@Brando
Maytech have a battery that seems similar, you may have to check the dimensions if using the original box.
The Turnigy batteries, plus buying a Hota D6 Pro to charge, at 6s and running in series is an easy option for a custom build.
The FD Assist Plus batteries and the Maytech are lithium ion, and in my experience not as good as lipo.
I also question the 12.6 ah of the FD batteries based on running them in series with a 12 ah lipo battery.
There are two types of people here, the builders and the constructors. The builders have time, equipment and skills creating their builds, and the constructors are like me and do simple designs that just do the job attaching random stuff off the shelf together that sometimes works.
I had a Assist plus and it wasnāt the best for my needs and was going to sell it to get a Max, but the electronics died, so I started my construction just replacing the electronics.
But a few builds failed and I improved it each time for more power, and my path to experimenting and likely more failed future builds has begun.
wow this sounds and looks very doable and simple ! Turnigy has a lot of different style batteries. Which ones did you choose to match the FD version? Did you combine two of them together to squeeze into the original FD battery box to get 12 ah ? THANKS
@Brando
I had 3x FD Assist Plus batteries, 8s alleged 12.6 ah. They range from one which is relatively new, to an old one with the old packaging and a date of 2022 written on it from a few owners ago.
So I got 3x 12 ah 6s Turnigy, and a Hota charger. I added my old FD box at the front and my new box at the back, running them in series for 14s.
Unfortunately the FD batteries arenāt 12.6 ah based on voltage when fully recovered at the end of sessions and that the Turnigy are 12 ah. I log the voltages, and have them in numbered groups to track. My oldest FD battery that takes the longest to charge due to age, has the most capacity at 10.5 ah, the others are less.
So I could have got away with 10 ah for the Turnigy, but they will probably last longer with less percentage used, and if I use my FD batteries to death, I will then use two of them in series for 12s.
The Turnigy are heavy and only slightly smaller than the FD batteries.
What voltage per cell do you have when you end your session on the FD battery? This will highly effect how many amps get put back into the battery during charging.
One more note is 3x 6s batteries in series is 18s, not 14s as noted above (might have been a typo).
Looks like this is the most powerful battery they have in stockā¦ is this on the right track? I am new to electronics and learning conversions. will this one battery alone be equal power to the FD 12.6 Ah? I am planning on mounting a battery pack on a belt and not on the board so Iād like to keep it contained into the original box. The box can have more than one battery and I can (although Iād rather not) make a custom box within reason to fit multiple batteries. thanks again
You can do this, though that battery really does seem to be on the small side at only 6.4ah. However I would not consider LiPo batteries a good choice to strap onto your waist. They are cheaper and at least claim to be capable of pushing the high amps that are needed. But LiPo are also a less stable chemistry and donāt have the cycle life of regular li-ion cells. Battery fires are more common with LiPo, YouTube can probably provide examples easily. There are reasons none of the off-the-shelf foil assist or efoil products use LiPo batteries.
Plenty of people have used LiPos in their builds, but just understand itās a compromise. Lower cost for shorter lifespan and a riskier battery type.
@s9tim
I bought 3 batteries to have 3 sessions, 3 pairs of batteries, one FD and one Turnigy.
Yes it could sound the way you interpreted it.
I record the pack voltage of all the batteries when they have recovered, and just give the data to ChatGpt. As the FD batteries are of varying age, I initially did it to monitor decline. Also because I thought the FD batteries had a higher ah, and I needed to make sure I didnāt run the Turnigy too low.
But ChatGPT early on informed me that the the 8s are way below 12.6 ah, based on the Turnigy being 12 ah, and session run times are now based on not running the FD batteries too low.
Based on %, the Turnigy are at 36% and the FD are around 25% when fully recovered after a session, which is my goal, but still messing around to get sessions right on that value. Exact voltages are written somewhere. I can find them if you are interested.
I have a finger injury from something else and havenāt been out for two months, and unlikely to return for at least another.
@Brando
When you run batteries in series, the voltage adds, but the same current flows through each pack.
So if you put a 10 Ah and a 5 Ah pack in series and pull 3 A, the 10 Ah pack drops to 7 Ah while the 5 Ah pack is already down to 2 Ah. Keep going and youāll over-discharge the smaller pack (or its BMS will shut the whole thing down if it has one).
So if the FD battery is 10 to 12 ah, the battery you linked is only 6 ah which means your total on water time is determined by the how low you want to discharge the 6 ah battery, leaving the FD battery with still lots of juice.
Even with my experiences, I would still go for a 12 ah Turnigy, if you can get it. You also have to check that ESC and motor will take 14s voltage, although I think most do.
Also, what I have done is not recommended because Iām mixing lipo and li-ion batteries of different voltage and ah, in series. But it works for now.
Iām interested in a backpack setup myself for the future, hope it works well if you do it.
Just be aware that the lipo and li ion cells have different safe discharge voltages. A lipo is generally discharged to around 3.6 volts per cell before the voltage drops rapidly, while the li ion cells can safely be discharged to 3.0 volts per cell.
This would explain why you are seeing 10 amps from using the li ion cells as you are probably not using the cell to its full capacity. If you take the li ion from 4.2 to 3 volts you will probably be much closer to the 12.6ah stated by FD.
Iām not arguing the point, if that is your view, then fair enough.
I measured recovered voltages an hour later. Iām really tired of this subject with the insults and questioning over it, Iām not upset, I just donāt need it.
