Off Grid 12v - Bulk Charging 15S5P

[c-roots]

Hello,

Just finished up the carbon/kevlar enclosure mounted permanently straight to the frame of my Klein Mantra for my new LiPo pack and man... It's a little on the tight side of my "precise" measurements, I really don't want to ever have to take the batts outta there and risk anything. Especially after my previous bright idea of using FOIL lined dollar bin lunch boxes to protect my optional reserve pack that still had bullets on it ended up in a flaming, smelly, welded ball of Chinese imports.

I am currently living off gird and have 2S2P (hehe, first time I get say it like that) of 6v Trojan T-105s charged by a 460W solar array. I have been charging 14S3P and broken down packs to parallel charge 15S3P on my beloved Hyperion on this 12v set up but.... Now that I am moving up to a 15S5P pack, the appeals of bulk charging are becoming more *painfully* apparent...

I was wondering what your ideal set up would be to bulk charge from a 12v power source, while prioritizing protecting my homestead's power supply. I have available a relay driver hooked up to a dedicated relay as a LVD / over temp and a various breakers and fuses to protect the circuit, but I am out of ideas for cheep, reliable, safe (ish), and preferable voltage adjustable components to step up the voltage to bulk charge from 12v.

Thanks to everyone on endless sphere who shares their knowledge, experiences and time! My bike is built 100% from lurking on this site, only downside is getting more crazy ideas and power thirst... Ive been riding my steed for a month and I can't help planning a new build...

Happy ridding,

Roots

[Alastor]

Hi ,

Check this out http://www.endless-sphere.com/w/index.p ... ttery_Pack

In order to do bulk charging the battery in between balanced charges you will need approx a nice 62vdc power supply that will support different stages of charge for the batteries you are having.

The problem is that this converters are kinda expensive.

Lets see what the others will suggest

[c-roots]

Thanks for your reply Alistor,

I guess bulk charging using two meanwells might still be the cheapest / most adaptable / easiest option, even if the origin is a 12v power source. That would allow me to bulk charge anywhere also. There is just something that seems a bit rough about going from 12v DC, inverted to 120 AC, back to DC through a PSU to a battery. I am looking to investigate if there is an other alternative and how it could be done.

I was ideally hoping there was a DC (12v) to DC (pack v) converter out there somewhere that I could use, hook it up to a Morningstar relay driver (http://www.morningstarcorp.com/en/relay-driver) by using 1 of the channels as a voltage sense for the pack v, and another channel to control a relay to cut the power when the pack is full. The main issue I am having with finding a compatible DC to DC converter that has an output that isn't just marginally better than my current Hyperion.

I'm thinking that in the end, power supplies will probably win out. I just cant bring myself to pull the trigger without having at least one other option to look at.

What do you guys think? Is there any other way of bulk charging off 12v? Or am I better off using meanwells off the inverter?

Thanks,

Roots

[wesnewell]

I think I'd prefer using one of these chargers instead of tying meanwells together. Size depending on the output of your inverter.
http://www.bmsbattery.com/18-alloy-shell

[Alastor]

Well your previous response made me think something .

Why do the relay setup and not use your solar charge controller as DC input ? you will not have to care about draining your system because the solar controller will take care of that.
Then make a little research in DC to DC lipo charger if they exist.

And i am telling you all this because otherwise you will need an inverter and the charger from bmsbattery site.If you use a cheap inverter for the charger you will convert DC to AC then the battery charger will convert again the AC to DC.With all this conversions you will loose 20% plus 20% from a modified sine inverter that works at 80% efficiency.A lot of losses overall.

If you can go DC its the best way to do it.Cheaper as well.More energy efficient since your main system is charging from solar panels.

[drutledge]

I use the small solar panels on my garage (170 watts in theory) to charge my three bikes. The panels go through a controller to a bank of marine batteries for storage and I have a Hyperion 1420 that is connected through the same controller. The Hyperion works fine as a bulk charger and I can always use it to balance charge if needed.

Most any RC charger works off of 12 or 24V. Seems easier than messing with an AC powered power supply. Or an inverter to a BMS Battery style charger. (though I do have one of those that I can carry with me for those really long trips. )

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[c-roots]

There are a few issues with using the charge controller as a charger directly to the Lipo. I would have to manually disconect and re-conect a 2ga cable... not to mention that my charge controller coulden't handle ~60v.

I think I'll just pick up a second Hyperion and give that a go. It will definately be faster than just using the one while staying safe. But I can't help thinking there must be a better (faster) way to bulk charge directly from a ~12v source considering I would not at all be getting the full 1100W on ~12v.

My house's current inverter is 1500W, so I coulden't really get the max out of any AC powersupply based bulk charger either.

[Alastor]

There are a few issues with using the charge controller as a charger directly to the Lipo. I would have to manually disconect and re-conect a 2ga cable... not to mention that my charge controller coulden't handle ~60v.

I think I'll just pick up a second Hyperion and give that a go. It will definately be faster than just using the one while staying safe. But I can't help thinking there must be a better (faster) way to bulk charge directly from a ~12v source considering I would not at all be getting the full 1100W on ~12v.

My house's current inverter is 1500W, so I coulden't really get the max out of any AC powersupply based bulk charger either.

I find it strange to use an inverter if you are having a 12V battery bank .You can just make a new line from your batteries to power your controller (or controllers) and you will save a lot of money and energy.

In small solar setups it is best to avoid using your inverter because you loose a lot in between and the system is not that efficient.There is nothing bad in using 1100W out from your batteries but you will have to make sure not to over discharge your trojan's.An inverter can protect you but still you are loosing precious energy from the conversions DC to AC and AC to DC again.

Now if you still want to use your inverter i think one member (i cant recall the name) made a lipo charger out of three LED power supplies if you search in the forum a little bit you might find the post.
If i can recall right he wanted something similar to your needs.There are tons of other possible solutions as well for example you can use simple Under voltage protector switch in line with your new line from your battery bank and use two hyperion chargers directly out from your bank to charge your lipos faster without breaking the pack a lot and without the use of the inverter.Or just buy the charger from BMSBatteries

[whereswally606]

what about a bc168 or three.

they do upto 6s so you could get one and do a tench style connector out of a db37 connector which would parallel the packs at say 5s 15p then charge at 8amps

or do the difference ie charge 10s with the hyperion and 5s with the bc168

or buy 3 and dont parallel the packs just remember to divide the pack into three 5s5p packs before charging.
they charger directly via the balance taps and are fast, i saw some for 66$ delivered which means you could probs buy upto 3 before spending as much or the same as a second hyperion.

btw i own a hyperion 1420i and i think its great but i think it would be overkill for you to buy another for that one extra cell.

hope thats made sense like it did in my head.