Using Server/Telecom power supplies as battery chargers

[jamiegreen]

Soon will be upgrading to 48v with a new Victron Multiplus, but I'd like to get away from using the dirty geni power on passthrough. Trying to find a 48v 70-100a charger is proving difficult (EG4 not available in UK)

I've come across some Eltek Flatpacks which are readily available here, two of them in series to make a 4kw charger to run my geni at near max load.
My problem is.. these units are set at a default 53.5v, and I don't know if this is high enough to charge a 48v lifepo4 pack.. I only charge up to about 65% with the geni, but will this voltage allow the full 4kw up to 65% or will the current taper off before then due to the lower voltage of the charger?

These units are CANBUS configurable but all that code and techy stuff goes a bit beyond me, unless I can find someone I could pay to reconfigure them to say 56v.

 

[42OhmsPA]

Check this out...

DIY 'Chargenectifier'

Based of the informative info recently posted by @ChrisFullPower in another thread I'm intrigued in DIY'ing a charger from used rectifiers. A quick search on eBay for '48v rectifier' has made me realize it's definitely doable at costs much lower than off the shelf options... I'll start with a...

diysolarforum.com

 

[jamiegreen]

Check this out...

DIY 'Chargenectifier'

Based of the informative info recently posted by @ChrisFullPower in another thread I'm intrigued in DIY'ing a charger from used rectifiers. A quick search on eBay for '48v rectifier' has made me realize it's definitely doable at costs much lower than off the shelf options... I'll start with a...

diysolarforum.com

Thanks, not sure how I missed that one!

 

[Sean Very North]

I've a fair quantity of Flatpacks, plus the chassis rack if you need anything - I went through a similar experience 7 years ago when I first started building systems with ex EV cells, these thing are bullet proof and CAN controlled so work well with Batrium and REC.

I'm wondering why you aren't using the charger built into the MP ?

 

[jamiegreen]

I've a fair quantity of Flatpacks, plus the chassis rack if you need anything - I went through a similar experience 7 years ago when I first started building systems with ex EV cells, these thing are bullet proof and CAN controlled so work well with Batrium and REC.

I'm wondering why you aren't using the charger built into the MP ?

I'd imagine most here would rather use a stand alone charger for the same reason as me, to prevent passthrough power from a generator being used whilst the batteries charge. My diesel geni is capacitor regulated and it's pretty dirty power, the LED bulbs flicker and I don't like running the hi-fi equipment on it, along with most other sensitive electronics.

I happened to see two 2000w flatpacks for sale on marketplace brand new for £100 each, up in Glasgow (assuming it's not you! ?)

Have you any experience changing their voltage settings via canbus? All that coding stuff is a bit beyond me..

 

[Sean Very North]

Do you not have a grid connection ?

It's been a few years since needed to use the Elteks, but I simply followed the Endless Sphere thread, which contains absolutely everything you'll need to know - you'll need an arduino canhat and an edge connector, the coding is easy as someone has already written it

I'm a lot further north than Glasgow.

ULtra Compact 1800W charger + Eltek programming

Guys i think i have found the world most compact and powerfull charger ever 8) It's a ELTEK 1.8kW flatpack S !! These are availlable in 24 and 48V and take from 100 to 240V. But what is fantastic is that they have the unbeatable 47 W/cu inch density !! and are 96.5% efficient!!! These are...

endless-sphere.com

 

[jamiegreen]

Do you not have a grid connection ?

It's been a few years since needed to use the Elteks, but I simply followed the Endless Sphere thread, which contains absolutely everything you'll need to know - you'll need an arduino canhat and an edge connector, the coding is easy as someone has already written it

I'm a lot further north than Glasgow.

ULtra Compact 1800W charger + Eltek programming

Guys i think i have found the world most compact and powerfull charger ever 8) It's a ELTEK 1.8kW flatpack S !! These are availlable in 24 and 48V and take from 100 to 240V. But what is fantastic is that they have the unbeatable 47 W/cu inch density !! and are 96.5% efficient!!! These are...

endless-sphere.com

I don't have a grid connection, just my solar array and a backup diesel generator. At the moment I just let my Victron Multiplus run in passthrough to charge the batteries, albeit not very often it happens, but soon I'll be upgrading it from 24v to 48v and I'd like to get the seperate charger sorted for that.

I will have a good look through the thread, and try and wrap my head around it. Although I only ever charge to around 65% with the geni, I'm not actually too sure if the standard 53.5v of the flatpack would be adequate for this or whether the current would taper off from it's max before the 65% soc mark due to the lower voltage. Worst case I'll try and find someone local with a little more canbus knowledge, I may know someone, and beyond that, if you still have the bits to do it and would be willing, I'd happily post and pay you to change the voltage.