So I’m trying to make a power box to power my fish finders and leds for ice fishing and rather than but a new battery I figured I’d use the battery from my ancheer e bike at 48v 10.4 ah. I’ve got it hooked up to a dc to dc converter and it works great. The thing can power 2 fish finders and 2 leds and ether charge the I phone or run the aerator to keep the minnows alive. The problem I run into is it won’t run longer than 15 minutes before it turns itself off supposedly due to low current draw and the bms thinks it’s not a sufficient load and turns itself off meaning I have to reset every 15 minutes. Does anyone on here have any ideas on how to prevent the bms from doing this?
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Turning an e-bike battery into a power box
- Thread starter bowmann94
- Start date
A-DamW
Regular
If it is in fact the case that the bms is shutting down output due to too low of a load, I wonder what the threshold is?
Some idea's;
Use a microcontroller like an arduino to connect the battery via relay to some arbitrary high (100-300W?) load for a few seconds every 10-15 min., might reset the timer?
Open the case and bypass the bms.
Install a smart bms.(you can get good ones for $10-$15)
Have you used this battery in other situations and confirmed it works for more than 15min with a higher load?
The pics posted dont suggest any 'fancy' battery comms getting in the way, so as long as thats the case.
A bms 'upgrade' would be the 'proper' solution, a bypass would work but also loose low voltage protection etc.. but if less confident cracking the battery pack case than fiddling with lower dc voltage circuits something like this £2 module might be worth a punt?
The switch is probably just grounding a pad on the bms rather than actually breaking a battery connection, if so no extra load may not be necessary , just hook up the switch terminals to the NO relay terminals of a timed module - tho that will require cracking the battery pack to confirm and wire up, but 2 x connections is less daunting than a BMS replacement, and the result will maintain the protections lost with a bypass, without the additional draw of an unnecessary load. The downside is you will loose power every period as the battery resets, employing a sufficient load (dc foot warmer??) instead would negate the power loss.. just need experimentation to confirm the load required.. ..
A bms 'upgrade' would be the 'proper' solution, a bypass would work but also loose low voltage protection etc.. but if less confident cracking the battery pack case than fiddling with lower dc voltage circuits something like this £2 module might be worth a punt?
The switch is probably just grounding a pad on the bms rather than actually breaking a battery connection, if so no extra load may not be necessary , just hook up the switch terminals to the NO relay terminals of a timed module - tho that will require cracking the battery pack to confirm and wire up, but 2 x connections is less daunting than a BMS replacement, and the result will maintain the protections lost with a bypass, without the additional draw of an unnecessary load. The downside is you will loose power every period as the battery resets, employing a sufficient load (dc foot warmer??) instead would negate the power loss.. just need experimentation to confirm the load required.. ..
You might be able to add a load intermittently to reset the timer without turning anything off. It probably doesn't need to be on very long to reset.
Is it possible there is another connection on the battery that gets a signal from the bike to stay on?
Is it possible there is another connection on the battery that gets a signal from the bike to stay on?
It works great running with the bike and often go all day exploring the local trails. Bms swap is an idea I’ll look at that if nothing else works.
I like this solution it might be my best option short of replacing the bms. I’ll crack open the battery and post some pictures tonight.The pics posted dont suggest any 'fancy' battery comms getting in the way, so as long as thats the case.
A bms 'upgrade' would be the 'proper' solution, a bypass would work but also loose low voltage protection etc.. but if less confident cracking the battery pack case than fiddling with lower dc voltage circuits something like this £2 module might be worth a punt?
The switch is probably just grounding a pad on the bms rather than actually breaking a battery connection, if so no extra load may not be necessary , just hook up the switch terminals to the NO relay terminals of a timed module - tho that will require cracking the battery pack to confirm and wire up, but 2 x connections is less daunting than a BMS replacement, and the result will maintain the protections lost with a bypass, without the additional draw of an unnecessary load. The downside is you will loose power every period as the battery resets, employing a sufficient load (dc foot warmer??) instead would negate the power loss.. just need experimentation to confirm the load required.. ..
hopefully we can figure something out as there’s a lot of potential with this thing. It weighs less than 1/2 the lead acid batteries I have and by my calculations has just about the same ah after converting down to 12v.So the center pins don’t support power even though there marked +- leading me to believe there data pins. I’ve tried jumping them to +- as there marked and that doesn’t seem to work. If I wasn’t pulling a sled through 2 feet of snow I’d just leave it hooked to the bike and tap the wires coming out of the bike but that limits portability.
docw009
Minor legend
What happens if you turn on the Ancheer and let it sit with nothing connected for an hour. Does it shut down? I am wondering why an ancheer BMS would have a minimum current requirement.
I've never seen my batteries with on/off switches shut off, either on bike or on the shelf if I forgot to turn them off. Often do that with the Dolphin packs. THe switch LED's will stay lit for weeks,
I've never seen my batteries with on/off switches shut off, either on bike or on the shelf if I forgot to turn them off. Often do that with the Dolphin packs. THe switch LED's will stay lit for weeks,
Can you provide a link to the article or wherever this was implied?
I’ll see if I can find a link but this is my real world experience it actually does this while I’m running my fish finder through the dc to dc converter. I think I remember it being mentioned in the ancheer bike manual I’ll see if I can find it.
I haven’t gotten to not shut off with 2 fish finders a 500w inverter running a phone charger and 2 led light strips. So I need to figure out how much more load it needs. On the bike turning the throttle on for a few seconds is enough I just don’t know how much load that is and what I could use to simulate that load… preferably with something that’s useful for ice fishing as I’m dragging everything out by hand in a sled so weight is important.
Depends on what strategy you employ? a) Continual sufficient draw, or b) regular but short duration 'nudges', I would go for the latter, as it will prolong the battery use life. Any old high drain headlamp bulbs laying about?? , point it at the sky and anyone asking can be told your contacting the mothership and they will be guaranteed to leave you alone too
bonus..Bypass the BMS for discharging, feeding the DC-DC converter through a low voltage cutoff circuit instead of the BMS. Still use the BMS for charging and balancing. Adjust the LVC circuit to something around 40V.
I like it Maine has a history of alien abductionDepends on what strategy you employ? a) Continual sufficient draw, or b) regular but short duration 'nudges', I would go for the latter, as it will prolong the battery use life. Any old high drain headlamp bulbs laying about?? , point it at the sky and anyone asking can be told your contacting the mothership and they will be guaranteed to leave you alone too
I agree the latter makes sense. I guess here’s where I get caught up so battery is 48v so presumably I’d need to draw something equivalent to bumping a 48v motor to I don’t know maybe 300w for a few seconds. My dc to dc converter has a fuse rated for 20 amps. I’m decent at wiring and soldering but I guess I don’t have the knowledge of the electrical math. When converted down to 12v is 300 watts the same as at 48c to the battery? What about when its then run through the inverter to 120 ac can I draw less watts to achieve the same thing? With no way to measure what load I’m putting on it all I can do is experiment. Currently I have a timer going and plan on running an angle grinder off the inverter to see if that resets the bms timer.So took me awhile to find something light enough to run on the inverter but also draw a significant amount of power. If I run a 120v ac rotary tool wide open it doesn’t shut off. Google says the max this tool could use is 170 watts so not sure what that actually equates to after stepping down to 12v then ran through the inverter but I need to find something 150-170watt that is preferably useful for my use. I foresee upgrading the dc to dc converter to handle more amperage and a bigger inverter for more usefulness while camping in summer.
There are cheap immersion heaters you can use to heat up a cup of coffee or tea. This one says 140W at 12v. There are many to choose from. You could make a timer circuit so it comes on just long enough to reset the BMS.
Nah more like making a work around to utilize a battery within its parameters… I added up all the power I’m consuming with 2 fish finders and LEDs and an aerator it’s 17 watts at 12v. If my math is right when stepped down my battery should give me 40 ah - losses from converting so say 35ah. Should have a 20h+ run time by my math even with a 10 second bump at 150 watts. Plenty for a day on the ice. Just have to test real world conditions now.
RunForTheHills
Regular
Why not stay with the fishing theme? This Fish Winch runs on 12V:
Electric Fishing Reels | FISH WINCH® 2.0 | FISH WINCH®
Electric Fishing Reels | FISH WINCH® 2.0 | FISH WINCH®
