Portable 56 VDC EGO Battery Charger Project

  • I am going to give this setup a try:
    3D Printed Ninjatek battery to MPPT controller (Final design pending, might produce as a DIY kit)....

    As a side note I have access to the battery via the EGO 16" chainsaw so it is an existing battery option but should offer multiple charges...

    *** Rough power calculations that started me down this path:
    Typical OW charge is 30 minutes from ~ 0% to 100% (58 VDC @ 3.5 Amps = 203 watts)
    EGO battery is rated at 5 amps for an hour @ 56VDC hopefully the MPPT is 85% efficient (should be better as 56 VDC is close enough to 58VDC). I calculate the battery will provide via the MPPT 238 watts for ~ an hour = two OW charges. Fingers crossed......

    Update planned for next week.

  • @LidPhones Sounds cool - keep us posted! I'll be working on a setup myself soon (same MPPT solar converter like everyone else), so I love to hear the feedback from all the attempts!

  • @LidPhones said in Portable 56 VDC EGO Battery Charger Project:


    I will say one thing though...

    The rated specs on that battery are only 5.0 Ah (5000 mAh), which is probably nowhere close to the capacity needed to fully charge a OW. Anyone else (that knows better) want to confirm or deny this? For reference, some of the tablet charging batteries like Anker, etc make are in the 10,000-20,000 mAh and up, and I doubt even those would suffice.

  • Search "AMSU" on Amazon. $299 and comes with a car charger too. They already did the hard part and its cheaper, lighter (7lbs), and arguably safer too. You also get 2 full charges out of it.

  • @kevinrwhitley

    I have added my power calculations in the original post. Fun to use my EE degree once more in application ( the management gig has taken some polish off I must admit).....

  • I think lidphones is pretty accurate in the sense that the battery he is using is 5 amp hours AT 56 volts..the key being that that means he has a 280 wh battery, which if I remember reading correctly, 250 wh is what is required for a full charge, so he should get roughly one charge out of it, assuming the efficiency is 80% or greater.

  • The Anker batteries that have 20000 ah are meant for small electronics, so their voltage is very low, equaling a low wh battery. Someone please correct me if I am mistaken.

  • Hey LidPhones, since you know so much about this, would that 7.5 ah battery be better? I was wondering if it could be used to power a trampa electric skate at one point too. Keep its form factor and just snap it in and out of a water proof/resistant case. It powers a 21 inch self propelled lawn mower for close to an hour through some st Augustine grass. Charges in 45 minutes with the quick charger. http://www.homedepot.com/p/EGO-56-Volt-7-5-Ah-Battery-BA4200/205983345

  • I stand corrected! Keep me posted for sure then! :)

  • @PixelPusher
    Absolutely the 7.5 amp hour model will have more available power. If you already have it for the mower (I am keeping an eye on that 21inch mower as well) then it should make a great power source if it matches the requirements of the attached load (motor). What does the motor require for voltage and max amps?

  • @LidPhones I have not gotten that far yet. I have some learning to do and I just got started with gathering sources. Finding online calculators that get me close, but knowing that i need to understand the math myself. I am brand new to both the idea of DYI and electronics. My only experience is building a guitar pedal from a kit so far ;) Total newbie at this point. I do have the mower and battery though.

  • @slydogstroh is using a chafon of amazon says he gets about 3 charges out of it and its about 20 dollars cheaper than the set up you have planned

  • @jew_fro_1009
    I was reviewing that solution too but have the EGO battery already and was looking for a more compact solution. We will see how it turns out and if the value is compelling enough for others. I should have initial results back this weekend once built.

  • @LidPhones if this works, I did see the bare battery and BMS for the 7.5 ah battery configuration on one of the Chinese sites somewhere. Samsung cells too. http://www.globalsources.com/gsol/I/Lithium-ion-battery/p/sm/1145347243.htm#1145347243

  • @LidPhones said in Portable 56 VDC EGO Battery Charger Project:

    I was reviewing that solution too but have the EGO battery already and was looking for a more compact solution. We will see how it turns out and if the value is compelling enough for others. I should have initial results back this weekend once built.

    I'm all for compact and light! I want the smallest and lightest (yet still functional) design period... that doesn't involve a bunch of loose cables and janky connections to get disturbed in a backpack. If we can simply find/settle on the best compact/light battery that has enough juice to fully charge one OW (once) through a solar charger or otherwise, I can probably design a shell to house the whole thing together...

  • @kevinrwhitley

    We are both on the same path for a reliable solution. I will be 3D printing the interface in a nylon material that will hold the MPPT and secure the EGO battery / contact terminals with XLR plug.

  • @LidPhones sounds perfect!

  • @LidPhones

    I have a working setup just like what you are envisioning, except I'm using my three 40v 95 WH Ryobi batteries that I have laying around for my mower and weed eater.

    The 95 WH battery will get me 60% charge in under 20 minutes.

    I picked up some alligator clips and soldered them to the adapters. I just clip them on and bingo.

    There is a higher capacity 5 ah version of this battery that is the same weight, only 3.5 lbs, which will have to get over one charge. $140


    The thing I like about this solution is the BMS is built in and they are tough as nails and come with a warranty.

    My solar charger fits perfectly inside a dakine GoPro soft case.

  • @jew_fro_1009
    I just got my Chafon battery back up,I got 2 full charges on my OW from 1% to 100%.
    Love it.

  • Initial results = Two charges from the EGO 5AH battery and MPPT. Need to fine tune the MPPT setting to optimize charge performance. 1st charge was from < 1% to 100%. 2nd charge was from <1% to 95% (some MPPT issues for OW to start charging, will sort these out and update).

    Next step is to design and 3D print the slide on battery interface tray which will hold the MPPT and wires/terminals (Yazaki blade terminals used). Overall this seems to be a very compact and powerful solution for the 58 VDC 2.17AH battery (should get two full charges from 5AH).

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