voltage I should keep in mind to avoid premature battery failure. Obviously I want to avoid a no start condition. What voltage could that occur at? I'm just charging my laptop with it (130w charger) and am assuming running it while the engine is off is fine for a while. I tried to google and youtube for some answers but was inundated with garbage results so hopefully this question is fine here. Any other inverter related advice that might not be obvious to consider would be appreciated too. And inverter recommendations. I'm pretty sure this is a modified sine wave (cheap, Everstart plus 400w), are the true sine wave models worth it?

If your battery is a 48PS, it has a reserve capacity of 110 minutes when new. So you can discharge the battery at 25 amps for 110 minutes and each cell will have 1.75 volts at the end. I have this battery which is now almost 4 years old and I doubt it would last half as long, it's usually barely at 12 volts, enough to start and run modules but it's getting tired and it's my game to see how long it lasts.

You can replace that battery with the 48PG or a better choice would be a 48HPG which gives a reserve capacity of 135 minutes. The GMT900 charging system is not optimized for 48AGM or the 48PGHRC batteries.

If you can spare about $400 plus a pair of new batteries, add the second battery up front on the driver's side. There are write ups here and elsewhere by InTheBurbs on what parts are needed and how to do it.