mighty max 100ah lithium ion battery

[Daniel sc]

We bought set mighty max 100ah batteries. They power our 26 foot rv nicely. Why can't we put them in a series? Has been anyone ever done a test on them?

 

[John Frum]

Please post a link to your batteries so that we can look at the specs and determine if they can be connected in series or not.
Some drop in lifepo4 batteries' bmss don't support being connected in series.

 

[Daniel sc]

Please post a link to your batteries so that we can look at the specs and determine if they can be connected in series or not.
Some drop in lifepo4 batteries' bmss don't support being connected in parallel.

In the speck sheet it quoted 4 batteries in parallel. Max.

 

[John Frum]

In the speck sheet it quoted 4 batteries in parallel. Max.

That doesn't tell us anything about its serial capabilities.

 

[Forbisher]

We bought set mighty max 100ah batteries. They power our 26 foot rv nicely. Why can't we put them in a series? Has been anyone ever done a test on them?

what the hell is a "set" of batteries?
Yeah they say no series connection.
Several LiFePO4 battery manufacturers say no serial connection due to their BMS.
Why don't you connect in Series and test them for us?
You should have bought Battle Born.

• ML100-12LI is a 12V 100Ah group 30H Lithium iron phosphate sealed, rechargeable and maintenance free battery. Direct drop in lead acid replacement.
• Dimensions 12.99 inches x 6.77 inches x 8.66 inches. Listing is for the battery and screws only. No wire harness or mounting accessories included.
• Stronger, Lighter and Longer 2500 cycle life expectancy compared to the traditional sealed lead acid batteries.
• Designed for safety with built in Battery protection BMS. BMS provides high voltage protection, low voltage protection, over high current protection, high temperature protection, short circuit protection, and over charge protection. Designed to be used in parallel with a maximum of 4 identical batteries. Do not connect in series. Make sure to only use a compatible lithium charger for this battery. Having loose terminals will cause

 

[Forbisher]

dp

 

[Forbisher]

In the speck sheet it quoted 4 batteries in parallel. Max.

Yes the spec sheet said parallel with a maximum of 4 batteries. AND also said Do not connect in series.
You must have seen that so why did you omit mentioning it?

 

[Ampster]

......... Why can't we put them in a series? ...........

I have a WAG why they can't be in series.
One explanation would be their High Voltage disconnect process or charging control mechanism in the BMS. For example if one battery reached full before the others it would disconnect and the others would not get any current. That would not be a problem in parallel batteries. A separate charger input to bypass that cell would not work because the pack voltage would change and probably drop the charger offline.

Out of curiosity, I checked Battle Born and they can be connected in series but they advise fully charging each battery first. Maybe Battle Born batteries don't have a High Voltage disconnect and rely on the charger disconnecting. They do recommend a Lithium charger.

 

[Daniel sc]

I have a WAG why they can't be in series.
One explanation would be their High Voltage disconnect process or charging control mechanism in the BMS. For example if one battery reached full before the others it would disconnect and the others would not get any current. That would not be a problem in parallel batteries. A separate charger input to bypass that cell would not work because the pack voltage would change and probably drop the charger offline.

Out of curiosity, I checked Battle Born and they can be connected in series but they advise fully charging each battery first. Maybe Battle Born batteries don't have a High Voltage disconnect and rely on the charger disconnecting. They do recommend a Lithium charger.

Yes.on lithium charger.. got a 25amp from a Ohio based company... not cheap .top balance each battery. Them linked them for overnight. Charged them together before hooking to inverted... going to mount windy nation 400 watt panels tomarrow. ( 4 100 watt) ... had to wait for concrete to setup. Can't wait to see how they do.

 

[tictag]

I have a WAG why they can't be in series.
One explanation would be their High Voltage disconnect process or charging control mechanism in the BMS.

Another possible reason is that only one of the batteries would have a stable ground reference, all the others would have a terminal voltage referenced to the sum of voltages preceding it, which would vary as current flow varied (because each battery has an internal resistance).

 

[Ampster]

Another possible reason is that only one of the batteries would have a stable ground reference, all the others would have a terminal voltage referenced to the sum of voltages preceding it, which would vary as current flow varied (because each battery has an internal resistance).

Can you translate that into simple voltage and Amps and explain why that would be different for a drop in versus a string of LFPs in series. Would it make a difference if neither the positive or the negative legs were grounded?

 

[tictag]

Can you translate that into simple voltage and Amps

Too hard to describe, a picture instead?


Points to note:

1. Only one of the batteries has a stable ground reference voltage, all other reference voltages vary (i.e. decrease) as load increases. Does this matter?
2. Each BMS, except the one connected to ground, has a higher-than-zero reference voltage. Does this matter?

I don't know the answers, hence the statement 'Another possible reason is that...", but these two points are peculiar to series-connected batteries with BMS' so maybe this is why some BMS' don't permit series connections?

explain why that would be different for a drop in versus a string of LFPs in series.

I'm not sure that it would be different, I mean, yes, the BMS has 'knowledge' of each cell's voltage, but it still would not have a stable 0v reference (except the first battery). Not quite sure what your point is here.

Would it make a difference if neither the positive or the negative legs were grounded?

I don't think grounding matters, I use the term 'ground reference' above to mean the negative return.

 

[Daniel sc]

Might be the lower cost of the BMS installed in the battery. But mighty max is not the only that can't be series connected.
Fyi. If your mighty max 100ah lithium ion battery hits low voltage disconnect.. a lithium ion battery charger will not wake it. Just hook a standard 12 volt battery for 2 or 3 seconds. Just enough time for it the see the 12 + voltage an it will wake up . Then you can charge it with your lithium ion battery charger. Don't waste your time contacting customer support. I found that out .that's 2 + hours of my life gone forever. Lol an 4 emails back an forth. They never could tell me how to wake them up. So I figured it out.

 

[Ampster]

If that is the only reason then you have a workaround. Congratulations. Staying away from the bottom is always a good strategy with any battery.

 

[Daniel sc]

If that is the only reason then you have a workaround. Congratulations. Staying away from the bottom is always a good strategy with any battery.

Yes .its a good work around. Staying away from bottom is best . Forgot fridge was on battery. Not on gas in camper .
rained 2 days straight while I was away.. mistake was added to check list for leaving the off grid fish camp.

 

[VanLife Jake]

Might be the lower cost of the BMS installed in the battery. But mighty max is not the only that can't be series connected.
Fyi. If your mighty max 100ah lithium ion battery hits low voltage disconnect.. a lithium ion battery charger will not wake it. Just hook a standard 12 volt battery for 2 or 3 seconds. Just enough time for it the see the 12 + voltage an it will wake up . Then you can charge it with your lithium ion battery charger. Don't waste your time contacting customer support. I found that out .that's 2 + hours of my life gone forever. Lol an 4 emails back an forth. They never could tell me how to wake them up. So I figured it out.

Thank You, for this tip on waking up the battery.
I bought 2 of these from Amazon because they were the cheapest option that i could find (that I didn't have to build myself). I really need 4 of these to supply my needs. But, the stimulus money only went so far. ..
I have over discharged these batteries twice since June. Due to being away from the van, and forgetting to shut off the mini refrigerator at night.
The first time, Amazon took care of the issue quickly and allowed me to return them for a replacement.
This time, I have had to call, and email Mighty Max directly with no success. All I have been asking them is for advice on how to wake up the batteries so that I can use my lithium charger on them. So, yeah... I agree with you on the lack of customer service from MIghty Max.
But, I will say that when they are charged. They do work well.
I admit that I have been a "power hog" running both my life support (fridge, instant pot, coffee maker, diesel heater), and my office (dual 12v computer monitors, and 2 laptop computers for 8 hours a day).
Basically, 200ah gets me through one day. If a snowstorm moves in. Then, I don't generate enough electric to recharge the battery bank.

 

[VanLife Jake]

Daniel sc's tip worked for waking up up the Mighty Max battery!
I hooked my jumper cables up to my van while it was running, and attached them to the mighty max battery for a several seconds.
I monitored the voltage level as it went up on the mighty max battery with a multimeter during the process.
Disconnected the mighty max battery just after it reached 12V
Then, put the mighty max battery on a lithium battery charger, and it started charging.
Just saved me weeks of being ignored by customer service.
Thanks, Daniel!

 

[VanLife Jake]

Update on the charging process of the mighty max battery after over discharging them:
(I simply do not have a large enough battery bank to run my all my gadgets)

Friday 12/18/2020.
Bumped batteries awake with jumper cables and my van. (DO NOT TRY THIS AT HOME)
12.0V at 10:00am (Placed on CTEK Lithium US charger)
Charger almost immediately went to stage 2 Bulk Charging mode and stayed there overnight.



Saturday 12/19/2020
13.56V at 8:30 am
13.63V at 11:00 am
13.78V at Noon
14.49V at 2:00 pm
14.10V at 3:30 pm
Charger entered float mode and gave the green light.
So there you have it.
My experience was that it takes about 2 days to recharge a 100ah mighty max battery.

 

[VanLife Jake]

The Circus is back in town!
I just finished charging 2 Mighty Max batteries (took 4 days total) after over discharging them.
Had to jump start them from my van to get past the BMS shutoff challenge.

Had to figure it out myself from information on this forum.
Because Mighty Max just ignored me.... 2 year warranty (yeah, right!)
I would not recommend this company. They do not stand behind their product.

Anyway, back up and running until I can build my own DIY battery.
Looking at Will's YouTube video recommendations on fortune cells / Overkill cells for high vibrations environments.
Since I am on jeep trails, and mountain roads most of the time.

The charge controller seems to be "happy".
So, I will keep on truck'n
Hope this helps somebody.
Have a nice day!