DIY: 105 AH LITHIUM POWERBANK with VICTRON MPPT and SMART BATTERY PROTECT

  • HTML tutorial

Boreal Overland

Rank II

Enthusiast III

473
Europe
First Name
s
Last Name
K
Hi all!

Wanted to share my latest DIY project with you guys..
Yes, yes i know.. another one of those "solar generators" that does not generate any solar.. LOL.

Last year i made my first so called "Solar Generator" with a 38AH VICTRON AGM battery and that worked out great on our road-trip last year.
Charging ipad's, camera's and such..

This year i wanted to build a much more powerfull one that could at least handle a small Dometic frigde for a day or so,
takes a fast charge and does not weigh a ton.. so i went the Lithium LIfePo4 way.
In the end it weight 1,5x at much as my DIY AGM powerbank but it has 5x times more power available.
I gathered all the components in the beginning of this year, bought the 4 "raw" lithium cells for a respectable seller and started building..
Finished the project a couple months ago but did not have time to make decent photo's and post it here on the forum.

This is what i came up with:

IMG_0982.jpg

It has a main power switch, a switch for the USB and Neutrik Powerplug 20A outlets,
and a switch that switches on a 200A relais that powers the 50A Anderson outlet and the 125A Anderson plug inside the box.
It has 2 Neutrik Powerplug "solar" or "DC" inputs, those power the VICTRON MPPT 75/15 solar controller.
I like to upgrade the MPPT to a larger and Smart ( i use a smart dongle) model in the near future..
When the MPPT is working / charging the battery it powers the two fans in the front so the box does not heat up inside.

IMG_0974.jpg

ALL outlets are "controlled" by the VICTRON SMART BATTERY PROTECT 100A (SBP),
and the SBP is connected via the Victron Smart Network with a VICTRON SMART BATTERY SENCE that checks battery voltage and temperature.
The MPPT is also connected to the battery sence so no charging below 5 degrees Celsius.
The 50A and 125A Anderson plugs are also connected to the SBP but via a relais that gets powered by the SBP because the SBP does not seem to like large inverters..
I won't use the 50A and 125A that much but i just wanted to have that capability to use a inverter or maybe charge the battery via the Andersons plugs since those are not directly in line with the SBP (sending power the wrong way into the battery protect will kill it!)
The SBP will switch off if the voltage drops to 12V, say about 9% battery life
and in turn gets switched off by the small BMS (Battery Management System) if something might go wrong with the LifePo4 cells.

IMG_0968.jpg

IMG_0971 (1).jpg

I attached a little cell monitor to the battery just to check now and then how the cells are doing and if they are still in balance..
They seem to do just fine and don't differ much from each other most of the time.. , sometimes the are within 2mv of each other.

IMG_0963.jpg

IMG_0986.jpg

Build a quick 12V to 24V car charger the day before we left home to go on adventure but did not have to use it..
I would like to have a VICTRON SMART DC to DC charger in the near future.

Pretty happy with how it came out and how it performs so far..
We just came back from a awesome 2 week round trip thru Norway and Sweden,
charging all are electric goodies almost each day and the pack is still 68% full from the 100% when we left home.
Overkill so far but should work out great once we throw in a nice little fridge on our next adventure.

Could i just have bought a portable powerbank from a populair brand.. yup.
Would that have been cheaper.. nope..
Would that have been easier.. yup, and more fun.. most definitely not!!

Thanks for watching guys.. stay safe!
 
Last edited:

EXPO_D1

Rank V
Launch Member

Member II

1,963
Bakersfield, CA, USA
First Name
James
Last Name
Coyle
Member #

17468

very good write up. I am curious to learn more about your battery choice. what raw lithium cell(s) did you use for this?
 

Boreal Overland

Rank II

Enthusiast III

473
Europe
First Name
s
Last Name
K
very good write up. I am curious to learn more about your battery choice. what raw lithium cell(s) did you use for this?
Hi, thanks.
I used 105 AH aluminum cased prismatic cells, 4 of them making 12V,
they came "matched" and all at the same voltage..IMG_9749.jpgIMG_9803.jpg

Only time will tell if they are any good but so far i have not found any major problems or bad reviews..
the only bad thing (i know of) with these cell are the tiny M4 treads which strip out far to easy if your not carefull.
 
Last edited:
  • Like
Reactions: EXPO_D1