[RE-wrenches] DKD Lithium Batteries

[Dan Fink]

Hi Kienan - DKD is a PV installation company in Texas. Looks to me they had
a Chinese battery manufacturer put a custom sticker on the ones they sold.
I would google the battery specs and dimensions and find something similar
from China where you might be able to get specs.
The lack of BMS would worry me very much.


Dan Fink
Director of Solar Education, Greendustrial Training LLC
IREC Certified Instructor™ for:
~ PV Installation Professional
~ Small Wind Installer
NABCEP PV Associate
Executive Director, Buckville Energy Consulting
NABCEP Registered Continuing Education Providers
dan.fink at greendustrialtraining.com
970-672-4342




On Mon, Mar 4, 2019 at 6:23 AM Kienan Maxfield <maxfieldsolar at hotmail.com>
wrote:

> Hello all,
>
> I just got back from looking at an off-grid system that is only about 4
> months old or so, and it has several problems. I have specialized in
> off-grid for 8 years, so most of the problems will be easy for me, but
> there's just one thing that is a bit perplexing and I'm hoping someone
> might have some advice.
>
> The system was "designed" by some retailer in Texas (I don't know who) and
> the home-owner found some local installer to put it together for him (they
> already charged a ridiculous price and they won't come back). The battery
> is a big bank of DKD LiFePO4 batteries, each one says 100 Ah @ 12.8V. They
> are in series sets of 4 for 48V. I think there were 5 strings (500 ah
> total). There are no com wires from battery to battery or anything like
> that (nor did I find anywhere for com ports). I have not yet been
> successful in finding any information about these batteries online. I'm not
> that familiar with this type of battery and I'm hoping that some of you
> might have some info/insight on a couple of questions about this situation.
> Here's a picture of one of the batteries,
>
>
>
>
>    1. The biggest question is if this configuration is okay. I'm not
>    familiar with this type of batteries, but I saw at least one brand that
>    said not to put their batteries in series. They said that (at least with
>    their brand) if you needed a 48V battery, you couldn't use (4) 12V
>    batteries.
>    2. Does anybody have any thoughts (positive or negative) or
>    experiences with these batteries?
>    3. Does anybody have any technical information (like a voltage/SOC
>    curve or anything else) for these batteries?
>
> I will be fixing the other things in his system, but when he asks what I
> think about his battery bank, I don't know what to tell him at this point.
> He also has no idea how to tell how full his batteries are, and since it
> doesn't seem like his batteries have any kind of readout or anything, I'm
> not sure what to tell him on that either. If I could find a Voltage/SOC
> curve or a voltage/SOC conversion table, that would help on that front.
>
> Thank-you,
> Kienan
>
>
> *Maxfield Solar*
> *maxfieldsolar at hotmail.com* <maxfieldsolar at hotmail.com>
> * (801) 477-0-SUN (477-0786) (801) 631-5584 (Cell) (preferable contact
> number) *
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