Build battery for Fluke 123 and question about the power supply - Page 1
Forum section: electronics / testgear

author: dimani4
author_rank: Contributor
timestamp: October 01, 2022, 02:59:16 pm
content: Hi people,I'm new to this forum so please be kind to meI know there are lot of questions about that topic but I didnt find answer to my specific question. I try to build my own battery for the Fluke123 according this video:.The same I want to buy 4 1.2 V 2200mAh Ni-Cd batteries in Aliexpress (https://www.aliexpress.com/item/1005004231418506.html?spm=a2g0o.productlist.0.0.f2045568EOGvVn&algo_pvid=404d0240-e5f6-4808-ad41-816799ff0c9d&algo_exp_id=404d0240-e5f6-4808-ad41-816799ff0c9d-5&pdp_ext_f=%7B%22sku_id%22%3A%2212000028464217791%22%7D&pdp_npi=2%40dis%21ILS%2138.92%2125.28%21%21%21%21%21%402100bddd16646301570381475e0ddf%2112000028464217791%21sea&curPageLogUid=8YPpTcA9QS21) (it turns out cheaper than in Amazon). Than I need to connect resistor and some thermistor (I'm not sure). My question where exactly to connect it and what parameters of these parts? I took some screenshots from the video:Here it is:The 3 wires (2 blacks and white one should be connected to one terminal) and the red wire to the other terminal. So what parameters of that thermistor which is connected to the white wire (see question mark in the picture)? There is also small resistance (another question mark). what parameters? I heard guy said 1.2Ohm but what power, 1/2W should be enough?All I have from the battery is the connection....One more question. Can I use power supply of 15V but the maximum current of 2A (instead 300mA) for fluke 123?Thank you very much.

author: picburner
author_rank: Frequent Contributor
timestamp: October 01, 2022, 04:57:33 pm
content: The mysterious object covered with heat shrink is a 70°C thermal fuse.Instead the little ball is an NTC.However inthis treadyou should find all the answers.

author: dimani4
author_rank: Contributor
timestamp: October 01, 2022, 05:07:04 pm
content: Thank you for the answer.Just to be sure for your answer:In 1 I connect thermal fuse of 70°C.In 2 I connect NTC thermistor.Right?And this question below. Here:https://www.eevblog.com/forum/testgear/fluke-123-scopemeter-and-battery-replacement/?allthey didnt speak about that.Can I use power supply of 15V but with the maximum current of 2A (instead of 300mA) for fluke 123?Thank you very much.

author: picburner
author_rank: Frequent Contributor
timestamp: October 01, 2022, 07:55:16 pm
content: Yes, 1 thermal fuse 2 NTC thermistor.I don't own a fluke 123 and I don't know the characteristics of the power supply.If the power supply is constant voltage then your 15V 2A power supply is fine too (thecharging current is generated internally by the instrument).If it is the power supply that directly generates the charging current for the battery,then a special constant current power supply (300 mA) or its original one is required.

author: dimani4
author_rank: Contributor
timestamp: October 02, 2022, 07:54:17 am
content: Thank you for the answer.Here I'm looking for the NTC thermistor and Thermal fuse. Can you tell me please which one fits?NTC Thermistorhttps://www.aliexpress.com/item/1005002742725642.html?spm=a2g0o.productlist.0.0.7c5e6381YLXViZ&algo_pvid=6a1d7cb2-bc84-49c2-950f-9b791892e4d7&aem_p4p_detail=202210020037275442154723973380005726442&algo_exp_id=6a1d7cb2-bc84-49c2-950f-9b791892e4d7-0&pdp_ext_f=%7B%22sku_id%22%3A%2212000022664837901%22%7D&pdp_npi=2%40dis%21ILS%212.98%212.98%21%21%215.24%21%21%402100bb5116646962471402047e1494%2112000022664837901%21sea&curPageLogUid=3nzlpC54mCLM&ad_pvid=202210020037275442154723973380005726442_1.What resistance?And thermal fuse:https://www.aliexpress.com/item/1005003146926636.html?spm=a2g0o.productlist.0.0.58c343acRxdeqv&algo_pvid=39e8f362-d116-4e8a-a3e1-f055def8251e&aem_p4p_detail=20221002003020454350349408820005773289&algo_exp_id=39e8f362-d116-4e8a-a3e1-f055def8251e-2&pdp_ext_f=%7B%22sku_id%22%3A%2212000024351023200%22%7D&pdp_npi=2%40dis%21ILS%216.45%216.32%21%21%212.42%21%21%400b0a182b16646958198375627e84db%2112000024351023200%21sea&curPageLogUid=vEnH1QCQcFUx&ad_pvid=20221002003020454350349408820005773289_3.What current?Thank you very much.

author: wasedadoc
author_rank: Super Contributor
timestamp: October 02, 2022, 05:35:13 pm
content: BTW. Do not attempt to connect the thermal fuse using a solder joint. Been there, done that.

author: dimani4
author_rank: Contributor
timestamp: October 02, 2022, 05:41:54 pm
content: thank you for this note. In this video the guy soldered this thermal fuse to the contacts. How did you connect it? maybe you can tell me the parameters of this thermal fuse. Thank you.

author: picburner
author_rank: Frequent Contributor
timestamp: October 02, 2022, 05:44:53 pm
content: The thermal fuse you found on Aliexpress, even if not identical to the original, can fit the same and 10A is sufficient for your application.On the other hand, the type of NTC thermistor you have chosen is not the right one: you have to look for the type as shown in the attached photo. (The spherical body is very small)The characteristics are given by the color code present on the body of the thermistor itself, unfortunately the only photo I found is not sufficiently defined to be able to obtain certain data, at least I can't.P.S. what wasedadoc told you is right: Only the spot welder is used for batteries.

author: dimani4
author_rank: Contributor
timestamp: October 02, 2022, 06:45:11 pm
content: Thank you very much for the info. I really appreciate it. Can you please maybe send me to the private msg or to my email the bigger photo of that NTC thermistor. I cannot really see the number written on that NTC thermistor (TB02-rb60?). By the way, I wrote a letter to Fluke about the parameters, lets see what they will tell me.

author: picburner
author_rank: Frequent Contributor
timestamp: October 03, 2022, 06:29:35 am
content: The last photo is a focus taken from two photos of the link I sent you in my first message, I couldn't find anything else.The original is also unreadable.Try contacting the author of that post if he still has the original photos or the two devices data.

author: dimani4
author_rank: Contributor
timestamp: October 04, 2022, 02:34:22 pm
content: Ok. the number is TB02-BB8D and it can be found here:https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20221004063215&isPremium=y&SearchText=tb02-bb8d&spm=a2g0o.productlist.1000002.0(big thanks to sorenkir)

author: picburner
author_rank: Frequent Contributor
timestamp: October 05, 2022, 05:22:45 am
content: The TB02-BB8D is not an NTC thermistor as erroneously reported in your post #8 but a simple thermal fuse (It opens when a certain temperature is reached, in this specific case 70 °C).You still have to find out the technical data of the real NTC thermistor, the device used to measure the temperature of the battery.

author: dimani4
author_rank: Contributor
timestamp: October 05, 2022, 06:26:07 am
content: Yes. I know this. Sorry for confusion.Thank you very much.By the way I found out the info aboutNTC Thermistor, thanks again to sorenkir."the colours are brown, black, orange, gold and it measures 10kOhms"- kind of Vishay's NTC thermistor:https://www.aliexpress.com/item/4001234441642.html?spm=a2g0o.productlist.0.0.6965ff3azrSGJu&algo_pvid=77884b4f-abf7-488b-903f-d261e51091bc&algo_exp_id=77884b4f-abf7-488b-903f-d261e51091bc-25&pdp_ext_f=%7B%22sku_id%22%3A%2210000015398788780%22%7D&pdp_npi=2%40dis%21ILS%2123.91%2123.91%21%21%2113.71%21%21%402100bddf16648991283577088e7316%2110000015398788780%21sea&curPageLogUid=gt7dVAP4OpRm

author: maki
author_rank: Newbie
timestamp: October 13, 2022, 10:12:21 am
content: I have a dam question: will Fluke 123 work without battery pack?I’ve received it without battery pack, tried to power it with its original power supply – it won’t turn on.Any advice is appreciated.