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A quick Review of the MIGHTY MAX 12V 100AH BATTERY


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A quick Review of the MIGHTY MAX 12V 100AH BATTERY

 

I recently purchased this battery for my portable 6 inch refractor solar imaging scope.

With all systems running and pulling 8 amps, it has run for 7 hours and still going.

I previously used a trolling motor battery, but could only get 3 hours before things began shutting down.

I would highly recommend this battery for your portable equipment, I am convinced.

My system:

- 6 inch f8 refractor on a GEM mount

-EQDRIVE drive system.

- STARLIGHT AUTO FOCUS SYSTEM

- DAYSTAR HA FILTER

- ZOW ASI178MM CAMERA

- HP LAPTOP

- 21 INCH LCD MONITOR

 

Here are a few images of what I use.

 

 

 


  • msmithmitsky likes this


13 Comments

On Amazon there are two types of Mighty Max 100 AH batteries.  Are you referring to the sealed lead acid battery or to the lithium iron phosphate battery?

Looks to be this one, a 'gel' battery.  DS-iGEL type. 

 

The OP's load is probably on the margin of cycle life and value.  My 120w load and on time would be very hard on this battery.

On Amazon there are two types of Mighty Max 100 AH batteries.  Are you referring to the sealed lead acid battery or to the lithium iron phosphate battery?

lead acid

For those looking to spend a little bit of money and tinker, AliExpress has very large LiFePo4 batteries. I ordered a 120AH LiFePo4 battery from the 'Kanavano Official Store' on aliexpress.com. The trick is to talk them down before ordering through the messaging service on the site. I got my battery for $380 and it is great. The same battery would cost over $1200 in the states. The battery will last essentially forever for my imaging purposes as long as don't drain it below 11v and keep it in temps above 0c. Also the battery only weighs about 15lbs.

    • Bill Lee and msmithmitsky like this

Battery should be resistant to complete discharge, therefore deep-cycle (marine) type would be preferable. Walmart has 125Ah deep cycle one for $90 up to 200Ah at $400+, for example.

    • Andrew Brown likes this

For those looking to spend a little bit of money and tinker, AliExpress has very large LiFePo4 batteries. I ordered a 120AH LiFePo4 battery from the 'Kanavano Official Store' on aliexpress.com. The trick is to talk them down before ordering through the messaging service on the site. I got my battery for $380 and it is great. The same battery would cost over $1200 in the states. The battery will last essentially forever for my imaging purposes as long as don't drain it below 11v and keep it in temps above 0c. Also the battery only weighs about 15lbs.

I did the same thing, and got a 100ah battery. I love it!

    • Kaydubbed likes this
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Andrew Brown
Sep 06 2020 08:32 AM

The trick is in the detail chaps! 

 

Do not drain below 11v

Do not recharge below 0C [32F]

Do not keep it in temps below0C [32K]

 

Note that these limitations will be acceptable for those around tropical regions [jealous moi?] however for the rest of us Northern Monkeys who look forwards to the long cold nights of winter for our observing season, well there's still some development to go in the battery world. Personally, as has been stated, my choice is marine or recreation batteries that have the robustness for our conditions.

Great thing about Li po batteries is you can draw them down much lower than marine deep cycle batteries, and they do better in cold. They are much lighter and easier to transport. Great at everything but price. I decided to dump the laptop get an asi air, then a small  battery has no problem running everything. My system (zwo1600, iopton mount, eaf focuser, filter wheel, asi air) only draws 2-4 amps depending on cooling. So a celestron power bank plus iPad can run everything for a couple of nights.

    • Jaimo! likes this

Thanks Skunk.  That's what I needed to know.

 

At 8A and 12 V, you're drawing about 100W

Might Max at 12V and 100Ah is 1200 Wh

So you have 12 hrs max available; and after running 7 hrs, you're at about half capacity.

 

My runtimes are only about 4 hrs, but I'd want 8 hrs capacity just in case.

8Ax12Vx8hrs=768 Wh or 64 Ah at 12V

 

Any recommendations for a 64 Ah battery?

Battery should be resistant to complete discharge, therefore deep-cycle (marine) type would be preferable. Walmart has 125Ah deep cycle one for $90 up to 200Ah at $400+, for example.

it is unfortunately a myth that deep-cycle lead-acid batteries are ‘resistant to complete discharge’. In practice the discharge should not exceed 50% of the stated capacity if you want to achieve longevity and repeatable performance. At 50% discharge an AGM battery will be operating around 12.3V. If your systems start shutting down you may be in the process of significantly cutting short the normal recharge life of 500 to 750 charge cycles.

    • palaback likes this
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charlesgeiger
Sep 20 2020 12:30 AM

I was in the battery business years ago.  If you discharge a lead acid battery, any type, and leave it discharged for 24 hours or more, your battery will probably be dead.  The lead turns to lead sulfate which will not convert back.  If you get away with a long discharge once, and it recharges, you are lucky but you will have lost a significant amount of capacity.  So you should recharge immediately when you get down to 12 to 12.5 volts.    

 

From what I have been told regarding lithium iron phosphate batteries is that you can completely discharge them and leave them discharged.  You will note you will have full power until it is discharged.  The power output does not ramp down such as a lead acid. 

Yes, lithium iron phosphate batteries are much smaller and lighter to comparable lead acid batteries.  

You will not want to over charge a lithium iron phosphate.  They  require precise charging.  If the charging system is aggressive, you can run into overheating which can lead to lithium ignition which is very bad.  It depends on the type of lithium battery and the age.  Most of you have seen what a phone or laptop lithium battery runaway can do. 

 

If you run a lead acid battery based system and want to get maximum utilization, you will need to put your charger on a 'timer' which will turn the charger off after a full period of charging.  If you have a wet lead acid, you will need to check the water in each cell (if possible) and top off with deionized water as needed.  Once fully charged, you will want to put a trickle charger on a timer also if you are away from the battery system.

 

I believe one can expect a life expectancy of a lithium iron phosphate battery to be about 10 times a lead acid battery (both properly charged and maintained).  Again, another precaution for lithium based batteries is to keep them away from moisture.  Lithium can react with water and explode or burst into high intensity flames which will be extremely toxic, high temperature, and difficult to put out any fire...don't use water!  Lithium was the fuel of choice to run torpedoes!

Charlie

    • starbug99 and Alabama Don like this
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gmartin2000
Sep 25 2020 03:17 PM

For what it's worth (or what my 2 cents buys) about the issue of battery performance and temperature:
 

My solution to keeping my batteries functional as the temperature drops, is to put them in a special built insulation/warming box and use just a little of their power to heat the inside of the box keeping them warm. Here is a link to that initial effort: 

 

https://tinyurl.com/battery-warmer

 

Since I created the page, I have used a cheap thermostat to keep the inside of the box at/above 40 degrees F on cold nights. Using a thermostat reduces the total amount of power needed to keep the battery functional as the ambient temperature drops.

 

While it seems like "using power to extend power" is counterintuitive, the insulation box means all I need is about .300Ah, in pulses, to keep my batteries running longer than without it.

 

This year I've upgraded my battery supply to a pair of $29 Miady 12v 8Ah LIFEPO4 batteries from Amazon. I'm in the process of making a warming box for them and will update my website in a month or so. But till then, 

 

I hope this helps.

As previously stated, Lead-Acid is only good for about 50% of it's rated capacity if you don't want to damage the battery and limit even further the charge/discharge cycles.  Deep charge L-A have heavier plates and can handle a longer discharge cycle down to 50%. Standard Lead Acid (car batteries)and AGM(motorcycle or ATV) (spill proof) batteries cannot.  These types of batteries are designed for float applications with short periods of heavy drain followed by immediate re-charge and return to float charging status. Basically, they are designed as Starter batteries or short term power backup. Using them for deep cycle they will quickly degrade. 

LiFePO4 (Lithium Iron Phosphate or LFP) batteries with a nominal 3.3 volts per cell are the best fit voltage wise for Lead Acid Replacement. They are a very stable low fire risk battery. You can run these batteries through about 80% of their full capacity without affecting cell life or performance. The cells can go through around 6,000 of cycles rather than the several hundred cycles of typical of Lead-Acid deep cycle batteries and it requires less power to recharge them then Lead-Acid. They do have some self discharge sitting on the shelf, but unlike Lead-Acid, the cells do not degrade. Leave a Lead-acid battery sitting on the shelf and they will sulfate and die unless they are float charged. As mentioned before, the only restriction with LFP chemistry is that they cannot be charged when the temperature is at freezing or below.

Li-Ion and Li-Po cells are not a good match for 12 volt applications since their nominal voltage of 3.7v per cell doesn't match 12 volt applications very well  They work great in 24 and 48 volt configurations when used to power AC inverters with better efficiency than 12 volt packs.

 

When comparing costs, you should take into consideration the difference in useable power between Lead-Acid and LFP.  A 12 volt 100 Ah LFP battery has 1200 Wh of power, and at 80% depth of charge that is 960 usable Wh of power.  The equivalent Lead Acid deep cycle battery would need to be sized at 160 Ah to get the same power at 50% depth of charge and the LFP battery will have 4 to 5 times more charge cycles in its lifetime. 

So if you look over the lifetime of a LFP battery, they are less expensive than Lead-Acid deep cycle options. 

    • sixela likes this


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