Can I charge lithium batteries with lead acid solar charge controller ?

Bernard

Joined Aug 7, 2008
5,744
If you had the SP , measurements would look something like: Peak power
with a 40 ohm load, V = 15.7 V, I = 370 mA, P = 5.8 W. 12-20- 2009, 12:30 PM, 33 deg. N.
 

Thread Starter

M3D0

Joined Oct 8, 2020
50
If you had the SP , measurements would look something like: Peak power
with a 40 ohm load, V = 15.7 V, I = 370 mA, P = 5.8 W. 12-20- 2009, 12:30 PM, 33 deg. N.
Thanks! I would like to know how you did those calculations. Thanks again !
 

Irving

Joined Jan 30, 2016
1,070
Well that panel won't charge a 12v lead-acid battery as its 12v out at 430mA with an open circuit voltage of 13.5v and a short-circuit current of approx 600mA so you have no headroom. You really need an 18v output panel for that charge controller as its not a boost converter by all accounts.

The battery is a triple 3mm x 45mm x 110mm pouch cell, 3s1p, nominally 11.1v with internal charge/discharge protection but no balancer. It needs to be charged with a constant current at 0.5A max to 4.2v/cell (12.6v max), then at constant voltage of 12.6v until charge current drops below 30mA. Only then it is fully & safely charged.

Ditch the charge controller, its of no use to you.

You could use the existing panel with a constant current boost converter based on the LT8490 chip, (eg https://wiki.beyondlogic.org/index.php?title=LT8490_MPPT_Buck_Boost_Solar_Regulator - but this isn't a commercial product, and I don't know of one)
 

Bernard

Joined Aug 7, 2008
5,744
Somewhere I think that I still have 5W & 3 X 15 W SPs, but back in 2009 I made a plot of load vs. power on the 5W SP. Measurements were taken every 10 ohm increase. The load was a 100 ohm 1A pot.
Plot of V vs. I is missing.
Digging deeper, found 5W SP, OC = 23V & SC = 450 mA, measured. Inf. with instructions, 5W, nominal 12 V. Model 41144, Harbor Freight
 
Last edited:

Thread Starter

M3D0

Joined Oct 8, 2020
50
Well that panel won't charge a 12v lead-acid battery as its 12v out at 430mA with an open circuit voltage of 13.5v and a short-circuit current of approx 600mA so you have no headroom. You really need an 18v output panel for that charge controller as its not a boost converter by all accounts.

The battery is a triple 3mm x 45mm x 110mm pouch cell, 3s1p, nominally 11.1v with internal charge/discharge protection but no balancer. It needs to be charged with a constant current at 0.5A max to 4.2v/cell (12.6v max), then at constant voltage of 12.6v until charge current drops below 30mA. Only then it is fully & safely charged.

Ditch the charge controller, its of no use to you.

You could use the existing panel with a constant current boost converter based on the LT8490 chip, (eg https://wiki.beyondlogic.org/index.php?title=LT8490_MPPT_Buck_Boost_Solar_Regulator - but this isn't a commercial product, and I don't know of one)
This will change my plans tremendously for the better of course, I'm grateful to know all of that though. Thanks a lot!
 

RIKRIK

Joined Oct 11, 2019
129
The issue just isn't stopping the charging when its done, don't these battery's have certain charging steps. You can make a simple charge controller using just two transistors but its how you charge the battery.

demonstrating a flawed concept is just going to cause you more hassle in the long run. Is the battery pack just 3 18650s?. they do make a solar charge controller for lithium cells. BIG BUT... i have seen a review and apparently the charging protocal isnt good for the batterys long term but may be good for the concept as-long as your idea is a item being used off the batteries to show off the grid capabilities and not claiming you can charge lithium ions from a solar panel.

https://www.amazon.co.uk/Kcnsieou-Controller-Lithium-Battery-Charging/dp/B08G84J1XG

kind regards,
rick
 

Thread Starter

M3D0

Joined Oct 8, 2020
50
The issue just isn't stopping the charging when its done, don't these battery's have certain charging steps. You can make a simple charge controller using just two transistors but its how you charge the battery.

demonstrating a flawed concept is just going to cause you more hassle in the long run. Is the battery pack just 3 18650s?. they do make a solar charge controller for lithium cells. BIG BUT... i have seen a review and apparently the charging protocal isnt good for the batterys long term but may be good for the concept as-long as your idea is a item being used off the batteries to show off the grid capabilities and not claiming you can charge lithium ions from a solar panel.

https://www.amazon.co.uk/Kcnsieou-Controller-Lithium-Battery-Charging/dp/B08G84J1XG

kind regards,
rick
Thanks! I will buy some of those charge controllers and give it a go, because I might blow some of them up ( as you saw from my recent posts)
 

Thread Starter

M3D0

Joined Oct 8, 2020
50
they do make a solar charge controller for lithium cells. BIG BUT... i have seen a review and apparently the charging protocal isnt good for the batterys long term but may be good for the concept as-long as your idea is a item being used off the batteries to show off the grid capabilities and not claiming you can charge lithium ions from a solar panel.

https://www.amazon.co.uk/Kcnsieou-Controller-Lithium-Battery-Charging/dp/B08G84J1XG

kind regards,
rick
Can I connect the battery to my circuit (load) as it being charged using this controller you mentioned earlier (MPPT kcnsieou controller) like at the same time?
 

Irving

Joined Jan 30, 2016
1,070
Can I connect the battery to my circuit (load) as it being charged using this controller you mentioned earlier (MPPT kcnsieou controller) like at the same time?
That wont work, it needs a higher voltage input by 2 - 3 volts than your battery voltage (ideally 18v). Also despite the title its charge profile is for lead acid, it'll ruin your batteries.

If you connect a load to the batteries while charging them with any charger that doesn't connect the load seperately, they will never charge properly and will die relatively quickly. The correct solution is a supply that can drive the load directly while disconnecting and charging the batteries - and that may mean much larger panels and batteries than you initially think.
 

Audioguru again

Joined Oct 21, 2019
2,692
Is the battery pack just 3 18650s?.
The link to the battery in the 1st post shows only 12V, 3000Ah and nothing else. It looks like a Li-PO.
It says it is 100% safe then it might have a protection circuit in it.
It has only 2 wires then it might have a balancing circuit in it.
 

Bernard

Joined Aug 7, 2008
5,744
Our 2 SPs rated as 12V & 5W might have small differences but more =s. I am charging 3- 18650, Li-ion, 1500 mAh cells of unknown condition. Started at 220 mA, up to 250 ma @ 11.6 V, 10:30 AM.
 

Bernard

Joined Aug 7, 2008
5,744
'Interupted charging so could finish charging around peak power. 12:30 PM, V @ 12.3, I =350 mA, about 80 % ?, halted charge. SC I =420 mA.
Battery University suggests that: Any charging current up to .7 C is acceptable. Load should be disconnected while charging, Remove load @ 9V , Remove charge @ 12.3 V for 80%.
I see no reason that a 5 W , "12V " SP should not be used to charge 3 18650 cells in series, with a simple on- off controller.

.
 
Last edited:
Top