mogulman Posted October 1, 2016 Share Posted October 1, 2016 Hi, We've had a Mohoo H3 since December last year. As of about 3-4 months ago, it will lockup. The unicycle will be fully charged (according to the charger and the display on the unicycle). My son will ride it and then all of a sudden it dies. The battery symbol doesn't show any charge. He will press the power button, and it shows a full charge for about 1 second and then shuts off. It seems to happen intermittently. When it does happen, the unicycle won't work again until we open it up and unplug the battery....wait....and then plug it back in. Sometimes we have to do this a few times to get it to start working again... He has crashed it a few times... Any ideas? Take the whole thing apart? Does it seem like a battery? It doesn't to me, but I guess I could try ordering a new one. I measured the voltage on the battery and it seems fine. Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted October 1, 2016 Share Posted October 1, 2016 @tjcooper has a MooHoo and had several issues with it. It sounded like a faulty battery in his case so it could very well be that your battery pack is faulty. Reading a proper voltage might be misleading as it could be that it is not able to supply enough current to drive the motor. A new pack might be a solution. Can you measure each cell voltage? You could try taking it apart to make sure the charging wires, power button, and other components look okay. A faulty wire or connection could also explain things as I've seen wires that have been broken down making things act all wonky. Link to comment Share on other sites More sharing options...
tjcooper Posted October 7, 2016 Share Posted October 7, 2016 @HunkaHunkaBurningLove ,@mogluman, I have the MoHoo H3 working fine now. Go elsewhere in this forum and follow the "SHUNT" fix for batteries. In our case, you need to shunt the P- to the B- pads on the battery PCB. Use at least 10 gauge wire. I have the intuition that every once i a while your circuit will send the signal to the GATE of the FETs for battery shutdown are going active. For me that meant a "face plant" when wheel stopped abruptly. Having done the SHUNT fix, I have gone through about 3 battery loads of riding and no more shut downs. If you are good at electronics, you might want to take a LM555 and wire into system (remember you are going to have to make a voltage drop from 67 volts DC to 5 volts DC) with an LED. You would hook up the GATE input of the FETS (which I suggest to cut open after you do the SHUNT) to the 555 input. This would light up the LED if your supply board ever issues a "shut down" command and you would see it on the LED. You would unplug battery to reset LED. I have found a source for Samsung battery supply in China....more powerful than MoHoo supply. But will not recommend it until it arrives and I can verify that it works well. Trouble shipping it from China now because of new Postal regulations. tjcooper Link to comment Share on other sites More sharing options...
tjcooper Posted October 21, 2016 Share Posted October 21, 2016 Battery from China just arrived. very nice Samsung 2600maH supply of 16S1. I will also SHUNT this pack. But just wanted to say that China DHgate initially had trouble shipping to USA. Then after two failed attempts they put the battery in a simple plastic black sack with foam padding and shipped it to the Netherlands; and had that source there ship it to California. It came with no markings saying DANGER LiPo battery. In only said " Battery car balance". Inside there were none of the warnings or other post office forms. I think that really says something about postal inspection. If a company know where to forward the package through, it comes through with no questions asked. tjcooper Link to comment Share on other sites More sharing options...
mogulman Posted November 8, 2016 Author Share Posted November 8, 2016 On 10/20/2016 at 10:31 PM, tjcooper said: Battery from China just arrived. very nice Samsung 2600maH supply of 16S1. I will also SHUNT this pack. But just wanted to say that China DHgate initially had trouble shipping to USA. Then after two failed attempts they put the battery in a simple plastic black sack with foam padding and shipped it to the Netherlands; and had that source there ship it to California. It came with no markings saying DANGER LiPo battery. In only said " Battery car balance". Inside there were none of the warnings or other post office forms. I think that really says something about postal inspection. If a company know where to forward the package through, it comes through with no questions asked. tjcooper TJ, Do you have a pic on how you shunted it? Where in the plastic of the battery is it? I'd rather not tear the whole thing apart. How is the bigger battery? Would you recommend it or a different one? Link to comment Share on other sites More sharing options...
mogulman Posted November 8, 2016 Author Share Posted November 8, 2016 Welp...couldn't wait so just cut off the plastic and found it. We'll see if it makes a difference. Link to comment Share on other sites More sharing options...
tjcooper Posted January 10, 2017 Share Posted January 10, 2017 sorry to be so long in replying. I just cut off the outer plastic blue layer. I could feel the 3 big MOSFETs inside the next layer and just cut around them. This battery was different because the P+ and P- has no wires connected. I just shorted the B- to the C- (if memory serves me). I have put in another thread the complete statement about what I did. I am out of storage space on this forum so I cannot put in the images. Anyway, it works just fine. I used shipping plastic tape to re-cover the battery and it works great. Did have a problem with it last week in that the MoHoo started lifting up the petals and forcing my son and I to get off. But no audio message that I normally get that says in horrible Chinglish "under voltage". Recharged and tested again. Nothing happened. Need to ride it down to the very bottom of battery level to see what happens. I am very used to the Chinglish announcement telling me when the end of battery is reached. Then 100 yards later the petals begin to lift up and force me off. tjcooper Link to comment Share on other sites More sharing options...
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