View Transcript

Hide Transcript

Transcript is auto-generated.

hi everyone welcome to

boatingtechtalk.com

we've got a question from a fellow voter

michelle michelle asks jeff i recently

had a high voltage 15.5 alarm on my

victron inverter charger and by the way

this high voltage is on the dc side 15.5

volts the technician said it was caused

by my coal batteries we have previous

temperatures here in the pacific

northwest for a couple of weeks can you

explain this

michelle great question and the reality

is yes there is an inverse correlation

especially for uh inverter chargers or

chargers that are temperature

compensated

meaning batteries that are coal need

higher charging voltages and batteries

that are hot need

lower charging voltages okay so there's

an inverse correlation between

temperature right and charging voltage

so in the winter time here in the

pacific northwest we're based out here

as well it's not uncommon in the winter

time when the batteries are really cold

you know maybe 55 degrees fahrenheit

right something like that

to have the battery voltage from the

charger

exceed what we would expect right and

most of us generally expect a charging

voltage on a flooded acid battery

14 4 14 6 agm same thing around there 14

to some of them but you know 14 2 to 14

6 is what we would see for a

non-temperature compensated big word

uh charging voltage

but if you have an inverter charger or a

charger or an alternator that is

temperature compensated

meaning that they adjust what they think

is the ideal charging voltage for the

temperature of the battery then you

should expect a different charging

voltage now some of you might worry like

zip we'll disconnect the truck don't

when i say disconnect i don't mean

disconnected from the battery because

now you're just going to be measuring

ambient temperature

and that little sensor should be

installed

directly on a battery post ideally and

negative never on top of the battery

because there's generally an air gap and

you're going to be measuring the

not the same temperatures inside the

battery the best way

and most of them are looks like battery

lugs with a wire connected to it it's

actually two wire because it's a

resistor measuring resistance

you basically what you want to do is you

want to have that temperature sensor on

the negative battery post

probably of what you would expect to be

the warmest battery of the bunch meaning

if there's a bunch of batteries that are

wired

figure out which one is going to be the

warmest if you don't know take a

temperature gun when it's uh infrared

temperature gun when your batteries are

charging and put the temperature sensor

in that location

and if you're doubting that your

inverter charger or your external

regulator or your battery charger is not

over charging disconnect the leads at

the inverter charger or at the external

regulator or at the charger

and if there's no temperature probe

connected

at the charger not at the battery then

you'll actually notice once you cycle

the inverter charger or those devices on

or off you'll probably see a lower

charging voltage

because when we think about battery

voltages 12 volts for example we're

actually thinking all those battery

voltages are for 77 degrees fahrenheit

so temperature changes everything right

um and so

for batteries if we assume it's 77

degrees fahrenheit now most of us

don't always have batteries at 77

degrees fahrenheit sometimes they're

colder sometimes they're warmer and so

that change of temperature is why

inverter chargers chargers external

regulators and even some controllers are

temperature compensated

and that's why you would see a higher

charging voltage in the winter time when

your batteries are cold so great

question michelle and thanks for asking

if you're curious we've written whole

articles about this go on our website

search it out

and we've got a lot of other tech talks

about this very topic if you haven't

subscribed to this channel please do um

it actually it really does make a

difference it encourages us to keep

posting so if you're watching this video

and haven't had a chance to subscribe we

really do care because the more of you

that are watching the more of us over

here are willing to put spend more time

in creating content so thanks again