MPPT Charge Controller for LifePO4 Batteries

[noelex 77]

I agree with Jedi.
Generally these cheaper MPPT controllers are not very good, with poor tracking and a short lifespan.
Powertech is at least a known brand (but on the cheap end of the market)

I would go with the better controllers from Outback. Midnite or Rogue.

[NahanniV]

Are there any good cheep shunting or PWM controllers that can be adjusted for LiFePo4 ?

I had planed to use an adjustable SES Flexcharge that I already had, but on re-reading the manual I see it has micro equalization pulses; And now their website warns against using them for Li.

[dennisail]

Originally Posted by NahanniV

Are there any good cheep shunting or PWM controllers that can be adjusted for LiFePo4 ?

I had planed to use an adjustable SES Flexcharge that I already had, but on re-reading the manual I see it has micro equalization pulses; And now their website warns against using them for Li.

A few posts ago I made a suggestion for this in this thread.

[s/v Jedi]

Cheap controllers for expensive LFP batteries ?

[noelex 77]

Have a look at the Plasmatronics range. Good quality, adjustable PWM regulators, reasonable value, rather than cheap. (Pl20, 40 and 60, I have not seen the new Dingo range)

[dennisail]

Originally Posted by s/v Jedi

Cheap controllers for expensive LFP batteries ?

If they have all the necessary adjustments to make them suitable, why not? The huge savings in the massively expensive charger will be enough to offset the cost of the lithium batteries.

Is this like the LEDs? The $1 ones I purchased were supposedly all going to stop working and/or burn my boat down and the only real option was to buy the then $30 odd dollar sensibulbs.

[NahanniV]

Originally Posted by dennisail

A few posts ago I made a suggestion for this in this thread.

I saw that, but it seemed more of a question than a recommendation.

Originally Posted by s/v Jedi

Cheap controllers for expensive LFP batteries ?

How about: simple, robust, inexpensive. When I look at the manuals of suggested controllers I'm thinking I will need to disable or work around most of the included functionality.

[goboatingnow]

Fundamentally , there isn't anything inherently expensive in a mppt controller, but they have been pitched at the upper end of the market, with a price to match.

lots of things, solar parking meters etc have mppt controllers
Dave

[senormechanico]

If anyone's worried about "micro pulses" how about paralleling the output with a super capacitor?

opcor n:

[goboatingnow]

Originally Posted by senormechanico

If anyone's worried about "micro pulses" how about paralleling the output with a super capacitor?

opcor n:

You the man , I suppose you could put tubes on it and make it into a RIB

Dave

[NahanniV]

Originally Posted by senormechanico

If anyone's worried about "micro pulses" how about paralleling the output with a super capacitor?

opcor n:

This from the SES website:


"Note: Flexcharge Charge controllers are not made for Lithium Batteries"

I guess what I'm looking for is a $50 (the panels only cost $200) controller that is (or can be) set to 13.8V max. and 13.2 resume levels. with no temperature compensation, or equalization. And preferably one that will not catch fire or destroy the batteries. I don't need a display, maybe a troubleshooting LED. Available in Canada or USA. Shunt, switching, MPPT whatever.

[dennisail]

Originally Posted by NahanniV

I saw that, but it seemed more of a question than a recommendation.



How about: simple, robust, inexpensive. When I look at the manuals of suggested controllers I'm thinking I will need to disable or work around most of the included functionality.

Yeah I can't recommend it because I have not used it, but it seems to tick all the boxes. Not sure about pulsing though.

[dennisail]

What about this morningstar MPPT?

60A MPPT Solar Controller With Maximum Power Point Tracking Tristar TS MPPT 60 | eBay

[dennisail]

I just done a cost comparison for a high quality lithium setup VS an AGM setup. Note I costed various AH banks. The lithium setup with good controller etc costs about twice as much, but will have much better efficiency and more useable AH.

I will be doing this shortly for my new boat so I need to make a decision. So many things to think about. If I get 4 x 250W panels they will be 24V which means I need an MPPT controller. Otherwise I can use 4 x 200W 12V panels and use 4 x $50 ebay chargers. I can always upgrade later... I think the batteries are stuffed as well but I am hesitant to buy lithium right now as the cost will be huge and possibly not worth it as I wont be going permanent cruising for 3 years. I guess the price will come down for chargers and lithium by then. So maybe I can just get the cheap AGM 430ah bank for now...

Lithium
Solar 1000w.................$1100
Outback 80 controller....$1000
Winston 1000AH .......................$4400
Winston 700.................$3400
Winston 520..............................$2840
Winston 400..............................$2128
Misc.............................$300

Total for 700ah.............$5700


AGM setup.
Solar 1000w.................$1100
Controllers 4 x ebay......$200
AGM 430ah....................................$700
AGM 645ah....................................$1050
AGM 860ah...................$1400
Misc..............................$150

Total for 860ah..............$2900

Note per AH the lithium is only half the weight. Depends on if you use the usable capacity or not. If you say lithium has double, well you can half the weight and cost again. Depends on how you look at it.

[Maine Sail]

Originally Posted by dennisail

I just done a cost comparison for a high quality lithium setup VS an AGM setup. Note I costed various AH banks. The lithium setup with good controller etc costs about twice as much, but will have much better efficiency and more useable AH.

I will be doing this shortly for my new boat so I need to make a decision. So many things to think about. If I get 4 x 250W panels they will be 24V which means I need an MPPT controller. Otherwise I can use 4 x 200W 12V panels and use 4 x $50 ebay chargers. I can always upgrade later... I think the batteries are stuffed as well but I am hesitant to buy lithium right now as the cost will be huge and possibly not worth it as I wont be going permanent cruising for 3 years. I guess the price will come down for chargers and lithium by then. So maybe I can just get the cheap AGM 430ah bank for now...

Lithium
Solar 1000w.................$1100
Outback 80 controller....$1000
Winston 1000AH .......................$4400
Winston 700.................$3400
Winston 520..............................$2840
Winston 400..............................$2128
Misc.............................$300

Total for 700ah.............$5700


AGM setup.
Solar 1000w.................$1100
Controllers 4 x ebay......$200
AGM 430ah....................................$700
AGM 645ah....................................$1050
AGM 860ah...................$1400
Misc..............................$150

Total for 860ah..............$2900

Note per AH the lithium is only half the weight. Depends on if you use the usable capacity or not. If you say lithium has double, well you can half the weight and cost again. Depends on how you look at it.

*AGM for best life max DOD = 50%

*AGM on the hook is hard to get back above 85% SOC* so 35% usable (*where you leave bulk and hit absorption voltage will depend upon your available current. Could be lower, could be higher. As AGM's sulfate the point at which they hit absorption voltage gets lower and lower over time.)

*Li can be cycled to 80% DOD and still provide in excess of 1500 cycles

*Li can be easily recharged to 98-100% so 78-80% usable capacity vs. approx 35%.

*Even what are arguably the best AGM's in the world only claim 400 cycles to 80% DOD, and that is in a lab....

Comparing AGM & Li Ah's/$$$ is like pitting Ronaldo against The Queen Mum in a one on one football game, not a very realistic comparison.

In order to do a more fair comparison expected cycle life & realistic usable capacity need to be taken into account.

A Li bank can be sized much smaller than a lead acid bank because you have more usable capacity and are not carrying around 50-65% of your battery as what I refer to as "dead lead".

Li also supports and holds higher voltages, and your equipment will love this. Even at 80% DOD voltage sag during high loads is extremely minimal.

Lead acid when subjected to high loads, motor starting, thrusters, windlass, water makers etc. suffer from fairly heavy voltage sag and it gets worse as you go deeper into the depth of dischage....

It is also interesting how the Ah ratings are arrived at:

Lead Acid Normally = 20 Hour Rating

*100 Ah Lead acid battery is rated at a 5A load

*100 Ah LiFePO4 battery is rated at a 50A load

A 100Ah AGM subjected to a 50A load will yield aprox 76Ah* in Ah capacity.(*depends upon brand and Peukert)

A 100 Ah LiFePO4 will yield 100Ah, or in many cases slightly more, at a 50A load...