Help to identify this 8 pin IC - Page 1
Forum section: electronics / general

author: paul_b_78
author_rank: Contributor
timestamp: August 17, 2025, 05:42:16 pm
content: I have a solar water fountain which has li-ion backup battery pack (2 x 18650 cells in series)My understanding is that the cell pack gets charged during the sunlight, and then kicks in and powers the mini water pump once the sun sets, then should run for a while into the evening.I have replaced the cell pack from 2 x 1500mAh to 2 x 3500mAh, but it worked for about a week, however now it doesn't seem to run on further through the evening.The main 8pin IC is blank so I am unable to identify what it is.I quickly drew up a Schematic (roughly drawn)Note: I thought it might have been TP4506 - but these can only charge 1 x cell (or 2 x in parallel not in series)Note also: I have reached out through other forums, yet nobody has been able to provide any further assistance - so if you recognise this then that is why).... just thought I would reach out to an official Electronics Forum with many many more skilled users online.

author: daisizhou
author_rank: Super Contributor
timestamp: August 17, 2025, 11:56:09 pm
content: Looks like a product from China.You need to flip the bottom of the SOP8 chip to see if there is a heat dissipation pad. Only in this way can you have more clues to determine the exact model.For example:IP2325..........

author: paul_b_78
author_rank: Contributor
timestamp: August 18, 2025, 04:47:51 pm
content: QuoteI checked the underside and it does not have a large Ground plan.Is it possible that it is a single cell Li-Ion charger chip could potentially run 2 18650 cells in series

author: Bud
author_rank: Super Contributor
timestamp: August 18, 2025, 04:57:48 pm
content: Your extended capacity cells do not run any better because the device's solar panel cannot charge them fully during daytime.

author: paul_b_78
author_rank: Contributor
timestamp: August 18, 2025, 05:20:34 pm
content: @Bud - please can you elaborate on that reply a little more. The Solar panel is capable of an output just over 10v with good strong sunlight

author: daisizhou
author_rank: Super Contributor
timestamp: August 18, 2025, 06:11:11 pm
content: Quote from: paul_b_78 on August 18, 2025, 05:20:34 pmCan you measure the charging current?

author: paul_b_78
author_rank: Contributor
timestamp: August 18, 2025, 06:42:41 pm
content: So this is what the old cell pack was doing but I switched out the 2x 18650 1500mAh for 2 x 3500mAh and replaced the BMS board for a new one…Solar panel -a) under strong direct sun = 10.8v outputb) in sun clouded over = 9.4v output; battery disconnected = 4.8v; battery connected and in off position before charge from sun = 2.1vSwitch in ON position - Battery charges quickly to a)8.8v with strong sunb) but drops a little with clouded over sun to 8.2vSwitch put in OFF positionAfter charge from sun - instantly drops to around 6.9v then rapidly drops within about 2 and half minute to about 2.3v then holds at this voltage.

author: Bud
author_rank: Super Contributor
timestamp: August 18, 2025, 10:29:19 pm
content: I do not understand your measurements. What points in the circuit did you measure?

author: Bud
author_rank: Super Contributor
timestamp: August 18, 2025, 10:42:33 pm
content: Quote from: paul_b_78 on August 18, 2025, 05:20:34 pmThere are 1x1 inch solar panels that produce 10v and there are 3x4 feet panels that also produce 10v. Did you think why are bigger panels made? Why not use 1x1 inch panel to power a house? It is because 1x1 inch panel will not be able to produce enough current that the house appliances need. Your device's solar panel was designed to fill a galon of electricity into a one galon bucket, figuratively speaking. Then you replaced the one galon bucket with a two galon bucket, but your solar panel can still only fill 1 galon of current into it, because this is the max it can do during a sunny day. Therefore you do not see an improvement.

author: fzabkar
author_rank: Super Contributor
timestamp: August 26, 2025, 12:42:15 am
content: Where is the path from the positive terminal of the solar panel to the positive terminal of the battery?