Mobile home LB

[Joeboy]

Hi guys, having a look at the Leisure Battery out of the Mazda Bongo. It's a two year old battery chargd off a 100W solar panel and I stuffed it last Winter, let it run flat after leaving the 240V inverter powered up. I have it out of the van and I'm slow charging it.

Started at 12.75v, since then I've put 1.77kW at 240V into it(7.4Ah) and V is now 14.44 after 30 secs not charging(16.03V).

I have been thinking about ways to test its capacity and as I type I've just realised I have a DC ampclamp from the home battery extension. So that's easy, top it right up, hook it up, run it for an hour on the van diesel heater or fridge and work out if the losses are within spec. Fingers crossed its good or the baby WT will be getting some shonky extra storage capacity and the Bongo a new 110Ah LB!

[Fintray]

I have been thinking about ways to test its capacity and as I type I've just realised I have a DC ampclamp from the home battery extension. So that's easy, top it right up, hook it up, run it for an hour on the van diesel heater or fridge and work out if the losses are within spec. Fingers crossed its good or the baby WT will be getting some shonky extra storage capacity and the Bongo a new 110Ah LB!

You could ask your local garage to put a load test on it.

[marshman]

I have been thinking about ways to test its capacity and as I type I've just realised I have a DC amp clamp from the home battery extension. So that's easy, top it right up, hook it up, run it for an hour on the van diesel heater or fridge and work out if the losses are within spec. Fingers crossed its good or the baby WT will be getting some shonky extra storage capacity and the Bongo a new 110Ah LB!

You could ask your local garage to put a load test on it.

A load test will not test its AH capacity which is the important bit for a "leisure battery".

It doesn't look that good if the charger has got 16V on it - shouldn't really go much above 14.4V, 14.7 V tops.

Joeboy - be very careful when connecting/disconnecting the charger not to cause any sparks at the terminals after it has been on charge. Knackered batteries have a nasty habit of "gassing" a lot and the slightest spark in the wrong place at the wrong time and you get a nice explosion due to the almost perfect mix of hydrogen and oxygen. Seen the results of a few of them when people have charged their knackered car batteries in situ overnight and then disconnected the charger leads from the battery terminals without switching the charger off at the mains, or gone straight away to start the car without letting the gas build up disperse - the results are not pretty.

No apologies for teaching anyone to suck eggs.

[Joeboy]

I have been thinking about ways to test its capacity and as I type I've just realised I have a DC amp clamp from the home battery extension. So that's easy, top it right up, hook it up, run it for an hour on the van diesel heater or fridge and work out if the losses are within spec. Fingers crossed its good or the baby WT will be getting some shonky extra storage capacity and the Bongo a new 110Ah LB!

You could ask your local garage to put a load test on it.

A load test will not test its AH capacity which is the important bit for a "leisure battery".

It doesn't look that good if the charger has got 16V on it - shouldn't really go much above 14.4V, 14.7 V tops.

Joeboy - be very careful when connecting/disconnecting the charger not to cause any sparks at the terminals after it has been on charge. Knackered batteries have a nasty habit of "gassing" a lot and the slightest spark in the wrong place at the wrong time and you get a nice explosion due to the almost perfect mix of hydrogen and oxygen. Seen the results of a few of them when people have charged their knackered car batteries in situ overnight and then disconnected the charger leads from the battery terminals without switching the charger off at the mains, or gone straight away to start the car without letting the gas build up disperse - the results are not pretty.

No apologies for teaching anyone to suck eggs.

Thank you for the thought marshman. We dwellers in the extreme have to look out for each other, much appreciated! I have the garage door open during this and you just slapped an extra layer of careful on there, thank you!

Edit- the charger is pulling 32W@240V. My multimeter is showing 16V on charge and 14.1V across the battery when charger off. No heat build up at all on flanks of battery and no smell of gas or cooking acid.

TBH, I'd quite like it to fail (but not explode) so we have the expanded yet spackered capacity for the single 12V light at the home battery system tied back to the WT and then extended fridge running capacity In the van for Italy next year.

[openspaceman]

Joeboy - be very careful when connecting/disconnecting the charger not to cause any sparks at the terminals after it has been on charge. Knackered batteries have a nasty habit of "gassing" a lot and the slightest spark in the wrong place at the wrong time and you get a nice explosion due to the almost perfect mix of hydrogen and oxygen.

That takes me back to when I was seventeen, my new girlfriend's father had a MF35 four cylinder tractor in the shed with a cracked block, so it hadn't been used for a while. I araldited the chunk of waterjacket back in and proceeded to start it, both 6V batteries were about dead but had a 200A welder with a 55A DC jump starter. After much churning and ether the engine ran so I disconnected the welding clamp off the positive of one battery...

The battery was of the type where individual cell's plates were held in the rubbery housing with pitch of some sort, the plates of one cell had jumped out spraying me with acid, no serious damage luckily but never did get on with her dad after that.

[Joeboy]

Just been out to garage and I passed by the wee WT lcd. After days of almost no wind the display was lit. 16V it said! Woohoo I said. Then I thought 'hmmn DC clamp owner these days'.

Leapt across the garage, grabbed the meter, feverishly selected DC and zero'd. The big reveal.....0.032A. Literally the spark in a piezo butane lighter from the 80's.

In its defense, had a quick look outside and its barely spinning. Surprised there's anything outputting at all. The forecast is on the up for wind. Hopefully a decent direction and I'll pray for 0.1A one day.

[Oldgreybeard]

It's a big investment, but have you thought about replacing the leisure battery with a LiFePO4 one? I made this suggestion to our motorhome owning neighbours a couple of years ago. They baulked a bit at the price at the time, but they came back from holiday a few months ago and made a point of coming around to thank me for the suggestion. It seems the same physical size LiFePO4 battery lasts a lot longer and needs zero maintenance. They aren't well-off, but his view was that the battery was worth every penny. One telling comment was that they'd just got used to never worrying about needing to run the engine to charge it, or risk discharging it by using the TV for too long, as the thing just took it all in its stride.

[Joeboy]

It's a big investment, but have you thought about replacing the leisure battery with a LiFePO4 one? I made this suggestion to our motorhome owning neighbours a couple of years ago. They baulked a bit at the price at the time, but they came back from holiday a few months ago and made a point of coming around to thank me for the suggestion. It seems the same physical size LiFePO4 battery lasts a lot longer and needs zero maintenance. They aren't well-off, but his view was that the battery was worth every penny. One telling comment was that they'd just got used to never worrying about needing to run the engine to charge it, or risk discharging it by using the TV for too long, as the thing just took it all in its stride.

That's a great call, especially if the useable capacity rises by a significant amount. Chilled food & beer offgrid in the van are cornerstones of mobile travel.

[marshman]

__

[Stinsy]

+1 for swapping your LB for 4x LF280k cells!