Can you store cheap rate leccy ?

[Pica-Pica]

steve-V8s said:

Just out of interest what is the efficiency of storing off peak in batteries. Presumably when you charge not all of the power actually ends up in the battery and again when you draw from the battery there most be losses.

I guess if you are charging from solar it is not an issue but if you are charging from the grid off peak and using later the system losses must have an effect on the cost calculation.

Just my hunch, some will be lost as heat, very minor though.

[craigjm]

steve-V8s said:

Just out of interest what is the efficiency of storing off peak in batteries. Presumably when you charge not all of the power actually ends up in the battery and again when you draw from the battery there most be losses.

I guess if you are charging from solar it is not an issue but if you are charging from the grid off peak and using later the system losses must have an effect on the cost calculation.

My system in South Africa that was used for the times they turned the grid off used to lose about 2%
Virtually every house has a decent size battery that charges from the mains and then when the power is switched off the house starts drawing from the battery

[Byker28i]

Desiderata said:

I was looking at something along these lines here in Scotland where most of the public EV charging is free. Charge the car up while at work then bring it home and drop 80% of the charge into the domestic supply.
It doesn't really make financial sense for me at the moment as I don't need a new car yet, but it might do in some circumstances.

Edited by Desiderata on Monday 16th August 08:54

...but a nice payback for those that can, however if you do this everyday it must be fraud of some sort?
wouldn't be worth it would it for 50Kw if it''s 5p per kw or whatever?

[steve-V8s]

craigjm said:

My system in South Africa that was used for the times they turned the grid off used to lose about 2%
Virtually every house has a decent size battery that charges from the mains and then when the power is switched off the house starts drawing from the battery

I would be astonished if the charge discharge power loss was only 2% Lead acid cells can be very efficient but I thought more commonly used chemistries in EV were typically in the region of 90% for the battery itself and then you have the losses in the charger and the gubbins turning the DC back to AC. 2% overall loss seems incredible but it is excellent if that is actually the case. Perhaps to achieve that you need to charge and discharge the cells very very slowly.

[Tye Green]

Lead acid cells cost about 10% - 20 the cost of lithium for the same capacity . Also the weight for a comparable battery capacity is about the same for each technology .

Why do people buy lithium for domestic use and why do manufacturers fit lithium in vehicles ?

[craigjm]

steve-V8s said:

craigjm said:

My system in South Africa that was used for the times they turned the grid off used to lose about 2%
Virtually every house has a decent size battery that charges from the mains and then when the power is switched off the house starts drawing from the battery

I would be astonished if the charge discharge power loss was only 2% Lead acid cells can be very efficient but I thought more commonly used chemistries in EV were typically in the region of 90% for the battery itself and then you have the losses in the charger and the gubbins turning the DC back to AC. 2% overall loss seems incredible but it is excellent if that is actually the case. Perhaps to achieve that you need to charge and discharge the cells very very slowly.

It not lead acid its lithium ion. Those were the claims made by the manufacturer and with rough calculations it was close. I would never by anything like that for the UK but out there where you can be off the grid for up to 6 hours a day it made sense

[dapprman]

Tye Green said:

Lead acid cells cost about 10% - 20 the cost of lithium for the same capacity . Also the weight for a comparable battery capacity is about the same for each technology .

Why do people buy lithium for domestic use and why do manufacturers fit lithium in vehicles ?

charge memory for a start. Start charging a nearly full battery and kiss goodbye to much of your capacity.

[Tye Green]

dapprman said:

Tye Green said:

Lead acid cells cost about 10% - 20 the cost of lithium for the same capacity . Also the weight for a comparable battery capacity is about the same for each technology .

Why do people buy lithium for domestic use and why do manufacturers fit lithium in vehicles ?

charge memory for a start. Start charging a nearly full battery and kiss goodbye to much of your capacity.

the chargers are clever and can measure cell voltage before they start charging. charging a nearly full lithium battery to 100% and it seems you reduce its life.

Little batteries (low A/ h ) can provide a lot of amps for a short period of time so weight-wise are handy to start an engine but can’t see any real benefit in lithium batteries otherwise

[dmsims]

2% loss is fantasy you have been watching too many EVman videos

[craigjm]

dmsims said:

2% loss is fantasy you have been watching too many EVman videos

To be quite honest when youre living somewhere where they cut the electricity off daily for up to six hours a day like I said and you want to function normally you dont give a fk

[dapprman]

Tye Green said:

the chargers are clever and can measure cell voltage before they start charging. charging a nearly full lithium battery to 100% and it seems you reduce its life.

Little batteries (low A/ h ) can provide a lot of amps for a short period of time so weight-wise are handy to start an engine but can’t see any real benefit in lithium batteries otherwise

You can safely and repeatedly charge lithium batteries to 100% but you have to condition charge them, which car and house chargers/batteries will do, much down to the time and method. The fuller the battery when you start the recharge the longer it takes. It's one of the things you learn if you start playing airsoft (like I did) or using remote vehicles.
As to the intelligence side - no clue with house or EV lead acid batteries, but none of the ones I've seen (airsoft/remote control ones) have had an additional cable for monitoring, where as all the lithium ones I've seen and used have come with one and required it to be plugged in to the charger to allow the monitoring and control to take place.

[jamei303]

If you have a big garden you could set up a pumped storage system.