Where find 86v->9v dc converter

[Allex]

I have a Magicshine MJ-872 that consumes around 2A and runs of 8.4V battery.
I want to connect it to the main Battery which is 86V hot off.
I searched a lot and can only find 74V converter tops.
Where can I find this badboy?
Or can i Simply use this kind?

I also want it to have power as soon as I turn the ignition key. I have CA 3.0 But I guess the AUX dc plug will not handle that current... is it possible to connect the Converter through my key switch?

 

[exco]

Where can I find this badboy?

Though not 86 to 8.4V http://de.mouser.com/Power/DC-DC-Converters/_/N-5gc7

Or can i Simply use this kind?

No.

I also want it to have power as soon as I turn the ignition key. I have CA 3.0 But I guess the AUX dc plug will not handle that current... is it possible to connect the Converter through my key switch?

If you mean the auxiliary pot connector - absolutely not.
If you mean the output power plug - yes you can connect to that (though I don't know - but suppose) it has 86V.

You could simply use a CC-CV step down module (CC-CV is the right charging technique for Li-Ion) and connect it to gnd of your battery
and the plus pole of the e.g. 6. battery (or the one with the power level for max efficiency of your step down) or to the balancing lead if you don't have access to the single cells.

 

[teklektik]

The CA Aux Power plug has a 1A auto-resetting polyfuse, so your light should work since you are drawing 2A x 9v = 18W or roughly 18W/80v/50%eff ~= 0.5A at the plug.

What you show in the picture looks like a little CC-CV (constant current - constant voltage) charger. You don't mention if you are leaving the batteries in the light.

• If so, your charger should work and will just do it's normal charger thing to keep the cells topped off.
• If not and you want to eliminate the batteries (preferred), then you will likely need to get a plain vanilla 9 to 12v supply that can supply 2A. I think your light has a CC LED driver in it, and trying to push it in turn with a CC charger may have unexpected results for the charger. You should have good luck using just about any switching wall supply since your Vbatt is quite a bit above the 40-45vdc where they typically get a little iffy - less than $10 on eBay should do the job - and pretty weatherproof...

As for the ignition switch question - you can do that as well - that's actually how the CA is powered via the CA-DP plug so the supply would be in parallel with the CA instead of running through it.

 

[Spacey]

So you are saying I can run my Cree LED light direct from my CA V3? I did wonder about this, but was too scared to break it.

I have been fiddling with dc converters and found that my Cree headlight drains a 20W 12v dc converter down to 5v? the dc converter is more than capable of this kind of power need...maybe it is the way the LED driver works?

 

[Spacey]

HI,I saw you find the products made in china input range from 100v-240V,but you wana to change the input to 86V?
if so,then why do you select the 74V?both 74V and 86V are out of range in your adaptor stand.

But still it works

 

[teklektik]

So you are saying I can run my Cree LED light direct from my CA V3? I did wonder about this, but was too scared to break it.

The numbers say the CA should handle the power, but you will still need to add a converter before the light if the voltages don't match up. The Aux Power plug is really provided as a convenience to avoid running additional wiring and can be used to run the Grin Tech Cycle Luminator LED light directly (it uses Vbatt - not 9v).

In any case, the 1A polyfuse will protect the CA if you draw too much current - it will 'reset' after it cools.

BTW - If you are using a temp sensor with a V3 that shares the controller hall ground connection (e.g. EM3EV MAC with built-in temp sensor), running a lot of current through the CA Aux Power plug can cause a small temperature offset as the added current raises the CA ground potential a bit. No big deal, but just so you know....

 

[Spacey]

Cheers for the info.

 

[Tench]

I was going to try one of these;

http://www.ebay.co.uk/itm/REALLY-12V-OUTPUT-In20-72V-Out12V-Step-down-Converter-/140586410360?pt=LH_DefaultDomain_0&hash=item20bb9a6178

Your light will probably be fine at 12v, some of the ones I looked at powered by the usual 4x18650 setups where rated at upto 13v input.

 

[100volts+]

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