I know there are a number of Tech savvy members here...so thought I would ask a question.
I initially upgraded my JJOB from 1 x 100 amp AGM to 2 x 140 amp AGM, at the same time I added an external 30 amp MPPT solar regulator and an external Anderson plug so as to be able to connect additional solar being the van only had a single 160w panel on the roof. (the MPPT is good for up to 450w or 80v input)
This has worked a treat so far, with 2 x 200w folding panels wired in series pumping up to 40v through the MPPT to the battery pack. Always full batteries by 9am. But...logically the solar charge input wouldn't show up anywhere as it was not being read by the BMS being the MPPT was connected directly to the battery pack...via a fuse of course.
I have just now upgraded to 2 x 135 amp Lithium batteries. The Jayco has a BMPro J35B BMS in it which isn't Lithium compatible.
So...I also bought a 30 amp Victron Lithium charger to carry out the charging duties while on shore power, being the BM Pro does not have a Lithium charging profile at all. I have unplugged the BMPro from 240v but left all 12v connected to it so it is a distribution and fuse point now. So when plugged in to shore power the Victron kicks in to charge the Lithiums, rather than the BM Pro.
I did fit a BMPro 300 amp shunt to the negative side of the battery pack and all connections go through that shunt. The van also has a "JControl" Digital Control Panel which displays what is going on as far as battery level, water tanks, solar input, or whether the batteries are charging or discharging etc. That Shunt is bluetooth connected to the JControl display. Therefore should feed any charge or discharge information to the JControl that would be missed by the BMPro...such as solar input via the external MPPT I fitted.(I have isolated the roof panel so it does not go through the BMPro, but can be plugged in to the MPPT as well)
When I plugged the van in to shore power the Victron lit up and would have been charging the battery pack as planned. But...the JControl Control Panel still showed the batteries as discharging, rather than charging which I thought was odd. I had the internal lights on which did show around 3.5 amps going out on the JControl panel.
I would have thought it still should have showed the battery as charging being the Victron would be pushing more power in than would be going out...or would it still show discharging as it was in fact discharging? The batteries were showing 13.9v, could it be that they were full and would not actually accept more charge so were discharging?
I haven't yet had the chance to spend any time in it off grid to try it all out...but meanwhile can any techies see any potential problems with my set up that I should address?
A sketch of your connections would help, trying to visualize what you are saying, I think I can almost see what is happening but there are a couple of variables.
Lol this is doing my head reading this late at night but yes your batteries are full at 13.9V. Some photos of your batteries, solar controller and shunt may be helpful but my question is. Do you have a connection from your negative terminal to the shunt. The shunt being the only connection to the negative battery terminal, and then after the shunt all your negative connections going to your loads and chargers.
Yeah, apologies, trying to describe the set up in words does leave room for some head scratching...lol To be honest I think a diagram would all look fine and good, maybe as they say a picture tells a thousands words...I'll see what I can scratch up.
Anyway, the Shunt has all negative connections at the one end, (supply to BMS, MPPT Solar input, Victron Charger etc) with the Shunt the only connection to the negative battery terminal at the other...so any current has to pass through the Shunt...in or out.
The Shunt has a Bluetooth connection to a Commlink which is connected in the lead between the original BMPro BMS and the JControl Panel...so theoretically any current movement should be passed through and displayed on the JControl Panel. Well according to the info supplied by BMPro with the Shunt this is the case. The Shunt has been Bluetooth paired with the Commlink of course.
"BMPRO BC300 External Shunt and CommLink provides additional battery monitoring for your BatteryPlus35 and J35 systems. The addition of the BC300 to the BatteryPlus35 and J35 battery management systems allows high current loads and external charge sources to connect direct to battery via the BC300 External Shunt. This enhances system behaviour with temperature monitoring of the battery for greater protection.
BC300 also provides your BatteryPlus35 and J35 with additional information on battery usage so your displays such as the Trek, JControl and JHub are always up-to-date on battery Time Remaining and State of Charge."
The query I had...according to above, if the JControl Panel reads all information correctly, I would have thought that with the battery charger connected and charging, the JControl Panel should have read that the batteries were charging...not discharging regardless of the 3 odd amps going to lights.
Previously with the AGM's and the BMPro handling charging etc, even with current being drawn such as with lights, the JControl panel would still show as charging when connected to shore power.
To ask such a question here is a long shot as it is difficult / impossible to diagnose anything at arms length so to speak. I was really only querying thoughts as I am heading off on the big lap in 4 weeks time, and between now and when i leave I have no opportunity to try it all out off grid. No issues at all while on power of course...
Ok so sounds like your shunt is wired correctly and not backwards as some have done .
Simple test, disconnect the charger and drain some serious power out of your batteries even if you have to run something off the inverter if you have one. Then connect the charger back up and see what results you get.
Do a test without the charger whilst running loads, a test with the charger whilst running loads and a test with the charger and no loads.
-- Edited by TimTim on Tuesday 18th of April 2023 10:06:13 AM
Ok so sounds like your shunt is wired correctly and not backwards as some have done .
Simple test, disconnect the charger and drain some serious power out of your batteries even if you have to run something off the inverter if you have one. Then connect the charger back up and see what results you get.
Thanks TimTim...yes, all connections are the right way around...fortunately I have a reasonable back ground in electronics and circuitry layouts so this update isn't difficult in any way...pretty straight forward as you would no doubt agree.
I plan to add an Inverter later, the Lithiums I bought have a 150 amp BMS so should handle what I have in mind. I can run some power out of the batteries no issue...but i guess I'll have to wait until I am on the road to do so...ay dramas can be attended to then.
I'll come back to this thread once on the road and able to update...
Hi HTR I did try and update my second post to show what tests to do but obviously you know what you are doing. Not sure why you are unable do the test now instead of on the road but good luck with it. The great thing about LiFePO4 is you don't need to leave them on charge whist in storage and no solar, although even when I put a cover on my van my panels still provide some charge.
Just to show you in relation to your first post of whether the batteries are fully charged I have attached a SOC table. The 100% at 13.6V is generally when they are at rest.
Yep 150A BMS in each battery gives you plenty of room to move some serious current
Tim
-- Edited by TimTim on Tuesday 18th of April 2023 10:39:29 AM
Thanks TimTim...I just read that addition...great idea...easy to do and that will tell me whether or not any charge current is being read by the Shunt / Commlink.
t is a bit frustrating as I don't have the van at home to play around with as it is kept in a storage shed...I do have access and am able to work on the van when ever I please which is great, but still a bit limited in what I can do.
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