Thread: lead acid charger schematic with maintenance charging

Hi,

i am looking for the schematic of a good lead acid chargeur with maintenance charging for a maximum battery of 65Ah.

thanks.

Totue.

The absolut simplest is to have 13.8 V applied to the battery at all times. If you want to get a bit more complex, use a current limiter so that when the 13.8 is applied to a discharged battery the current is limited to about 1/10 or 1/20 of the battery capacity. If you want to get even more complex, have the voltage 14.7 V while charging and when the current drops to 1% of the rated capacity drop to 13.8 V.

Check out http://www-s.ti.com/sc/psheets/slua055/slua055.pdf

We can design using simple digital ic's and a analogue muxer like 4067.

look at the EPE august 2001 in MCU fleman.

you can apply the idea supplied by flatulent
by building a variable voltage power supply arround LM317 and sens the current floww over a small power resistor, when the current drops use the output of the comparator that sense the current to switch the control terminal of the LM317 to drop the voltage to the current tackling mode.

A lead acid battery needs to be charged with a constant VOLTAGE rather thasn a constant current. Having built many of these that moniter the voltage and cut in at various times I have come to the conclusion that the best method is to use a very heavy rectifier and a well chosen transformer the secondry giving a voltage of 14 voltes to maintain the stait of the battery. this way will allow you to startthe car with the charger connected and not damage your charger.

Barrybear

try:
http://www.elektroda.pl/eboard/searchtopic46207-.html

I would not chose the constant current first part of the charge. There will be times when you will have to charge a battery from a terminal voltage of possibly 1or 2 voltes. A constant current at this point may not inicalise the battery for a full charge. I have found that lead acid batteries should banged charge to overcome any residual coating on the plates and then left to charge for the duration of the battery capacity.

Barrybear

What if the charging current comes from a set of solar panels and the current cannot be quaranteed?


ASIC

[align=justify:ac5d900154]Properly charging of sealed lead acid batteries is very importent thing for long and trouble free battery service the upload file contain a very good quality lead acid batteries charger
With these feature’s capable of quickly and safely charging of lead acid batteries providing with temperature compensation in addition two step charging level with automatic switch over and floating voltage charging.

Hope help full for other user to. I am using this charger with out any trouble and problem [/align:ac5d900154]

hi

re uploaded better version of the pdf file sory for trouble i forget to recompile it

You can use my reference design, AN2107 which is published at Cypress site. It capable to charge several battery types, including ACID.

hi


here is an other design very best with alarm reverse polarity protection and much more with it

I think, the best way is to refine specifications and later select appropriate device. It standart charging profile is reqired only, use fixed-function chips. For more advanced designs the best way build around CPU and implement all functions in the firmware.

hi,

here is the pcb for my first uploaded file

This is a very interesting question, in my opinion.
If you talk solar, then you have a number of parameters to take under consideration.
- Solar panel voltage
- Battery voltage
- Type of battery (lead acid, gel, etc)
- Current requirement of the inverter if used with a UPS

The best I could come up with is a digital solution using the very good A to D from Linear technology (24 bit resolution 0.5 ppm offset, 0.55 uV noise 110 dB rejection @ 50 or 60 Hz) and a micro such as the Motorola HC12. The end result is pretty nice. The battery is even disconnected from the UPS if the load requirement is low enough to be provided directly by the solar panel!

Due to the fact that such equipment can be placed outside where temperature can easily raise to 48 Celsius degrees, it is quite a very challenging analog design! So I forgot about analog and used pure digital technique.

Results are economic, no drift in time or no adjustment with 10 turns pot here and there... All parameters are programmable and all the floating parameters are taking care of in the digital world. A 4 lines x 20 characters LCD display the status and a simple keypad is used to modify and store in the HC12 EEprom the various desired parameters.

In short, efficient, economic and maintenance free! Try to do the same in the analog world... (I mean discrete components) and you would end up with a very large monster!

Originally Posted by ASIC

What if the charging current comes from a set of solar panels and the current cannot be quaranteed?


ASIC