Leisure Battery and Invertor ?

[Whitby Chris]

hi all I need help again I'm going away for a weekend and want to charge the hike 1 or 2 times. I have looked at the mini generator route and don't want fuel in the car been carried as I have children. what are my other options ? what sort of leisure battery would I need and what sort of invertor etc ?? thanks in advance ?

 

[flash]

@ 12.8V 500wH needs 39 aH of current, plus some inefficiency of the inverter. If you're using AGM batteries you can only use 50% of their capacity without damaging them (with repeated cycles) so you'll need 100aH per charge for a 504aH bike battery.

With Lithium you can use 80% of capacity without battery damage so you could use a 50aH battery to charge a 504wH bike battery.

Inverter depends on your charger. I have found that my Shimano chargers seem to be happy with 600w, although I have not tried lower. Specs indicate that it might work for multi voltage chargers.

 

[dobbyhasfriends]

@ 12.8V 500wH needs 39 aH of current, plus some inefficiency of the inverter. If you're using AGM batteries you can only use 50% of their capacity without damaging them (with repeated cycles) so you'll need 100aH per charge for a 504aH bike battery.

With Lithium you can use 80% of capacity without battery damage so you could use a 50aH battery to charge a 504wH bike battery.

Inverter depends on your charger. I have found that my Shimano chargers seem to be happy with 600w, although I have not tried lower. Specs indicate that it might work for multi voltage chargers.

You can use 80% of AGM batteries if you don't mind giving up a little of your battery life

AGM battery Depth of Discharge myth busted

I have been wondering for some time if the "don't discharge your batteries beyond 50%" rule really applies to AGM batteries. AGM batteries claim to be deep discharge, and 50% discharge doesn't seem very deep to me! So I did a little research...

tab-rv.vanillacommunity.com

 

[flash]

You can use 80% of AGM batteries if you don't mind giving up a little of your battery life

AGM battery Depth of Discharge myth busted

I have been wondering for some time if the "don't discharge your batteries beyond 50%" rule really applies to AGM batteries. AGM batteries claim to be deep discharge, and 50% discharge doesn't seem very deep to me! So I did a little research...

tab-rv.vanillacommunity.com

The problem with this type of information is that it's not telling the entire story. It's not that you can't deep discharge ANY battery. You may get away with it. But it's a lottery. You may kill the battery completely with any single deep discharge cycle, especially liquid chemical batteries, including AGM. Or more likely limit its ability to reach 100% full charge. I think we've all killed a car battery with just a couple of deep discharges. An AGM is somewhat less likely to die but not by a huge amount. And we haven't even started on the variation in quality across the spectrum of leisure batteries. So it'd hardly be general advice anyway.

I'd follow the manufacturers guidelines rather than some dude on the internet, including me.

Gordon

 

[dobbyhasfriends]

The problem with this type of information is that it's not telling the entire story. It's not that you can't deep discharge ANY battery. You may get away with it. But it's a lottery. You may kill the battery completely with any single deep discharge cycle, especially liquid chemical batteries, including AGM. Or more likely limit its ability to reach 100% full charge. I think we've all killed a car battery with just a couple of deep discharges. An AGM is somewhat less likely to die but not by a huge amount. And we haven't even started on the variation in quality across the spectrum of leisure batteries. So it'd hardly be general advice anyway.

I'd follow the manufacturers guidelines rather than some dude on the internet, including me.

Gordon

It's a problem for sure, I need to charge 2 700wh batteries at once, possibly multiple times before I drive anywhere and start recharging the leisure batteries again so unless I invest in a solar array and the weather is kind I would have to have a massive amount of ah on hand to do that if only discharging to 50 percent.
That's just the bikes, not even considering lighting or fridge etc

 

[dobbyhasfriends]

Just to expand on what I said above to charge two 700wh levo batteries from leisure batteries.

1400wh/12vdc plus 15% for losses = 134ah.
Inverter sizing.
8a x 42v plus 15% = 386w

So if you can only discharge 50% of the battery you would need at least 268ah capacity and this is if you only use it for charging ebikes.
This 268 would only have the capability to charge both batteries once.

 

[Slapbassmunky]

I looked into it, realised half of my car would be made of lead and the cost + weight was insane.

So now I use a small suitcase generator.... If you make sure to run the carb dry after use and lock the tank properly the smell is minimal.

 

[Whitby Chris]

ok I am lost now, all I wanted was to charge my battery on my bike maybe 2 times at the most on a weekends racing, I was looking at maybe a 100ah lesuire battery at 12v so 1200ah charging to 2 charges on a 600ah bike battery, and to use a standard 12v to 240v invertor around a 800w one, is this going yo be a problem can anyone recommend a decent battery and invertor

 

[Slapbassmunky]

You won't get two full charges. A 120 ah leisure battery will fully charge a 625 ebike battery once without killing itself (just, and you'd better get it on charge pretty quick after doing so). People forget that the Ah rating of a leisure battery is usually the C20 rate, not the C5 rate. This is usually 3/4 to 2/3 of the rated Ah. You'll need an AGM battery, a flooded one won't last 10 cycles being pushed so hard.

So no, you can't do what you're asking unless you have a hookup overnight, a LOT of solar for the day, or an 8 hour drive between charges and the appropriate split charging setup.

Hence why I use a generator ?

 

[stiv674]

If cost isn't an option then maybe something like this...
Bluetti AC200P

 

[Whitby Chris]

You won't get two full charges. A 120 ah leisure battery will fully charge a 625 ebike battery once without killing itself (just, and you'd better get it on charge pretty quick after doing so). People forget that the Ah rating of a leisure battery is usually the C20 rate, not the C5 rate. This is usually 3/4 to 2/3 of the rated Ah. You'll need an AGM battery, a flooded one won't last 10 cycles being pushed so hard.

So no, you can't do what you're asking unless you have a hookup overnight, a LOT of solar for the day, or an 8 hour drive between charges and the appropriate split charging setup.

Hence why I use a generator ?

what generator mate? is that a better way to go ?

 

[alan_sh]

If cost isn't an option then maybe something like this...
Bluetti AC200P

If cost isn't an option, buy spare batteries.

 

[Slapbassmunky]

what generator mate? is that a better way to go ?

If you're on a Bosch system grab the 6A fast charger, they're brilliant for days away, I use the older version of this generator...

Clarke IG1200C EURO 5 Compliant 1100W Inverter Generator - Machine Mart - Machine Mart

www.machinemart.co.uk

It's better (quieter) to run a slightly bigger generator at less load. And if you're at an event I can guarantee you'll make friends very quickly when you fire it up as everyone's chargers come out of the woodwork. Handy for charging other people's flat leisure/starter batteries on Sunday night as well ?

Make sure you check the specs for noise level before you buy, some are a lot noisier than others, especially the tiny 700W jobs.

 

[Whitby Chris]

If you're on a Bosch system grab the 6A fast charger, they're brilliant for days away, I use the older version of this generator...

Clarke IG1200C EURO 5 Compliant 1100W Inverter Generator - Machine Mart - Machine Mart

www.machinemart.co.uk

It's better (quieter) to run a slightly bigger generator at less load. And if you're at an event I can guarantee you'll make friends very quickly when you fire it up as everyone's chargers come out of the woodwork. Handy for charging other people's flat leisure/starter batteries on Sunday night as well ?

Make sure you check the specs for noise level before you buy, some are a lot noisier than others, especially the tiny 700W jobs.

View attachment 69942

thanks I think I have found a 1200 one for sale, do you know how long they last on 1 fill of petrol, just working out how much fuel to take with me etc

 

[Slapbassmunky]

thanks I think I have found a 1200 one for sale, do you know how long they last on 1 fill of petrol, just working out how much fuel to take with me etc

That's totally dependent on time to charge and load but will be in the spec sheet somewhere. It's usually written down as 5.5 hrs at 75% load or something like that. Mine will charge 3 bikes as above for a quick hour over lunch (hence the 6A Bosch charger) and the fuel barely moves.

Before we pack up again I flick the fuel off while it's idling to let the fuel pump and carb run dry. Then U lock it to a wheel so it can cool down until the end of the day. That way there's no stink in the car.

 

[Whitby Chris]

That's totally dependent on time to charge and load but will be in the spec sheet somewhere. It's usually written down as 5.5 hrs at 75% load or something like that. Mine will charge 3 bikes as above for a quick hour over lunch (hence the 6A Bosch charger) and the fuel barely moves.

Before we pack up again I flick the fuel off while it's idling to let the fuel pump and carb run dry. Then U lock it to a wheel so it can cool down until the end of the day. That was there's no stink in the car.

excellent cheers mate