Electrical Cooking The Battery - nearly well done.

[Axl]

I made a mistake when I said bring on lithium ion (I had consumed a few of the good ones by then) I meant to say LiFeP04 as mentioned above by those who know a lot more than I do about these batteries.

I've never had any issues with my AGM (touchwood) it's been charged by my 25amp Projecta smart charger from home and via my Honda eu10i at various charge rates (as required) and now via the Expandas Setec but I will pay more notice than I have before just encase.

But in saying that I'm glad I made it because I am now a lot more wiser than before, Thank you @NoWorries & @Bellbirdweb & everyone else.....

 

[Rockape]

So out of curiosity I performed some testing over the weekend comparing two 75 Ahr deep cycle batteries. One with a shorted cell and the other in good working order. The good one when connected to the solar and plug in charger had its current drop as the voltage rose and charged the battery correctly. When the faulty battery was connected to both charges, the maximum current was supplied to the battery from both chargers and after about 30 minutes it shared to get very warm and the Chargers were still supplying full charge current. I could hear a hissing noise coming from the battery. I disconnected the Chargers and allowed the battery to cool. Next I connected both batteries in parralel and connected the Chargers again. This was to simulate charging two batteries at the same time. The interesting thing here was that again full charge current was supplies by both Chargers and the faulty battery became quite warm again, this time after only 10 minutes. The good battery also started to hiss.
I am looking at trying to hook up a relay for the Chargers, which will be controlled by a thermal circuit breaker. I will do more testing to see if I can come up with a reliable circuit that will disconnect he battery from the charging circuit. So if you have a room battery with a shorted cell, you could have a situation where you will overcharge your battery and cause significant damage.
Cheers
Nick

 

[icetechaus]

You might want to try playing with one of these if you can handle a soldering iron http://www.jaycar.com.au/Kits,-Scie...tomation/Temperature-Switch-Kit-B048/p/KG9140 or http://www.jaycar.com.au/Kits,-Scie...conomy-Adjustable-Temperature-Switch/p/KC5381 . You could fit the thermocouple to the battery and have the relay unit separated. The big advantage is being able to set the temperature yourself.

 

[bigcol]

my limited knowledge of Auto electrics tells me that if you have a "dropped" cell / shorted Cell / goal cell (whatever................)

it will be a direct "short"................. and the weakest link will burn / explode / melt (whatever.............)

you are a brave man @Rockape to want to play with one that is already Cactii

but
on a positive note

sounds like a great idea wanting to creating a thermal cutout switch / circuit breaker / supply relay (whatever.........................)

I hope you succeed

 

[Bellbirdweb]

You might want to try playing with one of these if you can handle a soldering iron http://www.jaycar.com.au/Kits,-Science-&-Learning/Electronic-Project-Kits/Control-&-Automation/Temperature-Switch-Kit-B048/p/KG9140 or http://www.jaycar.com.au/Kits,-Science-&-Learning/Electronic-Project-Kits/Automotive/Economy-Adjustable-Temperature-Switch/p/KC5381 . You could fit the thermocouple to the battery and have the relay unit separated. The big advantage is being able to set the temperature yourself.

Will need to have a look at the way it all connects via the setec. Might need a fairly substantial relay

 

[icetechaus]

I haven't really looked at the setec but there may be a control wire that you can operate rather than having it inline with the charge current , if not you will need to need to have a heavy contactor or relay in line with the battery. Just keep in mind that you are drawing current to drive the relays so there are losses involved in safety.

 

[Rockape]

my limited knowledge of Auto electrics tells me that if you have a "dropped" cell / shorted Cell / goal cell (whatever................)

it will be a direct "short"................. and the weakest link will burn / explode / melt (whatever.............)

you are a brave man @Rockape to want to play with one that is already Cactii

but
on a positive note

sounds like a great idea wanting to creating a thermal cutout switch / circuit breaker / supply relay (whatever.........................)

I hope you succeed[/QUOTE

I performed the testing outside in a controlled environment. I used temperature probes to monitor temperatures and has an extinguisher and hose ready just in case. I have found a resettable thermal circuit breaker rated for 40 degrees and will test it using a series of 12 volt halogen lamps to simulate heat and charging load.
Cheers
Nick

 

[Drover]

Good concept @Rockape , I've been thinking of fitting a fan in my battery compartment. in the door actually so it will exhaust from the top vent and should cause a draw thru the lower vents and circulate the air also with a temp switch of say 40 deg which I could stick on the side of battery or cabinet, reach temp fan kicks in or something along those lines, still on the drawing board so will no doubt evolve into a heat activated cut out but then I could just get the temp fitting for the solar controller.......

 

[bigcol]

performed the testing outside in a controlled environment. I used temperature probes to monitor temperatures and has an extinguisher and hose ready just in case. I have found a resettable thermal circuit breaker rated for 40 degrees and will test it using a series of 12 volt halogen lamps to simulate heat and charging load.
Cheers
Nick


as I said, I am very limited in my knowledge, but it sounds like you were very conscious of mishaps and had adequate precautions

again

well done to you Sir..................

 

[Drover]

Ha !!!! :doh: I just realized, yesterday I was in Jaycar getting some bit and pieces for a mod and was looking at those kits, something was saying "Now they would be handy " but didn't think of what ?? ....must be an omen.......

 

[boots33]

While a temperature activated relay to break the charge circuit would be a step in the right direction it would still not make you aware of the problems existence in the first place.

My van is stored in a shed 30 to 40m away from the main residence and usually the van does not get a lot of attention between outings. If something as serious as a battery meltdown does occur it would be nice to be given some sort of notice. Perhaps the addition a buzzer in the relay circuit could be used.

The other thing to consider is that even if you isolate the charge supply the shorted battery will still feed off itself and any other batteries that may be connected at the time will be only too happy to supply large amounts of current to help it on its way to thermal bliss.

The setec 1 and 2 power supplies offer no easy way to isolate them other than breaking the main charging connection as already discussed. The series 3 setec is able to be isolated to some extent by utilising the "remote battery isolate" connectors but it will still leave a small trickle charge available to the battery. You could also break the 240v supply but that would most likely be outside the DIY solution.

While it would be a bit more complicated to build this task is one well suited to a micro controller as it would be able to sample a few different parameters and compare the results to determine if action was required.
It could for example measure both ambient and battery case temp and use the difference to decide if a fault was occurring. it could also measure the battery voltage to detect over/under charging or perhaps look for a rapid drop in voltage that usually happens with a shorted cell. . If needed you could even have it send an email to alert you of the situation.

 

[Drover]

Wow, @boots33 ...................just wow.

 

[boots33]

Yeah bit of a micro controller tragic I'm afraid

test bench always in a state of kaos

 

[chartrock]

You will have no shortage of customers on the forum when you start to market them @boots33.

 

[bigcol]

Wow, @boots33 ...................just wow.

O M F G

*Try posting a bit more so your post isn't boring* what @Drover said

W O W

 

[Dobbie]

I may be missing something here.

We carefully monitor battery charge if we boost with 240v which has been the case up till about September last year. I'm aware of the potential problems so have been paranoid about keeping the charge up to the battery while avoiding possible boiling etc etc. We always charged it for 8 hours on the first day of the month...pedantic, I know but it worked for us. That's what Jayco advised us to do years ago to keep battery conditioned, so we followed their advice and had no problems.

No change there.

However, since Sepember we've kept our battery fully charged by hooking up a spare 120w solar panel, on permanently, as the van is under cover and this panel can sit over the draw bar and faces the sun for about 6 hours a day.

I've just kept an eye on the state of the battery and its held a charge of over 13.6 for all of that time. Rain, hail, clear weather ...I've just ignored it.

My question is....does the battery run the same risk of "doing a drover" if the solar is keeping it fully charged?

I'm assuming it can't overcharge via solar, but I'm now wondering if I'm wrong.

I guess it's the state of the battery combined with the rate of charge....and then cross your fingers you don't have a dud battery.

 

[boots33]

You should not be too concerned, while events like @Drover has experienced do happen they certainly are not the norm.

What you are doing in monitoring and regular topping up of the battery is a good habit to have.

I think the thing to take away from all this is that even when not in use our vans still need to be allocated a little time now and then for a few simple checks.

I know I am guilty of largely ignoring the van once it is tucked away, a habit that needs to change I think

 

[Dobbie]

Having discovered the hard way (and the expensive way) that deep cycle batteries need regular top ups I did some checking and have charged it up regularly....so improved my habits, my understanding and my wallet.

I'm now very pleased that the redundant extra solar panel will do the same but, as said, I started wondering about the difference between the effect of 240v charging versus the solar.

As I'm now happy with the safety aspect and the efficiency aspect, I'll stick with it as it works.

 

[Drover]

You don't happen to have a Wet Deep Cycle battery stowed inside your van do you @Dobbie ?????

 

[Dobbie]

Just the 100 amp that came with the van.

AGM I think.