Charger/Math question

dottyback

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Hello everybody,
I am new to this forum/Hobby and have a question in regards to charger math.

So I am looking into to buy a Hota d6 plus as many here have recommend and it seems to fit my needs.
I just would like you all's opinion on if i did my math right.

I have two of these Batteries. Zeee power 9000mha.jpg

So I figured that at 1c charging rate i will need to apply this math,
Watts = Volts * Amps

charged voltage 16.8 x 9=151.2 x 2 batteries = 302.4w
storage voltage 14.8 x 9=133.2 x 2 batteries = 266.4w

(not sure to use the charged or storage voltage to apply)

The Hota D6 plus has and output AC of 300 watts.
This is cutting it more than close since chargers have usually an efficiency of 80%

300w/0.8%=375w

which is not enough to charge at 1C if i understand this correctly

So i am thinking to get a 24v DC power supply and i did my research but i just would like
to get everybody's input.

Mean Well RSP-1000-24/ 1000 watts, 42 amps, 24 volts
Hota charger output max DC 650
charger efficiency 80%
[email protected]% efficency = 812.5w draw from the power supply

I chose RSP over the SE model with the same Wattage because of PF which is on average 0.6%
in the average household, this gives me a little wiggle room if i decide to charge at maybe
1.5C or get into 6s Batteries.

Please let me know what you all think, if i missed something.
Every comment is appreciated.
Thank you

Pete
 

nino

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The rated output is exactly that, output. So it should be able to squeeze out the required 300W. You're good.
 

jkflow

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Rated output is 300W but limited to 210W (AC) on 1 channel per the latest HOTA D6+ spec. (210+90)
Limit is 325W max/channel on DC if input is above 24V.

Overall your math looks right. The voltage changes as you charge up and using the storage or end points is a good way to calculate.

Don't forget that you will need additional parts to make your power supply work, you have exposed wires, need balancing boards for parallel charging etc.
My guess, add another $50.

Only math I would question is the cost of that supply (~$350) vs just buying another charger ($150). You can easily charge a single pack and don't have to worry about them being balanced prior connecting.
 

dottyback

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Rated output is 300W but limited to 210W (AC) on 1 channel per the latest HOTA D6+ spec. (210+90)
Limit is 325W max/channel on DC if input is above 24V.

Overall your math looks right. The voltage changes as you charge up and using the storage or end points is a good way to calculate.

Don't forget that you will need additional parts to make your power supply work, you have exposed wires, need balancing boards for parallel charging etc.
My guess, add another $50.

Only math I would question is the cost of that supply (~$350) vs just buying another charger ($150). You can easily charge a single pack and don't have to worry about them being balanced prior connecting.
Hi jkflow,
I am not sure if i understand your last paragraph correctly.

This is the PSU i looked at
https://www.progressiverc.com/mean-well-rsp-1000-24-power-supply.html

I also thought that this charger would automatically balance the battery on each channel
and in regards of a balancing board, i do need to read up on this because i don't really understand
at this point how this works . I am just starting and only have a few Lipos.

thank you

Pete
 

Jerry-rigged

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jkflow

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Ok, I saw that one on Amazon for $350, even at $199 you will not get more out of it than purchasing a second charger ($150).
Your call to make though. Might get interesting with the $65 supply from @Jerry-rigged post.

I do not recommend parallel charging on the bigger packs, I have done it and maintenance and diligence needs to be spot on. I always do it on smaller packs for my mini stuff, always makes most sense if you have many of the same type.

Parallel charging
- packs must be of equal cell count (i.e. 4S etc)
- when connecting, always ensure that the cell voltages between the different packs should be within +/- 0.02V. Keep in mind that the higher pack will act as a source and sink into the lower voltage pack at max current (only limit is internal resistance)
- lower capacity packs (up to maybe ~2000mAh) have less problems with that and are less risky when unbalanced
You must check the packs before connecting, going by memory might be a big mistake with instant regret, typically a smoked balancing board

Charging itself is no different. I do it, occasionally, when I'm in a hurry but I rely more on individual charging.

Weigh the cost of a supply, added balancing boards and cables against the cost of a new charger and loss of flexibility when cells are not even across multiple packs.
You can charge up to storage individually and combine for full charge, that's typically what I do. Once at storage the Lipo's stay balanced but I still check prior connecting.
 

Boodaggy

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dottyback

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Ok, I saw that one on Amazon for $350, even at $199 you will not get more out of it than purchasing a second charger ($150).
Your call to make though. Might get interesting with the $65 supply from @Jerry-rigged post.

I do not recommend parallel charging on the bigger packs, I have done it and maintenance and diligence needs to be spot on. I always do it on smaller packs for my mini stuff, always makes most sense if you have many of the same type.

Parallel charging
- packs must be of equal cell count (i.e. 4S etc)
- when connecting, always ensure that the cell voltages between the different packs should be within +/- 0.02V. Keep in mind that the higher pack will act as a source and sink into the lower voltage pack at max current (only limit is internal resistance)
- lower capacity packs (up to maybe ~2000mAh) have less problems with that and are less risky when unbalanced
You must check the packs before connecting, going by memory might be a big mistake with instant regret, typically a smoked balancing board

Charging itself is no different. I do it, occasionally, when I'm in a hurry but I rely more on individual charging.

Weigh the cost of a supply, added balancing boards and cables against the cost of a new charger and loss of flexibility when cells are not even across multiple packs.
You can charge up to storage individually and combine for full charge, that's typically what I do. Once at storage the Lipo's stay balanced but I still check prior connecting.
So Just so I understand you right,
Are you saying you would not charge big batteries parallel on those boards and also on
the hota charger, each on on a separate chanell or would it be fine on the charger.

Thank you
I second the converted server PSU. I converted a pair of 1200watt power supplies (900 watt 75 amp each on 110v outlet) for about $40. My icharger loves it.
Thank you for that link.
 

Boodaggy

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So Just so I understand you right,
Are you saying you would not charge big batteries parallel on those boards and also on
the hota charger, each on on a separate chanell or would it be fine on the charger.

Thank you

Thank you for that link.
I charge my 7200 mAh 4s in parallel and my 6200 mAh 4s in parallel, without issues. I pay attention though, checking pack voltages etc, and my charger can put out 40 amps per channel.
 

jkflow

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@dottyback
I have an older Hyperion Duo which I use for parallel charging. I could do it on the HOTA with the same supply but I rather run the 2 chargers at the same time.

My point was, you have 1 charger and you want to add a $200 power supply to allow for parallel charging of a total of 4 batteries.
I'd rather get another $150 charger and charge all 4 batteries as single. Makes no economical sense if the power supply cost exceeds charger cost to accomplish the same. You just have to make sure that the charger has sufficient power (W).
 

Boodaggy

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what charger do you use?
Icharger 406 duo. It's dual channel, 40 amps per channel. I can charge 4 6200 mAh 4s packs in about 20 minutes with power to spare. I could charge 8 packs at a time but with my current setup I can charge them faster than I use them.
 

dottyback

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