Quote : Hi Solentlife, 120CCPM and rest,
Your detailed explanations about charging P3 batteries, are coming at the right time for me
I need and advice from you.
I have 2 batteries that run alternatively a P3A and I intend to buy another 2 batts and the DJI hub serial charger.
From what I read, the P3A charger (57W) provides just 0.7C while the P3P charger (100W) provides 1.2C.
I would like to understand, should I buy a non-DJI charger brick that will generate exacly 1.0C or either of the above 2 bricks might satisfy the needs ?
Personally I would not buy a non DJI brick - 17.4V is an unusual voltage and you may have problems with the battery charge board. If the board does not regulate voltage in fully - as I suspect - then you can damage the board and/or battery. So far my tests show that the board only terminates charge when voltage in basically equals voltage out (battery state). Board most likely has a slightly higher safety termination voltage - but I am not going to create situation to find it !!
I have battery hubs for various batterys in my inventory - but all exhibit the same property ... if charging two batterys - one seems to not charge as full as the other. My preferred method and I feel is safer - separate chargers.
I have read that the DJI battery hub does not charge both batterys simultaneously but chooses one before other. Now if the hub is powered by the DJI brick - it cannot be Series as it would require 2x voltage ... but a Parellel version would work OK with the DJI brick voltage of 17.4
The report I read of sequential charging instead of simultaneous is possible with switch controlled parellel hub.
I have no knowledge if it sequences or charges together. But it would be very slow to complete both whatever it does.... especially if the 57W brick used.
Quote :If I'm using the 57W brick will I slowly lose the batt capacity since the unit is not generating enough power to fully charge the battery ? (I've noticed my batts aren't reaching the 100% charge but placing them in the bird it shows from the very beginning just 92-93% @ say avg 40 charges)
By contrary, if I'm using the 100W brick will I jeopardise the battery by forcing a a too speedy charging process ?
No - the 57W brick will just take a long time to charge both packs up. The 100W brick would be the better choice of the two bricks.
Generally the reason DJI batterys only charge to 92 / 93% is that the board has terminated early based on the high start capacity limits. To ensure 100% or at least best the DJI system allows whatever power input - is to switch battery ON before connecting charger ... to override the limitation... as per manual. I switch on my batterys for every charge cycle - even if flown to low level - having found same as you. But switching on has given me 99% etc.
Also please note that just because a charger says 100% charged - that is what we call HOT of the charger ... wait a few minutes and you will find the charge has dropped a few %. I would not expect such a drop as you report - but to about 96 - 97% is common.
100W brick is still well down on charge rate to not risk any DJI P3 battery ...
Quote :What I've noticed these weeks to a 3rd battery that was used up to now to a P3P (means charged with the 100W brick), is that after 2-3 charges with my 57W brick, it has gained over 200mAh in its total capacity. Is it because the 57W is not forcing the battery as the 100W?
Highly unlikely as a result of change of brick rate ... but could be due to innacuracy of voltage output of the respective bricks. Nothings perfect in this world and regulated power supplies are built to a specified range not an absolute fixed point.
Look at this way .. DJI go to a factory to provide them with PSU bricks of 17.4v. DJI sell them out at about $50 for the 57W and $75 for the 100W .. what price do you think they buy in at ? Less than half that price. I'm in business and often see even larger mark-ups for brand names ! For the price they pay - they will not get Laboratory grade PSU bricks.
So if you want to use a Hub - and worried to stay with DJI products - then get the 100W brick.
Now here I will give my personal choice alternative. For the price of the Hub and 100W brick - I can set up at least 2 or even 3 LiPo chargers to charge at 1C or slightly higher each. I get full charged packs in reasonable charge time and do not stress the packs at all. The packs are charged independent of each other. I get full read out of mAh in and Voltage state. I can check Internal Resistance as a total which over time indicates pack ageing and when likely to fail or not deliver required power. I can discharge automatically to safe storage level faster than DJI built in system.
Its my choice and I know others are skeptical and that's understandable given DJI insistence in their Literature to only use their gear ... just same as Ford / BMW etc. want you to only buy their parts for their cars .. but we do have alternatives that work and can be better ...
I hope the above helps ... I am not trying to force you to my way .. just trying to balance the equation and explain each part.
I repeat - If you are worried and unsure - then the 100W brick for a hub or without ...
If you want to change and have similar to my setup (I do use DJI brick as well ... right now I have two batterys charging .. one on the DJi brick .. other on my LiPo charger - Guess which one just reached full charge first .. it aint the DJI bick one !! ) - then I am always ready to help in any way ... PM or email ...
Nigel
Your detailed explanations about charging P3 batteries, are coming at the right time for me
I need and advice from you.
I have 2 batteries that run alternatively a P3A and I intend to buy another 2 batts and the DJI hub serial charger.
From what I read, the P3A charger (57W) provides just 0.7C while the P3P charger (100W) provides 1.2C.
I would like to understand, should I buy a non-DJI charger brick that will generate exacly 1.0C or either of the above 2 bricks might satisfy the needs ?
Personally I would not buy a non DJI brick - 17.4V is an unusual voltage and you may have problems with the battery charge board. If the board does not regulate voltage in fully - as I suspect - then you can damage the board and/or battery. So far my tests show that the board only terminates charge when voltage in basically equals voltage out (battery state). Board most likely has a slightly higher safety termination voltage - but I am not going to create situation to find it !!
I have battery hubs for various batterys in my inventory - but all exhibit the same property ... if charging two batterys - one seems to not charge as full as the other. My preferred method and I feel is safer - separate chargers.
I have read that the DJI battery hub does not charge both batterys simultaneously but chooses one before other. Now if the hub is powered by the DJI brick - it cannot be Series as it would require 2x voltage ... but a Parellel version would work OK with the DJI brick voltage of 17.4
The report I read of sequential charging instead of simultaneous is possible with switch controlled parellel hub.
I have no knowledge if it sequences or charges together. But it would be very slow to complete both whatever it does.... especially if the 57W brick used.
Quote :If I'm using the 57W brick will I slowly lose the batt capacity since the unit is not generating enough power to fully charge the battery ? (I've noticed my batts aren't reaching the 100% charge but placing them in the bird it shows from the very beginning just 92-93% @ say avg 40 charges)
By contrary, if I'm using the 100W brick will I jeopardise the battery by forcing a a too speedy charging process ?
No - the 57W brick will just take a long time to charge both packs up. The 100W brick would be the better choice of the two bricks.
Generally the reason DJI batterys only charge to 92 / 93% is that the board has terminated early based on the high start capacity limits. To ensure 100% or at least best the DJI system allows whatever power input - is to switch battery ON before connecting charger ... to override the limitation... as per manual. I switch on my batterys for every charge cycle - even if flown to low level - having found same as you. But switching on has given me 99% etc.
Also please note that just because a charger says 100% charged - that is what we call HOT of the charger ... wait a few minutes and you will find the charge has dropped a few %. I would not expect such a drop as you report - but to about 96 - 97% is common.
100W brick is still well down on charge rate to not risk any DJI P3 battery ...
Quote :What I've noticed these weeks to a 3rd battery that was used up to now to a P3P (means charged with the 100W brick), is that after 2-3 charges with my 57W brick, it has gained over 200mAh in its total capacity. Is it because the 57W is not forcing the battery as the 100W?
Highly unlikely as a result of change of brick rate ... but could be due to innacuracy of voltage output of the respective bricks. Nothings perfect in this world and regulated power supplies are built to a specified range not an absolute fixed point.
Look at this way .. DJI go to a factory to provide them with PSU bricks of 17.4v. DJI sell them out at about $50 for the 57W and $75 for the 100W .. what price do you think they buy in at ? Less than half that price. I'm in business and often see even larger mark-ups for brand names ! For the price they pay - they will not get Laboratory grade PSU bricks.
So if you want to use a Hub - and worried to stay with DJI products - then get the 100W brick.
Now here I will give my personal choice alternative. For the price of the Hub and 100W brick - I can set up at least 2 or even 3 LiPo chargers to charge at 1C or slightly higher each. I get full charged packs in reasonable charge time and do not stress the packs at all. The packs are charged independent of each other. I get full read out of mAh in and Voltage state. I can check Internal Resistance as a total which over time indicates pack ageing and when likely to fail or not deliver required power. I can discharge automatically to safe storage level faster than DJI built in system.
Its my choice and I know others are skeptical and that's understandable given DJI insistence in their Literature to only use their gear ... just same as Ford / BMW etc. want you to only buy their parts for their cars .. but we do have alternatives that work and can be better ...
I hope the above helps ... I am not trying to force you to my way .. just trying to balance the equation and explain each part.
I repeat - If you are worried and unsure - then the 100W brick for a hub or without ...
If you want to change and have similar to my setup (I do use DJI brick as well ... right now I have two batterys charging .. one on the DJi brick .. other on my LiPo charger - Guess which one just reached full charge first .. it aint the DJI bick one !! ) - then I am always ready to help in any way ... PM or email ...
Nigel
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