A low cost dashcam battery pack for the parking mode.

Methlal Pallewatta

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Oct 8, 2014
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Location
Sunnyvale, CA
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United States
Dash Cam
Transcend DrivePro, Street Guardian, Viofo
If your dashcam can run at 5V here's a low cost alternative to Cellink Neo etc for using in the the parking mode. Will cost around $75 to build. Of course won't charge as fast as a Cellink but at the fraction of the cost. No BLE based monitoring via app.


LiFePO4 (not Li-Ion/LiPo) battery pack (supports UPS like functionality) and has a capacity around 80WH (haven't done a capacity test yet).

https://www.amazon.com/gp/B07YRZYLKV

Buck-boost converter with a voltage limit of 14.6v and a current limit of 2A is used as a charger. According the manufacturer the battery pack can be charged at 4A and has a built in BMS to prevent overcharging. Prefer to limit the charging current to around 3A (0.5C).

https://www.amazon.com/gp/B07VNDGFT6

An electronic load drawing 2A is emulating the camera load.
IMG_20201103_010315.jpg


Charging at 2A with the buck-boost converter. A programmable DC power supply (14.7v) emulates the car battery when the alternator is running in a 12V vehicle but this buck-boost can accept 24V too or you can use a buck converter with the 24V vehicles.
IMG_20201103_010401.jpg
 
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Seems nice enough, but one review of the buck/boost converter warned to set the output before connecting the load, as it defaults to turning on at maximum voltage/current when battery power is first connected. We do need solutions like this instead of the over-priced Cellink (y)

Phil
 
> set the output before connecting the load, as it defaults to turning on at maximum voltage/current when battery power is first connected


The one I have holds the settings across power off/on events and has back-flow protection as well. I have secured the position of the voltage control knob with hot glue. Since the max power the converter can deliver is 35W I am limited to 2.3A. Will be testing with a more powerful converter / charger later on. Charging at 3A (0.5C) should be ok.
 
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Seems nice enough, but one review of the buck/boost converter warned to set the output before connecting the load, as it defaults to turning on at maximum voltage/current when battery power is first connected. We do need solutions like this instead of the over-priced Cellink (y)

Phil

Hi, I'm new to this forum and dashcams, but have been studying for a while as to my requirements. I agree, the Cellink et al is too overpriced for my taste, so I've been trying to come up with other solutions that would do something similar.

Has anyone tried or have any thoughts on using say, a jump starter pack as a separate power module? Some have a USB out port, and are charged with a USB in port, while having the 12V power to jumpstart a dead battery. If they weren't overly discharged powering the dashcam, they can also be used in their original purpose.

Or how about using a battery isolator and having a second utility battery to power the dashcam? These range in price from $30 to $150, and a good agm or lithium utility battery can be had in the $100-$150 range. Some thought would have to go into placement and correct wiring, but at less than half the cost could be an alternative to a Cellink.

I will be ordering my dashcam shortly, and will originally be going with an OBD adapter, but depending on how much use I find parking mode, may look to something different in the future, so I'm interested if anyone has any thoughts on the matter.

Cheers
JP
 
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The issue is that the jump starter packs cannot be charged quickly. This pack can be charged at about 4A it's LifePo4 and not LiPo.
 
Welcome to DCT @Bullwinkle :) (and I'm still waiting to see a rabbit :ROFLMAO:)

A few RV'ers have posted using dual-battery systems (using battery isolater), a few have posted using jump packs for longer term parking protection, and several folks use 2 powerbanks swapped out daily with one charging at home.. Most people not using a Cellink choose the last option as being simple and relatively cheap but it's not hands-off nor is a jump-pack. That's the real appeal of a Cellink or dual-battery system.

Charging time may be relevant if you plan to use the system regularly, but might not be an issue if you only use it occasionally. Using 5V USB charging will be achingly slow as you can get only a few amps at best :( so much better to use 12V charging. If you DIY a system all options are yours as to battery types and sizes and charging schemes :cool:

My own plans are to use an 20+ amp AGM battery with a DPDT 30 relay for switching between charging and cam use- super simple as a 12V AGM needs no charging circuit or regulation. It just runs and charges parallel to the car battery with the engine running and is isolated with the car turned off. AGM batteries are very safe and relatively cheap, but are bulkier and heavier than equal-capacity Lithium type batteries.

If you do choose to use a factory-made battery isolator, do some research on RV forums as to which one to get as some of these are junk or nearly so
, which is why the vast price range exists with them. I haven't researched these in several years so I can't offer a recommendation.

Phil
 
Thanks folks. This is exactly the kind of feedback I was looking for. The slow charging rate of the jumpstarter packs makes sense when you factor in the 5V versus the 12V charge voltage, and is probably enough to eliminate them from consideration even without issues like reserve capacity and effective life cycle.

@SawMaster , I like your thoughts of an isolating relay as an even simpler solution than a commercial battery isolater. Great food for thought.

And Phil, about that rabbit... You should know, "That trick never works!"

JP ;)
 
My DPDT relay scheme is super-simple and should be very reliable based on my use of relays and high-amp loads in the past. It does require a high-quality relay or you may find the contact points arcing and sticking; a buffering capacitor should eliminate that if it's a problem.

Automotive relays should do well here I think. They're relatively cheap, available everywhere, and if you wire it in with a 1-piece relay socket swapping it out couldn't be easier. Look for a type meant for continuous use. Allow 15%-20% extra capacity to make life easier on the relay. Ditto on wire sizes for the max current expected, and as always fuse everything well.

The downside of this is that there's no low voltage protection for the auxiliary battery so you'll want to add that or use a HWK for the cams which has that. Otherwise you can over-discharge your secondary battery and greatly shorten it's capacity and user-life.

A battery isolator may have all these goodies built in; they come in several flavors and would be easier to do. Might be a better approach if you're not familiar with high-amp DC wiring.

Phil
 
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