Inverter settings

[oldiesontour]

Yeah, but I love cooking in the van and the missus appreciates it too and that way there is more to spend on wine.....

And batteries !!!!

 

[Barriesimpson]

And batteries !!!!

True

 

[Barriesimpson]

Well today I was controlling the consumption all through using the 'fryer' and maximum draw was 96A, well below the maximum of the battery (150). So there must be gremlins in the system No cut off today, so not really sure what to make of all this.

 

[Barriesimpson]

Having done a couple more usage observations, this is what happens:

Start the air fryer and use it for 20 minutes (plus 3 minutes pre-heat), take out the potatoes and then add the meat. Another 20 or 25 minutes of use and in the last minute or two is when I have the problem, battery starts to click on and off (audibly, I presume it's the BMS), the inverter alarms sounds a couple of times, it behaves like a loose connection almost (there are none) and the whole 12v system shuts down. So I unplug the air fryer and switch off the inverter. If I then immediately try again it does the same show, however, if I wait 5 minutes I can switch on the inverter again, plug in the air fryer and carry on cooking for the 3 or 4 minutes that I need. This is the screen capture of the BMS just before the 'happening' and, at least to me, it seems withing the parameters of the battery. Any ideas guys?

 

[mikash]

With those symptoms my first instict would be to check if something's overheating somewhere. I'd maybe suspect battery first since it takes quite some time for the symptoms to appear so that might suggest it's something big enough to take a while to overheat. So something with mass. Inverter might be a candidate too. Poor ventilation in electronics closure I guess could cause just about anything to eventually overheat if the waste heat from running that big load on the inverter can't go anywhere.
No clue really though so just shooting in ther dark.

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[Barriesimpson]

The last time it happened I check all the system, apparatus, cables etc. but nothing seemed hot.

 

[bigtwin]

Can you check if the BMS is actually registering a protection activation (at cell or battery level)?

Ian

 

[Lenny HB]

I still reckon the BMS is shutting the battery down due to over current. All though it's set to 145 amps there will probably be a few percentage leeway in that setting.

 

[LithiumConvert]

Yes it is BT but I do not yet have a shunt as I thought I could get by without one.

Get by - yes.
But why just 'get by'? When you can have a proper meter?

 

[Raul]

Does your bms give you any info on temperature? Usually any battery will have at least two temp probes, some, even give the mossfet temperature.
It may be the cable connection to the bms or battery inside.

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[Barriesimpson]

Can you check if the BMS is actually registering a protection activation (at cell or battery level)?

Ian

I'm not sure how to do that, but I'll check later. Thanks.

 

[Barriesimpson]

I still reckon the BMS is shutting the battery down due to over current. All though it's set to 145 amps there will probably be a few percentage leeway in that setting.

I was wondering that. Yes I can input a different value, say 146 or 147? The limit must be 150 as that is the value according to the manufacturer, correct? Or do I just put in the max of 150?

 

[Barriesimpson]

Get by - yes.
But why just 'get by'? When you can have a proper meter?

I'm beginning to think that now.

 

[Barriesimpson]

Does your bms give you any info on temperature? Usually any battery will have at least two temp probes, some, even give the mossfet temperature.
It may be the cable connection to the bms or battery inside.

Yes, I think so, I'll check and see.

 

[Lenny HB]

I was wondering that. Yes I can input a different value, say 146 or 147? The limit must be 150 as that is the value according to the manufacturer, correct? Or do I just put in the max of 150?

By upping it you nay crate more problems they set it at 145 for a reason.

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[Barriesimpson]

By upping it you nay crate more problems they set it at 145 for a reason.

Ok, so you're saying 'get a lower power air fryer' is that it?

 

[Raul]

Just a thought, it may be bms overheating or bms connection. When is in a battery box, its hard to dissipate the heat. Next time you put a load on it to replicate fault, two things springs to mind to look for:
-monitor heat reading from bms, also feel for hot spots on the case, right at the moment of disconnection.
-second, have a multimeter to measure the voltage on the batt, and inverter terminals as it disconnects.

For reference, I take chinese Amps with caution, and make my own mind. As example JK bms comes with two 7awg cables soldered in, that you connect the battery negative. The bms is rated for 200A and it will do that for 30-40 mins as a test. No way I will let the bms settings on 200A, I knock that down to 110, as those two 7awg cables can't do 200A for to long.

 

[Raul]

Ok, so you're saying 'get a lower power air fryer' is that it?

Or, another battery to share the load, plus you have much more storage. This is the reason sometimes two batteries in parallel are better than a single large one. The current sharing is a good thing.

 

[Barriesimpson]

Just a thought, it may be bms overheating or bms connection. When is in a battery box, its hard to dissipate the heat. Next time you put a load on it to replicate fault, two things springs to mind to look for:
-monitor heat reading from bms, also feel for hot spots on the case, right at the moment of disconnection.
-second, have a multimeter to measure the voltage on the batt, and inverter terminals as it disconnects.

For reference, I take chinese Amps with caution, and make my own mind. As example JK bms comes with two 7awg cables soldered in, that you connect the battery negative. The bms is rated for 200A and it will do that for 30-40 mins as a test. No way I will let the bms settings on 200A, I knock that down to 110, as those two 7awg cables can't do 200A for to long.

The BMS is on the outside of the battery, so easy to check the temperature and the cables to it are not that big. I'll take a photo and post it here. Thanks for that.

 

[Barriesimpson]

Or, another battery to share the load, plus you have much more storage. This is the reason sometimes two batteries in parallel are better than a single large one. The current sharing is a good thing.

Well another battery is not going to happen this year because if I were to buy another, I would need more solar to charge it. Maybe next year. So I'll look at less power hungry air fryers for now. Thanks for the input.

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[Peavy]

The BMS is on the outside of the battery

I think it's a Daly BMS? The app looks like it is. Not sure though.

 

[Barriesimpson]

I think it's a Daly BMS? The app looks like it is. Not sure though.

I don't know to be honest, but the app is proprietary to Cymasol (the company) it seems. The battery is locally built here in Las Palmas, obviously the parts come from China, but I'll take a photo and post it so we can all see what it is

 

[Lenny HB]

Ok, so you're saying 'get a lower power air fryer' is that it?

Yep.

 

[bigtwin]

This is the reason sometimes two batteries in parallel are better than a single large one. The current sharing is a good thing.

You can’t beat redundancy whatever the naysayers might say.

if I were to buy another, I would need more solar to charge it.

No, the two are not related. You only need more solar if you increase your consumption. Extra capacity buys you endurance, a greater maximum discharge current and, effective, de-rating of your batteries.

Ian

 

[Barriesimpson]

Yep.

Ok, I guess you are right. I understand there are air fryers out there @ 900w rather than the 1.400w that I have, so shopping on Monday it seems... Thank you Lenny HB for your input. I will let you all know how I get on. I need to sort this out before the 22nd of May as that is the date we leave the Island for our Irish Raid

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[Barriesimpson]

You can’t beat redundancy whatever the naysayers might say.


No, the two are not related. You only need more solar if you increase your consumption. Extra capacity buys you endurance, a greater maximum discharge current and, effective, de-rating of your batteries.

Ian

Ok, I didn't realise that and thanks for the heads up, but I would rather not add another 30kg to the weight of the van because that would mean trying to explain to the missus that she can only take 10 pairs of shoes rather than 25 or 30, so it's probably better I find a lower powered air fryer

 

[Lenny HB]

Ok, I didn't realise that and thanks for the heads up, but I would rather not add another 30kg to the weight of the van because that would mean trying to explain to the missus that she can only take 10 pairs of shoes rather than 25 or 30, so it's probably better I find a lower powered air fryer

Just upgrade it to 4t problem solved.

 

[Barriesimpson]

Just upgrade it to 4t problem solved.

Ah, but being 66 already and not having the C1, I find it difficult to justify the 2 grand to get one and then possibly lose it within 4 years. Our van could go to 3.850 with no modifications but the change in the license, albeit it is ratified by the EU, is still a while away it seems.

 

[Raul]

Contrary to popular belive, lithium with its own bms can be in parallel with other make and size. I have a Frankestein in my van, as the conversion took existence, originaly was one 200Ah ultramax no BT no bells. About 3 months later I realised if I was going to exploit it properly I need double that, and stuck another 200Ah Ultramax in. That was in 2019. As the cells came down in price, in 2023 built one with 304Ah B grade EVE cells and JK bms. Total 700Ah and working happily together. Now I'm thinking get another 4 envision cells, and stick them in parallel on the same JK bms, extending it to 1000Ah.
That will allow me to get rid of LPG. The only niggle I have to sort out is hot water, currently is on LPG and 700W element, not enough electric power on its own, to heat in reasonable time.

 

[bigtwin]

Contrary to popular belive, lithium with its own bms can be in parallel with other make and size. I have a Frankestein in my van, as the conversion took existence, originaly was one 200Ah ultramax no BT no bells. About 3 months later I realised if I was going to exploit it properly I need double that, and stuck another 200Ah Ultramax in. That was in 2019. As the cells came down in price, in 2023 built one with 304Ah B grade EVE cells and JK bms. Total 700Ah and working happily together. Now I'm thinking get another 4 envision cells, and stick them in parallel on the same JK bms, extending it to 1000Ah.

Have you ever monitored the distribution of the charge/discharge currents across the individual batteries. If so, were they more or less in proportion to their relative capacities?

Ian

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