View Transcript

Hide Transcript

Transcript is auto-generated.

hi welcome to votingtechtalk.com we've

got another question from a fellow voter

dave asks jeff i'm about to complete the

purchase of a new used boat congrats

there are two 12 volt lead acid

batteries both around 98 hours in size

one for engine fast start and the other

for house loads

is there a way to establish the

condition of these batteries i don't

want height i don't wish to head out in

the new boat to find out that the

batteries are not holding a charge okay

so how do we go about testing batteries

of water boats either because we

purchased them or we really don't know

the condition

uh

the good news is

it's a little bit of a little bit of

good news a little bit of bad news so

let's start with the good news um

when it comes to testing a starter

battery uh a good way to test your

starter battery is actually to

start your boat

realistically if your starter is

functional

and you have a circuit there you know

what i would do is i would actually try

to start my boat um i might even have to

choke on

or something to disable it to start and

see what happens to the voltage as

you're cranking

right it's normal on a boat to see

around ten and a half

you know ten ish nine and a half eleven

maybe some people have bigger batteries

eleven and a half but see how quickly

the engine starts

right um compared to what you would

expect

you know for technicians they would

probably put in a uh a load tester so a

carbon pile low tester on the battery

and they would stimulate a large current

drop you know they might be able to

choose a 300 amp or 400 amp or 600

current draw and they would hold that

current draw for about 10 seconds and

you want to see that the voltage doesn't

sag

for it's normally going to sag you're

going to start maybe you know 12 8

maybe it's a residual like floating

voltage maybe it's 13 3 volts for 12

volt battery and the moment you put the

load on the voltage is going to drop to

probably around 10 and a half and then

it's going to stay there and that's what

you want you want to see that voltage be

able to hold on

while the engine is starting

and obviously when the engine starts

then the alternator kicks in when the

alternate kicks in then obviously things

change so it's really about the moment

prior to the engine starting right when

you're turning it over but the engine

hasn't actually started yet

so that's how you would test your

starting battery

in terms of testing your house battery

that's harder

because now you're not testing a

small load or a large load for a short

period of time you're testing

small loads for a long period of time

and to do that is called a c20 discharge

test right so you want to

in your case you've got a 90 and a half

hour battery you divide that 90 hour

divided by 20 so you get around 4.5 amps

of load and you apply a 4.5 amps

and that can't be an intermittent load

right because otherwise it comes on and

off that doesn't count so a fridge for

example would not count a light would

right or something that just stays on

refrigerator would also be a problem

because they normally turn on and off

and you're basically going to

see how long it takes you from the

moment the batteries are full till you

get to 10.5 volts and once you get to

10.5 your batteries are

that's the floor

if it took you 10 hours to get there at

4.5 that means your batteries are 50 of

capacity right this 45 over 90 is a half

now

some of you will only get three hours

out of your battery some of you might

get 16 17 18 maybe 19 hours over your

batteries but when you do a c20

discharge it's really basically another

way of describing it is a little bit

like

how long is it going to take me to run a

marathon well

you know you might not need it's hard to

extrapolate running a you know 100 meter

dash or 200 meter dash and saying how

someone's going to run a marathon so

what you end up doing is you run a 10k

and then from that you can sort of

extrapolate

and that's what a

c20 test is it's a little bit like

running a 10k you gotta you got to run

some time just for a day 20 hours

and then you can extrapolate that to

figure out how the battery would do if

you had to discharge it over a longer

period of time so two different ways one

way for testing engine batteries which

is a carbon low carbon pile load tester

which can be easily simulated with a

starter if you've got a good starter on

remotes on our engines

and the other one is called the c20 test

so great question dave and thanks for

asking

and any of you have comments on how you

go testing your batteries please post

them down below because sharing is

caring all right thanks everyone thanks

for watching 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 uh 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