Anyone have any thoughts on this setup?

I don’t need a video. I’m making a point that if you are stating you can do something it would be good if you provided detail about HOW you did it.

For example what PS are you using and what is it capable of doing, how is it controlled, how is the cell balancing handled, how are you ensuring you are not overcharging etc etc etc

You should confirm you are not charging tooooo fast.

See the specs on charge current per cell here.

I am charging at 7.5amps and I find that a decent time for my uses efoiing. So way less than spec but that will likely help in cycle life. I also only charge to 41v so far. I have a few long distance tours planned where I will go to 42.

I don’t know the answers to your questions at all. I just connect the battery to the charger and it charges. I bought it on Facebook.

Now it charges at 60% of the charge level more slowly than I said above (1:40 for every 1%), maybe I was wrong, or maybe the speed is different at different charge levels, or maybe it’s because it’s very hot in my apartment today.

Here’s the video, as I promised. Next time I’ll try to make a longer video when the battery is more discharged.

I can’t control the charging speed because it’s a ready-made waterproof battery with a BMS inside and just two wires to connect the charger or ESC.

Most devices have a “name plate” on them that contain info such as manufacturer, model # etc. I would think for PS it would also state values for V and A. Is there one on your Sur-Ron device.

Like I said I don’t need a video but facts would be useful.

Do your packs have a built in BMS or do you charge with an RC charger with separate balancing connectors. If the pack is charged through a built in BMS, the problem why it takes so long is brobably balancing the cells, not charging. Most BMS can only balance cells with a very low current (50-100mA), therefore it takes long if cells are out of balance. The deeper you discharge, the higher the cell voltage drift.
Some smart BMS have BT, you can connect your mobile phone and see the voltage of every single S row and voltage delta between the lowest and highest row. This helps to estimate how long it could take to balance.

I removed the BMS and balance using the i12 maybe 1/5 charges. So far they have all been within spec of each other without balancing.

Thinking about trying something like this. Specs say 50Ah battery in less than 5 hours.,scm-url:1007.40050.354490.0,pvid:1fe43067-d6d2-4fa6-9013-6c2e58d7a8a4,tpp_buckets:668%232846%238107%231934&pdp_npi=4%40dis!USD!82.12!45.16!!!595.08!327.29!%402103245417207141301316079e4957!12000038039447630!rec!US!4066168195!&utparam-url=scene%3ApcDetailTopMoreOtherSeller|query_from%3A

I got a charger from this manufacturer and it nearly started burning. The dc wire was thick and nice - but the thickness inside the outer insulation was bunched plastic wrap and not copper so it melted and slowly short circuited.

Luckily i have smoke detectors but the burnt smell took some weeks to get rid of… don’t buy it



I’m anything but an expert so I go with published best practice and advice from others that have far superior knowledge.

Both say charging lithium pack without balancing is not a good idea. Yes these packs we have are amazing but safety and longevity should be factored in :grinning:

Same logic holds true with the equipment used to charge the pack. The old adages about “you get what you pay for and if it looks to good to be true “ are likely true in this case.

From my “shopping” experience searching for a variable PS the ones that are capable of a
Voltage level above 42V (in our case) are usually rated at up to 60V at least.

Amperage level capability typically starts at 5A and goes up from there to 10A (maybe 15A) and then. 20A.

As the Voltage and Amp levels increase so does the $ :grinning:

All of the ones I saw from what appeared to be reputable companies cost in the hundreds of dollars. Although I found a 60V 5A unit on Amazon for less than $100. As I have multiple packs I bought two so I can always have several packs charged up for a session. Charging at my 5A rate produces very little heat.

Your single pack drives a different logic where you likely have a desire to charge quickly to get back out there. Our large capacity pack at 5A take about 10-12hr to go from ~30V to max 42V and I really don’t know what a sensible “fast rate” A level would be. Perhaps a more knowledgeable person can provide an opinion on that.

Depends on the cell and how long life cycle you’re aiming for. It’s a gray zone. I charge my hybrid auto cells with 0.5c / 20A max and it takes about 2-3h to full charge for 40Ah

They can take a lot higher charge current if i need it but i don’t have a charger for it😀


This is the cell used in these packs


The data sheet is linked by @windego above

Between 0.3c-0.7c charge :grinning:
Standard charge time 4.5h according to this:

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@stinkwhistle I think I actually have the same power supply you have that I am using to charge my version of this pack. I connect that to a DC-DC boost converter that has been adjusted to 41.7V at the output and I think I set the current to 6A or 7A (I forget). It holds that current constant up until it approaches the 41.7V limit then tapers off to 0A. Can probably run it at a higher current if I want to as nothing is warming up but so far I’ve kept it where it is. This converter connects to the battery and BMS to charge.

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