Lipo low power charging

Sprinter 1 cup

Forum Member
All lithium battery have no charging below or at 0 degrees.
My b2b puts out 30amp per hour = about 25amp . So no no.
My solar 200watts puts out low wattage as pic , but 1 amp dose it really matter ? The spikes are when tilted in Preston pic 2
Is that no charge malarkey for 5 amps and over, ?
Also this is for when not in use.all turned off.
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MarkJ

Forum Member
I'm afraid I don't know the answer to your question, but you've had more sun up there than we've had down south (Essex coast).

Feels like it's been grey murk most days, and I've only had a few days of any sort of decent solar in Dec and Jan so far.
 

PeteS

Forum Member
My Lithium hasnt charged for 10 days down here in the midlands mainly due to low tempearture. Plenty of Sun although only getting around 14w and that was yesterday for the first time above 5C
I'm not sure about small charge amounts, there are conflicting reports out there as to wether its pk or not, I'm of the opinion it cost a lot so I'm not pushing it until its proved to be ok.
 

wildebus

Forum Member
My Lithium hasnt charged for 10 days down here in the midlands mainly due to low tempearture. Plenty of Sun although only getting around 14w and that was yesterday for the first time above 5C
I'm not sure about small charge amounts, there are conflicting reports out there as to wether its pk or not, I'm of the opinion it cost a lot so I'm not pushing it until its proved to be ok.
This might be an interesting read .... https://relionbattery.com/blog/lithium-battery-cold-weather

It also explains how the "Low Temperature" Lithium Batteries manufacturers allow charge at down to -20C (in that they don't actually charge, but use the charge power to heat the battery to then allow charge).

Cold up here in Scotland and a standard Lithium Battery would see little charging going on for prolonged times. Having a Battery with a heater takes a lot of hassle out of running Lithium I have to say. Recharging mine at >30A when the room is just 3C as the Battery heater will ensure it is safe
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(One of the downsides however with battery heaters internal to the battery is if you have a Battery SOC monitor such as a Victron BMV, it sees any current going into the battery as recharging the battery cells, but when at low temps that power will actually be going to the heaters for a period of course, so the Monitor will be reporting a greater State of Charge than correct - but at least you do get charging, so a worthwhile price to pay).
 
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Nabsim

Forum Member
Can you clarify the last paragraph Dave, do you mean on your particular make of battery with inbuilt heating the SoC will be incorrect? I think that’s what you mean rather than if someone fits separate heating pads but it’s early and my head is murky :)
 

Derekoak

Forum Member
Yes I carefully kept my heating leads away from the shunt to avoid that but if everything is sold in one box with 2 external terminals there is no choice?
 

wildebus

Forum Member
Can you clarify the last paragraph Dave, do you mean on your particular make of battery with inbuilt heating the SoC will be incorrect? I think that’s what you mean rather than if someone fits separate heating pads but it’s early and my head is murky :)
I was meaning ANY battery with integral heaters. The reason being, as Derek alludes to, the heaters will be on the wrong side of the shunt.
If you add heating, you want to connect to the LOAD side of a shunt, not the BAT side. As ANYTHING on the BAT side is considered to be the Battery.
And to reiterate, I am talking about external SOC monitors. Any monitor that is built into the battery Itself should be reading the current into the battery Itself and not into any heaters within the box to give an accurate SOC.
 

wildebus

Forum Member
Also, just to say, the amount of time on the year that the SOC will in inaccurate will be pretty small.
Only in the colder months when the battery is below 5C AND the incoming charge rate is >C/10 (at lower charge rates, such as you would see from Solar in winter, the current will still go into the battery even when it is cold).
 

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