inverter batteries clamps strait to starter batteries is it safe

[capt_caveman]

my cigarette lighter was disabled back in the 80s (school bus) and I cant get the screws out of the dash two are striped .
I have a 400 watt inverter with both cig. plug and pos. and neg. clamps is it safe to clamp them to my big Interstate starter batteries ?

 

[John61CT]

It won't hurt you if that's what you mean.

But it may flatten the battery so you need a jump, depends how many AH you need to pull between recharges.

 

[capt_caveman]

I just need to recharge my cell phone and watch two movies a night on my laptop off of the hard drive no dvd
I just dont want to hurt that $200 Interstate school bus battery

 

[John61CT]

You don't need an inverter for either of those uses, much more efficient to use a native DC converter from 12V to what your device needs.

Get an AH counter, start with a full batt, and stop when it says you've used 40-50% of the batt's capacity.

The lower you discharge it the faster it will wear out.

Next one get a proper deep cycling bank instead.

Have one of those jumpstarter powerpacks handy, keep fully charged, just in case.

 

[John61CT]

How are you recharging your bank back to full each day?

Should make sure you are getting to true 100% at least a few times per week or the bank won't last long.

Takes 5-7 hours, if your charge source puts out enough amps current, long enough at Absorb voltage. Otherwise much longer.

Need an ammeter to confirm your charge source is doing it right, most drop to Float voltage too early.

 

[capt_caveman]

.

Have one of those jumpstarter powerpacks handy, keep fully charged, just in case.

thats what I have been using to power my laptop but its all most dead the only way to recharge it is to put it in a back pack and pack it into the library to recharge it (stealth) 

 

[capt_caveman]

How are you recharging your bank back to full each day?

Should make sure you are getting to true 100% at least a few times per week or the bank won't last long.

Takes 5-7 hours, if your charge source puts out enough amps current, long enough at Absorb voltage. Otherwise much longer.

Need an ammeter to confirm your charge source is doing it right, most drop to Float voltage too early.

I  dont have a bank yet just want to us starter batt. for small stuff

 

[John61CT]

thats what I have been using to power my laptop but its all most dead the only way to recharge it is to put it in a back pack and pack it into the library to recharge it (stealth)  [emoji14]

Yes, they don't have much AH capacity, laptop uses so much more than a phone or tablet.

Keep it charged up for jumpstarting.

So again, how are you going to keep your **big lead** battery charged up?

 

[John61CT]

I  dont have a bank yet just want to us starter batt. for small stuff

A laptop is not small usage for a small bank.

Bank = batt, no difference

As I said when you need to replace your Starter, get one designed for this deep cycling usage.

Batteries are consumables, like tires and brakes.

Or get a better bank and save money in the long run.

In any case if you don't have enough power inputs for charging, none of this matters, batts only store energy, not produce it.

 

[capt_caveman]

Yes, they don't have much AH capacity, laptop uses so much more than a phone or tablet.

Keep it charged up for jumpstarting.

So again, how are you going to keep your **big lead** battery charged up?

Im going to start out with the jumper cables setup that Bob suggested running jumper cables from main battery to house battery charge while driving 
tell I figure out my solar setup

 

[capt_caveman]

raining every day in Seattle now even my Lucy light wont charge
charging everything at the Library right now

 

[John61CT]

Im going to start out with the jumper cables setup that Bob suggested running jumper cables from main battery to house battery charge while driving 
tell I figure out my solar setup

This is the first you mention a House battery.

Unless you drive 7+ hours a day, you will need another power source

 

[John61CT]

raining every day in Seattle now even my Lucy light wont charge
charging everything at the Library right now

I doubt they'll be OK with you lugging in a big lead battery.

Yes, solar is not too reliable in many parts of the country.

Maybe look for a place will let you run shore power to your vehicle overnight?

A genny has the same problem as driving, too many hours to get to Full.

 

[capt_caveman]

I doubt they'll be OK with you lugging in a big lead battery.

Yes, solar is not too reliable in many parts of the country.

Maybe look for a place will let you run shore power to your vehicle overnight?

A genny has the same problem as driving, too many hours to get to Full.

I meant charging my laptop and cell phone LOL I dont have a working cig. plug

 

[John61CT]

Forget a ciggie port, those are unreliable even dangerous anyway.

So, until you work out a way to regularly charge your big lead bank back to 100% Full, you should not use it for anything but starting your vehicle.

Unless you accept that will mean having to replace it maybe 10x faster.

 

[max+sophia]

John, Perhaps you can help.  My purchase of Greybeard 1987 Ford MH van, has fallen through.  So I will concentrate for now on Ruby, my 2005 Ford Explorer.
I have a cot setup, luggable loo, and a 75w inverter to cig plug. 
The major problem is that Ruby seems to have a short somewhere, or something other that keeps her from charging the battery properly.  in winter I don't use her often, and the battery has died.  Last year it even blew up when my son tried to jump start it.
So, wanting to be able to KNOW my car will start, I installed a battery maintainer,with the plug conveniently sticking outside the hood.  So far so good, but is there a gizmo that will tell me when I should connect the maintainer? At this point, I plug it in the day before an important appointment or when I MUST have a working vehicle.
Thanks, Max

 

[AuricTech]

Given that your primary source of power to recharge your electronic devices is, for now, your local library, here are some ideas:

1. Buy a replacement battery for your laptop and charge both batteries before you leave the library for the day. When one gets low during your evening movies, swap the other one in.

2. See if a Chromebook would fill most of your light computing needs. They tend to be power sippers (no internal hard drive or optical drive), so you might be able to watch your movies without needing to recharge a Chromebook as frequently as you would need to recharge a Windows or Mac laptop.

3. Buy one or two Goal Zero Sherpa 50 power packs, along with the available laptop charging cables (the Sherpa series has a dedicated DC port for powering laptops, thus avoiding the inefficiencies of using the inverter to run a power brick). That would give you over 100 Watt-hours of power storage, while still being light enough to take to the library for recharging. As a bonus, they also have USB ports for recharging your phone and such. You can currently buy "certified refurbished" Sherpa 50s (with the MSW inverter included) on Amazon for $99.95 each (use this link to this site's Amazon affiliate page (look on the right-hand side of the screen for the Amazon search box) to find them on Amazon, so our host gets a bit of cash from your purchase).

I hope these ideas help, either directly or by giving you new ideas.

 

[John61CT]

John, Perhaps you can help.  My purchase of Greybeard 1987 Ford MH van, has fallen through.  So I will concentrate for now on Ruby, my 2005 Ford Explorer.
I have a cot setup, luggable loo, and a 75w inverter to cig plug. 
The major problem is that Ruby seems to have a short somewhere, or something other that keeps her from charging the battery properly.  in winter I don't use her often, and the battery has died.  Last year it even blew up when my son tried to jump start it.
So, wanting to be able to KNOW my car will start, I installed a battery maintainer,with the plug conveniently sticking outside the hood.  So far so good, but is there a gizmo that will tell me when I should connect the maintainer? At this point, I plug it in the day before an important appointment or when I MUST have a working vehicle.
Thanks, Max

The two variables are, how cold does it get, and how new / good is the battery?

Isolate the battery while sitting many days, against the computer and other parasitic draws.

You could check voltage, but not precise, might as well just plug it in.

 

[highdesertranger]

find the problem and fix it, would be my recommendation. highdesertranger

 

[QinReno]

Max, it sounds like you likely need a new battery for the truck. Realistically speaking, after about 3-years and depending upon how cold the climate is where you live, you can start expecting the battery will need replacing in the next year or so. That's always the first thing on the list. The other thing to check is whether there is oxidation on the battery terminals - they probably need cleaning in any case .... wire brush or if the old style terminals,
https://www.walmart.com/ip/Hyper-Tough-Battery-Terminal-Brush/716187847

If you can charge the battery overnight and then can run the truck in the daytime with multiple starts, it's probably not the charging circuit, or alternator, that is bad. Garages have a tester that puts a heavy load on the car battery and can easily tell if it has adequate reserve energy, similar to this,
https://www.walmart.com/ip/Battery-Load-Tester-HD-130-AMP/16487237
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In regards laptops, they typically draw in the area of 40W, which translated back to 12V is 40W/12V = 3.3A, so figure a nominal 4A draw at 12V compensating for the inverter. So that estimates how much you're pulling from your battery when running the laptop. IE, in 6-hours, you'll pull about 24 Amp-Hr. That'll be the draw when you get a separate RV battery.

Also, you can run a 120VAC 60W-equivalent Led bulb off the inverter, which is what I do, and these draw only 11W, or about 1A at 12V. Quite efficient. So 6-hours of that is another 6 Amp-Hr draw from your RV battery. So, laptop and Led together will pull 30 AH, or about 1/3 the energy available from a standard 100 AH battery.

You can also get a cheap voltmeter at Harbor Freight or Home Depot to directly measure battery voltages. These will be accurate enough to tell how low your battery is getting, eg, below 12.5V or so is probably too low, and need of charging.
https://www.homedepot.com/p/Powerbuilt-Digital-Multi-Meter-648349/204505225