Dilemma
Active Member
Hi Greg. Thanks for the link to the battery box.
I've checked through the alternator and charger settings. It all adds up.
Thanks again for your great write up.
Lithium 304Ah Build
- Thread starter gregcope
- Start date
I've checked through the alternator and charger settings. It all adds up.
Thanks again for your great write up.
gregcope
Well-Known Member
200A BMS
An update ...
After having built confidence with the 120A JDB BMS I was thinking about something a little bigger Amps wise as I am thinking of fitting an inverter. A 3000 kva inverter at a nominal 12V would pull around 250A. This would be pushing two 120A BMS!
JDB do a 150A BMS that is nearly identical to the 120A model. I also found the 200A version. 200A would give a nominal 400A with two packs or I could de-ratethem for longevity.
This video from LithiumSolar about AO Lithium packs and this one from DIY Solar Power with Will Prowse both seem to rate the BMS. One issue is that it cannot go higher than two in series (ie can only do 24V not 48V).
It has three temp sensors (Two on wires, one on the FETs), works with the same XiaoziangBMS App, has nice M6 terminals instead of multiple flyleads and importantly fits the box! There are bluetooth and RS485 versions.
One model has a heating pad negative terminal. I have not tried it, but from what I have found out from this DiySolarForum posts, it will support around 30W of silicone heating mats. The logic is that if below 0C and a charge is applied it will enable the heating until above a certain temp. Charging is disabled at this time.
I ordered the “4S LFP 200A U 485 H” model (RS485, Bluetooth, Heater port) from the official JDB store on Aliexpress. Delivery took around four weeks. It arrives in a plain box, wrapped in bubble wrap. No instructions! Also has what looks like a thermal switch, but not guidance as to what to do with it!
Interestingly a datasheet I was sent has the C- and B- the wrong way round. This caused mild panic as I had already wired it up.
An update ...
After having built confidence with the 120A JDB BMS I was thinking about something a little bigger Amps wise as I am thinking of fitting an inverter. A 3000 kva inverter at a nominal 12V would pull around 250A. This would be pushing two 120A BMS!
JDB do a 150A BMS that is nearly identical to the 120A model. I also found the 200A version. 200A would give a nominal 400A with two packs or I could de-ratethem for longevity.
This video from LithiumSolar about AO Lithium packs and this one from DIY Solar Power with Will Prowse both seem to rate the BMS. One issue is that it cannot go higher than two in series (ie can only do 24V not 48V).
It has three temp sensors (Two on wires, one on the FETs), works with the same XiaoziangBMS App, has nice M6 terminals instead of multiple flyleads and importantly fits the box! There are bluetooth and RS485 versions.
One model has a heating pad negative terminal. I have not tried it, but from what I have found out from this DiySolarForum posts, it will support around 30W of silicone heating mats. The logic is that if below 0C and a charge is applied it will enable the heating until above a certain temp. Charging is disabled at this time.
I ordered the “4S LFP 200A U 485 H” model (RS485, Bluetooth, Heater port) from the official JDB store on Aliexpress. Delivery took around four weeks. It arrives in a plain box, wrapped in bubble wrap. No instructions! Also has what looks like a thermal switch, but not guidance as to what to do with it!
Interestingly a datasheet I was sent has the C- and B- the wrong way round. This caused mild panic as I had already wired it up.
geem
Well-Known Member
I have to say that the thought of building my own lifePO4 battery is a little scary. Your last comment does nothing to reduce my home build anxiety ?
A trawl through the various DIY battery forum's seems to be filled with tails of woe
Kelpie
Well-Known Member
Interesting, thanks. I'm very happy with my 120A JBD. I only have a 271Ah pack so I'm not sure how wise it is to pull much more current than that. My inverter is 3kw and I can barely use half of its capacity.
I did buy a relay and was all set up to run the inverter bypassing the BMS... but then I'd lose my SOC info through the app which I rather like. And yes a battery monitor would solve that but it's yet more money.
I would really like to build a second pack, but prices seem to have gone up a fair bit. So maybe just upgrading my BMS would be a worthwhile plan.
Kelpie
Well-Known Member
It's really not a big deal. You need to sift out the real world necessities from the geeky "look what I can make it do" projects.
My system essentially comprises four cells and a BMS, total cost was just over £400. Charged by solar, not engine. The BMS looks after the cells and it is in many ways more idiot proof than lead acid.
Once you start complicating things- inverter chargers, engine charging, automated this and that- it can all spiral out of control. Some people like that, of course.
Then there are the arguments in favour of very expensive cells and BMSs... which I'm sure are very good indeed, but there are thousands of installations using cheaper gear who are getting on just fine.
For me it was a no-brainer. Trojans would have cost £700. When you look at all of the benefits of LFP, it's obvious that outside a few niche applications (engine start etc) lead is dead.
gregcope
Well-Known Member
Your initial comments reinforced my thoughts on using JBD, so thank you.
What do you use your inverter for? Kettle? Induction? Water heating? Reason I ask is that I would have thought 3000kva might be marginal and if your only using half, why is that?
geem
Well-Known Member
Sorry but I don't agree. Lead is far from dead. I am not a na sayer. I am actually working on a liquid cooled lithium project. I just really don't think it suits everyone. Lead is very simple and very effective. It stands up to far more abuse than lithium under normal circumstances. It can take windlass loads and starting loads easily. Something that gets expensive to do with lithium. Lead will run power tools through a cheap inverter. Lithium gets complex as soon as you try to use high current even for short duration. Complex = expensive.
Kelpie
Well-Known Member
We do all of our cooking on it (induction hob, oven, toaster) plus occasional hoover, laser printer. I went 3kw to give myself headroom, and also I was originally planning to bypass the BMS.
Kelpie
Well-Known Member
Windlass, bow thruster, engine start- all best done with lead acid. That's what I mean by niche.
All other loads are better handled by lithium.
What do you consider a high current? I can draw 120A and my system cost substantially less than it would have if I had chosen lead acid.
geem
Well-Known Member
My four Trojan batteries cost less than £500. I had no other costs whatsoever. I purchased them in Puerto Rico. I happened to be there.
My windlass is 1700w it runs from the domestic bank. I do this because it has a larger capacity than the engine bank and we often use the windlass to lift the dinghy each evening. We don't start the engine to do that. Solar puts back the amps we use.
The inverter is 3000w but peaks at double that. The biggest load is the watermaker. This is 2000w. Our emergency back up should the generator fail is engine running and inverter on running watermaker.
Edit. The watermaker inrush current is about 6000w I believe. We also run a vacuum cleaner. It's a large Henry type. Essential when you have a dog!
Last edited:
gregcope
Well-Known Member
and
Thanks. With those loads I would expect you to be drawing more than half. I assume you never have them all on full at once.
Kelpie
Well-Known Member
Shows the importance of location.
Four T 105s delivered to my home in Scotland was substantially more than what you paid.
Lithium from China came with no extra shipping costs.
Frankklose
Well-Known Member
My Setup:
Volvo Penta 2003T with 60A original alternator
4X EVE Blue Cells 280A use same plastic box as on the Photo 330mm long
JBD BMS 120A
Renogy DC-DC 40A
Victron IP22 30A Single Output Charger.
The Batteries deliverd at test 295A. The original alternator supplied only 30A on test, rig got repaired and delivers now 49,7 A.
This was insufficient and orderd another alternator 120A but it did not fit 5mm smaller. According to the seller should have fitted.
Now I can charge only with 20A. The Renogy is very inefficient, with 36A output it draws 62 A on input (49,7a from alternator and 12A out of the starter battery). At the 20A setting on the Renogy 19 A charging current and 32 A from the alternator. This setup works and charges alsowith the remaining power the start battery. I´m happy with the Victron charger, it suppies 29A Charing current.
When I started after the winter the batteries was inbalanced at charging (the batterie was left at 70%). Every cell was unbalanced. Discharged down to about 10%and recharged and battery was ok again.
The alternator (Valeo lable are unreadable) heats up only to 75 degrees on the hottest spot after 1 hour and delivering 49,7A.,wich is very good.
On bench testing the JBD BMS,I discoverd a problem when the charge switch is turned off and no charging voltage applied, the discharge route is via the charging Mosfet Backfire diodes. The Mosfet´s heat up and voltage drop of .5 Volts, normaly it has no effect since the voltage from the charger stay´s on....but not good
Would like to change the alternator for a stronger type (100A?), but since the exchange type did not fit....I would like to hear from other VP 200X user´s which alternator they used...before I order the next one. P4e has a 75 A...
The Renogy I would not buy again and would rather use the Victron DC-DC 30A. Still thinking about swapping...
In the next few weeks I will install the old Sterling A2B 80A. It charges first the start battery, than it turns on the dc-dc converter and charges the house battery with 72A (have tested it on the bench ). The 72 A where from my view too much, but since the alternator does not overheat....will try again. The 72A where too much, this was the reason for buying the Renogy DC-DC 40A. One other feature of the Sterling is that it monitors the alternator for overheating. Tested it (held a solder iron onto the NTC) and charge current dropped to 20A. Expected a linear decrease , but it turns off the inverter and charges via the internal diode bridge.
Having more then 250Ain the house battery is nice to have.
Frank
Volvo Penta 2003T with 60A original alternator
4X EVE Blue Cells 280A use same plastic box as on the Photo 330mm long
JBD BMS 120A
Renogy DC-DC 40A
Victron IP22 30A Single Output Charger.
The Batteries deliverd at test 295A. The original alternator supplied only 30A on test, rig got repaired and delivers now 49,7 A.
This was insufficient and orderd another alternator 120A but it did not fit 5mm smaller. According to the seller should have fitted.
Now I can charge only with 20A. The Renogy is very inefficient, with 36A output it draws 62 A on input (49,7a from alternator and 12A out of the starter battery). At the 20A setting on the Renogy 19 A charging current and 32 A from the alternator. This setup works and charges alsowith the remaining power the start battery. I´m happy with the Victron charger, it suppies 29A Charing current.
When I started after the winter the batteries was inbalanced at charging (the batterie was left at 70%). Every cell was unbalanced. Discharged down to about 10%and recharged and battery was ok again.
The alternator (Valeo lable are unreadable) heats up only to 75 degrees on the hottest spot after 1 hour and delivering 49,7A.,wich is very good.
On bench testing the JBD BMS,I discoverd a problem when the charge switch is turned off and no charging voltage applied, the discharge route is via the charging Mosfet Backfire diodes. The Mosfet´s heat up and voltage drop of .5 Volts, normaly it has no effect since the voltage from the charger stay´s on....but not good
Would like to change the alternator for a stronger type (100A?), but since the exchange type did not fit....I would like to hear from other VP 200X user´s which alternator they used...before I order the next one. P4e has a 75 A...
The Renogy I would not buy again and would rather use the Victron DC-DC 30A. Still thinking about swapping...
In the next few weeks I will install the old Sterling A2B 80A. It charges first the start battery, than it turns on the dc-dc converter and charges the house battery with 72A (have tested it on the bench ). The 72 A where from my view too much, but since the alternator does not overheat....will try again. The 72A where too much, this was the reason for buying the Renogy DC-DC 40A. One other feature of the Sterling is that it monitors the alternator for overheating. Tested it (held a solder iron onto the NTC) and charge current dropped to 20A. Expected a linear decrease , but it turns off the inverter and charges via the internal diode bridge.
Having more then 250Ain the house battery is nice to have.
Frank
vas
Well-Known Member
please keep in mind that a BMS DOESNT need to be dealing with the current flowing through the cells. I hated the concept and didn't do it.
There are BMSs that do the monitoring/passive balancing for your cells, ideally talk to and instruct the solar/inverter/charger and a last level of defence BlueSea 400A relay can do the disconnect if things go silly. Obvs need a FLA bank in parallel with the LiFePO4 which is what I've done. Works absolutely fine.
This way I can easily draw 120-150A or more (but I really don't have a reason to!) with no Mosfets et al in the way.
V.
There are BMSs that do the monitoring/passive balancing for your cells, ideally talk to and instruct the solar/inverter/charger and a last level of defence BlueSea 400A relay can do the disconnect if things go silly. Obvs need a FLA bank in parallel with the LiFePO4 which is what I've done. Works absolutely fine.
This way I can easily draw 120-150A or more (but I really don't have a reason to!) with no Mosfets et al in the way.
V.
Frankklose
Well-Known Member
vas
I´m not using more than a few amp´s. Most sailors will use the Lithium the same way as the did with the lead acid. Who whants 120 to 150 A? The remark about the parallel switch is ok , but for this I use the old 1-2-Off switch. Aircondition might be nice but not on my old Moody.
I´m not using more than a few amp´s. Most sailors will use the Lithium the same way as the did with the lead acid. Who whants 120 to 150 A? The remark about the parallel switch is ok , but for this I use the old 1-2-Off switch. Aircondition might be nice but not on my old Moody.
vas
Well-Known Member
sure, if your consumption is exclusively in the lower spectrum, mosfet bms is fine, I have to run a 80-90A load for an hour every couple of days (watermaker) wasn't happy doing it via mosfets hence I followed the other approach
Pete7
Well-Known Member
Frank,
I fitted one of these last winter. However, be aware that the alternator belt on the VP 2003 is quite thin, perhaps 3/8th or so. It came from Neil on here and he left the VP pulley on from his engine as he didn't need it. His belt pulley was wider and the 2003 belt bottomed out before reaching the correct tension. Alternator outputs 55A at high tick over, might go higher if you had a big load on it or an external alternator but I do wonder if the belt will take that long term.
12V 100 AMP UPRATED VOLVO PENTA ALTERNATOR A3673
Me
To answer a point by Greg higher up, 3Kva is a lot. Assuming you have left the household electric kettle at home and bought something smaller say about 1Kw, that's 75A for 4 minutes. The induction hob is slightly different. Whilst its rated at 1500w that's way too much heat and likely to burn anything in a pan. An omelette needs 400w. Sapagetti simmering, 200w and bacon about 800w. The hob will still draw say 75A, but it cycles on and off to control the temperature.Pete
Last edited:
gregcope
Well-Known Member
An update;
Mk2 redesign Part I
Having built one pack I decided to build another. Reasons being I wanted to increase the effective Amp hour capacity as well as higher Amperage capacity to run a decent inverter as well as having redundancy.
I brought the same cells from the same supplier. I decided to capacity test all my cells and then match them. This would give one pack that has slightly more capacity than the other (1Ah delta in the end or 0.33%).
I also decided to move to the 200A BMS to enable a theoretical 400A between the two packs. These BMSs also have more balancing capacity (150mA compared to 60A on the 120A version). In reality I am downgrading the BMS to 150A each (300A total) and also the effective capacity to 80% ~ 250Ah from a tested 311Ah (tested 3.65v to 2.5V). This should increase the effective longevity. In extremis I could reconfigure the cells and increase their capacity by resetting the voltage cut off if required. I would assume many things would have to go wrong to get to this point.
As the 1.5mm end plates flexed when tensioned I replaced these with 3mm of FR4/G10 plates. These are seriously tough as my circular saw complains more about doing these than oak sleepers! This should also give better end protection in the corners.
I gave up on the 1.5mm EDPM surround that went down the sides and underneath. The box is very tight in the lower corners and it required two people to remove them. Instead I put 1.5mm EDPM and 1mm Neoprene foam rubber on the base as well as 1mm of Neoprene down the sides and over the top. To get this in flipping the battery on side and swapping gives enough space to slide it in. When upright there is no movement. In theory the cells and BMS could move as there is a little gap between the BMS and box end. I doubt it would move due to the friction of both the base and side rubbers. This could also be overcome by adding a foam wedge between the cell ends and walls.
I also purchased some M3 countersunk nylon machine screws and drilled/tapped these into the lid/base join. There is around +/-1mm vertically to spare as there is little overlap between the lid, base and lid rebate. This allows me to bolt down the lid and then seal with insulation tape. I am not claiming any IP level but it should be pretty good (IP65?) as the glands are IP68.
Mk2 redesign Part I
Having built one pack I decided to build another. Reasons being I wanted to increase the effective Amp hour capacity as well as higher Amperage capacity to run a decent inverter as well as having redundancy.
I brought the same cells from the same supplier. I decided to capacity test all my cells and then match them. This would give one pack that has slightly more capacity than the other (1Ah delta in the end or 0.33%).
I also decided to move to the 200A BMS to enable a theoretical 400A between the two packs. These BMSs also have more balancing capacity (150mA compared to 60A on the 120A version). In reality I am downgrading the BMS to 150A each (300A total) and also the effective capacity to 80% ~ 250Ah from a tested 311Ah (tested 3.65v to 2.5V). This should increase the effective longevity. In extremis I could reconfigure the cells and increase their capacity by resetting the voltage cut off if required. I would assume many things would have to go wrong to get to this point.
As the 1.5mm end plates flexed when tensioned I replaced these with 3mm of FR4/G10 plates. These are seriously tough as my circular saw complains more about doing these than oak sleepers! This should also give better end protection in the corners.
I gave up on the 1.5mm EDPM surround that went down the sides and underneath. The box is very tight in the lower corners and it required two people to remove them. Instead I put 1.5mm EDPM and 1mm Neoprene foam rubber on the base as well as 1mm of Neoprene down the sides and over the top. To get this in flipping the battery on side and swapping gives enough space to slide it in. When upright there is no movement. In theory the cells and BMS could move as there is a little gap between the BMS and box end. I doubt it would move due to the friction of both the base and side rubbers. This could also be overcome by adding a foam wedge between the cell ends and walls.
I also purchased some M3 countersunk nylon machine screws and drilled/tapped these into the lid/base join. There is around +/-1mm vertically to spare as there is little overlap between the lid, base and lid rebate. This allows me to bolt down the lid and then seal with insulation tape. I am not claiming any IP level but it should be pretty good (IP65?) as the glands are IP68.
gregcope
Well-Known Member
Some images of the 3mm nylon counter sunk machine screws.
gregcope
Well-Known Member
And why does the forum software do this too me? Uploading from an iPhone it seems to spin them round 90deg the wrong way ...