May 3, 20178 yr Author Nkon also has good press. Delivery from the Netherlands to here is quite fast... 174€ for 40 GAs plus the kit plus a bit of ply and glass makes for an economical 12.6 Ah battery (90% of nominative). The 35E is a bit cheaper, having had a good run with Samsung I may pinch pennies and stick with them. I have read a review by Ron aka Spinningmagnets on ES the 35E although a good high mah battery the amp rating is optimistic and is no more then a 6a cell much the same as the 29E which I have found to be not a great cell. lygte.dk rate it as a 10a battery. For an inexpensive build using a very good 10a cell with good mah, PF cells are well worth considering 118 euros for 40 cells. Edited May 3, 20178 yr by Nealh
May 4, 20178 yr 6 Amps per cell constant discharge seems reasonable in a 5P10S battery with a 17 Amp max controller. If I am calculating correctly that is a 0.6C discharge per cell. Yes the PF cell looks OK too, Elon Musk seems cool with them Full mAh printed on the labels are for 2 Amp laboratory load, all cells give much less when it comes to real life discharge and Ah (as those of us using Samsung 26F with a GSM or other mid-drive have discovered) than advertised.
May 4, 20178 yr Would these kits not start to oxodise/corrode at the point of contact, like what we see on a car battery? As opposed to direct welds as a means of current transfer? I think that depends on the metal of the bolts and nuts. If they are made of stainless steel, then no. I think the whole pack needs to be shrink-wrapped to retain the contact pressure and reduce airflow.
May 4, 20178 yr Author I think that depends on the metal of the bolts and nuts. If they are made of stainless steel, then no. I think the whole pack needs to be shrink-wrapped to retain the contact pressure and reduce airflow. On ES the chap from India who's company is selling the kits has been answering these concerns. R & D has been going on for 2 years in Mumbai, which he states as a hot humid part of the country he is reporting no oxidising issues. Heat shrinking is the sensible option to keep all wiring and other components safe from accidental damage also will prevent any possible 3rd party contact shorting. Though in India looks like shrink wrap isn't on their radar . Edited May 4, 20178 yr by Nealh
May 5, 20178 yr Author My kits are now in the post so hopefully should be here by the end of May, Once I start I will post construction pics as I progress. Have yet to order or decide which cells to finally get, looks like it will be either PF cells for a cheaper build or GA's for a more expensive build.
May 6, 20178 yr Here is a BMS for you [mention=9614]Nealh[/mention] https://bmsbattery.com/bmspcm/833-smart-bms-10s13s-60a-with-blue-tooth-android-or-ios-app.html 10 to 15 S so room for expansion and non more faffing about Bluetooth!
May 6, 20178 yr My kits are now in the post so hopefully should be here by the end of May, Once I start I will post construction pics as I progress. Have yet to order or decide which cells to finally get, looks like it will be either PF cells for a cheaper build or GA's for a more expensive build. Excellent, thanks Nealh
May 6, 20178 yr Author Here is a BMS for you [mention=9614]Nealh[/mention] https://bmsbattery.com/bmspcm/833-smart-bms-10s13s-60a-with-blue-tooth-android-or-ios-app.html 10 to 15 S so room for expansion and non more faffing about Bluetooth! No use to me as I don't have a smart phone and also hate anything to techy. Have got a 30a & 40a 10s BMS coming. Also decide probably will ditch the S/S buzz bars for copper ones, my brothers says he got it on reels at work just like Jimmy who ordered 30k's worth.
May 15, 20178 yr I paid on the 23rd April and was told there would be a delay because their machine was down. They posted on the 5th may the kit arrived today 15th April. Very quick delivery even Urvakhsha from Vruzend said that was quick for India post.
May 15, 20178 yr Author That's 's good news Craiggor mine were also posted on the same date so could be with me this week ? They were in the Mumbai PO on the 5th.
May 15, 20178 yr My invoice was stamped 5.5.17,not sure if this was done at the Mumbai PO.No customs or taxes to pay. Delivered by Parcel Force. Sent from my D101 using Tapatalk Edited May 15, 20178 yr by craiggor
May 16, 20178 yr http://uploads.tapatalk-cdn.com/20170515/302566c8f55ee86ff2b44c70350ed196.jpg . I am a bit concerned about the design of the spring (picture above). The metal seems to be stainless steel. I can foresee a possible issue with the formation of Chromium oxide and Nickel oxide which will introduce a resistance in the junction between cells and their busbars.
May 16, 20178 yr Yeh I have a bit of oxidisation on my one of my lawn mower batteries. No problem getting it off the contact point with a bit of sand paper. This would be a little more difficult to do on the vruzend spring,but nothing a wire brush on a dremel wouldn't cope with. The ultimate reusable battery pack for me would use 18650's /21700's with threads incorporated into the cell as on Headway cells
May 16, 20178 yr I can foresee a possible issue with the formation of Chromium oxide and Nickel oxide which will introduce a resistance in the junction between cells and their busbars. What problem could that cause?
May 16, 20178 yr Author Resistance will add heat and loss of capacity supplied but nothing to worry about in the short term. A spray of ACF50 will help to keep oxidisation at bay for 18 months or so in a confined space. Resists high temperature and is non conductive. Edited May 16, 20178 yr by Nealh
May 16, 20178 yr What about a tiny dab of copper grease on the ends of the cells before fitting the plastic caps?
May 16, 20178 yr Author What about a tiny dab of copper grease on the ends of the cells before fitting the plastic caps? Not a good idea as it contains copper hence the title and is conductive also corrosive in contact with any non ferrous. Use non conductive ACF block grease same as the spray apply with a small brush, spray would be wasteful as most would miss.
May 16, 20178 yr I was scratching my head about the use of copper bus bars instead of the SS ones. That would add another metal oxide into the mix wouldn't it? Isn't the shell of a 18650 cell made of steel?
May 16, 20178 yr Author My kits are in Coventry , have been so since the 5th apparently held up due to invoice issues .
May 18, 20178 yr Author Bloody customs . My kits have been released to PF by customs but customs have deemed I need to pay import duty on $57 package, so PF won't deliver until it is paid. Now waiting for payment invoice, thought these would slip through due to their low value. 18650's from Nkon B.V on the way but no cell holders yet , no duty due on these though as I believe we are still in the E.U.
May 18, 20178 yr Correction UK customs... There is no duty on packages under 150€ in France Sorry couldn't resist
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