Wolfeman
1 kW
I'm looking for a bulk charger for my 18S Multistar pack. It's made of 3 6S 16aH Multistars connected in series with an XT90 harness. Ideas? Thanks all.
Bulk charger for 18S Multistars?
- Thread starter Wolfeman
- Start date
Alan B
100 GW
I use three of the Meanwell HLG LED supplies, 320 watts each, for 900 watts total. One across each 6S section.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=42169
https://endless-sphere.com/forums/viewtopic.php?f=14&t=42169
skeetab5780
1 MW
I use the HV satiator charger, its not the fastest thing but i love it
Alan B
100 GW
skeetab5780 said:
This is also a great choice. The higher voltage model wasn't yet available in UL approved form when I built the KW charger linked above, but I procured one later, and it is excellent. I charge at 12 amps with the KW charger, the Satiator is about 5 amps at 18S.
The Meanwell HLGs are UL approved, which was a requirement to use it at work. I also wanted to charge fairly fast at work so I could monitor it, and be done quickly in case I had to come home early. I was planning to mount a Satiator on the bike, but I haven't done that.
dirttorpedo
1 W
- Joined
- Mar 21, 2017
- Messages
- 53
I can also vouch for the HLGs , although some have pointed out to me that it's not traditional bulk charging. It's pretty easy to pull my load harness and plug in a parallel harness. Currently I only have one HLG, the same one as Alan B. I can charge 6 10ah bricks in about 3 hours which is plenty fast for me.
Alan B
100 GW
The only thing non-traditional about the HLGs is the manual shutoff, generally a bulk charger has an automatic charge termination when the current falls to some point. Some have timers, that's an easy thing to add. Even a low current disconnect would not be hard to do. I never got around to it as I was monitoring the charging fairly closely. The current drops to essentially zero anyway with the fixed maximum voltage, so it is not a critical turn-off.
But if you want something with a lot of flexibility and safety features as well as auto-shutof the Satiator is a great choice.
I've heard the Meanwell HLGs have been used in some models of onboard Zero motorcycle chargers, they are rugged, but a bit heavy for an onboard ebike charger. Even the Satiator is a bit heavy for onboard mounting, but it is rugged and not too large.
But if you want something with a lot of flexibility and safety features as well as auto-shutof the Satiator is a great choice.
I've heard the Meanwell HLGs have been used in some models of onboard Zero motorcycle chargers, they are rugged, but a bit heavy for an onboard ebike charger. Even the Satiator is a bit heavy for onboard mounting, but it is rugged and not too large.
dirttorpedo
1 W
- Joined
- Mar 21, 2017
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Hey Alan. Early on an ES member said I wasn't really bulk charging because I was breaking the string. He thought it was silly that I was charging multiple 6s packs instead of leaving it at 18 or 24s. I did explain that I charge all the packs at once so there is no difference in the result. The only difference is I have 3 or 4 connections instead of 1, the time involved with them is seconds. I actually prefer this setup because it's so versatile. I can charge any number of 6s packs and I don't require multiple or more expensive chargers if I run 12, 18, or 24s. Honestly, I can get 2 more HLGs and run 3 like you do for about half the cost of a Satiator. With your setup I could charge 6 10ah bricks in just under an hour.
Like you, I generally pay a lot of attention while charging. Lately though I just set an alarm and unplug right at the end. I do appreciate the fact that the current drops to almost nothing at the end of the charge as well.
Like you, I generally pay a lot of attention while charging. Lately though I just set an alarm and unplug right at the end. I do appreciate the fact that the current drops to almost nothing at the end of the charge as well.
Alan B
100 GW
It is still bulk in 6S. And arguably a little safer with fewer cells in series to get out of balance and accumulate less of an out of balance voltage.
On my 18S setup the three separate power supplies each charge a separate section of the 3x 6S packs which remain in series in the bike, but in the charger they are separate, and a 6 pin Anderson connector was used. This way the charger, which is connected to the AC mains, doesn't produce a voltage over 50VDC, it produces three separate 25V outputs. If it produced a single voltage output over 50VDC it would fall under hazardous DC voltage regulations. The ebike itself had over 50V of course but it was not itself connected to AC mains so did not fall under the workplace electrical regulations. That way I avoided problems with electrical safety work rules. The Satiator is UL listed for these voltages so would avoid the issue. But when you start building a charger from series connected power supplies the overall box would require a separate new UL listing which I of course wanted to avoid.
Most people don't know it, but in most cases at least in the US, workplace electrical devices must be UL listed. It is not always the case, but most companies, at some level, need to adhere to electrical safety regulations, and that follows. It may be ignored, but when someone gets injured it becomes an issue.
On my 18S setup the three separate power supplies each charge a separate section of the 3x 6S packs which remain in series in the bike, but in the charger they are separate, and a 6 pin Anderson connector was used. This way the charger, which is connected to the AC mains, doesn't produce a voltage over 50VDC, it produces three separate 25V outputs. If it produced a single voltage output over 50VDC it would fall under hazardous DC voltage regulations. The ebike itself had over 50V of course but it was not itself connected to AC mains so did not fall under the workplace electrical regulations. That way I avoided problems with electrical safety work rules. The Satiator is UL listed for these voltages so would avoid the issue. But when you start building a charger from series connected power supplies the overall box would require a separate new UL listing which I of course wanted to avoid.
Most people don't know it, but in most cases at least in the US, workplace electrical devices must be UL listed. It is not always the case, but most companies, at some level, need to adhere to electrical safety regulations, and that follows. It may be ignored, but when someone gets injured it becomes an issue.
harmonist
10 W
I "break the string" also when charging my 3 6s 20ah packs, I plug each into a balance board and charge all at once using a iCharger 306B and a MeanWell 36v 16.6a 600w power supply, works great and doesn't take as long as I thought it would.
Alan B
100 GW
I don't like to break the string for several reasons. For one, the connection in the pack between the series bricks is short, low resistance, and low inductance inside the pack, inside the cowl. There is no connector to "break" it with, and adding those connectors adds loss and inductance to the pack.
For another, it opens the potential for errors. Changing pack configurations can lead to errors which can damage wiring, connectors and cells, and even cause personal injury, fire or worse.
When I want to balance the three series "blocks" which are each 4P, I plug the balance charger into each section, one at a time. The balance charger I use charges through the balance leads so there is no "error" factor due to a second connector, or getting some sequence correct. It takes a little longer, but since I bulk charge first, and then balance charge, there is not much work left to do, so the balancing portion is very fast. The balance charger I use is the BC168 which can charge at up to 8 amps through the balance leads, however I generally limit it to 3 or 4 amps for each cell group in the 6S block, and this is enough current to balance very quickly. I have to plug it in 3 times, once for each block, but this is simple and foolproof. One connector. The blocks are already permanently paralleled, so there are three connectors on the bike, one for each group, and only one is used at a time. These same connectors are used to check balance, most of the time they are tucked under the cowl.
Simple is best. Balancing is rarely needed, I generally do it twice a year but it hasn't needed it that often. I can check it anytime, I generally use one of the little 6 cell battery medics to measure the cell groups every few days when I am using the bike.
That's the way I approach it. There are many ways to do it. My goal is to have a very solid pack that can deliver a lot of current to the controller with robust, short cables that minimize the impedance. Both resistance and inductance in the battery cabling is not good for the controller as it increases the voltage spikes on the FETs and ripple current in the controller's capacitor bank. This pack is 18S 32AH and can be asked to supply 80 amps continuous when climbing a big hill (2.5C). Between each Multistar brick and the controller are only 2 connectors and a couple feet total of dual 12 gauge wires in parallel, so about 9 gauge. That's from memory, it might be dual 10 gauge, but either way it is sweet and short. All the connections are hydraulically crimped into nearly solid masses of copper with multiple layers of heatshrink for a rugged system. The connectors are the XT's on the battery as they came, and the Anderson PP75 to the controller. Big and beefy. As far as I know, nothing gets warm. But making a path this low in resistance and inductance (all wires are paired to minimize inductance) makes it hard to parallel the blocks for charging, and there is really no need to.
For another, it opens the potential for errors. Changing pack configurations can lead to errors which can damage wiring, connectors and cells, and even cause personal injury, fire or worse.
When I want to balance the three series "blocks" which are each 4P, I plug the balance charger into each section, one at a time. The balance charger I use charges through the balance leads so there is no "error" factor due to a second connector, or getting some sequence correct. It takes a little longer, but since I bulk charge first, and then balance charge, there is not much work left to do, so the balancing portion is very fast. The balance charger I use is the BC168 which can charge at up to 8 amps through the balance leads, however I generally limit it to 3 or 4 amps for each cell group in the 6S block, and this is enough current to balance very quickly. I have to plug it in 3 times, once for each block, but this is simple and foolproof. One connector. The blocks are already permanently paralleled, so there are three connectors on the bike, one for each group, and only one is used at a time. These same connectors are used to check balance, most of the time they are tucked under the cowl.
Simple is best. Balancing is rarely needed, I generally do it twice a year but it hasn't needed it that often. I can check it anytime, I generally use one of the little 6 cell battery medics to measure the cell groups every few days when I am using the bike.
That's the way I approach it. There are many ways to do it. My goal is to have a very solid pack that can deliver a lot of current to the controller with robust, short cables that minimize the impedance. Both resistance and inductance in the battery cabling is not good for the controller as it increases the voltage spikes on the FETs and ripple current in the controller's capacitor bank. This pack is 18S 32AH and can be asked to supply 80 amps continuous when climbing a big hill (2.5C). Between each Multistar brick and the controller are only 2 connectors and a couple feet total of dual 12 gauge wires in parallel, so about 9 gauge. That's from memory, it might be dual 10 gauge, but either way it is sweet and short. All the connections are hydraulically crimped into nearly solid masses of copper with multiple layers of heatshrink for a rugged system. The connectors are the XT's on the battery as they came, and the Anderson PP75 to the controller. Big and beefy. As far as I know, nothing gets warm. But making a path this low in resistance and inductance (all wires are paired to minimize inductance) makes it hard to parallel the blocks for charging, and there is really no need to.
Wolfeman
1 kW
Thank you for the great info everyone. I love that people from all over the world are chiming in with their experience.
dirttorpedo
1 W
- Joined
- Mar 21, 2017
- Messages
- 53
Hey Alan. How do you wire it up to charge the 3x 6s packs as separate units while they're still in series? Is it as simple as adding a charge connector to each or would that show series voltage at the connection? On my current setup I run 3 sets of 2x 6s packs for 18s 20ah. On the bike I have a 3 port series harness, XT90s to a single XT150. When I charge I unplug the 90s and plug into 3 paralleled 90s coming off the charger. I would love to switch to your method since it does sound superior but I'm not sure how to wire it.
Alan B
100 GW
It is very simple. From each block of four paralleled 6S bricks I run a pair of 14 gauge red/black conductors to a PP30 for charging. So there are three PP30's coming out. I actually combined them into a single block of six pins for a "one plug" charging hookup, but it doesn't matter as long as the connections are right. At 12-13 amps of charging current the 14 gauge does get somewhat warm, so don't go any lighter if you are going to charge at these currents.
The three HLGs are wired separately on the outputs, each to its own PP30 with it's own red/black paired cable. It doesn't matter which supply is plugged into which battery block. The supply outputs must be independent of ground, which they are on these LED supplies.
When I am balance charging I only do one block at a time. That's because the balance charger and power supply is not independent of ground. So in that case I need enough time to plug into each block, balance it, and do that a total of 3 times. I bulk charge first to 75V which is 4.167/cell, then I can balance charge to 4.2. Or I stop the bulk early and balance charge to some other value. It doesn't matter much what the balance charge voltage is, just that all are the same, and in the vicinity of 4.1-4.2V.
The series connections in the bike pack do cause the supplies outputs to be floating at different voltage levels, so they MUST be independent of their grounds for this to work. However because the only series connection is inside the bike, there is no loop for any series current to flow. There will be 75VDC present between the highest and lowest supply output pins (only when plugged into the battery pack), so make sure all the DC is covered up.
The 120VAC Inputs of the supplies are paralleled, so the hot, neutral and green ground wire from the cord goes to all three supplies. So they all have the safety ground. Of course all the AC wiring should be covered up for safety as well.
The three HLGs are wired separately on the outputs, each to its own PP30 with it's own red/black paired cable. It doesn't matter which supply is plugged into which battery block. The supply outputs must be independent of ground, which they are on these LED supplies.
When I am balance charging I only do one block at a time. That's because the balance charger and power supply is not independent of ground. So in that case I need enough time to plug into each block, balance it, and do that a total of 3 times. I bulk charge first to 75V which is 4.167/cell, then I can balance charge to 4.2. Or I stop the bulk early and balance charge to some other value. It doesn't matter much what the balance charge voltage is, just that all are the same, and in the vicinity of 4.1-4.2V.
The series connections in the bike pack do cause the supplies outputs to be floating at different voltage levels, so they MUST be independent of their grounds for this to work. However because the only series connection is inside the bike, there is no loop for any series current to flow. There will be 75VDC present between the highest and lowest supply output pins (only when plugged into the battery pack), so make sure all the DC is covered up.
The 120VAC Inputs of the supplies are paralleled, so the hot, neutral and green ground wire from the cord goes to all three supplies. So they all have the safety ground. Of course all the AC wiring should be covered up for safety as well.
dirttorpedo
1 W
- Joined
- Mar 21, 2017
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Well that's just beautiful. I forgot that each paralleled block reads it's own voltage at +/- and series voltage only at the ends. The funny thing is I'm pretty much already set to charge this way. Each of my 2x paralleled packs has an extra lead from an older setup where I was running 3x.
Thanks man!
Thanks man!
