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solar charge controller, use of to charge 24V lithium battery


notrub

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I have just picked up a small solar controller to use at the naa to recharge batteries and phones.  This one is 30A and 12V/24 with an LCD screen  Here is the question.  The battery I want to charge is 24V lithium on a small brush cutter.  The plug in wall charger has a 100V to 240V input and 21V to 98V output.  I assume the input is AC and the output is DC (?).  Can I just get the appropriate cable connector with the male socket wire it to the converter battery charger terminal, set the voltage output to 24V to be able to charge the battery?  I plan to use a small solar panel that was for a light that no longer works (due to water damage). 

 

Any comments please?  Thanks.17364526_solarcontroller20210620_110023.thumb.jpg.87cbfce6fc261c5feed24271392d9bfb.jpg

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I would like to help but not sure what you are asking. 

 

You are trying to charge your brush cutter's 24 bolt battery with a wall charger?

Or

You are trying the above with the solar charger?

 

If trying to charge the brush cutters 24v battery using the solar panel.  If that is the case, just follow the steps in the picture you attached.  Order is important and don't flip steps one and two because the charge controller can be damaged if the battery is connect after the the panel is connected.  

 

I have lifePO4 12v  batteries.  Think I may have the same charge controller and it automatically determines if 12v or 24v.  I use simple alligator clips to clamp to the battery terminals if the  battery will be removed after charged.

 

I buy batteries and then use them to power things.  I've never extracted a preinstalled battery from an appliance/tool and tried to charge with a solar panel but assume it is no different. 

 

 

 

 

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What voltage is your solar panel?

 

These controllers need a battery in order to determine their output voltage but your brush-cutter battery ought to work so long as it's not completely flat.

 

Can you post a photo of the rating plate of the wall charger please, I'm a little concerned with the output voltage.

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What I am trying to do is charge the battery using the solar charge converter as we have no power at the farm.  Here is a picture of the wall charger unit and the battery also showing the connector plug that is on the charger supplied with the cutter.  There is also a pic of the little panel I had hoped to use.  There is no writing on either the panel or the light other than what you can see in the photo.  Thanks very much for your interest and advice.1961554019_batterycharger20210620_142820.thumb.jpg.d5d4dc5dc98b83be876e17cb1a89fa5a.jpg1195467290_solarpanel20210620_144050.thumb.jpg.1fe188a46cc5c7fefa6ff489b25a8064.jpg

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OK, that wall charger looks like it might have some "smarts", at the very least it's going to be a constant-current charger. 

 

It's very easy to kill lithium batteries with poor charging technique. 

 

To be safe I think I'd get a small inverter and a small 12V battery and run the wall charger off the inverter.

 

Then use solar to charge the 12V battery.

 

I suspect that panel will be way too small, can you measure the output voltage of the panel in full sun please and let us have the dimensions of the panel (so we can work out its power output).

 

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Thanks,  the problem is that the lithium batteries are specific for the tool and the tool cannot be adapted for a different power source.  I have several of these batteries so just bringing them home in the evening is an easy option.  I put in a solar pump a couple of years ago and have just built a new little cabin up there.  We have solar lights and even a small solar powered fan with a built in battery up there.  I am just attracted to the idea of using solar power for little things like charging these batteries.  The converter has USB outlets on it so it will be good for phone charging anyway.  The little panel is 24x16 cm of solar receptor inside the frame.  I have a small (Polo) inverter generator so can provide power for tools etc. if needs be.  Thanks again for your comments.

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I'd be tempted to do a "proper job".

 

A couple of 150W panels in parallel on the roof (a single 300W may over-volt that controller), 50Ah x 24V (or 100Ah x 12V) of LiFePO4 batteries and a 24V/12V x 500W inverter.

 

That would allow you to run all manner of small 220V stuff with no mucking about and shouldn't break the bank. 

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Thank you, sorry for the delay of this reply.  Putting in a 'proper job' solar system is what I have in mind, eventually.   But for now I have my sights set lower than that.  Just recharging a couple of batteries would do for now.  That little controller will not produce 220V power, I don't think.  

 

If the family was electric dependent then I would consider the full on option but they are not so I won't.  On top of that the little cabin is not secure and leaving it empty is the best way to discourage theft in its remote location.  

 

A couple of pics to show what they have now and what they have been using for over 50 years.  (The new one is green btw.)  The older one is in the shade and still very much in use.

 

Thanks again for your interest and comments.  Kind Regards, notrub

IMG_20210503_165155666_edited.jpg

beside pond IMG_20210424_110555183_edited.jpg

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