Do I stop using leisure battery when it hits 50%?

[Tony68000]

I’ve read that to maintain good battery health, you should only use them down to 50% (unless lithium).

Do I therefore have to keep an eye on the battery level and if the voltage is down to the 50% capacity level just stop using it until it charges again?

 

[Richard n Ann]

I’ve read that to maintain good battery health, you should only use them down to 50% (unless lithium).

Do I therefore have to keep an eye on the battery level and if the voltage is down to the 50% capacity level just stop using it until it charges again?

Yes unless it's a gel type which are tolerant of 80% discharge.
Just minimise your usage if it gets low

 

[pappajohn]

Yes, but 50% is the max recommended discharge. recharge before 50% if possible.
The fewer times you discharge the more charge cycles and life time you can expect from a battery.
.

 

[Minxy]

Check what the discharge reading is for your type of battery, eg some say 12.3 is 50% whereas others may say 12.5 is 50% so don't assume that 12.3% is only 50% on yours.

 

[Richard n Ann]

I’ve read that to maintain good battery health, you should only use them down to 50% (unless lithium).

Do I therefore have to keep an eye on the battery level and if the voltage is down to the 50% capacity level just stop using it until it charges again?

Have you got a battery monitor with a shunt fitted? It's difficult to rely on voltage readings to determine charge level as the battery has to be unloaded for at least an hour before the reading is relevant.

^{_{Subscribers  do not see these advertisements}}

 

[Tony68000]

Have you got a battery monitor with a shunt fitted? It's difficult to rely on voltage readings to determine charge level as the battery has to be unloaded for at least an hour before the reading is relevant.

Ah. Not not sure. I suspect it won’t have one.

 

[eddie]

It's a good rule to aim for, but, life's too short to sit in the dark to lengthen the life of a leisure battery

 

[Richard n Ann]

Ah. Not not sure. I suspect it won’t have one.

You need one of these

NASA BM1 or 2 monitor, about £100 there's Bluetooth versions and Victron make them too

 

[Tony68000]

You need one of these

View attachment 565671
NASA BM1 or 2 monitor, about £100 there's Bluetooth versions and Victron make them too

That looks great. I'm in the market for a new B2B charger and MPPT for the solar, so perhaps there might be something all-in-one?

 

[gerry mcg]

That looks great. I'm in the market for a new B2B charger and MPPT for the solar, so perhaps there might be something all-in-one?

IIRC, there was some issue with the NASA BM1/2s not working well with solar panels.
i think you would be hard pushed to look beyond a Victron BMV 700/701 / 702 or smartshunt…
a bit dearer (not a lot) but proven and great https://www.12voltplanet.co.uk/victron-smartshunt-500a.html

^{_{Subscribers  do not see these advertisements}}

 

[two]

For the longest life, always drain your battery as little as possible. If you keep taking it to the limit of its tolerance, its life will be shortened over what it could be capable of. A battery monitor will help you to monitor and understand your 12V consumption better, but is not essential.

 

[Richard n Ann]

IIRC, there was some issue with the NASA BM1/2s not working well with solar panels.
i think you would be hard pushed to look beyond a Victron BMV 700/701 / 702 or smartshunt…
a bit dearer (not a lot) but proven and great https://www.12voltplanet.co.uk/victron-smartshunt-500a.html

Yeah I remember Lenny HB saying there was a problem with the NASA BM monitors just after I bought ours c2018, but I think it was earlier models, ours has been ok anyway.

 

[68c]

For the longest life, always drain your battery as little as possible. If you keep taking it to the limit of its tolerance, its life will be shortened over what it could be capable of. A battery monitor will help you to monitor and understand your 12V consumption better, but is not essential.

What you are saying is true, but what is the point of having a large battery, or even two, that you are scared to use fully? May be a better idea to fit a smaller cheap battery and hammer it, then replace every two or three years.

 

[Richard n Ann]

What you are saying is true, but what is the point of having a large battery, or even two, that you are scared to use fully? May be a better idea to fit a smaller cheap battery and hammer it, then replace every two or three years.

They aren't that cheap though are they, £80? for "three years" versus £160 for a likely 10+ years (exide gel)

 

[two]

You need greater capacity if going out in Winter, because capacity is reduced with low temperature and it's also a time when you use more (for light and to circulate heat). The main thing is to realise how finite your batty power is and use it with respect.
I used to be resigned to changing the battery once a year 40 yrs ago, when chargers were more basic and I understood less about batteries. I soon learned that deep or rapid discharges should be avoided and leaving a wet battery discharged was not a good way to promote longevity.

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

To get an accurate percentage reading from a battery monitor it takes a fair bit of setting up and is often beyond the average Motorhome owner, they are not just a case of plug & play. Although monitoring the current usage will give you an accurate picture.

I thought my BMV700 was pretty good until we were stuck in Germany last year (me in hospital) found out when my BMV was reading 40% the batteries were actually at less than 20% they are Gels so not a major problem.
Anyway after getting back I spent one to two weeks playing with the setting and now the percentage readout is spot on.

 

[Lenny HB]

To get an accurate percentage reading from a battery monitor it takes a fair bit of setting up and is often beyond the average Motorhome owner, they are not just a case of plug & play. Although monitoring the current usage will give you an accurate picture.

I thought my BMV700 was pretty good until we were stuck in Germany last year (me in hospital) found out when my BMV was reading 40% the batteries were actually at less than 20% they are Gels so not a major problem.
Anyway after getting back I spent one to two weeks playing with the setting and now the percentage readout is spot on.

 

[two]

Did you do it twice?

 

[Lenny HB]

Did you do it twice?

You were lucky other threads I've posted on it's loaded 4 times, only appears to happen on my Win10 PC.

 

[Lenny HB]

Did you do it twice?

You were lucky other threads I've posted on it's loaded 4 times, only appears to happen on my Win10 PC.

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

What did I say!

 

[Lenny HB]

Help Jim this is getting rediculass.

 

[Jim]

Help Jim this is getting rediculass.

Does it only happen when your hungover and shaky

 

[Lenny HB]

Crazy, post #19 loaded 4 times now it's only showing 2.

 

[Lenny HB]

Does it only happen when your hungover and shaky

Only had one glass of wine last night so, no.

^{_{Subscribers  do not see these advertisements}}

 

[Minxy]

Only had one glass of wine last night so, no.

How big was the glass?

 

[Stealaway]

I’ve read that to maintain good battery health, you should only use them down to 50% (unless lithium).

Do I therefore have to keep an eye on the battery level and if the voltage is down to the 50% capacity level just stop using it until it charges again?

I've always assumed that a good quality battery will have a life of around 200 cycles.
That is from fully charged to fully flat --- OR ----a combination of part charges and part discharges.

I judge my two leisure battery's state of charge simply by a volt meter.
I have no real control over how much charge they will get during the day - it is what it is on any given day.
I glance at the voltmeter in the dash just behind me from time to time while watching the TV of an evening.
Almost every evening we can watch TV for three hours without a problem. Normally the voltage will drop to around 12.4 V.
If for some reason I've not gotten enough charge during the day we then turn the TV off at 12.2V. Simples

 

[Lenny HB]

I've always assumed that a good quality battery will have a life of around 200 cycles.
That is from fully charged to fully flat --- OR ----a combination of part charges and part discharges.

I judge my two leisure battery's state of charge simply by a volt meter.
I have no real control over how much charge they will get during the day - it is what it is on any given day.
I glance at the voltmeter in the dash just behind me from time to time while watching the TV of an evening.
Almost every evening we can watch TV for three hours without a problem. Normally the voltage will drop to around 12.4 V.
If for some reason I've not gotten enough charge during the day we then turn the TV off at 12.2V. Simples

View attachment 565825

The chart I use gives 12.2 as 50% & 12.0 for 25% and it seems fairly accurate.

 

[Minxy]

The chart I use gives 12.2 as 50% & 12.0 for 25% and it seems fairly accurate.

That's why it's important to use the correct chart for the type of battery in use as they vary.

 

[two]

With wet batteries, I used to become careful when the voltage displayed less than 12.5V and distinctly parsimonious when it got as low as 12.2V.
As long as you watch the level, you may avoid serious damage. I think it's those who only discover the poor state of their battery after things have stopped working, that experience irrecoverable harm.

^{_{Subscribers  do not see these advertisements}}