need 110v battery pack for laptop and printer

[ke6guj]

We are setting up some mobile carts that will have a laptop (65w), direct thermal printer (100w), and a wireless bridge (15w). Do those small emergency packs that you can start your car from, http://www.amazon.com/Duracell-DRPP6.../dp/B009YR00MI , have enough capacity to run all day and be able to recharged overnight, or should I go with something like this, http://www.amazon.com/Duracell-852-1.../dp/B000S0VFTM . I would need to be able to get 16 hours (2 8-hour shifts) off of them without the battery going dead and be able to recharge for the next morning.

Or am I just best served getting a Optima battery, an inverter and battery tender, wiring it all together and calling it done.

There might be the need to put a small laser printer on the cart and I'm really afraid of that. I'm definitely going to try to get a permanent stand for any laser printers.

[freonr22]

you have 180w if all on at same time

180w/110-120v = 1.6? amps?

p=i times e
p=ie
p=watts
i= amps
e=volts


from your first link
On a full charge a 60W AC appliance runs for 3.5 hrs
and
non-spillable 26 ampere-hour AGM (Absorbed Glass Mat) battery. The Powerpack can be safely and conveniently recharged from any household AC outlet or DC cigarette-lighter outlet [Works while car is running and should be limited to 4 hrs

from the second link

Sealed, non-spillable 60Ah AGM battery

you have about 1.6? amps +-

i would think the second would better suit you as the first talks about a 4 hour duty cycle.

maybe look on duracells website to see duty cycle on first..

[ke6guj]

what, you mean I have to use Math?

I was writing this post and just grabbed the first link I saw and didn' see that "On a full charge a 60W AC appliance runs for 3.5 hrs". that defintely isn't going to be enough to do what we need. I'll need to research the second one some more, but it has plenty of bad reviews which scare me. Need to see if I can find comparable items out there.

[ExtremeX]

You can do the math on run time and capacity after you figure out your final load… the printer doesn’t run 24/7, so you won’t be under peak conditions all day. (Get a kill-a-watt meter and get an average kwh for an average working day)

One of the units you listed has 26Ah of capacity and the other has 60Ah… not that much capacity, and i'm sure the internal overhead is higher than something like a stand alone inverter.

I would go inverter/charger route, with deep cycle golf cart or solar batteries (4v/6v/12v). The entire setup would be somewhat similar to a solar install without the panels and with a charger to top them off.

Look for batteries from reputable vendors like this.

http://www.trojanbattery.com/markets/renewable-energy/

http://www.batterysizingcalculator.com/

Ideally you do NOT want to discharge more than 30-40% of the total capacity. Running them into the ground every day will drastically reduce the amount of charge cycles and life of the batteries.

Also, buy the smallest more efficient inverter you can find as it will have a lower overhead on the system as your current draw isn’t very high.

Sizing it correctly will give you years of reliable operation.

[Victor Cachat]

One or two sealed automotive batteries (Optima) and an appropriately sized inverter will provide a lot of power/time.

[ExtremeX]

I don’t really see point of using automotive specific batteries for applications like this… since it’s not going in a vehicle there is no reason to conform to any sizing constraints.

Optima makes a good battery for their respected application (auto and marine, size specific cells with good shock and vibration resistance), but id look elsewhere for what the OP is doing. The biggest Yellow top they make I believe is 75Ah which cost about $225. Two in parallel would cost you $450 for 150Ah.

For that money you can get a better battery for less money.

http://www.batterystuff.com/batteries/golf-cart-products/6-volt-deep-cycle/t-105-6-volt-trojan-golf-cart-batteries.html

Two Trojan T-105 6v wired in series for a 12v final output @ $150 each. $300 total for 225-250Ah. They also make a 12v version for the same price and Ah rating.

Plus if you contact a stocking dealer in your area for whatever brand solar or golf battery, you skip out on shipping plus there usually buy them in large QTY and discounts can be had.

[Victor Cachat]

http://www.batterystuff.com/batteries/golf-cart-products/6-volt-deep-cycle/t-105-6-volt-trojan-golf-cart-batteries.html

Two Trojan T-105 6v wired in series for a 12v final output @ $150 each. $300 total for 225-250Ah. They also make a 12v version for the same price and Ah rating.

Plus if you contact a stocking dealer in your area for whatever brand solar or golf battery, you skip out on shipping plus there usually buy them in large QTY and discounts can be had.

It all depends on your tolerance for hazardous spills.
You can also parallel a lot of sealed led acid (SLA) batteries that are designed to be used in UPSs (which are also available at Batteries Plus).

[SkyHawk]

If you don't go with a deep cycle battery, the batteries will become useless prematurely, probably pretty quick. Deep cycle batteries are designed to take a deep discharge over and over. Normal auto batteries are not designed for that type of cycling. Normal auto batteries have a constant charge being applied to them by the alternator so they never become deeply discharged. And those emergency jump start packs would be useless in the application you describe.

I would go with deep cycle marine batteries or golf cart batteries and a good inverter. You can always wire the batteries in parallel to double/triple etc the run time (and current capacity) if you find one battery is not enough to meet your time between charges.

If you use a laser printer you're going to need a powerful inverter.

You should also consider that overnight may not be enough time to recharge depending on the capacity of battery you end up using, so you may need to use different sets of batteries in rotating shifts every other day.

[Scout2Diesel]

Biggest size RV battery from Walmart and 640w inverter ran 2 laptops, switch,, router Ap, modem, and 2 VoIP phones 8hrs day. Took 2a charge overnight to full charge. ymmv

Add bigger inverter and run only when laser printing is needed. That how I roll. When there's no juice.