DC converter anyone tried this one?

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Bikegirl   1 W

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DC converter anyone tried this one?

Post by Bikegirl » Aug 11 2019 6:46am

Just about to order this for my 20s lipo pack for 12v control/start circuit, which includes zeva smart precharger and gigavac p105 contactor to bring in dual motor controllers to 2x 1000w gng motors.

AU $20.71 | Step down Transformer Electric DC Converter Adapter 48V 72V 96V TO 12V 10A USB 5V
https://s.click.aliexpress.com/e/cEcScHmu

Any opinions?
Could I use something else?

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john61ct   100 GW

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Re: DC converter anyone tried this one?

Post by john61ct » Aug 11 2019 11:32am

There is a river of much better quality, western made surplus / NOS discontinued, from telecom / industry, DC-DC converters flowing through eBay.

Good stuff is worth hundreds new, so cheap might mean $50. Talking makers like Ericsson, Tyco, Lucent, Astec, GE, ABB, Delta, Artesyn, TDK Lambda, Samlex etc.

If you go cheap Chinese like that, size for 30-50% so if you need 10A buy one rated for 40-50A.

And carry spares.

Mouser, Digikey, E14/Newark/Farnell are good sources for current.

Bikegirl   1 W

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Re: DC converter anyone tried this one?

Post by Bikegirl » Aug 17 2019 8:57pm

Thanks John. I was on mouser/element 14 but I couldn't size right for my specs without it being through hole mount

I will keep an ebay stuff, but 80-84v in us hard to find so far

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john61ct   100 GW

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Re: DC converter anyone tried this one?

Post by john61ct » Aug 18 2019 3:45am

OK, if possible split the pack into two halves with a mid tap point and get two 40-42V units going, no need to disconnect them, each will be independent for charging purposes but function as a single pack in use.

Some also use mid-point voltage monitoring comparing the two sides as a protective "meta BMS" while in use, Victron BMV-712 for example.

Bikegirl   1 W

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Re: DC converter anyone tried this one?

Post by Bikegirl » Aug 18 2019 2:51pm

It's not possible for me to split as I have only one bms. Trying to use chargery 24T but voltage readings seem a bit off (over 100mv range) but have to cross check with my meter.

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john61ct   100 GW

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Re: DC converter anyone tried this one?

Post by john61ct » Aug 18 2019 7:47pm


Bikegirl wrote:It's not possible for me to split as I have only one bms. Trying to use chargery 24T
Sure it is, they specifically make it easy to connect disconnect.

For normal cycling, charge at high current, no balancing, stop at say 4.05V for longevity.

Do the more precise, higher voltage + top balancing after the above bulk charge, as a maintenance routine as needed.

Low amp charge sources are not so expensive.

_____
Or do all in one, if say 1kW 30A is fast enough

Turnigy Reaktor 3010B Balance Charger
https://www.rcgroups.com/forums/showthr ... 0S-Charger

Charsoon Antimatter is a clone.

Much better quality, Revolectrix Cellpro 10S, can do charging directly through the balance leads at up to 4A, or bulk charge at 40-42V much faster, only use balance leads for balancing, or not at all.

Lets you have two separate choices for balancing, test which works better.

_____
Also check out Delta-Q ICL series, 1200 or 1500W models go to 85V


john61ct   100 GW

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Re: DC converter anyone tried this one?

Post by john61ct » Aug 18 2019 7:55pm

It's a kludge, but if you find a cheap but too high-voltage PSU, you could use one of these

https://www.droking.com/battery-charge- ... tion-board

To cut off its input when reaching your (adjustable) target voltage. CC-only, no Absorb/CV stage, so can go higher than you usually would even say 85V if at a high C-rate.

But only for the normal-usage cycling bulk charging, still need the hold-Absorb time for balancing cycles.

john61ct   100 GW

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Re: DC converter anyone tried this one?

Post by john61ct » Aug 18 2019 7:59pm

Very sorry, just re-read your OP.

I'm all about charging in the recent posts.

Not stepping from your 70-80V down to a utility 12V circuit.

Roseanne Roseannadanna voice "never mind". . .

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