Can I use Harbor freight thunderbolt magnum 100w kit with a lithium battery?

[ElectricNoob]

I have the 100w harbor freight solar kit with the 500w charge controller, I want to upgrade to a lithium battery but I can't find if the controller is MPPT or PWM. I know I will ruin a lithium battery with a PWM charge controller. The unit has user controls to change the charge profile. The instructions say thing like "... When using a lead-acid battery" or "... To charge a lead-acid or gel battery..." But nowhere does it say anything like "Do Not use with lithium batteries". I feel like somewhere I had read that the charge controller was MPPT but went to double check and can't find it. Any info on the kit would be helpful. The model number is 63585 at harbor freight.

 

[Samsonite801]

Does it have a charge profile for AGM?

I have an old PWM charge controller which came on my motorhome, and it had a profile for AGM I used for awhile on LFP...

If you get the manual for the charge controller, they many times, have a chart showing the voltages for each of the stages in the profiles, and if you compare the voltages for an AGM profile, they are typically usable / compatible with an LFP chemistry.

 

[ElectricNoob]

It has settings for sealed, flooded, and gel batteries. It also has a "User" setting to customize values. I used the User setting and put in values appropriate for a lithium battery. However, I've read that PWM charge controllers will ruin lithium batteries due to the nature of PWM's constantly switching on and off. I attached a pic of the charger settings I used.

 

[Hedges]

I would rather have MPPT for lithium. I think PWM might push voltage above disconnect of BMS.

One function of BMS is to balance cells, which it does by bleeding off charge from high cells. That should be much more effective if held at a steady voltage for an extended time.

 

[ElectricNoob]

So the harbor freight charge controller is most likely PWM? Is there a way to verify if a charge controller is PWM or MPPT without an oscilloscope?

 

[Hedges]

Input voltage specification.
Price.
Weight.

Most will say which, but there are some of brand "MPPT" which are really PWM. They have USB ports on them.

 

[ElectricNoob]

So if it has USB it's most likely PWM? Here's a pic of mine

 

[wholybee]

MPPT is just a more sophisticated PWM. It still pulses and works on the same basic principles, and is still technically a PWM controller.
If the controller is inexpensive, it is probably not MPPT. But as long as you program the "user" settings correctly, it won't damage the battery or BMS, it will only be less efficient on cloudy days.

 

[ElectricNoob]

What user settings should I use? There's settings for boost, float, low cutoff, and recovery.

 

[wholybee]

What user settings should I use? There's settings for boost, float, low cutoff, and recovery.

Those are not the normal terms used, but I will assume "boost" means "bulk" and "recovery" means "equalize"
The exact values should be confirmed with the battery mfgr, but bulk is around 14.4, float 13.5, and equalize should be disabled, either 0 or maybe 14.4.

 

[backwoods]

So the harbor freight charge controller is most likely PWM? Is there a way to verify if a charge controller is PWM or MPPT without an oscilloscope?

I'd say with 99.999% it is pwm, I don't believe they even sell a mppt, I could be wrong also.
But I want to say I recall all their kits come with a pwm controller.

 

[Samsonite801]

Those are not the normal terms used, but I will assume "boost" means "bulk" and "recovery" means "equalize"
The exact values should be confirmed with the battery mfgr, but bulk is around 14.4, float 13.5, and equalize should be disabled, either 0 or maybe 14.4.

My interpretation of what the 'low-cutoff' and 'recovery' might be, is that a lot of these cheaper PWM style controllers have a 'load' port on them, and the cutoff / recovery may be options being made available to mimic inverters where they have a low voltage cutoff (to the load port), and a corresponding 'recovery' voltage where it turns back on the port (for the 12v appliances), so the battery can't run down beyond a certain voltage.

I would doubt the cheaper CC has an equalize stage on it at all...

 

[Mattb4]

I would not use that controller for a lithium battery. Go and buy a decent and low cost MPPT controller like Makeskyblue V118. The 30 amp model will allow you to add more panels in the future. It also auto selects for battery voltage so that you can charge 12/24/48 vDC battery setups.

ETA: I must rescind this recommendation. I just read in another Thread a person that fried their inverter using a lithium battery with a solar controller that auto selects for battery voltage.