Told Ya! 6.8 A/H Lithium Battery With Charger Under $20

Objective: Gang enough lithium in parallel to carry to and from hotel rooms, that would allow 8 hour use of CPAP with humidifier plus a 5 watt LED reading light for 3 hours. Because of a bad disc, lift ability is limited to 2 kilos. This is Mexico. Electricity is about as dependable as safe drinking water out of a faucet.

Golden_HVAC wrote:
I have been buying 5,000 ma batteries for a couple of years from China, they are rated at 3.7 volts, and used in many flashlights. It is a 18650 battery, with 18 mm diameter, and 650 mm length. So 5 amp hours each. You can buy 3 gang battery holder, that would give you 11.1 volts total, so it will not work out well for a 12 volt system. 14.8 four batteries would be a little to high voltage.

The 5 AH 3.7 volt cells are running about $3 each when you buy them 10 at a time. Less if you buy 50 or 100 each. 48 of the cells, when wired 4 to a string, and 6 strings would give about 14 volts and 30 amp hours.

I was looking up this battery, the slightly larger diameter 26650 cell, 100 each for $411 with free shipping. This could give 25 strings of 7.2 AH each, or a fairly decent battery pack at 14.4 volts. Clicky Problem being it is 14.4 volts, not the nominal 12 volts used by motorhomes that is actually about 13.6 when charging and 12.8 when discharging. So it is a slightly higher charge voltage, and about 1.2 volts higher while discharging. I wonder how much of a difference this can make?

You can search the Aliexpress website for various batteries, and the holders to hold strings of 4 batteries, if you want to. They have some great prices. I bought a lot of LED light panels there as well.

Fred.

In a large system like an RV or automobile, a 95+% efficient buck converter would easily deal with the over-voltage, if it's needed at all. I think my Magnum inverter accepts up to 16vdc input, and I've seen the trailer's 12v gear operate at 15v in very cold weather during temperature compensated charging periods. The batteries would also likely need an efficient boost converter to charge them at 4.1/4.2 volts per cell, and there's no margin for error in that charging voltage.

I have been buying 5,000 ma batteries for a couple of years from China, they are rated at 3.7 volts, and used in many flashlights. It is a 18650 battery, with 18 mm diameter, and 650 mm length. So 5 amp hours each. You can buy 3 gang battery holder, that would give you 11.1 volts total, so it will not work out well for a 12 volt system. 14.8 four batteries would be a little to high voltage.

The 5 AH 3.7 volt cells are running about $3 each when you buy them 10 at a time. Less if you buy 50 or 100 each. 48 of the cells, when wired 4 to a string, and 6 strings would give about 14 volts and 30 amp hours.

I was looking up this battery, the slightly larger diameter 26650 cell, 100 each for $411 with free shipping. This could give 25 strings of 7.2 AH each, or a fairly decent battery pack at 14.4 volts. Clicky Problem being it is 14.4 volts, not the nominal 12 volts used by motorhomes that is actually about 13.6 when charging and 12.8 when discharging. So it is a slightly higher charge voltage, and about 1.2 volts higher while discharging. I wonder how much of a difference this can make?

You can search the Aliexpress website for various batteries, and the holders to hold strings of 4 batteries, if you want to. They have some great prices. I bought a lot of LED light panels there as well.

Fred.

Trackrig wrote:
Look at the 20,000 MAH battery pack for $79.99.

Clicky

Bill

I fly with a 12,000ma pack and it doesn't have anywhere near the cap it claims. This one is 50% smoke at least! and WAY over priced

There's gotta be a reason I can use these. :)

I'll stick with heavy lead acid AGM batteries...

clicky!
(ps it gets interesting about 1:15 in)

I Pad I Phone, "I" am so dumb about these gizmos. My new 100 button cellular is so smart it arrived broken, meaning electronically unusable for text messages. I wonder if it knows that it is mentally challenged?

IPhone 10 times, IPad ? 5 times
Mexi your idea is better, more capacity

Uh, 20 amp hours charges an Iphone 5 times? I gotta play dumb here.

Look at the 20,000 MAH battery pack for $79.99.

Clicky

Bill