200 amp lithium

[170968]

7 minutes ago, ditchcrawler said:

Will the LA be constantly connected to the alternator?

If you have a diode splitter as opposed to a relay you may be dropping half a volt already.

Also you can run the long cable from the split charge device to the Lithium and not back to the alternator. So depending what you have installed already you may or may not need a longer wire

 

The starter battery (LA) will be, yes.

I'm not sure what kind of split charge device I have atm, but I'll investigate when I can.

 

9 minutes ago, ditchcrawler said:

If you connect a digital voltmeter between the B+ terminal of your alternator and the positive battery terminal of your domestic batteries, then run the engine while your batteries are well depleted you will see what sort of volt drop you have in your charge circuit already. The inefficiency of some systems from new may mean you don't need to do anything

Could you possibly explain this further, as I don't understand it. What exactly is being measured here?

 

Thanks.

[ditchcrawler]

13 minutes ago, 170968 said:

The starter battery (LA) will be, yes.

I'm not sure what kind of split charge device I have atm, but I'll investigate when I can.

 

Could you possibly explain this further, as I don't understand it. What exactly is being measured here?

 

Thanks.

If you take a multimeter, and on the VOLTAGE range put one probe on the B+ , the alternator output terminal and the other on the domestic batter positive terminal while the engine is running with the domestic batteries at a low state of charge, so the alternator is working hard and the current is high, you will measure the voltdrop in your existing system, ie. between almost zero to in a bad case 1 volt. This may already be enough to limit the output of your alternator. Lots of boats were fitted with less than perfect charging systems, especially with single alternators and split charge systems which is why people fit things like Adverc's to make up for it.

Sorry I am not the greatest of explaining things, I am sure someone else can elaborate on these readings

[170968]

29 minutes ago, ditchcrawler said:

If you take a multimeter, and on the VOLTAGE range put one probe on the B+ , the alternator output terminal and the other on the domestic batter positive terminal while the engine is running with the domestic batteries at a low state of charge, so the alternator is working hard and the current is high, you will measure the voltdrop in your existing system, ie. between almost zero to in a bad case 1 volt. This may already be enough to limit the output of your alternator. Lots of boats were fitted with less than perfect charging systems, especially with single alternators and split charge systems which is why people fit things like Adverc's to make up for it.

Sorry I am not the greatest of explaining things, I am sure someone else can elaborate on these readings

 

I think I understand. It's not you, I just had no idea you could use a voltmeter to do this. Thanks!

[PeterF]

2 hours ago, ditchcrawler said:

If you take a multimeter, and on the VOLTAGE range put one probe on the B+ , the alternator output terminal and the other on the domestic batter positive terminal while the engine is running with the domestic batteries at a low state of charge, so the alternator is working hard and the current is high, you will measure the voltdrop in your existing system, ie. between almost zero to in a bad case 1 volt. This may already be enough to limit the output of your alternator. Lots of boats were fitted with less than perfect charging systems, especially with single alternators and split charge systems which is why people fit things like Adverc's to make up for it.

Sorry I am not the greatest of explaining things, I am sure someone else can elaborate on these readings

You can also do the same from the alternator case to the battery negative because you can get voltage drop on that part of the circuit as well. I did mine yesterday out of interest, new build, 106 A on the shunt into the batteries, 14.37V on the alternator B+ to alternator case and 14.05V on the batteries, charging AGMs, not too bad but could be better.

[ditchcrawler]

14 minutes ago, PeterF said:

You can also do the same from the alternator case to the battery negative because you can get voltage drop on that part of the circuit as well. I did mine yesterday out of interest, new build, 106 A on the shunt into the batteries, 14.37V on the alternator B+ to alternator case and 14.05V on the batteries, charging AGMs, not too bad but could be better.

But what changed between you measuring the voltage at the alternator to earth and then moving over to measure the battery voltage and how much current was flowing if the voltage was 14 volts+ ?

[PeterF]

1 hour ago, ditchcrawler said:

But what changed between you measuring the voltage at the alternator to earth and then moving over to measure the battery voltage and how much current was flowing if the voltage was 14 volts+ ?

Current = 106A as stated, nothing changed alternator delivering 14.37V batteries receiving 14.05V, 0.32V drop in cables, did not check how this was split between the positive and negative wiring.

[ditchcrawler]

2 hours ago, PeterF said:

Current = 106A as stated, nothing changed alternator delivering 14.37V batteries receiving 14.05V, 0.32V drop in cables, did not check how this was split between the positive and negative wiring.

Thats a good voltage taking that sort of load, what alternator have you got?

[PeterF]

Beta 43 with the standard Iskra 175A alternator.

[Naughty Cal]

On 12/09/2022 at 10:44, 170968 said:

Thanks all. Very helpful.

 

Do these drop in replacement type lithium batteries protect themselves from overcharging, or do I still need to add this?

 

What I'm thinking of doing is using one of these drop in batteries as a temporary measure, until I can get a proper system installed. Otherwise I am going to need to buy some lead acids to tide me over anyway. I really want to avoid this if possible.

So if I dropped in a 100ah lithium, in place of the mostly dead LA batteries, do I even need to worry about overheating my alternator? Lets say I charge the lithium when it reaches 50%, using a 90amp alternator? So approximately a half hour charge.

 

ETA: the LA starter will still be in place.

 

We fitted a drop in Lithium on our van and it has high voltage protect, low voltage protect, low temperature protect, high temperature protect, cell imbalance disconnect, over current disconnect and short circuit protect.

 

Have only seen the low temperature protect in action so far on a couple of occasions last winter. The rest of the time it has stayed within the present parameters.

 

We fitted it just under 12 months ago and so far it has worked as expected. No issues with the alternator running hot at all.

[170968]

1 hour ago, Naughty Cal said:

We fitted a drop in Lithium on our van and it has high voltage protect, low voltage protect, low temperature protect, high temperature protect, cell imbalance disconnect, over current disconnect and short circuit protect.

 

Have only seen the low temperature protect in action so far on a couple of occasions last winter. The rest of the time it has stayed within the present parameters.

 

We fitted it just under 12 months ago and so far it has worked as expected. No issues with the alternator running hot at all.

 

I just had one delivered this morning which also does all these things. It can also be configured to whatever numbers you like. I'm not sure whether to use the BMS to cut the charge or to do it with an isolator switch (manually or with a BMV). Probably the latter, and leave the BMS for emergency cut-offs. How do you handle this in your van?

[ditchcrawler]

2 hours ago, 170968 said:

 

I just had one delivered this morning which also does all these things. It can also be configured to whatever numbers you like. I'm not sure whether to use the BMS to cut the charge or to do it with an isolator switch (manually or with a BMV). Probably the latter, and leave the BMS for emergency cut-offs. How do you handle this in your van?

Will that automatically reconnect with load. The BMS will remove the charging but still allow discharging. 

[170968]

16 hours ago, ditchcrawler said:

Will that automatically reconnect with load. The BMS will remove the charging but still allow discharging. 

 

What I intended to do was put a cut off switch on the added positive cable coming from the charge source (the alternator via starter battery), leaving the load connected. Is this OK or am I missing something?

[rusty69]

5 minutes ago, 170968 said:

 

What I intended to do was put a cut off switch on the added positive cable coming from the charge source (the alternator via starter battery), leaving the load connected. Is this OK or am I missing something?

That is the way I have mine connected. All the loads/charge sources are connected to the LA battery, which is separated from the lithium by a motorised switch controlled by a battery monitor. 

[MtB]

1 minute ago, rusty69 said:

That is the way I have mine connected. All the loads/charge sources are connected to the LA battery, which is separated from the lithium by a motorised switch controlled by a battery monitor. 

 

Same here and it worked fine. 

 

Except mine just had a manual switch which I only turned ON when I was aboard. Hobby boat, yersee. 

 

Oh and an audio alarm if any single cell went above or below pre-set voltage limits. It did go off once and scared the bejesus out of me....

 

 

[rusty69]

9 minutes ago, MtB said:

 

Same here and it worked fine. 

 

Except mine just had a manual switch which I only turned ON when I was aboard. Hobby boat, yersee. 

 

Oh and an audio alarm if any single cell went above or below pre-set voltage limits. It did go off once and scared the bejesus out of me....

 

 

The switch I have can be manually operated too, and the knob removed when turned off, which is a nice touch. Not cheap though. 

 

I got 2 spares too😂

[170968]

1 hour ago, rusty69 said:

The switch I have can be manually operated too, and the knob removed when turned off, which is a nice touch. Not cheap though. 

 

I got 2 spares too😂

Which switch have you got?

 

 

[rusty69]

51 minutes ago, 170968 said:

Which switch have you got?

 

 

I seem to recall it is a BEP 720 MDO. 

 

Although other switches and solutions are available. 

[Naughty Cal]

22 hours ago, 170968 said:

 

I just had one delivered this morning which also does all these things. It can also be configured to whatever numbers you like. I'm not sure whether to use the BMS to cut the charge or to do it with an isolator switch (manually or with a BMV). Probably the latter, and leave the BMS for emergency cut-offs. How do you handle this in your van?

We leave the BMS to do it's job.

 

Why have a dog and bark yourself?

Edited September 15, 2022 by Naughty Cal